Compression high enough

[Drewfinn]

Hey Folks, I'm just looking for some verification. I'm running a Model A block, stock pistons, with a 6:1 Snyders head. I'm getting a even 95-96 psi across the board, warm, at 1300 feet above sea level. Is it high enough?

 

[J Franklin]

Yes.

 

[Drewfinn]

Thank you.

 

[old31]

Yes x2. It's very good.

 

[old31]

I just picked up a roadster to tinker with. It runs pretty good in town and highway at 55mph.

I checked the compression and was surprised that it was only 35psi across the board.

 

[Fullraceflathead]

That sounds like a stock head with a slightly weak motor or you don't have the throttle open during the compression test.

 

[BButturff]

I just picked up a roadster to tinker with. It runs pretty good in town and highway at 55mph.

I checked the compression and was surprised that it was only 35psi across the board.

I have a compression tester from the early 1970's that recently began to gradually leak air after testing. Not knowing any better, I replaced the leaking valve core with a brand new one from my collection of tire valve cores. Then I found out they are not even close to being the same.


With a tire valve core installed my model A engine tested at 25psi across all cylinders even though it started and ran great. I replaced the valve core with a Lisle 20100 compression tester valve core and it tested at 65psi across all cylinders.


Lesson learned......

 

[old31]

Fullrace, you are correct that I forgot to have the throttle wide open. I knew I had forgotten this and decided that it probably would not make much of a difference.