E: Engine Cam Suppliers

clevtrev

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I figured I’d ask Oilite and they just received an email back....referring me to the link about machining practices. It appears they have updated “carbide inserts to PDC.

Kyocera's diamond material is a synthetic material sintered under high temperature and high pressure. PCD(polycrystalline diamond) is ideal for non-ferrous metals, non-metal turning, milling and other types of cutting.

I’m assuming that skimming .0005” or whatever off the bushing doesn’t qualify as major machining, so no re-impregnating would be required.

Anyone here versed on broaching, burnishing, or ball sizing? Seem to me I read something somewhere written by (I think) John Healey about connecting rod small ends being done that way. I think the term broaching was used, but wouldn’t bet my life on it.
Definitely not to use PCD for finishing oilite. The top rake is normally negative, the the tip generates heat to move the material. If you use a carbide tip, get one specifically for aluminium, sharp and polished.
 

Cyborg

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Doesn’t that depend on the type of insert? They have ones for non ferrous... brass etc. I’m still figuring all this stuff out, but don’t see why you couldn’t just use an old fashioned bit of tool steel freshly sharpened, honed and then a final polish on the buffing wheel. Then turn the bushing as fast as the poor little South Bend will spin. It’s not like you’re removing much material and as long as it actually cuts and doesn’t smush the pours closed....or am I missing something?

 

davidd

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I have not looked at the catalog for quite a while, but I think a sharp steel tool is fine. I use a hand reamer. As I remember, they want something sharp to cut it. No honing or smearing. I buy the bushings from McMaster and size them with an adjustable reamer.

David
 

Cyborg

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This is from the Oilite site. I’m a little surprised the ball sizing would work without affecting the pores.

“There are a few basic machining practices required to optimize retaining surface micro-porosity and the self lubricating properties of Oilite® bearing materials.

Cutting tools must be sharp. For this reason, PCD-Diamond inserts are very highly recommended since they hold a cutting edge much longer. This preserves the open-pore structure from which oil can flow freely. A dull tool will smear the pores, greatly reducing the self-lubricating qualities of the material.

Turning: Cutting Feed Rate: 0.002-0.006 IPM
Speed: Oilite® Bronze 375-500 SFM
Speed: Super-Oilite® 250-500 SFM

Roller Burnishing is an excellent choice to modify an ID slightly. Ball sizing can also be used on the ID effectively for final sizing.

Honing and grinding are never recommended on Oilite® bearing materials. Using these methods on any surface which will become the bearing surface will introduce grinding media and could easily smear the bronze pores sealing the micro-porosity.

After extensive machining, bearings should be re-impregnated with appropriate / specified oils. Vacuumed impregnation is recommended. If bearings were not lubricated prior to machining and if cutting fluids were used, that medium must be removed prior to any impregnation of the oil selected for the application. Your authorized distributor can provide oils for re-impregnation after machining.”
 

oexing

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Why would one be so focused on oilite bushes in the camshafts when you have continuous lubrication into them ? I´d take tin bronce (phosphor bronce?) any time instead. For sizing oilite bushes a simple HSS tool should be allright - as long as it is not blunt. And speed is only secondary to sharp cutting tools.
I believe a good oil supply into the cams is most important and one or two oil holes just before the opening ramps at the end of the base circle . Also I believe the oil hole in the cam followers at its place of max. load is very wrong. All it does is to interrupt the oil wedge that forms on the cam lobe with accelerated wear around the hole. You can check this effect in other bikes like Yam XT or SR 500 with their oil hole in the hard chromed followers . Any oil pressure from the oil pump is nothing compared to pressure within the oil wedge so any hole there is simply wrong. I laser welded all holes in the followers for keeping an undisrupted face for oil wedge forming. Another mod is crowded needle bearings in the camshafts for better oil flow from the oil holes in the base circles.

Vic
 

vibrac

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Wow! needle roller camshafts, back to the future indeed! who was it who used to offer then in the seventies ... Dolphin Motors? didd'ent they slap em in the followers as well ? I think I have some cam with them in somewhere.
I seem to recall some resistance to the whole concept but cant recall the argument
 

timetraveller

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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?
 

Cyborg

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Why would one be so focused on oilite bushes in the camshafts when you have continuous lubrication into them ? I´d take tin bronce (phosphor bronce?) any time instead. For sizing oilite bushes a simple HSS tool should be allright - as long as it is not blunt. And speed is only secondary to sharp cutting tools. Vic

I can’t answer that... just going by what I have heard. Some folks had problems with the bushings supplied by Megacycle and switched to oilite. I wonder if you are being too kind when saying “continuous lubrication”, and the oilite helps to save the day?
 

oexing

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Still thinking positive about positive lubrication into the cam spindles - am I too naive ?? But then I would not expect to have cams and followers surviving for substantional times, the bushes my least concern. Maybe the fits were too tight for decent oil film buildup? I´d want one thou play in the bushes at this kind of size, so half a thou oil film.
The needle bearing mod has no races or cages, real crowded rollers design with 1.5mm needles. So the cam spindles, factory new sets from Andrews, just required minimal lapping for a fraction below 16 mm i.d. and the case hardened shafts are 13 mm , so not too bad - plus you have a steady plate outside for support. All fits have to be correct for sure. I had the engine case with shafts on the mill for getting all dimensions so the steady plates were bored with all correct sizes after measuring the shafts etc. .

Vic
 
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