High compresion 325i block casting number/s?

Post Sat Dec 06, 2014 5:05 pm

As above does anyone have any info?

Post Sat Dec 06, 2014 5:32 pm

Look on the machined flat to the right of the inlet side engine mount, just above the block:sump interface. High Comp = 25 6E, Low comp = 25 6K.

There may be additional info, e.g.;
25 6E 1 = Early high comp. 9.7:1 CR.
25 6E 2 = Later high comp. 9.4:1 CR.

(25 6K = Low comp. 8.8:1 CR.)

You may need to wire brush/Jenolite the area to see it, and use a strong torch.

Post Sat Dec 06, 2014 5:36 pm

I have 25 6e 1 here..

Post Sat Dec 06, 2014 5:37 pm

Congratulations, that will probably be the early high comp. with 9.7:1 compression ratio. Normally good for 180bhp or so.

Post Sat Dec 06, 2014 5:40 pm

trying to identify the pistons for a customer .block on the oval casting say's 86

Post Sat Dec 06, 2014 5:55 pm

Sounds about right - the 325i was introduced in 1986.

This guide gives info on pistons:

http://www.e30zone.net/e30zonewiki/index.php/M20

You may also find info on RealOEM, etc.

Post Sat Dec 06, 2014 6:02 pm

Thanks .