Swapped injectors and decided to do a compression test on the old girl with 210,000 miles.

#1 340 psi.
#2 335 psi.
#3 325 psi.
#4 375 psi.
#5 365 psi.
#6 340 psi.

Dodge FSM calls for a minimum of 350 psi and 70 psi max from weakest to strongest.

Those figures are for sea level and mine was tested at 5200 feet. Not sure how much to add to get accurate results.

Is it the same as figuring for drag racing at this elevation; 15%??????

If you decide to do the same I found that with all injectors removed, it takes 7 or 8 revolutions to get an accurate and consistant reading.

Six or less, the numbers could be way low.

 

looks perfect to me!!!

 

Atmospheric pressure at sea level is roughly 14.7 psi or 760 mmHg. At 5000ft the atmospheric pressure is roughly 12.25psi or 633.5 mmHg, so I would say with the numbers you recieved during your test at the higher elevation put you well within spec.

 

wish mine were that good.

 

Sound good to me, We did a compression test on my buddies 7.3 powerstroke that had 280,000 on it and it had anywhere from 190 to 240 psi. He had a bad knock and one cylinder was cracked.

 

was the engine warm or cold?

 

Also makes a difference if the cylinders were wet or bone dry.

My Mercedes manual said at LEAST 6 revolutions before taking a reading.

I didn't know the specs/tolerances for a Cummins... good to know. I have a diesel compression tester and just bought the Cummins B series adapter but havn't done it yet. My old Ford IDI 7.3 was just +/- 500psi, but she was 21.5:1 compression ratio. Surprised the heck out of me though!

 

Looks darn good to me too!


Turn the wick up in that ride
Chris

 

You guys really think this is good? I don't know. It is using a quart or two of oil between oil changes (3500-4000 miles).

I can turn the engine over by hand if I get under it and grab the balancer......little by little of course.

Would like to hear results from others.

The truck had cooled down a bit before testing. I would say the cylinder head felt like it was 90-100*.

What is the compression ratio of our 1st gens?

Did later generations come with higher or lower compression?

What is the spec for doing a compression test; revolutions or so many seconds?

I will look this up.

 

I'd say if you're above or around 350 you should be doing pretty well, especially at elevation.

 

Stock compression is 17.5:1. That's on my '93, not sure if the later version has a different ratio. And looking at your numbers, I'd say you're golden!

 

Some oil consumption is not a bad thing. Its when it gets to the point of having to add at every fillup. Even a gallon in the run of 5000 miles is not that bad. I have had diesels that were so worn it was a gallon every couple of days.

 

My ol girl has close to 300k on her, and she spins the belt everytime I shut her off. Ive never checked it, but Id say it fine the way it starts in the -15 degree weather!!

Id say your in good shape for being up in the altitude like that.

Kasey

 

I thought 2 quarts of oil every 4k miles was a built in feature

 

have you checked your turdbo for oil???