I tested it dry and then squirted oil in there. This is my Jeeps 5.9 Magnum with 123k on it. I do believe the Jeep 5.9 has a higher compression ratio then the dodge because i have to use 93 octane

#1. 160, with oil 167

#2. 149, with oil 155

#3. 164, with oil 167

#4. 165, with oil 168

#5. 163, with oil 169

#6. 163, with oil 168

#7. 164, with oil 166

#8. 160, with oil 165


Is this ok ? Number 2 seems low, but it didnt Jump anymore then the others did with oil in it. I checked it twice to make sure and this was with a hot/warm engine. The spark plugs were clean, i didnt see any oil on them or even any carbon. Well #7-8 were a little dirty on the threads but not the actuall plug.

Here is what all the plugs looks like

http://i1083.photobucket.com/albums/...2/IMAG0070.jpg

This is what 7 and 8 look like

http://i1083.photobucket.com/albums/...2/IMAG0163.jpg

 

How many miles in the truck and the year ?

 

1998, Grand Cherokee 5.9 Limited, with 123,500 miles.

 

those numbers are awesome!

 

very awesome. drive on.

 

any ideas what the numbers are suppose to be ? Someone told me 160-170 is the compression from a new engine if so thats great. Im wondering tho why 1 cylinder is a tad lower then the rest.

 

Heheheheheheee... Because the valve seat has a crack... Sorry, couldn't resist... But, its likely true..

 

 

Different amounts of carbon on the valves.... you could try giving it a good seafoam treatment, and then running the test again..... might be enlightening. Or it may not....

Chrysler says, anything over 100 pounds is "acceptable", and all cylinders should be within 25% of each other. (which seems awful generous to me.... but, hey...... that's just me.) Your numbers look pretty good for an engine with over 100K on it.