I just pulled down an A65 motor, and found another variation of a roller conversion. This motor is a '69 model and runs the std roller on the D/side with another roller on the timing side. This roller is 62mm OD and 30mm ID has 12 rollers about 10-11mm wide. the inside of the case has been welded so the roller can fit well inboard. It fits only about half way through the case being narrower than the std bush. The outer part of the case where the bush used to go is left because a 62mm hole right through would take off the outer boss and remove the place for the front oilpump bolt. The thing would spinn freely but had no discerable end float and the only way I can see that being controled was with the spacing of the roller bearings. Naturally its modified for end feed. Anyone seen one like that before.
Mark, this sounds like the A10 drive side bearing. A chap up this way is building my engine with this bearing and an A10 crank set at 90 degrees. He has done this many times and has good reliability. Got any pictures?
Bougor, may be one of his, its neat where the case is welded to put the oil feed through. I'll get some photos tomorrow. Are you having the crank cut and bolted up? Anyway I hope it all goes good with it.
Mark, I would think that if that timing side roller is a separable bearing with a lip on the outside, then whoever set it up, located that bearing just right so that he could use the shims and shim cup that was stock on the primary side to ensure he had minimal clearance when the cases are bolted together. He is then using as Rich suggests, the lips to control end play. It is a less than desireable way to control end play, but with light axial thrust and minimal endplay it probably works ok. You might consider replacing that roller on the timing side with a ball bearing of identical dimensions. That might be an ideal solution. Love to see pics.
Yes the crank is being cut and bolted to a flywheel similar to the method you used on your A65 crank conversions. The only real difference is that the bob weights are made as part of the flywheel and, of course, the bearing. Not sure how progress is going as I've been working in Canberra for the last few weeks and am only back for the weekend.
The guy doing my engine basically confirmed what you have said about load capacity of the combined needle/ball bearing commonly used in the A65 end feed conversion. He has been using this bearing set up (A10 drive side bearing as A65 timing side bearing) for some time in his, and others, racing outfits. The only problem he has encountered is blowing gearboxes apart and that has been purely due to excessive power. Yes the primary alignment is very important to minimise loads on the bearings lips.
IMO, the primary alignment is one of the keys to any A65 bottom end life. I think a lot of people over look that simple, but critical part of a rebuild. And glad someone else sees what I have with the need/ball conversion...hate it when I am right Needle bearings are just not intended for an engine main bearing application.
What has he failed in the gearbox? Normally, A65 gearboxes are pretty tough. Is he running an outrigger bearing on the mainshaft?
Need to know what to look for in the trans. as the A65 proddy racer from h*ll is going to get the gearbox tweaked soon. And hopefully a bit more power dialed in . Right Alex :p Of course we are going to see how far you can stretch a plain main bearing ...... but that is another thread.
Crunching them into gear with a broken clutch cable can remove teeth on first gear (brothers done it), or top gear (I've done that) a missfire and a lot of throttle will break a tooth off top gear as well, probably the jackhammer action,(Son's done that) I warned him though, because I'd also done some on mine, all top gear, which the lower gears drive through, so it pays to have a good cable and not rev them hard with a missfire. They are the only conditions I've had something break. Jumping out of gear fixed by modifying camplate. Generally I think they are quite a good and strong box. Sidecars might stress them more though, if youve seen how racers sometimes use the gears to help slow down. Be nice to see the A65 proddy racer getting some tweeking, I wish I could help, maybe when Alex finaly gets the data logger working and I get the 750 motor going (maybe a month or two away) we can compare graphs to see what going deeper into the motor can do.
Hello gentlemen. Plain versus needle bearing....... I cannot see anything wrong in using needlebearings in a crankshaft....the one SRM uses in their conv. can cope very well beein able to go to 11500rpm and having dynamically excellent figures. My Laverda 1200 is depending on needlerollers as main and conrod bearings....I know Laverda engines that has passed the 300 000 miles mark without beeing opened. All of the old famous Honda racing machines used needlerollers in all the engine bearings because of their ability to cope with the dynamically high loads spinning sometimes to more than 20 000 rpm. MV Agusta,Suzuki,Kawasaki,Yamaha all have been manufactured with needlebearing cranks more than with plain ones.
I'm pretty sure he told me that he had problems with the cases splitting normally preceeded by missfiring or a missed and then slapped in gear. He's got a Norton crank in there and it's bored out to 77.5. The top of the barrels are also pinned down to base flange. Must be pushing out some serious grunt. He is forced to use cases no later than '63 and, yes, an out rigger is fitted. I'll also have one of these on my build. It has got to make things much better for the gearbox.
