What's up with these cylinders?

Tom '74 911 · 11-02-2009, 04:17 PM

Are these for real? These are supposed to be for a 3.2 and the seller said they could be RS or RSR cylinders, but he wasn't certain. Am I an idiot or have the cooling fins and head stud thru holes been machined off one side of each one? What are they?
Thanks,
Tom

MBruns · 11-02-2009, 04:57 PM

They are 3.3 turbo cyls. 97mm bore, the later C2 3.3 cyls were full fin.
Mike Bruns

Tom '74 911 · 11-02-2009, 06:18 PM

Mike -
Thanks for the info. I know next to nothing about the turbo versions of the 911 engine - and I know only enough about the NA versions to be extremely dangerous. Could these cylinders be used with a 3.2 case? Another general question - could you build a NA engine using a turbo engine as a platform with higher compression etc.... Would this be a worthwhile project or a waste of time and resource?

Tom

Eagledriver · 11-02-2009, 07:17 PM

You could use these cylinders on any 3.0 or 3.2 engine. They are out of favor however due to the lack of fins on the upper half. I wouldn't use them myself.

-Andy

MBruns · 11-03-2009, 04:14 AM

I agree with Andy, they will fit but not proper app. I believe they found that the full fin was more important in the later design than the extra material without fins.
Mike

Henry Schmidt · Henry Schmidt's Garage

The fins were removed from the cylinders during a development project in an attempt to make the cylinders expand and contract (especially during cool down) so the heads wouldn't weep oil. It was part and parcel of the Dilivar debacle that plagued the air-cooled design for many years.
I have seen many club racers use these cylinder over the years in normally aspirated applications with great success but cooling the oil with external coolers is a must.
BTW:
If you are looking to sell those cylinders you should have little or no trouble. Try EBS, they buy lots of Nikasil cylinders.
Good luck
cheers