ET: Engine (Twin) oil holes in Crank pin?

[Vincent Brake]

To all in the Know, Question:

where would one let the oil out to bearings, 90 degree to rear of TDC? left n right hand different?

Maughans drill 2 holes per side, 30degree before and after top of the crank, no difference for front or rear cylinder.

Ok, with let oil in both sides to the rollers (INA) 20mm wide, so 2 holes round 1mm on 18,5mm pitch (rollers are 16mm)
so rollers do not run on holes.

Making some cranks now, (with adjustable balance factor, from cylinder openings)
both 90 and 100mm. 84 and 92 JE pistons adjustable from 52-60% balance

Cheers

 

[oexing]

I can see no good reason to have 2 holes plus-minus 30 degrees from TDC. My idea, like at BMW, have two holes for each conrod at 90 degrees past TDC. So then, with a central hole of ca. 16mm in the plugged 40 mm crankpin you get a "sump" in the pin and even supply to both conrod bearings. Plus, when blipping the throttle the accelerating crank will shift oil to the rear of the crankpin - 90 degrees to the rear. So extra oiling in acceleration.
No mainshafts from one solid block ???

Vic

 

[Vincent Brake]

Mains in with press fit.
Made the flywheels from en36c.
And hardend.
Now to be annealed again, than mill them round. Epoch mill, up to 65Hrc easy.

What i dont get is why 90 degr after tdc. At is point there is a lot of presure there.
Would nt it be better to drill before? E.g. at or before tdc?

 

[DucATIRadeon]

just my thoughts:
- holes@TDC the centrifugal force is maximum so all oil is slung out there with largest (radial) velocity.
depending on where you have the holes (inside or outside the running surface of the bearings) the oil can be slung past the bearings and Conrad to the pistons en cylinder walls (or even go nowhere if the spacer is between the conrods), or slung direct into the bearing rollers (where you actually want the oil to be cooling the bearings).

- holes 30 degrees before and after TDC still gives you the centrifugal force for the oil to get out, and distributes the oil more evenly for cooling during compression and working strokes.
if the holes are within the running surface of the bearing track, and if done properly, the needles wil not suffer nor will the holes in the main pin get chipped.

have look at how modern, high powered single piston performance engines with needle bearing bigends have the oil ways located (for example JAWA 500 889/ICE engine, 500cc capable of running at 13000rpm producing anywhere from 65 to 95hp depending on camshaft used, on standard 35x42x19 needle bearing running direct in the conrod).

 

[greg brillus]

Some of this probably relates to how good an oil pump you use as well........the stock Vincent pump is probably not even as good as a hand held oil can........look at a bevel Ducati, has a much higher constant delivery pump.......still same roller big end.......Ok they had lots of big end failures, but i'm sure that was from a manufacture/hardness issue yes.......not from lack of oil.......Mr Speet, are you making these cranks to sell or for your own use only........Asking as i would like a shorter stroke crank for my race engine.......currently 92 x 100 but would like to go back to either 90 stroke or even less.......we are thinking of making a bigger bore race engine easy to go 95 mm but would need new cases with hold down studs moved out to go to 100 bore.......If you look at the Horner brother engines they use same spec bore/stroke ratio as a 327 Chev.......4 inch bore by 3 3/8" stroke.......this combo gives one of the best ratio's for good valve sizes verses piston travel/speed .......i would like some new cases with the hold down studs moved further out.......this was what John Renwick did on his 1600 cc sidecar engine.........Cheers......G.

 

[Vincent Brake]

Balance is calculated for a twin @greg brillus
Is that what you would need?

 

[DucATIRadeon]

Some of this probably relates to how good an oil pump you use as well........the stock Vincent pump is probably not even as good as a hand held oil can........look at a bevel Ducati, has a much higher constant delivery pump.......still same roller big end.......Ok they had lots of big end failures, but i'm sure that was from a manufacture/hardness issue yes.......not from lack of oil.......

had quite a few Ducati Bevels (still have one) and the oil pump is a spur gear pump.
the bigend failures were more from the non-filtered oil going only through a stone-catcher oil strainer, and ending up between the needle bearings. another bigend failure is when plonking alone at too low revs in too higher gear, the needles are effectively hammered and rolled into the conrod moe than the bigend pin.

Mr Speet, are you making these cranks to sell or for your own use only........Asking as i would like a shorter stroke crank for my race engine.......currently 92 x 100 but would like to go back to either 90 stroke or even less.......we are thinking of making a bigger bore race engine easy to go 95 mm but would need new cases with hold down studs moved out to go to 100 bore.......If you look at the Horner brother engines they use same spec bore/stroke ratio as a 327 Chev.......4 inch bore by 3 3/8" stroke.......this combo gives one of the best ratio's for good valve sizes verses piston travel/speed .......i would like some new cases with the hold down studs moved further out.......this was what John Renwick did on his 1600 cc sidecar engine.........Cheers......G.

would you not then need displaced stud holes in the cylinders and heads and brackets holding the UFM?

 

[greg brillus]

Mr Speet, Sorry no for a single.........could bore large hole opposite the pin as per stock Comet wheels I'd say and i could fine tune the ballance from here.......we are using lighter pistons with a slipper type skirt and different pin height.........Yes the larger hold down stud spacing would mess with barrels and heads.......but this is easier to fix than the cases. Prefer larger diamter main shaft on drive side........extra strength, plus we use taper rollers on here as well.......standard set up on timing side.

 

[Vincent Brake]

That would be a very diffrent one as I make now, If you would be able to sell 3 on, I m your man!!

 

[greg brillus]

No matter........I want to reduce the total reciprocating mass anyway........Just another project perhaps some time not too far in the future.