Compression Questions

[BigD_83]

If you have a compressor with some quick connects and a decent hardware store nearby, you can make a leakdown tester for around $40.00. Here is one plan I have seen that is fairly simple. The hardest thing for me to track down was the female T required:

http://www.motorcycleproject.com/motorcycle/text/leakdown.html

[Normk]

One tip regarding the Schrader valve cores used in compression testers: they are not the same as tire valve cores. The most obvious difference is the much weaker coil spring used on the compression tester valve core. Use a tire valve core and you'll read 30-40 PSI lower than it should be on a compression test.

A leakdown tester is easy to make, and although I used to own a tool business it was much more cost effective to make one as suggested.

Keep in mind though, a compression test or leakdown test will indicate compression sealing problems but not oil control problems. A good compression or leakdown indication does not prove anything regarding oil control/oil burning.

Took me a bit to test it again. The compression tester I was using didn't have a valve in it so I bought a new one. HOT+WOT= #1 110PSI #2 100PSI #3 90PSI #4 110PSI. #3 scares me. The book says 114-170PSI on a fresh rebuild. 100PSI limit and 28PSI difference.

[daturat100r]

New set of rings in an unhoned bore can almost guarantee a low comp reading and increase of oil consumption till/if they manage to bed in.
Not that i would ever dream of doing it to my engine but i have seen my uncle pour a teaspoon of brasso polish down the plug holes of an engine which completely seated the rings in a worn engine and stopped the clouds of smoke pouring out the back.Did not last very long though just long enough to sell the car.
You could just keep running it and try to get the rings to bed and maybe replace the oil with a plain running in oil to help things on a little

[hampshirehog]

Not that i would ever dream of doing it to my engine but i have seen my uncle pour a teaspoon of brasso polish down the plug holes of an engine which completely seated the rings in a worn engine and stopped the clouds of smoke pouring out the back.Did not last very long though just long enough to sell the car.

I had almost forgotten about the Brasso trick and it's funny to hear it travelled across the globe. The old car auctions were full of cars treated like this by the sellers and you could spot the buyers with their little bottles of brake fluid trying to do the opposite. Drop of brake fluid in a near empty tank will make an engine smoke like it's going out of fashion.