E: Engine Cam Suppliers

[stumpy lord]

Well, all the needle roller cam conversions I know of require either a reduced diameter for the cam spindle (less stiff) or grinding out the camshaft (weaker and less stiff). I know it has been done for racing but has anyone seen it survive for long time road use?

The ones I had, did not last very long before I ended up with a lode of needles in the crank cases, the spindles where not hard enough, an due to wear the cams dropped until the bearing case wore away allowing the needles to escape, fortunately with out any further damage.
stumpy

 

[oexing]

. . . . so my guess , you had the deep drawn needle bearings with cages like below ? In that case they are not crowded needle bearings with way lower load numbers.

Vic
needle bearings

 

[Monkeypants]

I did not think about or know about any of these problems when John McDougall put new bushings in my old cams in 2004.
The old cams had a bit of a line visible, not much, he used a fine stone to remove it.
Without nary a thought in my head other than to have fun, it's covered 60,000 miles since, mostly two up with luggage. It has done lots of big high speed pulls up mountain highways all over western Canada, the US and even one in Scotland!

I think I have maybe adjusted the tappets twice and only a couple thou change at that.
No special holes or redesigned anything.
They run and run.
I did pull the top end down for a looksee last year. One valve guide was loose. Fixed that and measured cylinder taper with an old ring.
Max variation was 3 thou end gap change top to bottom. This translates to about 1 thou of taper.
Hastings rings say it's time to rebore at anything over 12 thou taper.
I'll be 110 and won't have 12 thou variation!
At some point the ring lands will wear out. That's probably a long way off yet.

Change the oil fairly often and there doesn't seem to be much to worry about. I haven't looked in the timing chest. It's making about the same amount of clacking sounds as it was 60,000 miles ago.
Maybe I've just been very lucky, but it seems that if you have a Vincent that is well put together, you can get on and go, no need for much in the way of redesign or re-engineering.


Glen

 

[stumpy lord]

. . . . so my guess , you had the deep drawn needle bearings with cages like below ? In that case they are not crowded needle bearings with way lower load numbers.

Vic
needle bearings

they where as supplied by dolphin motors who did the mod

 

[timetraveller]

Vic, how does one constrain the needles from moving along their length when totally uncaged? My guess is that one would need to have a step in the internal diameter of the camshaft, possibly with end stops. Not arguing, just asking.

 

[oexing]

Norman, simple mod, just fabricate some loose hardened steel bushes for spacers between needle sets. The genuine Andrews cam sets had very large chamfers at the ends so I made chamfered rings as well to keep the needles at their place. The spacers are nice push fit on the shafts but half a mm smaller o.d. in the cam spindles, for not obstructing oil flow along the shafts.
By the way, the layshafts in car gear boxes have typically crowded needle rollers at their ends for max. loads when e.g. in first gear and very high load in that state. Even in some gearboxes the individual gears got crowded needle bearings in them - just remembering the old Moss box on our 3.8 E-Type.
I do have some affection for crowded needle bearings - after decent considerations about operating conditions and suitability for that type of bearing. Certainly you would not decide on this when expecting very high speeds. The classic Guzzi singles up to the late sixties had crowded needle big end bearings for many decades , 3.5 mm needles 25mm long, - and that with split conrods due to one piece cranks !! No problems with that, at least no risk of breaking stone age brass cages in big ends as is a big thing today with vintage bikes still on the old cages.

Vic

 

[davidd]

Needle rollers are generally available with crowded rollers, caged rollers, internal sleeves and seals. The end of the bearing can be open or closed (this means one end of the bearing is closed usually because it is at the end of a shaft). Examples of open bearings:

The crowded roller is often a heavy duty needle roller (but possibly lower rpm) when compared to a caged roller that contains many fewer rollers. Check the load rating and rpms for the application:

The bearing shell usually constrains the rollers or the cage. You can usually buy sleeves separately for the inside of the bearing. This is useful if the shaft is not hardened.

Attached is an article on the conversion.

David

 

[oexing]

Yes, but for the cam spindles I would not want to weaken all parts to get those bearings into the cam gear. That is why I chose to fill in just the needles and fabricated new hardened shafts exactly to size from files at INA for crowded bearings , no outer or inner races wanted. The camshaft spindles of the Andrews sets are hardened in the i.d. and only a few thou had to be lapped to get the sizes listed in the file. So now I have about 15.90 mm i.d. in the spindle and 12.90 mm shafts for 30 needles 1.5mm dia. .
You can find these files and sizes for all needle diameters when looking up the PDF below , from page 76 on:
PDF crowded needle bearings pages 76 on

Vic

 

[Cyborg]

Maybe I've just been very lucky, but it seems that if you have a Vincent that is well put together, you can get on and go, no need for much in the way of redesign or re-engineering.
Glen

Well in your case the proof is in the pudding. I’ve never personally experienced any cam failures (or clutch problems for that matter). I think it’s safe to say the oil supply to the cams is borderline. Obviously some of the failures occur from lack of maintenance,”workmanship”, ignorance, or questionable cams and followers. The pile of knackered cams and followers that came with my current Rapide, plus all discussion on the subject over the years certainly makes me want to spend some extra time inside that timing chest.

 

[vibrac]

Well I am glad I remembered that right I thought it was Dolphin motors I think at the time when I was racing a lot my thoughts were that engine comes down each season so I guess standard bushes are OK (especially as I was on R). All in all I think that those fitting long full length bushes are on the best path for road use on the mineral juice.