compression?? odd readings

WE3RX7 · 09-26-2008, 02:00 PM

My two cents on this....

The piston tester is ok for "general" assumptions. What it proves is that you haven't lossed a seal or one isnt stuck.

50psi is low, even for a cold engine so vex's suggestion of letting it pump up to the overall psi is a better assumption. for the s4 NA 100psi would be better, but 95 isn't the end of the world (but I would start saving for that rebuild).

I would not do the ATF/MMO/Water trick. In certain cases, this is acceptable such as a motor that has been sitting in storage or got completely locked. Its a last ditch effort for freeing an engine, but not something you should do on a running one primarily because what it can "free up" can also cause MORE damage to the seals/springs in the engine than good.

Start running premix 100:1 at least on the ratio, do regular oil changes and start saving.

This is all speaking from experience on two separate NA engines - so I'm sure some people have had different experiences...

09-26-2008, 02:00 PM	#19
WE3RX7 RCC Addict Join Date: Feb 2008 Location: VA Posts: 1,812 Rep Power: 19	My two cents on this.... The piston tester is ok for "general" assumptions. What it proves is that you haven't lossed a seal or one isnt stuck. 50psi is low, even for a cold engine so vex's suggestion of letting it pump up to the overall psi is a better assumption. for the s4 NA 100psi would be better, but 95 isn't the end of the world (but I would start saving for that rebuild). I would not do the ATF/MMO/Water trick. In certain cases, this is acceptable such as a motor that has been sitting in storage or got completely locked. Its a last ditch effort for freeing an engine, but not something you should do on a running one primarily because what it can "free up" can also cause MORE damage to the seals/springs in the engine than good. Start running premix 100:1 at least on the ratio, do regular oil changes and start saving. This is all speaking from experience on two separate NA engines - so I'm sure some people have had different experiences...