M20 may be toast

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EBSF
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M20 may be toast

Postby EBSF » Fri Aug 19, 2016 11:28 pm

So, the OE M20 in my E30 may have given up the ghost. Ran roughly, mechanic tells me that in a compression test, cylinder 5 shows 35psi with 90% pass-through into the crankcase. Other cylinders fine with 185psi.

So, I'm thinking this means rings, possibly a compromised piston, but definitely a block (not a head) issue. Correct me if I'm wrong.

Quote is $6000 to recondition and install a used engine. I'm wondering what the alternatives are. I lack the facilities to rebuild the thing myself. I haven't found anyone who sells remanufactured M20s but would be interested to learn of anyone who does. My sense is that rebuilding this engine is either DIY or a local job. If the latter, it's probably prohibitively costly.

Mileage 157K, 1990 4-door, AT.

Thoughts?
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Re: M20 may be toast

Postby 87e30 » Sat Aug 20, 2016 1:18 am

$6000?!? Where are you located? I swapped out the m20b25 from my white car for $80! Well, it wasn't reconditioned, and I did everything myself (with a little help from a couple friends). A few hundred more for misc parts, and I abused that engine for years. Did you get a price for the swap if you supply the engine? Is it a b25 or b27? Could get either one of those around by me for like $150-$300 from a junkyard. Of course you would be taking your chances with it if you don't want to rebuild it. Check your local yards. If you can find one with a side or rear accident there's good odds the engine is still fine.
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Re: M20 may be toast

Postby Yoshi » Sat Aug 20, 2016 11:33 am

$6k to pay someone to put in a good (repaired) engine sounds about right honestly. You could junk yard it but most mechanics won't put it in since it doesn't come with any warranty. Basically, DIY for cheap, or $6k. Or sell the car.
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Re: M20 may be toast

Postby M20_fever » Sat Aug 20, 2016 4:04 pm

Yoshi wrote:$6k to pay someone to put in a good (repaired) engine sounds about right honestly. You could junk yard it but most mechanics won't put it in since it doesn't come with any warranty. Basically, DIY for cheap, or $6k. Or sell the car.


Labor must be WAY more expensive by you. $6k will get you a Metric Mechanic rally motor installed around here. Swapping an m20 is maybe 8 hours book time. Even at $100/hr shop time thats around $1k with shop material charges. I built my stroker for less than $6k. That is just lunacy for a stock rebuilt m20 installed at any reputable indy, MAYBE a dealer price?

Honestly, hit up your local BMW forum, you can get a good used m20 for under $500 complete, and I'm sure there a fellow enthusiasts local to you that would help swap them out for some pizza and beer.

If you find someone with space and tools you could pull that motor and put a set of rings in it over a weekend for a couple hundred bucks...
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