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+--- Thread: rebuilt engine leaking oil.... (/showthread.php?tid=9271)
RE: rebuilt engine leaking oil.... - goodwoodweirdo - 06-05-2024
Finally found the problem after pulling the flywheel...
Lets hope with a modern seal we're back in business...
RE: rebuilt engine leaking oil.... - Reckless Rat - 06-05-2024
Isn't the rear main supposed to be a roller bearing? (or am I having a senior moment?)
RE: rebuilt engine leaking oil.... - Alan - 06-05-2024
Er, normally, yes.
Just check, there’s supposed to be an oil drain hole at the bottom of the steel bearing housing. It’s important that the carrier is fitted the right way up because it will go the wrong way. I only mention it because I can’t see it in your photograph.
RE: rebuilt engine leaking oil.... - Chris KC - 06-05-2024
Possibly someone knows something I don't (highly likely!) but that ball race would worry me far more than any oil leak. Next thing I would do is find out what the bearing arrangement is at the front end.
RE: rebuilt engine leaking oil.... - Charles P - 06-05-2024
I run a ball race in the rear bearing of my engine, but that's in conjunction with a very carefully fitted flywheel.
The objective is to retain the axial movement of the crank at the rear bearing, not the front lip. However, the grinding of the spacer that goes between the flywheel and bearing is a job where a couple of thou is important. It's a Frank Hernandez suggested mod.
Charles
RE: rebuilt engine leaking oil.... - Alan - 06-05-2024
Where is Frank. I’ve not heard of him in ages.
RE: rebuilt engine leaking oil.... - Bob Kneale - 06-05-2024
(06-05-2024, 12:30 PM)Charles P Wrote: I run a ball race in the rear bearing of my engine, but that's in conjunction with a very carefully fitted flywheel.
The objective is to retain the axial movement of the crank at the rear bearing, not the front lip. However, the grinding of the spacer that goes between the flywheel and bearing is a job where a couple of thou is important. It's a Frank Hernandez suggested mod.
Charles
Using a ball race in the rear main bearing is a modification I have considered for years, but apart from sourcing the bits, haven't yet got around to it yet!
It would be at its most beneficial in a 3 bearing engine, where it would isolate the thin center webs from the bending forces that surely occur when depressing the clutch pedal puts a heavy axial load over the full length of the crank. Leaving the front bearings floating (as in a modern plain bearing engine) is surely kinder to the crankshaft, particularly under normal i.e. non racing conditions. The gyroscopic loads on the flywheel might be a problem when cornering, but only slightly more than with a roller race.
We'll never know if we don't try it... Here's to a healthy discussion!
Bob
RE: rebuilt engine leaking oil.... - Charles P - 06-05-2024
(06-05-2024, 02:57 PM)Bob Kneale Wrote:(06-05-2024, 12:30 PM)Charles P Wrote: I run a ball race in the rear bearing of my engine, but that's in conjunction with a very carefully fitted flywheel.
The objective is to retain the axial movement of the crank at the rear bearing, not the front lip. However, the grinding of the spacer that goes between the flywheel and bearing is a job where a couple of thou is important. It's a Frank Hernandez suggested mod.
Charles
Using a ball race in the rear main bearing is a modification I have considered for years, but apart from sourcing the bits, haven't yet got around to it yet!
It would be at its most beneficial in a 3 bearing engine, where it would isolate the thin center webs from the bending forces that surely occur when depressing the clutch pedal puts a heavy axial load over the full length of the crank. Leaving the front bearings floating (as in a modern plain bearing engine) is surely kinder to the crankshaft, particularly under normal i.e. non racing conditions. The gyroscopic loads on the flywheel might be a problem when cornering, but only slightly more than with a roller race.
We'll never know if we don't try it... Here's to a healthy discussion!
Bob
There are a lot of theoretical benefits but you cant get away from the fact that a ball race has less load capacity than a roller.
If you have a desire to tour the world with your family, a la Dunford, then it may not be the mod for you. That said, most rear rollers seem to wear through the gentle misalignment caused by crank whip and corrosion, rather than through excess mileage.
Cue Tony Press with an educated view of the bearing choice!
PS - mine has been like this for a decade or so
RE: rebuilt engine leaking oil.... - AustinWood - 06-05-2024
If the surface of the flywheel boss is poor a modern oil seal won't work.
RE: rebuilt engine leaking oil.... - Austin in the Shed - 07-05-2024
(06-05-2024, 10:54 AM)Alan Wrote: Er, normally, yes.The reverse scroll rear bearing cover normally holds the oil in unless as said the oil drain hole isn’t at the bottom of the housing.Why has it got a ball race at the rear,is it a wheel bearing?
Just check, there’s supposed to be an oil drain hole at the bottom of the steel bearing housing. It’s important that the carrier is fitted the right way up because it will go the wrong way. I only mention it because I can’t see it in your photograph.
Stuart Rolt used to use two self aligning double row ball races but with this arrangement how does the crank grow and shrink in length when whipping ?
If indeed the oil has come out of the back of the crank you must have had a bell housing and clutch full of oil ?