Unwrapping the CS1. She finally arrived in Rotterdam where I picked her up. Stupid lorry driver almost dropped the crate.
Off course further dismantling started the same evening.
Showing posts with label -Technical. Show all posts
Showing posts with label -Technical. Show all posts
Sunday, July 10, 2011
Unwrapping the CS1
Unwrapping the CS1. She finally arrived in Rotterdam where I picked her up. Stupid lorry driver almost dropped the crate.
CS1 Reassembly
This C
S1 will forever be a Bitza; the frame is 1931, engine 1932. The replica oiltank was made for an older frame and did not fit because it is too high; an evening of cutting and welding solved that problem. An original gearbox came with the machine but it has some parts missing. The WD16H item was dismantled and treated to new bearings and will be used untill the parts for the original box have been sourced. The front forks should be narrow on this machine; again a problem that could be solved using an angle-grinder and a MIG welder, though I needed expert help to fit bushes for
the forkspindle in the hole that by now had the shape of a banana.
Monday, June 6, 2011
Early OHV heads
A discussion spurred by pictures of a Model 18 Ron is selling; it's a 1928 model but clearly has an earlier cylinder head. The fins 'on top' are higher near the exhaust. The fins on later heads are all the same hight. Also check this entry.
Simon:"The good thing about this particular 1923 head (above; not a very good picture!) is that it still appears to have its original valves and springs - see the drawing (below). Note that the valve sizes agree with recorded history that the early OHV engines had a larger exhaust than inlet valve. I guess it's a bit 'anorak' to record this sort of stuff but it's not written down anywhere else as far as I know"
"Regarding valve springs.......I don't propose to go into detail about the various valve spring retainers as there are bound to be chaps who pop up and say theirs are different in some way or another! However it seems to me that MOST of the '26 to '28 OHV engines were fitted with retainers which take the following springs:
Simon:"The good thing about this particular 1923 head (above; not a very good picture!) is that it still appears to have its original valves and springs - see the drawing (below). Note that the valve sizes agree with recorded history that the early OHV engines had a larger exhaust than inlet valve. I guess it's a bit 'anorak' to record this sort of stuff but it's not written down anywhere else as far as I know"
"Regarding valve springs.......I don't propose to go into detail about the various valve spring retainers as there are bound to be chaps who pop up and say theirs are different in some way or another! However it seems to me that MOST of the '26 to '28 OHV engines were fitted with retainers which take the following springs:
Outer - length 2.125 outer dia. 1.490 inner dia. 1.170 wire dia. 0.160 number of coils 7
Inner - length 1.845 outer dia. 0.950 inner dia. 0.740 wire dia. 0.105 number of coils 7
Peter Roydhouse made the comment to me a while back that Norton springs were unduly strong and he suggested using springs from post war 350 engines BUT the diameter of these may be too great for use on the open pushrod engines and one would have to change the valve spring retainers. Might be better to get the spring maker to use a slightly lighter gauge wire to reduce poundage although he would need to stick to the internal diameters given."
Peter Roydhouse made the comment to me a while back that Norton springs were unduly strong and he suggested using springs from post war 350 engines BUT the diameter of these may be too great for use on the open pushrod engines and one would have to change the valve spring retainers. Might be better to get the spring maker to use a slightly lighter gauge wire to reduce poundage although he would need to stick to the internal diameters given."
Monday, May 16, 2011
Model 21-25 oil pump parts - For sale
On Ebay. Chance to buy a rare oil pump worm drive gear set and related parts which were originally fitted to a 1926 Model 21 OHV flat tank Norton, but which will fit also the TT Model 25 of the flat tank era. A similar arrengement is used on the early CS1 camshaft models and they may possibly suit this model or be modified to fit.
Friday, May 13, 2011
1930 valve lifts
By Simon
Open push rod engines (1926 - 1929). Cam followers - contact point with cam 1.63" inches from pivot point; contact with tappet foot 2.037" from pivot point. Thus cam lift is magnified by a factor of 1.249. Rockers - centre of ball end to centre of pivot point 1.329"; centre of pivot point to centre of contact point with valve stem 1.476". Thus tappet lift is magnified by a factor of 1.11. Average cam lift on W7 inlet cam (they all seem to vary a bit) 0.290" so lift at valve is 0,290 x 1.249 x 1.11 = 0.402".
Closed push rod 1930 engines with standard cams (NB; not ES2 cams which have higher lift). Cam followers - contact point with cam 1.87" from pivot point; contact with centre of push rod socket 2.193" from pivot point. Thus cam lift is magnified by a factor of 1.172. Rockers in cast alloy rocker box - centre of ball end to centre of pivot point 1.528"; centre of pivot point to centre of contact point with valve stem 1.5". Thus push rod lift is actually very slightly reduced by a factor of 0.981. Average cam lift on 1930 cams 0.300 inches so lift on valve is 0.300 x 1.172 x 0.981 = 0.345".
The 1930 ES2 cams (marked E2720 and 2721) have substantially greater lift than the 1930 Model 18 type and have the same small base circle. The lift is 0.343" and use of these cams in a 1930 engine will increase the valve lift from 0.345" to 0.394".
I find it interesting that even with the sporty ES2 cams, valve lift on the 1930 engines does not quite match that of the earlier open push rod/W7 engines and there is such a big difference between valve lifts using the standard 1930 cams and the earlier set-up.
The 1930 ES2 cams (marked E2720 and 2721) have substantially greater lift than the 1930 Model 18 type and have the same small base circle. The lift is 0.343" and use of these cams in a 1930 engine will increase the valve lift from 0.345" to 0.394".
