I was wondering if anybody knows what the compression should be with tigerlly 8:5:1 pistons.

I did a check today and got (warm engine) 176 - 180- 177 - 179 (give or take 1 or 2 psi). I have about 3000 kms on the motor since the rebuild.

I thought the injectors were disabled, but it turns out they weren't. (not sure if this would have any effect.)

I needed an oil change anyway

Are these in the normal, ok range?

Currently running 16 psi for the last 1000 kms.

thanks,
Gary

 

Looks very good to me... seem like they are taking boost nicely.

 

Stock readings are between 199 and 213 PSI for 10.3:1 compression, so I would say you're doing fine.

When you do a compression check, make sure you pin the throttle WIDE OPEN. Have a buddy step on the gas while cranking.

If you can't disable the fuel pump, cheat and pull the injector wiring harness from each injector.

 

I don't want to hijack but is there a special tool that is needed for a compression check??

16 psi eh? Nice. According to the numbers that faith, and Random have posted recently, all your numbers look good.

 

Yep had the throttle wide open when doing the test. I had the injector disabled on the haltech but they never turnt off..sigh..maybe i never hit the right button. oh well.

thanks for the replies.

 

It's very easy to do and the tool you can buy from a parts store for around $15.
It's a great tool to have.

 

going further offtopic.. found a cheap on on eBay.

Compression tester Kit <--- click me!

 

good way to tell if u have good compression is that they are all close to eachother....