Is a 2.7 CIS engine with 7R Case 90mm?

[matty74]

Is a 2.7 CIS engine with 7R Case 90mm cyliner diameter?

Can I use 92mm on a 7R case?

[Steve@Rennsport]

Perhaps I can help,.........

All 2.7 engines use 90mm cylinders. 2.8 engines use 92mm cylinders.

Both have 97mm spigot diameters and are interchangeable so no machine work is necessary to install 92's instead of 90mm ones.

If you use the Mahle 92mm RSR ones, be aware that those were designed for the RSR heads which have much bigger chambers than 2.7 heads have and this results in a very high CR unless some modifications are made.

I always recommend twin-ignition for 92mm engines,....

[matty74]

Has anyone used the cylinders? QSC?

http://cgi.ebay.com/ebaymotors/Porsche-911-90mm-Cylinder-JE-Piston-Kit_W0QQitemZ260109802080QQihZ016QQcategoryZ33623Q QrdZ1QQssPageNameZWD1VQQcmdZViewItem