I find it interesting that even with the sporty ES2 cams, valve lift on the 1930 engines does not quite match that of the earlier open push rod/W7 engines and there is such a big difference between valve lifts using the standard 1930 cams and the earlier set-up.
Friday, May 6, 2011
The Franks redesign of 1931
By Simon
The Franks redesign which resulted in the 1931 range of production Nortons was not an unmitigated success! I have already mentioned my late friend Jack Bindley's experiences with his new '31 ES2. He was as disappointed with the bike as he was with Norton's response to his complaints. Last week I came across a few back numbers of the Beaulieu magazine 'Veteran and Vintage' and found further criticism therein from Richard Chapman, who worked for Eric Fernihough (amongst other well known people) at Brooklands in the thirties. Richard bought a new 1931 Model 18 from dealers in Trowbridge, to which, after careful running-in, he attached a new TT Hughes sidecar. He goes on to say..
"This machine was the slowest thing on wheels and a great disappointment. With the light TT sidecar and a passenger, the maximum speed was about 50 mph and after a while I rode the machine to Birmingham to see the makers about her. A tester took her for a run round the houses and reported that she was up to standard, which drew from me the comment that their standards must be pretty low! After a lot of postal haggling, Nortons gave me a set of what they described as 'dirt track rockers' (ie cam followers) for the crankcase and these improved matters a little. I then got going on my own and raised the compression. I increased the inlet tract bore, fitted a larger inlet valve and a 10TT25 carburettor. This, with stronger valve springs, rebalancing and some work all over the engine, improved matters. The final result was that I could get 80 mph with a passenger in the sidecar, under reasonable conditions."
Richard must have had considerable tuning skills - doubtless enhanced by later experiences with Fernihough.
The reference to Dirt Track Rockers is intriguing as the dirt track model (above) was only made in 1930 - not '31 - and it would be interesting to know just how the rockers differed from the standard profile. And there is a possibility we can find out: a 1930 dirt track engine bottom end has surfaced in NZ and although rather hacked about, I am encouraging the owner to take it apart and see just what is inside! So watch this space!
The decline actually seems to have started with the 1930 enclosed rocker box set-up. The geometry of this rocker box is such that the valves open less than the lift on the cams while with the open rockers they open more...And why did Norton dowtune these engines? My guess is that they were seeking longer term reliability. What else could it be? From a marketing (doubt if the word had been coined then!) point of view it was perhaps no bad thing to have the OHC machines as real flyers and the over the counter bikes as just reliable moderate performance means of transport.
The Franks redesign which resulted in the 1931 range of production Nortons was not an unmitigated success! I have already mentioned my late friend Jack Bindley's experiences with his new '31 ES2. He was as disappointed with the bike as he was with Norton's response to his complaints. Last week I came across a few back numbers of the Beaulieu magazine 'Veteran and Vintage' and found further criticism therein from Richard Chapman, who worked for Eric Fernihough (amongst other well known people) at Brooklands in the thirties. Richard bought a new 1931 Model 18 from dealers in Trowbridge, to which, after careful running-in, he attached a new TT Hughes sidecar. He goes on to say..
"This machine was the slowest thing on wheels and a great disappointment. With the light TT sidecar and a passenger, the maximum speed was about 50 mph and after a while I rode the machine to Birmingham to see the makers about her. A tester took her for a run round the houses and reported that she was up to standard, which drew from me the comment that their standards must be pretty low! After a lot of postal haggling, Nortons gave me a set of what they described as 'dirt track rockers' (ie cam followers) for the crankcase and these improved matters a little. I then got going on my own and raised the compression. I increased the inlet tract bore, fitted a larger inlet valve and a 10TT25 carburettor. This, with stronger valve springs, rebalancing and some work all over the engine, improved matters. The final result was that I could get 80 mph with a passenger in the sidecar, under reasonable conditions."
Richard must have had considerable tuning skills - doubtless enhanced by later experiences with Fernihough.
The reference to Dirt Track Rockers is intriguing as the dirt track model (above) was only made in 1930 - not '31 - and it would be interesting to know just how the rockers differed from the standard profile. And there is a possibility we can find out: a 1930 dirt track engine bottom end has surfaced in NZ and although rather hacked about, I am encouraging the owner to take it apart and see just what is inside! So watch this space!
The decline actually seems to have started with the 1930 enclosed rocker box set-up. The geometry of this rocker box is such that the valves open less than the lift on the cams while with the open rockers they open more...And why did Norton dowtune these engines? My guess is that they were seeking longer term reliability. What else could it be? From a marketing (doubt if the word had been coined then!) point of view it was perhaps no bad thing to have the OHC machines as real flyers and the over the counter bikes as just reliable moderate performance means of transport.
Thursday, March 17, 2011
121 MPH Model 16H racer
By Nigel Fox
I run a unique Model 16H Norton racer; it’s based on a very special side valve barrel provided by VMCC founder Titch Allen who got it from Ivan Wicksteed; a summary is in the cutting below. The machine has reached a top speed of 121 miles per hour which is faster that the speeds obtained by famous tuners of side valve engines in the 1920s.
General comments (mostly subjective!)
