My forged 2.1 shat itself whilst up on axle stands after not having been run for some time (primed prior to firing up etc etc).

The issue seems to have been oil starvation to the no5 main bearing (ie thrust bearing). No 5 has completely melted away with crank damage etc, but luckily the big ends survived at least (so no rod or piston damage)

Anyway, I was looking into reusing the block, when I discovered that the block itself seems warped. I can fit a 12 thousandth feeler gauge between the block halves on no5 when the block is tightened up with case bolts.

Not looking for sympathy, but has anyone seen anything similar in the past? I can't believe the block would have warped like that tbh. Reckon the gap would have contributed to low oil pressure and subsequent bearing failure?

The bearings for no3 big end (or whichever one it is) showed early signs of oil starvation as well, so real lucky I stripped it down before that broke too at least.

 

That block is scrap, the crank has end loaded the rear thrust face, which is very odd for a pull clutch, what work were you undertaking if it was on stands ? a six speed conversion ?


The gap is the result of the failure not the cause.

 

Thought as much re the block, sadly. Luckily it's just a cheapo OD.

It's been my project car for some time, but kids and work has been in the way for the last 4+ years, so the car's sat in the air for all that time (with the engine out).

I originally took the engine out to swap the 2.1 into this car (from my old daily). As it was out, I also fitted an exedy twin plate and a PPG 5 speed. The engine has/had about 20k miles on it with about 350hp.

Have you got any good bare blocks on the shelf you'd like to part with? I don't particularly mind OD, it's not going to be running crazy power (aiming for a reliable 400).

In two minds about breaking the car or fixing, but leaning towards fixing it, as it's a "one careful owner" (me ) with 45k miles on it, and nobody seems to pay any money for shells with welded in cages anyway.


Edit: I should mention, I didn't build the original engine, but I'd like to build the next one (it's an after work kind of hobby)

 

Just buy a cheap Na engine and use the block and crank, they are all the same

 

Hmm, are the liners not thinner on the NA blocks?

I need to measure up my pistons and rods, as I don't know if I've got stroker rods or pistons. If I've got stroker rods at the moment, I suppose I could get some standard length WMS rods and a 2.0 crank, but then again I might as well shell out on a new 2.5 crank... decisions, decisions.

I've also got an old engine that's sat around for ages. Think I might strip that down and see if the block is usable (it's got a failed big end).

 

Liners are the same on all ODB 2.0

 

You say you had fitted a different clutch & g/box, was this the result of its first start up with these fitted ? as you need to find out what has caused the loading to the crank, as it could happen to the next engine.


Not got any blocks at the moment, even open deck ones, as Boosted has mentioned n/a blocks are the same liner wise.

 

The gearbox / engine has been apart more times than I can remember, because the twin plate has refused to disengage properly.

I think I've probably busted it by not having the splines on the twin plate engaged properly one time. The gearbox kind of mated up and I thought it was hanging on the dowels (this box/engine combo has always been a right sod to separate). Anyway, long story short, I screwed the block together with the nuts/bolts and now that I've inspected the clutch there are some witness marks on the inner plate in the splines. It's entirely possible that that is when it broke.

I've got another engine sitting around with suspected big end failure, so will strip that down first to see if the block is still OK, but the NA engine sounds like a potential option otherwise.

My rods are the 131.5mm k1, so would need some pistons to go with that if I went for a 2.0 crank. Then again, I might as well sell those bits and get some sti rods and after market pistons if that was the case.

 

The last time I saw a failure like yours it was clutch related, that had an Exedy multi plate fitted, & had one of the plates the wrong way round.


There are pistons for 131.5mm rods & 2.0 75mm crank available, RCM/Omega & Wiseco do them, others are available, but that's the 2 I have used.


If you need a 2.0 crank I have a V9 crossdrilled available.

 

Reasonably good news today. I've stripped the other engine down (so much faster the second time!), and it does indeed look like a usable block, and it's on original bores, so will have that bored out to 92.5mm.

I've done some calculations, and I think it makes financial sense for me at the moment to stick with a 2.5 crank, as I have all the other bits for that. Pistons seem to cost more than a crank, unfortunately...