Joined: Mar 12, 2008 Posts: 92 Location: Oro Valley, Arizona
Posted: Tue Oct 09, 2012 6:55 pm Post subject: Engine comprssion
What is the min compression in an old engine that has never been rebuilt. Trying to decide if I should do a rebiuld or try to fix the little things in the engine to make it run. Thank you _________________ Mario
U.S. Army
The actual number is not as important as the relative numbers between the 4 cylinders. The Book gives you a minimum of 100 PSI with 135 as the norm. It also suggests that there should not be a difference between cylinders of more than 20 PSI.
You should include the vacuum test on page 80 before making a final decision.
If you do not mind a lack of performance then you could tolerate compressions as low as 80 PSI as long as each cylinder is with 10 PSI of the others. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Do the vacuum test and a leak down test before you tear down the engine. This will give you valuable information to use as you inspect the disassembled engine and help you avoid overlooking any needed repairs. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum