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I may be way off here but, haven't crank failures been attributed to big end and/or main bearings prematurely wearing, causing said bearings to spin?
This being the case, wouldn't a presumptive replacement of the bearings, with a superior composition, future proof the engine?
Can the sump be removed with the engine in situ, allowing new bearings to be rolled in?
Nobody has a definitive answer on the bearing issue. I've read everything from soft cranks through to the block shifting as it ages. A preemptive bearing roll sounds like a good idea, and I've done a lot of reading on it but still not managed to find out if it's actually possible.
I've read somewhere there is a youtube video of some bloke in Eastern Europe doing it, but I've been comprehensively unsuccessful in finding it.
Yes, but the diff has to come out to get the sump pan out the way, actually I think there's two pans. My mechanic doesn't like doing it for inspection as the bearing caps may not go back exactly unless they are cold break conrods, not sure how all this applies to fitting new shells in situ.
Mine got new bearings at 225,000km. It’s now 385,000km. The engine was removed as part of a body off but it wasn’t a complete strip down, and was done from the bottom, leaving the heads in place.
The 2.7 has 2 pans, the 3.0 only 1.Quote:
Originally Posted by RANDLOVER
I can see that on an engine stand. You just flip it over, and pull the crank out. Easy if it's out of the car. What I'm wondering is if it can be done with the crank mostly in place? I've done it once on a much simpler and smaller motor. I made up a pin that went into the oil hole in the crank, and as I rotated the crank by hand it slipped the bearing shell out. I could then push the new one in the same way (no tabs or pins on these).Quote:
Originally Posted by DiscoJeffster
Looking at what I've been able to find on the net, I can see that working for the middle bearings, but I don't know how they're managed at the nose and thrust ends.
I suppose if you drop the oil pump and gearbox you could drop the crank out entirely, but by the time that's done it might be quicker to pop the body and pull the block out.
All main bearing slippers in the 120K kms engine that went into my D4 were rotated out/in with the crankshaft in-situ, with the engine upside down and all main caps loosened, then re-torqued once all mains had been replaced. The front seal had already been replaced when the new camshaft sprockets and belt were replaced, so was flexible. The rear seal had previously been leaking so the seal and timing plate were replaced after the bearings had been replaced. The timing plate was aligned using a tool for the 2.7 Territory.
Edit: The hard surface on the original bearings had not been breached. The bearing surface by design is not a wearing surface and if breached then the bearing has failed.