With an OHV engine the required flow past the inlet valve is needed INLINE with the stem. With a SV engine the required flow past the inlet valve is needed at RIGHT ANGLES to the stem. The special used Wicksteed Barrel mentioned has just two changes in direction of inlet flow, a typical SV engine has three and arguably four! SV barrels distort the piston rings are best pegged to let the rings bed in to the shape. A lot of piston squish makes for a cool running engine. I did run an engine with 100% squish over the piston with “pop up pistons (0.5“) ala some USA performance side valve car motors albeit with normal type inlet ports with reasonable results but the inlet flow over and into the barrel can be restrictive. The race version of a good side valve engine will have a lower compression ratio than a good road version. I suspect low CR engines react better (as an improvement on power) to tuned Inlet and Exhaust lengths than higher CR engines (the cylinder pressure at inlet valve closing is lower). The Norton pre war barrel makes a better high performance engine with more space around the inlet valve. I built an engine with a pre war top on a post war bottom (with standard inlet port position) and this was nearly as quick as the Wicksteed motor. This engine was run on 10% water/methanol fuel as it had just a two-piece flat top plate aluminium head. It had a very light flat top OHV piston (lightening an already very light piston plus an HE30TF small end bush) and this blew up eventually - it was so smooth. The rev limit with the SV Norton engine is not the full compliment roller big end (as Titch suspected) but the 8” con rod (the area below the small end). Titch working with his son Roger on the OHV with a stronger and shorter 7-1/2”con rod found the big end bearing was the limit. I road raced a post war Big 4 and the more metal I removed from the head around the Inlet valve the faster it went, the limit was the stud holes, it had a severe undercut around the valve to leave a gasket sealing face. Head sealing with methanol and petrol: I use a half dried out thin coat of Hammerite aluminium paint! Titch is well remembered for recommending a touch of paraffin to modern fuel with the old low CR engines. Prompted by this I carried out some tests with paraffin on a SV road bike. Titches theory (by my understanding) on this regarding old engines and the low octane petrol that was available and used with them is as follows: old engines pitched their compression ratios just below the detonating CR of the low octane fuel available, but put a higher octane in the same engine and the fuel air mixture so lowly compressed is nowhere near the optimum temperature: it’s going to burn slowly and create all sorts of problems. My road paraffin tests were very interesting - I went up to 25 %
Lazarus’ engine specifications
Basis a pre-war rocker follower type engine. 82x100 (528cc). Special Wicksteed modified upswept inlet port barrel. (Titch seemed to think this work was carried out by Granville Grenfell at Brooklands). Special alloy head with modified chamber shape (Titch seemed to think this was made by Roland Cross). Inlet length 13” overall. Exhaust valve std 1.61” G2 (Austenitic). Inlet valve 1.75” (magnetic) modified diesel lorry valve. 2mm head clearance over Inlet valve at full lift. 6.5mm head clearance over Exhaust valve at full lift. Std cast iron valve guides. Valve clearances Inlet 0.004”, Exhaust 0.012”. Moto Guzzi LeMans valve springs (inner and outer). Both valves 103lbf load seated , 157lbf load at 0.375”lift. Insulating washer under exhaust. CR 6.67:1 , 50% squish over piston - 1.7mm clearance. Norton domed solid skirt piston, skirt shortened, (not 16H!). No top ring - slot filled with alloy ring and peened over, 2nd ring pegged two stroke fashion , standard oil ring. Std 8” En24 conrod , polished and shot peened, std big end. Flywheels turned down and ½” steel ring shrunk on. Flat bottomed tappets (Titch seemed to think these may have been an option for the OHV engine). Special Cams Inlet and Exhaust modified by myself for more and gentler lift from std Exhaust cams. Timings at 0.030” lift. Exhaust opens 71deg closes 45deg (total lift 0.334”lift). Inlet opens 57deg closes 60deg (total lift 0.375”lift) (These cam timings are very close to the KTT Mark VI cams). 40” total exhaust length - plain pipe.
1-1/16th Amal TT carburetter bored out to 31.5mm, rubber mounted. 0.118” needle jet, 2.5mm dia, main jet (820). Modified needle (more taper at tip to suit a large jet). Float level adjusted to give a drip at carburettor. Fuel 100% methanol + dash R40. R40 engine oil.
Ignition timing 40deg adv., NGK B8EV spark plug.
Gearing 21,42,24,43 teeth. 5,500rpm giving 114.1mph in top and 103.7mph in 3rd. Gearbox ratios 1,1.1,1.61,2.33 (a mix of gears from International and trials (?) available).
Bantam forks and wheel (19” ) Tyre pressure 30,34 psi. Fairing modified Sprint Super Nero replica (supplied by Titch).
Sculthorpe 29th September 1996
Times and speeds recorded
Standing Kilometer
Run 1 30.25sec - terminal speed 113.2mph
Run 2 28.13sec - terminal speed 111mph
Run 3 28.47sec - terminal speed 112mph
Flying ¼ mile timed after the above standing kilometer run ups
Run 1 No time recorded
Run 2 7.80sec - average speed 115.38mph
Run 3 7.71sec - average speed 116.73mph
Standing ¼ mile with fairing - 15.3sec - terminal speed 92mph
Comment on Run 3: Titch commissioned a friend to do some calculations on Run 3, and as the bike entered the timing lights at 112mph the calculations indicated the machine must have reached at least 121mph to have averaged 116.73 mph over the quarter mile.
Best standing ¼ mile to date:
Wroughton 17th Aug 2008
14.727sec - terminal 90.171mph
No fairing Gearbox ratios 1,1.21,1.614,2.33, Sprockets 21,42,19,43, 1200jet, on 25% nitro, ignition on 45 deg adv., Inlet 13“ overall, Exhaust 46” overall, no megaphone.
Doug Hele and Joe Craig
(Not about side valve tuning but very interesting nevertheless...)
