Engine/Transmission (1994 - 1998) Compression Testing

[CToney]

Where can a guy get the tools to do a compression test? What is the normal compression? I am going to charge my injectors and just wanted to see if I have low compression in any cylinders. I hope that my headgasket is ok. I don't seem to have any bubbles in my antifreeze but the truck is hard to start and smokes too much when cold.





Thanks for the help



CR Toney

 

[JoeBioDiesel]

www.snapon.com or find a local Dealer to get it for you. You'll need the diesel compression tester and the correct adapter to make it work. Brace yourself for some sticker shock.

Joe

 

[HeavyHauler]

If you want to go with the fancy stuff, the Snap-on part numbers are below.



Compression gauge kit (0-800) - MT33C



Adapter for 89-98 12V - M3584



All that will run you over $250. Check around and see if anybody in your area has the tools. You might could borrow gauge and adapter. If you weren't 1800 miles away, I'd let you borrow mine. :-laf



Compression numbers reported on here always vary. It seems that most people come back with numbers in the high 400s and above.

 

[Graphic man]

Check E-bay... . do a search for "Cummins"



you will find a few kit's..... not sure if it would have the right Adapter or not



Scott

 

[DonTX]

Are you ever in luck. I bought a new compression tester when I was having fits with my motorhome cummins, and have no use for it. A new injection pump fixed the problem in fine shape, the comprssion tester has never been used, new in the box, works on lots of other diesels as well. $80 and its yours. It is NOT a snap-on brand.

 

[Vaughn MacKenzie]

When I tested mine it was 500-525psi per hole. This was on a 365k-mile motor. But after doing the test I found it you are supposed to take the reading on the 3rd compression hit, instead of letting it pump up to max after 5-6 hits like on a gasser. If a cylinder comes up slow then it's showing compression loss. I would do each cylinder 3 times and average it to get a good reading before moving on to the next hole. And practice a couple before actually "starting" your test.



Vaughn

 

[Graphic man]

When I tested mine it was 500-525psi per hole. This was on a 365k-mile motor. But after doing the test I found it you are supposed to take the reading on the 3 compression hit, instead of letting it pump up to max after 5-6 hits like on a gasser. If a cylinder comes up slow then it's showing compression loss. I would do each cylinder 3 times and average it to get a good reading, and practice a couple before making it "official. "



Vaughn

A leak down tester will give you a better reading



i used mine on my pro street car tons of times..... any more then 5% it got pulled



Scott