I have a few sets of NOS Cosworth Engineering 92mm RSR type pistons for 2.8 long stroke or 2.6 short stroke. Top quality pistons with wrist pins and rings, no circlips (use regular round wire type).Use with Mahle RSR, JB Racing or LN nickies cylinders.$400set/6 or 2 sets (12) for $750 price reduced.
Last edited by 66S; 12-31-2018 at 07:47 AM.
What is the comp ratio on these? What brand rings are they?
Thanks, Rick
I will take a set.
Thank you!
They are a copy of the Mahle RSR piston as far as I know, 10.3 to 1 C.R.. The RSR heads had a larger combustion chamber so your actual compression depends on your heads. The oil control rings are Goetze, the compression rimgs are made in Japan for Cosworth. I have 3 more sets available, 2 are sold. Im going to use some for a dual purpose 2.6 short stroke twin plug motor. With 2.7 heads and 66mm crank Ill be looking for about 10-10.3 to 1 C.R., with stock heads and 70.4 crank it is something like 11.25-12 to 1. . Chamfering the combustion chamber to change the squish band is recommended to reduce detonation and CR.. 2.7 heads have a chamfer. Enlarging the spark plug opening can also help.
Last edited by 66S; 12-30-2018 at 04:07 PM.
From Bruce Andersons book. Research says boring 90mm cylinders is not recommended. The more limited use I find for these makes me reduce the price to $400/6 or $750/12. With the right heads and cylinders these will work nicely. Im using JBR cylinders myself.. AA Performance products sells cast iron 92mm cylinders that should work also at a lower price. All sets will be sold for the reduced price.
Last edited by 66S; 12-31-2018 at 02:57 PM.
Hi do you have any sets left?
Thanks, Rick
Yes I do, PM sent.
Hi 66S-- I have been considering a 66X 92 engine for some time as well. I am going with Mahle P/C set with 40 mm Weber's. Do you have favorite cam for this engine? And how will it relate to the power band? I have a set of 2.7 twin plug heads. they have the air injection ports. I suppose they can be capped. Chris
- Chris-Early S Registry#205
- '70 911S Tangerine
- '68 911L Euro Ossi Blue
The cam choice will depend on your planned use, Id ask Dougherty or other experts. I built a 2.5 short stroke single plug with Dougherty mod S cams, it has a very flat torque curve and is in a street car now but the owner mixes av gas with pump fuel for 10.5-1 CR. 2.7 heads are a good start because of the bevel on the chamber perimeter, twin plug even better.
EMail Sent
Rusty
Posting Permissions
Reply With Quote