When I was washing it up I noticed the oilway was still feeding up into the main bearing so some oil would be going into the roller, I don't know if that was intended but on the conversion I do I block that totaly off and drill a little hole and run in area from above, like the cam bushes have which seems adequate. There was a very fast A65 outfit from Qld I think at Eastern Creek when we were there in 99 or 2000 its pretty rediculous the rules they have for the racers; like having to use early cases, when power will be the same, and all they are doing is making reliability more difficult and discouraging participation, for things that look and are essentially the same.
Mark I can see in the second photo that original oil feed hole is half exposed. I think you might find a bit of tube shoved up into the gallery from the access grub screw underneath the pressure relief. What condition are the roller bearings and big ends in? Nigel
The rods are still on the crank as yet, this main bearing is fine as would be the drive side accept its loose on the crank as is the Primary drive sprocket on the spline, (which must have made a lot of noise)the alt nut wasn't very tight and it looks like it has done some miles, like there are no teeth left on the rear drive sprocket, so it wasn't being looked after all that good either. Bougor does it have a tube in the drilling to let a restricted oil fow go to the roller? Do you know? Like I was saying I've got a little gravity/splash fed hole going into the centre of the needle roller I use, though with it there is no endfloat control, I do that with a bearing mounted in a plate outside the alternator, the later models have a strong casting supporting the alt, the early ones with just long studs might be a bit flexy to do that. I think this rule applies; "I'll agree that a substitution of bearing type, size or fit that has already been used successfully strongly suggests that a repetition will be successful," And thanks also for the rundown on bearing types and characteristics Panic. Its nice to see how different people work to solve the same problem. I originally used a combination bearing which worked reliably till it came loose in the case and the easy fix I could think of was to control endfloat a different way and use an INA-NKIS30 roller bearing, which they refere to as 'Heavy series' wich has been in my BSA since about '95, used every day. These are specs for it; http://medias.ina.de/medias/en!hp.ec.br.pr/NKIS*NKIS30
Contolling end float is not as big an issue as most people think IMHO, a Commando engine with 2 superblend mains has no endfloat control other than restricting it to 3/15 thou with shims behind one or both of the roller bearing inners. Never heard of an issue with Commando engines that has been put down to this setup so I don't see why it wouldn't work on a BSA or Triumph. I beleive the key is to reduce the endfloat to a miniumum eg 3 to 5 thou which stops the crank from picking up much sideways speed so the rollers are not hit sideways at high speed and ensuring the primary is aligned as accurately as possible to reduce the sideways force to a minimum.
Panic, The drive side ball that I used to replace the roller was the exact same width, ID and OD. It was a Japanese made bearing in the inch series. It is true that it has less radial capacity than a roller by a good margin, but I would think that the timing side has less stress and an adequately sized (possible since you have to weld in material and remachine)ball bearing would be a good solution. Mr Mike
Mr mike, I just looked up the load carrying capacity on this size bearing 30X62X16mm; dynamic load; 19,000 ball 45,000N roller 41,000N 30x52x22 N/roller I use 61,000N 30x72x27 roller Norton D/side size NJ306e as I use in my A65 D/side. Static load: 11,200N 36,000N 50,000N 48,000N Fatigue limit load: 680N 5,700N 8,000N 8,000N Not sure what SRM use in their combination bearing if to fit a 30 or 35mm shaft does anyone know? A good plain bearing may take a greater load again? But what complicates matters is how they actually work in operation, how they last and how easy to service.
Thumbing through my SRM catalog I found the following info about the needle roller bearings:
NK1B 5906 C3 (A10) NK1B 5907 C3 (A65) NK 40/20 (Tri) NK 35/20 (No longer used)
The folks at SRM claim that these bearings have the same load capacity as the drive side roller. I don't know if that's true, but it seems that they've had a good deal of success doing these conversions. Since they're a little far away from where I live I'm going to inquire with British Cycle Supply since I can just drop the stuff off in Hackensack which is only a hop, skip & a jump away.
Joined: Sep 2002 Posts: 7,812Alex
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Originally posted by blimey-bill: Since they're a little far away from where I live I'm going to inquire with British Cycle Supply since I can just drop the stuff off in Hackensack which is only a hop, skip & a jump away.
Frank Diehl is the SRM rep for the US. He advertises on this site.
A smattering: '53 Gold Flash '67 Royal Star '71 Rickman Metisse '40 Silver Star '37 Rudge Special sixtyseventy Lightboltrocket road racer...and many more.
INA-FAG has a proprietary slogan called X-life which is supposed to mean that with modern materials and tolerances these bearings should last a long time. Maybe their older stuff had different/lower ratings? Not tryin' to beat a dead horse, but if I go with the A10 crank I don't have much choice other than converting the timing side bearing. I know Frank Deihl does the conversions as well as a few others. I think B.C.S. farms the job out, but I don't know who they send the stuff to. I figured I'd use them mainly for convenience since their U.S. warehouse is only minutes from where I live.