Need help dead m20

[ADEN]

89 m20b20 lost power with oil burning opened it and found piston to bore too much clearance bad pistons and cylinder wall , searched for ages for b25 but couldn't find one but found only complete b25 block with no 885.

I searched if i can mate it with my 731 head couldn't find an answer. Is this compnation doable?

[ADEN]

Any thoughts?

[jeffnhiscars]

The 731 is perfect for an eta block since it matches up w the flat pistons and preserves compression. If you put it on a 2.5 block I'm quite sure you will have valve to piston problems

[ADEN]

Thanks for your replay, That means no success with 2.5 upgrade

[ADEN]

What if i got a flat 2.5 pistons with the 2.5 block and 731 head on top of them.possible?

[digger]

You certainly could machine the m20b25 pistons so they are essentially flat ( whatever gives the appropriate stack height) but net result might lower the compression ratio not sure.

[jeffnhiscars]

I put a 731 w a 272 on our eta and it's a great engine. I'd look for a 2.7 block and not mess w a worn out 2.5 for which you don't have a head.

[ADEN]

You certainly could machine the m20b25 pistons so they are essentially flat ( whatever gives the appropriate stack height) but net result might lower the compression ratio not sure.

Is that OK and safe??????
If that's possible i would be very happy and appreciated

[ADEN]

I put a 731 w a 272 on our eta and it's a great engine. I'd look for a 2.7 block and not mess w a worn out 2.5 for which you don't have a head.

I am working here with very limited options where i live. I am trying to keep the E30 alive and in good shape
That WORN 2.5 block searched for it for almost 2 years i can order parts online (rings, bearings, gaskets...etc)but shipping a block or a head cost a fortune.
My E30 is parked sadly waiting for a good upgraded motor after the b20 encounted a piston slap in the morning and lost alot of power.

[digger]

Is that OK and safe??????
If that's possible i would be very happy and appreciated

Yes, it’ll be fine

[ADEN]

Thanks digger