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Engine Specific Info and Questions => IDI Engine => Topic started by: oblique on January 25, 2023, 11:41:50 am

Title: Question on compression testing
Post by: oblique on January 25, 2023, 11:41:50 am

So. Our IDI combustion chamber volumes are pretty small. I think I remember reading on here the precup volume being around 5cc for 1.6, and closer to 6cc for 1.9aaz, add to that the remaining volume of the piston under the head (which isnt very much, maybe 4cc?) and you've got about 10cc total volume..not much so the injector adapter MUST take the same volume as the injector and the check valve on there should be designed with it mind if precise readings are to be expected.

So, i'm in the market for a tester. Has anyone used the PP one? It seems reasonably priced. The other end of the spectrum are full commercial grade kits...bit pricey with accessories ill never use. Anyone have luck with the PP one or a decent unit? Purely for my hobby, friends, etc.

Title: Re: Question on compression testing
Post by: fatmobile on January 25, 2023, 12:58:42 pm

I've gone to spinning the engine by hand and feeling the compression.
 If it tries to go backward it's over 375psi.