Compression Estimation

[Guest Anonymous]

Here is the deal. I am stationed in Italy so Z-car parts are scarce. When my buddy decided to scrap his 260, I saw it as an opportunity to build a little rat motor. L26 block, early E-88 head shaved .030, big valves, mild cam. I was wondering if anyone could give me an estimation of the CR. I cannot run more than 7deg initial advance and the car will after-run 50% of the time after shut-down. Should I use a 2mm HKS gasket to reduce CR, and how much would it? I have tried octane boosters, but apperently they have no effect on leaded gas, and the unleaded here is so crappy that it would take over 2 bottles @ 8 bucks a bottle to get to the octane rating of the leaded gas here. On a happy note. The car runs like a scalded dog, made a run from Aviano to Venice, and she purred easily at 4500rpm @ over 100mph.

[DavD3]

Hi,your engine is running after you turn your ignition switch off because it has to much CR.Here is the formula and you can count yourself:Swept volume+gasket thickness volume+head cc volume divide that number by gasket volume+head cc volume+any dish volume.If you have flat top pistons you don't have any dish volume, head gasket cc is 7.47 E88 head cc volume is 44.7.But i think your head was shaved too much (happend to me) so you probably have to go to two head gaskets,or use high octane gas like 110.If you have more questions e-mail me DavD3@aol.com i'll try to help you .

[Arif]

Super,

Go to www.zdriver.com and click on links, from there go to downloads. Scroll down and they have a program that will estimate the CR of an engine once you input the parts that make up your engine.

 

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