I worked at Norton (Shenstone) in the 1980s as a draughtsman and later a designer under David Garside and Doug Hele. Doug told me he designed and drew up the laydown Norton gearbox mechanism (I did not know this at the time - a very nice piece of work!). Doug just post war was working on the best flywheel balance factor for the Big4 and a young tester got killed on the test bike somehow and Doug received threats from the poor chaps family - to his life! While there in the 1980s Doug was doing tests with angled (back cut) face dogs on the Norton Wankel gearbox gears to aid selection, a young chap on the test bike crashed mysteriously on a road into Walsall, poor Doug perhaps haunted by the earlier events with the Big4 abandoned the angled dogs project there and then. This is only my interpretation - but he did relate the Big4 incident to me at the time of the crash.
Doug also in conversation about past times also mentioned the Desmo Manx work but he did not seem that enamoured or over excited with the project, Cross rotary valve head - oil everywhere, and also a curious twin carb Manx engine sent over from Australia with much promise, that on test developed no more power than a standard Manx, I said maybe the carburettors were meant to be opened progressively to improve power spread, he gave me the same look; well similar to when I questioned the relatively small size of the carbs fitted to the Manx compared to the G50, Gold Star and racing Italian engines; I was relatively a young man and he was a real gentleman; I only ever heard him raise his voice once!
Doug also recalled to me that when in the 1950s working under Joe Craig he was given a design job for a new wheel spindle, Joe supplied a Velocette sample for Doug to copy, Doug went away and did his calculations and drew up what he thought was a better spindle design and showed it to Joe, his reaction was very abrupt “No just make it like the Velocette !”. Maybe poor Joe too was haunted by the past for Jimmy Guthrie riding was killed while riding a works Norton in 1937; there were also rumours of his crash being caused by the rear wheel spindle breaking.
I run a unique Model 16H Norton racer; it’s based on a very special side valve barrel provided by VMCC founder Titch Allen who got it from Ivan Wicksteed; a summary is in the cutting below. The machine has reached a top speed of 121 miles per hour which is faster that the speeds obtained by famous tuners of side valve engines in the 1920s.
General comments (mostly subjective!)
With an OHV engine the required flow past the inlet valve is needed INLINE with the stem. With a SV engine the required flow past the inlet valve is needed at RIGHT ANGLES to the stem. The special used Wicksteed Barrel mentioned has just two changes in direction of inlet flow, a typical SV engine has three and arguably four! SV barrels distort the piston rings are best pegged to let the rings bed in to the shape. A lot of piston squish makes for a cool running engine. I did run an engine with 100% squish over the piston with “pop up pistons (0.5“) ala some USA performance side valve car motors albeit with normal type inlet ports with reasonable results but the inlet flow over and into the barrel can be restrictive. The race version of a good side valve engine will have a lower compression ratio than a good road version. I suspect low CR engines react better (as an improvement on power) to tuned Inlet and Exhaust lengths than higher CR engines (the cylinder pressure at inlet valve closing is lower). The Norton pre war barrel makes a better high performance engine with more space around the inlet valve. I built an engine with a pre war top on a post war bottom (with standard inlet port position) and this was nearly as quick as the Wicksteed motor. This engine was run on 10% water/methanol fuel as it had just a two-piece flat top plate aluminium head. It had a very light flat top OHV piston (lightening an already very light piston plus an HE30TF small end bush) and this blew up eventually - it was so smooth. The rev limit with the SV Norton engine is not the full compliment roller big end (as Titch suspected) but the 8” con rod (the area below the small end). Titch working with his son Roger on the OHV with a stronger and shorter 7-1/2”con rod found the big end bearing was the limit. I road raced a post war Big 4 and the more metal I removed from the head around the Inlet valve the faster it went, the limit was the stud holes, it had a severe undercut around the valve to leave a gasket sealing face. Head sealing with methanol and petrol: I use a half dried out thin coat of Hammerite aluminium paint! Titch is well remembered for recommending a touch of paraffin to modern fuel with the old low CR engines. Prompted by this I carried out some tests with paraffin on a SV road bike. Titches theory (by my understanding) on this regarding old engines and the low octane petrol that was available and used with them is as follows: old engines pitched their compression ratios just below the detonating CR of the low octane fuel available, but put a higher octane in the same engine and the fuel air mixture so lowly compressed is nowhere near the optimum temperature: it’s going to burn slowly and create all sorts of problems. My road paraffin tests were very interesting - I went up to 25 %
 |
| Titch enjoys a cuppa... |
Basis a pre-war rocker follower type engine. 82x100 (528cc). Special Wicksteed modified upswept inlet port barrel. (Titch seemed to think this work was carried out by Granville Grenfell at Brooklands). Special alloy head with modified chamber shape (Titch seemed to think this was made by Roland Cross). Inlet length 13” overall. Exhaust valve std 1.61” G2 (Austenitic). Inlet valve 1.75” (magnetic) modified diesel lorry valve. 2mm head clearance over Inlet valve at full lift. 6.5mm head clearance over Exhaust valve at full lift. Std cast iron valve guides. Valve clearances Inlet 0.004”, Exhaust 0.012”. Moto Guzzi LeMans valve springs (inner and outer). Both valves 103lbf load seated , 157lbf load at 0.375”lift. Insulating washer under exhaust. CR 6.67:1 , 50% squish over piston - 1.7mm clearance. Norton domed solid skirt piston, skirt shortened, (not 16H!). No top ring - slot filled with alloy ring and peened over, 2nd ring pegged two stroke fashion , standard oil ring. Std 8” En24 conrod , polished and shot peened, std big end. Flywheels turned down and ½” steel ring shrunk on. Flat bottomed tappets (Titch seemed to think these may have been an option for the OHV engine). Special Cams Inlet and Exhaust modified by myself for more and gentler lift from std Exhaust cams. Timings at 0.030” lift. Exhaust opens 71deg closes 45deg (total lift 0.334”lift). Inlet opens 57deg closes 60deg (total lift 0.375”lift) (These cam timings are very close to the KTT Mark VI cams). 40” total exhaust length - plain pipe.
