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Registered
Join Date: Jun 2004
Posts: 340
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2.5 motor
I would like to build a 2.5 liter short stroke motor starting with a 7r case, 66mm crank , 2.4 heads.
For the P & C's would it be viable to use 90mm nickasils and resleeve them with steel liners to 89mm , pistons will be custom 10.1 to 1 89mm pistons, Any ideas for cam types for this motor, would a solex cam be good enough, thanks, |
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Registered User
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Why not keep the 90mm cylinders and custom make the 90mm pistons?
Early S cams and MFI would be fun. Mark
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Mark Jung Bend, OR MFI Werks.com |
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Registered
Join Date: Jun 2004
Posts: 340
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The cylinders i am looking to use are in need of renickeling, i thought then that it may be a good idea to resleeve them in steel and in 89mm. I read that this was done in some race rsr's cuz they retain the shape better at high rpms. There are no nickeling facilities where i am and the steel resleeving was done well in my 2.2t engine. What i am not sure of is if there will be problems having two types of material force fited, that is the nickasil cylinders with steel liners, thanks
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Stressed Member
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Your 2.2T cylinders were cast iron, and the 90mm cylinders are aluminum. I have not heard of anyone resleeving them. The only reason someone might do that is to meet race regulations requiring displacement to remain under 2.5 liters. I would think that many problems would result from the introduction of steel liners. Heat disipation will be poorer, and some thought would need to be given to the matter of the relative expansion of piston and cylinder as temperatures fluctuate. Shipping the cylinders to EBS seems like an awfully attractive alternative. But then again, that's what I did!
As for cams, I'm using E cams. I think that Solex would be great as well. If you are concerned with track performance the S cam might be a better choice. I am not rulling out the possibility of using S cams in the future. -Scott
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'70 911E short stroke 2.5 MFI. Sold ![]() ![]() ![]() '56 Cliff May Prefab Last edited by Scott Clarke; 06-24-2005 at 12:27 PM.. |
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Registered
Join Date: Nov 2003
Posts: 234
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I have been planning to build the same motor for some time now. The 89mm P/C are to get in under 2500cc to meet regulations. The only cost effective way to do this is JE pistons in steel sleeved cylinders but I am unable to get any opinions as to whether this setup would be inferior to JE pistons in Nickasil cylinders, and am therefore a bit hesitant to go this route at the moment.
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Stressed Member
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Yes, it would be inferior. The iron cylinders will not disapate heat as well, and create more friction than Nikasil cylinders. You should contact Pelicanite Plavan, as he has such a race motor with, I believe, 89mm Nikasil cylinders.
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'70 911E short stroke 2.5 MFI. Sold ![]() ![]() ![]() '56 Cliff May Prefab |
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Registered
Join Date: Nov 2003
Posts: 234
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Yea - unfortunately I think the only alternaive is Mahle 89mm P/C's
which would be rather pricey if one could find them. Robert |
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