Realistic cost on m20 short block rebuild?

[ajt3nc]

I purchased an 89 525 with a new head installed . It previously overheated and after a couple thousand miles I have a high pitch rattle all through the rpm range.
I thought it was the valves seating but unfortunately an adjustment did not silence the noise. I tried different oil and that was no help.
I think I will need new mains. I moved and do not have the place or time to do this myself, and plan to drop it off next week with a local german speed shop.
What is a fair price to freshen up the short block?

AJ

[Jeff N.]

Huge "it depends". Depends on the condition and what you decide to do with the cylinder bores and pistons. A full rebuild would include an overbore + new pistons. A light rebuild might be able to just get away with a hone and new rings and use the existing pistons.

I'd suspect it'd be cheaper to purchase a used engine over rebuilding what you have.

[Rigmaster]

I agree with the "it depends" assessment.

If you are confident that it's the bottom end making noise- I would seriously consider finding a used engine, or used bottom end and just putting that in there. Once you start tearing into the bottom end, $$$ adds up quickly as there are so many "while I'm in there" things to do. Once you decide to do mains, you might as well do rod bearings as well, then what about the oil pump, maybe some rings, etc, etc, etc......

The going rate for known good M20's seems to be $5-600 or so, should be able to find a short block for $3-400 max. Let me know if you are in NC and want to go this route- I have an '89 525i parts car with ~100k on the engine.........



Bret.

[Dave M]

Rigmaster knows,

I'm swapping out my M50 block and, seeing as I've now got a garage, found it quite reasonable to purchase a block ($350 U.S.) and rebuild it. New main / rod bearing and rings. But,....Things do add up quickly. Even if you do it yourself, factor in all the above ($550+) plus head gasket kit, valve cover gasket, oil pan gasket, other assorted engine seals/gaskets, various bolts and do-dads, engine / tranny mounts, exhaust hangers/gaskets, fluids etc..... do I need a guibo?, clutch? center bearing? how about a thermostat/waterpump? Messy shift linkage? Cup holder? $hit, this could get expensive.

I'd look for a new engine to drop in. Or a new car?

Good luck with whatever you pursue,

Dave M

[ajt3nc]

Would this be a fairly direct swap ? http://www.salvagedirect.com/asp/vie...=585455&bhcp=1

[Kalevera]

Yes. You'll want to swap the engine harness and probably need to do the mounts and pan (can't remember if the E30 has an oil level sender in the bottom of the pan or not ATM...pretty sure it doesn't from what I recall).

One thing to do before embarking on all of this is to check the current engine's timing; make sure the timing belt is correctly set and not a tooth off or something....not that it would make much of a difference after driving potentially thousands of miles on it, anyway...but...


best, whit