WTB: E21 High compression pistons

[Mookenstein]

I'm rebuilding my engine and since I am going to freshen up the motor, if anybody has some 1st or 2nd oversize bore pistons I'd be happy to buy them from you. I'd like a 9-10 compression ratio, but if you have some 13:1 pistons I'll mill them down (or buy an adjustable MSD ignition box). 

 

Must fit a 2.0L M10 with the E21 head. Thank you.

 

~Mike

 

:Edited based on recomendations:

Edited April 7, 2020 by Mookenstein
trying not to be an idiot

[wegweiser]

After all these years, the bores are still within standard spec? Impressive! No taper? That would surprise me! Think long and hard about having the bores professionally measured from top to bottom. Otherwise all that new compression is gonna blow right past the rings. BTDT!

 

 

[jfahuna]

Read above post again.

[Mookenstein]

Bores are *JUST* out of spec. Taper is just inside spec (if you don't measure the lip at the top of the bore). 

 

I was trying to keep this rebuild as simple as possible (ie: cheap) but I am taking apart the engine to fix problems. So I don't have an excuse to skip over the "minor" problems because they'll just become bigger problems later on. So I revised my initial post to reflect that. Thank you.

 

~Mike

Edited April 2, 2020 by Mookenstein

[Conserv]

On 4/2/2020 at 11:25 AM, Mookenstein said:

Bores are *JUST* out of spec. Taper is just inside spec (if you don't measure the lip at the top of the bore). 

 

I was trying to keep this rebuild as simple as possible (ie: cheap) but I am taking apart the engine to fix problems. So I don't have an excuse to skip over the "minor" problems because they'll just become bigger problems later on. So I revised my initial post to reflect that. Thank you.

 

~Mike

Don’t limit yourself solely to 90mm pistons. First oversize is like 89.23mm, second oversize is like 89.47mm, and so forth. Wear on a 100K mile ‘02 engine often requires only first or second oversize...

 

My ‘76’s engine cleaned up at first oversize — although cylinder one was sleeved because of a leak in the cylinder head water jacket. The pistons were custom as high-compression pistons for E21 heads are relatively rare. My pistons are 9.5:1-ish.

 

Regards,

 

Steve

 

 

 

[Mookenstein]

I swear I've built engines before. Really I have....

 

I found the piston specs from the repair manual, and I'm going to start referring to the sizes as 1st and 2nd oversize. I haven't even found an engine shop that's less than 5 months out so should pistons appear in whatever bizzaro size I can just get the machine shop to cut the cylinders to match.

 

~Mike

[Mookenstein]

Bump.

[mac]

You have a problem.  "Cheap, High compression, Oversize".  .............Ain't gonna happen. 

 

Ever heard of "Military Intelligence"?  Same category. 

 

email Wegweiser,  tell him you want 2nd oversize for '75-'77 EURO 320i/520i.  Maybe he'll find someone with some sitting on a shelf collecting dust.  

 

Good Luck. 

 

Mac. 

 

PS. Oh,  these will be 9.3:1 C/R

 

-m-

[Mookenstein]

Mac, In none of my posts did I mention cheap. ? I wanted a simple project, but if I have to bore and hone a cylinder block simple was throw out the window a long time ago. 

 

Thank you for the recommendation. I will look into it. 9.3:1 is still better than the 8:1 I had before. 

 

~Mike