1-1/16th Amal TT carburetter bored out to 31.5mm, rubber mounted. 0.118” needle jet, 2.5mm dia, main jet (820). Modified needle (more taper at tip to suit a large jet). Float level adjusted to give a drip at carburettor. Fuel 100% methanol + dash R40. R40 engine oil.
Ignition timing 40deg adv., NGK B8EV spark plug.
Gearing 21,42,24,43 teeth. 5,500rpm giving 114.1mph in top and 103.7mph in 3rd. Gearbox ratios 1,1.1,1.61,2.33 (a mix of gears from International and trials (?) available).
Bantam forks and wheel (19” ) Tyre pressure 30,34 psi. Fairing modified Sprint Super Nero replica (supplied by Titch).
Sculthorpe 29th September 1996
Times and speeds recorded
Standing Kilometer
Run 1 30.25sec - terminal speed 113.2mph
Run 2 28.13sec - terminal speed 111mph
Run 3 28.47sec - terminal speed 112mph
Flying ¼ mile timed after the above standing kilometer run ups
Run 1 No time recorded
Run 2 7.80sec - average speed 115.38mph
Run 3 7.71sec - average speed 116.73mph
Standing ¼ mile with fairing - 15.3sec - terminal speed 92mph
Comment on Run 3: Titch commissioned a friend to do some calculations on Run 3, and as the bike entered the timing lights at 112mph the calculations indicated the machine must have reached at least 121mph to have averaged 116.73 mph over the quarter mile.
Best standing ¼ mile to date:
Wroughton 17th Aug 2008
14.727sec - terminal 90.171mph
No fairing Gearbox ratios 1,1.21,1.614,2.33, Sprockets 21,42,19,43, 1200jet, on 25% nitro, ignition on 45 deg adv., Inlet 13“ overall, Exhaust 46” overall, no megaphone.
Doug Hele and Joe Craig
(Not about side valve tuning but very interesting nevertheless...)
I worked at Norton (Shenstone) in the 1980s as a draughtsman and later a designer under David Garside and Doug Hele. Doug told me he designed and drew up the laydown Norton gearbox mechanism (I did not know this at the time - a very nice piece of work!). Doug just post war was working on the best flywheel balance factor for the Big4 and a young tester got killed on the test bike somehow and Doug received threats from the poor chaps family - to his life! While there in the 1980s Doug was doing tests with angled (back cut) face dogs on the Norton Wankel gearbox gears to aid selection, a young chap on the test bike crashed mysteriously on a road into Walsall, poor Doug perhaps haunted by the earlier events with the Big4 abandoned the angled dogs project there and then. This is only my interpretation - but he did relate the Big4 incident to me at the time of the crash.
Doug also in conversation about past times also mentioned the Desmo Manx work but he did not seem that enamoured or over excited with the project, Cross rotary valve head - oil everywhere, and also a curious twin carb Manx engine sent over from Australia with much promise, that on test developed no more power than a standard Manx, I said maybe the carburettors were meant to be opened progressively to improve power spread, he gave me the same look; well similar to when I questioned the relatively small size of the carbs fitted to the Manx compared to the G50, Gold Star and racing Italian engines; I was relatively a young man and he was a real gentleman; I only ever heard him raise his voice once!
Doug also recalled to me that when in the 1950s working under Joe Craig he was given a design job for a new wheel spindle, Joe supplied a Velocette sample for Doug to copy, Doug went away and did his calculations and drew up what he thought was a better spindle design and showed it to Joe, his reaction was very abrupt “No just make it like the Velocette !”. Maybe poor Joe too was haunted by the past for Jimmy Guthrie riding was killed while riding a works Norton in 1937; there were also rumours of his crash being caused by the rear wheel spindle breaking.
Friday, March 11, 2011
Norton Manx engine art
These drawings were made by Niels, Marcel's brother. Niels is a wizard with computers and a big fan of cammy Nortons. When he got one of his uncle's (Ko Konijn) Nortons he took it apart, measured all the components and entered the dimensions and position of each part into his computer. No clue how it works but the results are amazing! It allows him to look 'into' the engine from any angle.
Surprisingly, these are the low quality prints. Niels is working on a book that will contain many more pics of his Manx, in much higher resolution, in addition to photo's and technical data sheets. It may take 'till the end of this year before the book is available though.
Thursday, February 10, 2011
Gears anyone?
Ben and Marcus Deutscher: We noticed a recent post on the blog with a request for expressions of interest for 17 tooth gears at 150 pound each. We've had a look at the photos and feel that we might be able to do the job at a significantly lower price than the 150 pounds as this is the sort of work which we specialise in. We are professional gearcutters with an interest in Nortons who would be interested in quoting for the job. We've been manufacturing gears for Big Port AJSs, P model Triumph, Rudge and close ratio BSA sets for a number of years. We also made some Sturmey Archer 1st gears.
We are located in Australia but have sent gears to New Zealand, Canada and Ireland in recent years. All we require is a sample which would be returned on the completion of the job. Above a few photos of gears we have made in the past. Contact us at longstroke500-at-yahoo.com.au (use @ for -at-)
Saturday, February 5, 2011
1927 rear carrier
Sent by Albert
Attached a drawing of the 1927 Norton Model 18 carrier. It may be useful to someone who is missing this this item. The measurements are off an original 1927 one.
