My buddy had a compression test done today and the numbers were 190 across the board.The shop told him the motor is bulit and they also said to him, due to the high numbers it read there's a bump up in compression ratio..Is this true??Also do bulit motors read higher then stock ones?Thanks.

 

If the motor has high compression pistons, or a decked head, Yes, the compression ratio will be higher. If the motor has stock compression pistons, it will not be higher. Sounds like it has like 10:1 pistons in it. Motor sounds healthy though.

 

Sounds correct what the shop said. Compression is surelly high.

 

?? Anyone else let's elbarote ..This was on a cold motor by the way

 

Anyone else knows. ?

 

Stock is 9:1 and around 175psi at sea level. My motor is 11:1 and 230psi at sea level.

 

Holy crap, failing all around in this thread.

Compression RATIO and compression PRESSURE are two different things.

 

Cam timing plays a major factor in building compression. You may have stock compression but altered valve events.... Something to look at of you tear into the motor

 

Bump on an old thread. What would make a stock block have higher compression pressure than normal?

 

Anything that makes the piston stroke longer or the combustion chamber smaller when the piston is at the top of its stroke.

 

So considering it's a stock block neither of those things would be possible...

 

Not necessarily, can be a stock block/head but if the head has been milled that would reduce the volume inside the chamber and in turn bump up the compression. All on what appears to be a completely stock setup.

 

I doubt that would be the case either. For my particular situation at least. Bought the car with 17k miles and I have not pulled the head since I have had the car.

 

What are the pressures you're getting?

 

195-200 across the board