602 crate cranking pressure?

evilbanshee · Post by **evilbanshee** » Wed Jul 30, 2014 12:26 pm

Buddy has a 602 Gm crate for circle track.

Its about 10 years old, We are wondering if its getting seasoned.

Put the Gauge in 3 different cylinders, They range from 45-55psi??? LOW?

So we bring the same gauge to a friends shop who has a new 602 crate with only 1 season on it, Same thing. 55psi??

Is this SNAP-on gauge really messed up? orr... ? do they just make nothing for cylinder pressure?

Fordracer347 · Post by **Fordracer347** » Wed Jul 30, 2014 12:41 pm

Our MAC compression tester was showing some funky readings until we replaced the valve stem check valve in it. If you really want a check, pop a sparkplug on your truck and see.

evilbanshee · Post by **evilbanshee** » Wed Jul 30, 2014 12:49 pm

we did replace the valve for fun. Read the same??

I would imagine those engines would have been 150psi or so?

Fordracer347 · Post by **Fordracer347** » Wed Jul 30, 2014 1:18 pm

If its running halfway decent its going to have more than 50 PSI cranking pressure. I'd try another tester, the parts store has a free tool rental program you can use.

CNC BLOCKS · Post by **CNC BLOCKS** » Wed Jul 30, 2014 1:23 pm

Try it a WOT.

user-612937456 · Post by **user-612937456** » Wed Jul 30, 2014 6:57 pm

usually an engine will not even start below 70-80 psi

adam728 · Post by **adam728** » Wed Jul 30, 2014 7:35 pm

CNC BLOCKS wrote:Try it a WOT.

That's what I was thinking. I've seen many times a compression test done at idle and the results come out half or much less than a proper test.

rp930 · Post by **rp930** » Wed Jul 30, 2014 8:11 pm

Put a little oil in the cylinder and see if it comes up. Cranking speed ok?

evilbanshee · Post by **evilbanshee** » Thu Jul 31, 2014 7:57 am

ya cranking speed is normal, ( healthy battery in both cars)

Ill try another tester, and at WOT.

both engines run good. Lots of oil pressure

swatson454 · Post by **swatson454** » Thu Jul 31, 2014 8:35 am

At operating temp, too, if you're able to do so.

Shawn

MadBill · Post by **MadBill** » Thu Jul 31, 2014 1:23 pm

evilbanshee wrote:we did replace the valve for fun. Read the same??

I would imagine those engines would have been 150psi or so?

Tire Schrader valves have way too stiff a spring to give accurate compression tester readings...

evilbanshee · Post by **evilbanshee** » Fri Aug 01, 2014 8:23 pm

the gauge turned out to be junk.

havent tried a different gauge yet.

MadBill · Post by **MadBill** » Sat Aug 02, 2014 12:02 am

You likely don't need a new gauge, just install the correct Schrader valve for under a dollar. Compression tester check valves are pretty well all interchangeable; the Snap On p.n. is MT24DA1.

Don Terrill’s Speed-Talk

602 crate cranking pressure?

602 crate cranking pressure?

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