Thursday, February 3, 2011
Gears anyone?
Geoff: "I am looking for a 17 teeth gear for my Sturmey Archer CS gearbox. O/D is 1.825", width is .5625", centre hole I/D is .750", it has six splines in the centre hole (.8625") and goes on the layshaft which has a six splined section which is just under .8625" O/D to take the gear. I can get some made for £150 each...but I need to order five to get them at this price! So if anyone wants one, let me know (via John)"
Saturday, January 15, 2011
Sturmey Archer positive stop mechanisms
A few blogs ago Colin sent a few pics of a positive stop mechanism he had just bought, wondering whether it would fit his Sturmey Archer box. A few people have suggested that the positive stop he bought is actually Albion. Rob now sent a few pics of early 1930s Sturmey Archer positive stops that can be bolted to four speed boxes.
Wednesday, November 17, 2010
Getting the best out of a side valve engine
A reprint from Motor Cycling, 1936, by Hartley.
A very informative article (contributed by Simon) that describes the forgotten art of side valve engine tuning; the author suggests that your 16H can be as fast as a standard Model 18. Many of the other suggestions are well worth a try when rebuilding your Norton engine, whether it is an SV or OHV.
Simon: "Back in the dim distant past Stan Johnson - vintage Norton tuner par excellence - put a hot 16H engine in his Vintage ES2 (John Wilkinson used to ride for him). It finished third in one of the Vintage races at Brands Hatch beating all sorts of regular front runners as well as the also-rans (like me!!). Stan has been dead for about 20 years and Wilkinson died as a result of a disagreement with a Spanish policeman in Bilbao - the policeman shot him..."
(Click the images for a larger version)
A very informative article (contributed by Simon) that describes the forgotten art of side valve engine tuning; the author suggests that your 16H can be as fast as a standard Model 18. Many of the other suggestions are well worth a try when rebuilding your Norton engine, whether it is an SV or OHV.
Simon: "Back in the dim distant past Stan Johnson - vintage Norton tuner par excellence - put a hot 16H engine in his Vintage ES2 (John Wilkinson used to ride for him). It finished third in one of the Vintage races at Brands Hatch beating all sorts of regular front runners as well as the also-rans (like me!!). Stan has been dead for about 20 years and Wilkinson died as a result of a disagreement with a Spanish policeman in Bilbao - the policeman shot him..."
(Click the images for a larger version)
Friday, October 1, 2010
Wanted: Model 18 tappets
This tappet from my 1927 Model 18 has worn beyond further use and my spare tappets look even worse! For someone with the right tools it should not be too difficult to reproduce the part (see below) but I don't have a lathe or a milling cutter. Who has a few decent spare tappets laying around and is willing to sell?
"Tappets are not hard to make with a lathe and a ball ended milling cutter to make the spherical socket for the push rod end. I made some several years ago and had the stems ground to size after hardening. The tappet guide can be bored and sleeved back to original size or can be opened out and the new tappet given an oversized stem to suit. The tappet guides are not hardened."
Thursday, September 30, 2010
Enclosed rockers, springs and double camshafts
By Roger
One of the main disadvantages of bound copies of "The Motor Cycle" that are in the Brooklands Museum library is that the advertisements have been removed. A small number of complete copies of the magazine have recently been added to the collection and some of the "small ads" have revealed some interesting machines. The one below from Kings offers a Norton International to racing specification with totally enclosed rockers and valve springs (!) and this made me have another look at an earlier blog.
The "mystery" of the single versus double overhead valve Nortons in the 1937 TT has already been resolved by Mick Woollett but this is an opportunity to add some more to the background. The Norton and Velocette directors were on very good terms and often lunched together. In 1935 the introduction by Velocette of enclosed rockers using the "dog kennel" cambox was so well publicised that when Norton used its enclosed box for the TT there were rumours that it had been made by Velocette. The rumour gained enough credibility that Norton were forced to advertise the fact that it was their own design and manufacture.
This cambox (above) is the type that appears in the 1983 article where the springs are exposed and the valves operated by short tappets that protrude from the bottom of the box. For 1936 Joe Craig was keen for the Nortons to use a double overhead camshaft arrangement and engines were taken to the Isle of Man. Lack of time for development meant that the small diameter solid tappets were retained and in an article in 1943, entitled "Development and the Time Factor", Joe Craig said that this lack of time caused Guthrie and Frith to revert to the 1935 type of valve gear. This is the likely explanation for the confusion over which type was used the subsequent year.
One of the main disadvantages of bound copies of "The Motor Cycle" that are in the Brooklands Museum library is that the advertisements have been removed. A small number of complete copies of the magazine have recently been added to the collection and some of the "small ads" have revealed some interesting machines. The one below from Kings offers a Norton International to racing specification with totally enclosed rockers and valve springs (!) and this made me have another look at an earlier blog.
The "mystery" of the single versus double overhead valve Nortons in the 1937 TT has already been resolved by Mick Woollett but this is an opportunity to add some more to the background. The Norton and Velocette directors were on very good terms and often lunched together. In 1935 the introduction by Velocette of enclosed rockers using the "dog kennel" cambox was so well publicised that when Norton used its enclosed box for the TT there were rumours that it had been made by Velocette. The rumour gained enough credibility that Norton were forced to advertise the fact that it was their own design and manufacture.
