Compression tests???????
 

Finally home from Kuwait and did a compression test on the 307...

I have read different theories on compression tests and am looking for some input.

I used a new craftsman screw in gauge, took all the plugs out and left choke open for more air. -no oil in cylinders-

I got 155-165 in all. Does anybody know what these motors had when they were new? How bad is 155 on that motor?
Thanks for the input!



The 1947 - 1998 Chevrolet & GMC Pickup Message Board Network > 47 - Current classic GM Trucks > The 1967-1972 Chevrolet & GMC Pickups Message Board
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Forum: The 1967-1972 Chevrolet & GMC Pickups Message Board Post New Thread

Re: Compression tests???????
 

I have been hoping for a more specific answer, too. My Haynes manual only lists 150psi, with 20psi max variation between cylinders, for V6 and V8 engines. Nothing specific for each displacement size.

I have original shop service manuals from 68 that I bought off of Ebay. The only note about compression is the same thing. 150psi w/ 20psi variation.

Re: Compression tests???????
 

you have a higher compression rate from carbon build up , sea foam could help .

Re: Compression tests???????
 

That looks about right for a stock 307, but the main thing to look for is a big variation between cylinders. 10 psi differnce is pretty good.

Re: Compression tests???????
 

You are still in good shape those readings.

Re: Compression tests???????
 

You are good to go with those numbers. As stated: The concern is the difference between the readings.:bowtie:

Re: Compression tests???????
 

Sounds like good numbers for an 87-89 octane capable engine. Good variation. No worries! :metal:

Re: Compression tests???????
 

You are "good to go".....a fresh 327(+ 040 on the bore, with Fuelie heads & a mild cam) was 160-170 psi. Man did that F...er run good! :crazy: L