Bore 84 mm Biral cylinders to 86 mm?

[jsoderbe]

Hi,

I was just wondering how far I can push the original 84 mm Biral T cylinder, from 2.2 and 2.4 l engines? I am contemplating a 2.45 l engine, which would require to bore them to 86 mm.

Does that work, or do I need to buy the AA cylinders?



Regards,

Johan

[RD911T]

Johan,

I'm interested too. Looking forward to opinions.

Tom

[RD911T]

Johan,

Per Henry (I emailed him):


"The largest you can bore the 84 cast irons cylinders is 85.
The cost to bore, hone and purchase 85mm pistons is generally more than the cost of a new set."

I hope he doesn't mind me quoting him on here!

Tom

[jsoderbe]

Thanks, I just read another post where he claim that 86 mm is too large, due to heat transfer problems.

Thanks Tom!


Johan

[RD911T]

Can you post a link to that thread?

Thanks

[jsoderbe]

2.5 mid size six..... What is needed to build??

If you scroll down you will find it.

We are very fortunate to have an expert like Henry contributing here on the board. Thanks Henry for sharing you knowledge!

Regards,

Johan

[jsoderbe]

Hmm, now I found the 86 mm AA cylinders on ebay. $849 for cylinders AND pistons?! Plus rings, pins and locks. Can that really be right? This is with AA pistons, with JE they are $1375.

They claim 9:1 CR for 2.2 liter, and 9.9:1 for the 2.4. That is for AA, there only says 9.9:1 for the JE ones.

Any thoughs?


Regards,

Johan

[regency]

A word of warning, do some detailed research on the seller of this 86mm AA stuff. If it's coming out of the Bay Area, make sure the seller is "legit". Or anywhere for that matter.

Steve

73 911 T MFI Coupe, Aubergine