For 1937 the double cam arrangement (above) had been developed using larger diameter hollow tappets and this was used in the race as it had proved to be reliable in testing. The main advantage was that they proved to be considerably faster as even the 500cc could be revved to 6,500 rpm.
So what was the machine that was advertised in February 1939 as neither of these boxes had enclosed springs? There was a third layout attributed to Edgar Franks which is reported to have been tried by the factory which used coil springs which together with the rockers were enclosed (above) so the King’s advertisement is likely to have been for this experimental machine which with a top speed of 105mph as a fully road equipped machine would have been quite impressive!
Wednesday, September 22, 2010
Improvements in the valve mechanism of internal combustion engines
A patent application written by James Lansdowne Norton in 1919. It describes a balance lever and valve springs at the position where you’ll normally find the pushrod check springs on your vintage OHV Norton. In the invention, opening of one valve puts more pressure on the other valve resulting in that valve to seat more strongly. A further benefit as described is that the valve springs would be remote from the heat of the cylinder head, in a period when valve springs were still prone to break.
Does it work? Perhaps, but problems with valve springs were overcome by use of better materials and longer springs and further, the construction looks rather complex to me compared to the normal setup. It would be interesting if someone could give it a try though!
Monday, September 20, 2010
Removing the pinion from the crankshaft
How to remove the pinion from the crankshaft of your vintage Norton? It's a tapered press-fit and there is not enough room behind the pinion to use a normal puller. Clumsy attempts to use the weight of the crankshaft invariably result in cracking of the thin wall between the bearing and the pinion. The Norton manual suggests to give the pinion an almigthy blow with a hammer and a soft metal drift...which works OK but I need a stiff drink before I dare to abuse the delicate pinion in that manner.
Viktor found a much better way and the pics below explain it all. The puller was made from grained steel grade 600 MPa.
Friday, September 10, 2010
Sturmey Archer gearboxes fitted to Vintage Nortons
By Simon
Until the cradle framed CS1/ES2/CJ/JE models were introduced in the late twenties, the vast majority of all Nortons produced from 1915 up to and including 1930 were fitted with the Sturmey Archer CS type gearbox. The exceptions are the single speed belt drivers (before anyone picks me up for not remembering them!), the four speed models with the cross-over drive box introduced in the mid twenties, and the few, mainly racing, machines fitted with the Heavyweight (HW) LS type gearbox.
The CS box (above) was Sturmey Archer’s first motorcycle gearbox and was designed by ‘Ike’ Cohen. Although there were changes to the gearbox casing, gear pitch, clutch, final drive bearing and kickstart over the next fifteen years, the basic design remained unaltered. Having worked on quite a few CS boxes over the years, I can say with certainty that they seem to last surprisingly well, and certainly better than the later LS design. Their disadvantage of the CS is their sheer physical size in that the kick start gear and mechanism is housed in the casing extension to the rear of the box. One of their advantages to Norton restorers lies in the fact that all CS boxes including those fitted to machines made by other manufacturers, have the same method of attaching to the frame and the same chain line, so for instance, a gearbox casing from 1928 will fit a machine from 1918.
The earliest examples used by Nortons were all chain or chain-cum-belt, depending on the model, and an illustration from the 1916 Sturmey parts list (above) shows what they looked like. The clutch was a six spring design (taper fitting to mainshaft) with 30 teeth 5/8 x 3/8 and the gear change was mounted on two lugs on the casing. According to S-A literature, in 1916 and 1921, there were detail changes to the clutch and in 1920 changes to the gearbox casing – see illustration 1 which shows a 1927 example – which co-incided with the introduction of the disc type gear-change mounted on the seat tube.
For 1926, the gear pitch was changed from the original 12 to 10. This had the effect of strengthening the gear teeth and radically altering the number of them. With the earlier gears, the teeth on any pair add up to 50, while with the later type the teeth on any pair add up to 42. At the same time the single spring clutch originally designed for the LS gearbox was fitted. This had 34 teeth 5/8 x 3/8 and continued in use until 1928 inclusive. Its use necessitated a change to the mainshaft as it is a spline fitting clutch. The diameter of the k/s axle was also increased for 1926, going from 5/8” to ¾”.
1929 saw the next alterations, with a change to the clutch – still single spring but now ½ x 5/16 42 teeth - and to the clutch worm/housing – increased in size and given a felt seal. At the same time the gear change mechanism was simplified and re-located to an inverted tee shaped bracket fixed to the top of the gear box casing. Final drive sprocket changed at this point also to 5/8 x ¼ from 5/8 x 3/8 previously used.
Then we come to the final year of CS gearbox production – 1930. The casing was slightly changed in that the letters of the Sturmey Archer name were now recessed into the end cover casting rather than raised. The kick start axle diameter was again increased, this time to 1 ¼” , and the kick start mechanism internally strengthened and improved. The kick start axle fitted to Model 20 twin port machines was extended to clear the right hand exhaust pipe. Many 1930 Nortons were fitted with the same type of gear change as for 1929 but the fashion for tank mounted gear changes meant that many more utilised this latter system. This did not affect the gear box itself except that the two studs on the upper casing to carry the ‘change on box’ mechanism were omitted and the actual change lever on the gearbox was a different length.
Without going into too much detail, it is worth mentioning that a racing version of the CS box was used on a few Nortons in the early twenties. This had no rear extension housing the kick start mechanism. I have never come across any literature about this gearbox although it appears in the earliest catalogue illustrations of the Model 18. It is recognisable in that, although it resembles the HW LS gearbox, the filler plug is on the left of the end cover rather than the right. I know of but two of these – one fitted to the decidedly pseudo racing 16H outfit built back in the sixties by the late Bill Fruin which carried number CSTT11 and another in private hands (no, the owner doesn’t want to sell it!) bearing number CSTT298. There may well be a few others but the despatch records do not give any clues as gearbox numbers were not inserted in the ledgers at this period.
