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TonyL
10-28-2003, 07:18
I finaly did my compression test this morning, hers what I got:

1.320 psi
2.320 psi
3.300 psi
4.300.psi
5.320 psi
6.320 psi
7.340psi
8.300 psi

I want to get some more experienced opinions on the results. I ant remember for sure but i thought anyting over 300 was fairly good it is 83 6.2 odometer shows about 80,000 and i am sure its been around once.

Thanks
Tony
slagona
10-28-2003, 15:10
Your numbers are ok, but getting towards the low end of the spectrum. If it starts well in cold weather, you can probably let it go a while. It will also lose power as the numbers decrease.

If I remember correctly, anything around 280 is getting too weak. A new engine should be in the range of 400 or better. My 6.5 TD's cylinders read from 480 to 440.

My old 6.2 with unknown mileage wasn't starting well in cold weather - it had readings in the 300 to 380 range. I replaced it as it just wasn't starting in the winter.

--Scott
Ratau
10-29-2003, 01:50
At what engine temperature are one suppose to do the compression test (cold or warm)?
Danie
CleviteKid
10-29-2003, 16:36
Warm engine is recommended for compression tests.

Look at

http://www.matcotools.com/Catalog/toolcatalog***p?cattype=T&cat=2318&select=&page=2

for the Matco CT15 at a good price - you will also need the CT152 adapter on the page 1.

Dr. Lee :cool:
Deib
10-29-2003, 18:36
How did you measrue it?
Did you turn it over for 3 puffs, or is that the maximum it will achieve.

If that is 3 puffs, you have a little wear, but still lots of life.

If that is max it will build, well then start shopping.

At 240K miles I would get 310-330 on the 3 puff rule, but 400-420 for max pressure. That was over 30k ago.

Yes the engine should be tested warm, it seats the rings better, readings will be higher. I tested mine cold.
doncannon
10-30-2003, 20:21
Hello All,
what determines warm? would it be when the engine reaches it's operating temp while idling?
Also what is a puff?
Deib
10-31-2003, 19:06
Warm is described as running the engine for 10 minutes, up to normal operating temperature.
Basically they want you to get it too hot to work on, then pull the glow plugs and test compression.

If you are watching the needle it will bounce everytime the piston reaches Top Dead Center, Hence the term "PUFF"
TonyL
11-02-2003, 03:33
i tested mine cold as well and cranked it about fove seconds for eack cylinder.