The HW LS gearbox (above) fitted to certain racing machines from about 1923 onwards was far more compact – it contained six pinions to provide three speeds (and a kick start when fitted) while the CS type contained eight. A change from the four stud top mounting method to the familiar top and bottom pivoting system (below - a Norton patent incidentally) meant it could be used for the cradle framed models when they came along, as mentioned in my opening paragraph. (The CS1 box below is missing the pivot stud which fits into the gear- change disc and on which the upper clevis should pivot. This is part number 4652 in the CS1 parts list and quite an important little item. Its official description is 'gearbox control quadrant stud.' Also the rod which links the g/change to the arm on the box has a bend in it rather than being straight as appears in the photo). Regrettably, the LS box does not last well with dog wear often causing the box to jump out of second gear at inconvenient moments.
The clutches used on these cradle framed machines differed – the ES2 and CS1 models being fitted with a four plate clutch (1/2 x 5/16 42 teeth) while the CJ and JE used the same three plate clutch as fitted to 1929/30 Model 18s etc.
Much more information has been gathered over the last fifty years as regards the different gear sets which were available and other technical changes which took place. If desired, these could form the subject of future easily digestible screeds!
Find out more about assembly of these gearboxes by following this link.
The earliest examples used by Nortons were all chain or chain-cum-belt, depending on the model, and an illustration from the 1916 Sturmey parts list (above) shows what they looked like. The clutch was a six spring design (taper fitting to mainshaft) with 30 teeth 5/8 x 3/8 and the gear change was mounted on two lugs on the casing. According to S-A literature, in 1916 and 1921, there were detail changes to the clutch and in 1920 changes to the gearbox casing – see illustration 1 which shows a 1927 example – which co-incided with the introduction of the disc type gear-change mounted on the seat tube.
For 1926, the gear pitch was changed from the original 12 to 10. This had the effect of strengthening the gear teeth and radically altering the number of them. With the earlier gears, the teeth on any pair add up to 50, while with the later type the teeth on any pair add up to 42. At the same time the single spring clutch originally designed for the LS gearbox was fitted. This had 34 teeth 5/8 x 3/8 and continued in use until 1928 inclusive. Its use necessitated a change to the mainshaft as it is a spline fitting clutch. The diameter of the k/s axle was also increased for 1926, going from 5/8” to ¾”.
1929 saw the next alterations, with a change to the clutch – still single spring but now ½ x 5/16 42 teeth - and to the clutch worm/housing – increased in size and given a felt seal. At the same time the gear change mechanism was simplified and re-located to an inverted tee shaped bracket fixed to the top of the gear box casing. Final drive sprocket changed at this point also to 5/8 x ¼ from 5/8 x 3/8 previously used.
Then we come to the final year of CS gearbox production – 1930. The casing was slightly changed in that the letters of the Sturmey Archer name were now recessed into the end cover casting rather than raised. The kick start axle diameter was again increased, this time to 1 ¼” , and the kick start mechanism internally strengthened and improved. The kick start axle fitted to Model 20 twin port machines was extended to clear the right hand exhaust pipe. Many 1930 Nortons were fitted with the same type of gear change as for 1929 but the fashion for tank mounted gear changes meant that many more utilised this latter system. This did not affect the gear box itself except that the two studs on the upper casing to carry the ‘change on box’ mechanism were omitted and the actual change lever on the gearbox was a different length.
Without going into too much detail, it is worth mentioning that a racing version of the CS box was used on a few Nortons in the early twenties. This had no rear extension housing the kick start mechanism. I have never come across any literature about this gearbox although it appears in the earliest catalogue illustrations of the Model 18. It is recognisable in that, although it resembles the HW LS gearbox, the filler plug is on the left of the end cover rather than the right. I know of but two of these – one fitted to the decidedly pseudo racing 16H outfit built back in the sixties by the late Bill Fruin which carried number CSTT11 and another in private hands (no, the owner doesn’t want to sell it!) bearing number CSTT298. There may well be a few others but the despatch records do not give any clues as gearbox numbers were not inserted in the ledgers at this period.
The HW LS gearbox (above) fitted to certain racing machines from about 1923 onwards was far more compact – it contained six pinions to provide three speeds (and a kick start when fitted) while the CS type contained eight. A change from the four stud top mounting method to the familiar top and bottom pivoting system (below - a Norton patent incidentally) meant it could be used for the cradle framed models when they came along, as mentioned in my opening paragraph. (The CS1 box below is missing the pivot stud which fits into the gear- change disc and on which the upper clevis should pivot. This is part number 4652 in the CS1 parts list and quite an important little item. Its official description is 'gearbox control quadrant stud.' Also the rod which links the g/change to the arm on the box has a bend in it rather than being straight as appears in the photo). Regrettably, the LS box does not last well with dog wear often causing the box to jump out of second gear at inconvenient moments.
The clutches used on these cradle framed machines differed – the ES2 and CS1 models being fitted with a four plate clutch (1/2 x 5/16 42 teeth) while the CJ and JE used the same three plate clutch as fitted to 1929/30 Model 18s etc.
Much more information has been gathered over the last fifty years as regards the different gear sets which were available and other technical changes which took place. If desired, these could form the subject of future easily digestible screeds!
Find out more about assembly of these gearboxes by following this link.
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