How can you tell if your piston rings are bad?
#11
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Someone once told me to do the compression test, then put a SMALL amount of oil in the cylinder, and if the pressure reading jumps significantly, your rings are going. (The oil that isnt normally on top of the piston will seal the rings for the test)
#12
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Originally Posted by DSMtuner
Someone once told me to do the compression test, then put a SMALL amount of oil in the cylinder, and if the pressure reading jumps significantly, your rings are going. (The oil that isnt normally on top of the piston will seal the rings for the test)
There are some exceptions to that rule, though. You have to keep in mind that there are two functions that the rings serve: compression and scraping the oil off the cylinder walls. The bottom rings scrape and the first ring holds the compression, so you might have good compression but are burning a lot of oil and that is due to bad oil control rings, not compression rings, so the compression test will mean nothing to you.
I had perfect compression on mine, but I was going through a quart a week, so it wasn't the first ring, but rather the 4 underneath it.
#13
Originally Posted by Däs Schmoo
That is a wet compression test.
There are some exceptions to that rule, though. You have to keep in mind that there are two functions that the rings serve: compression and scraping the oil off the cylinder walls. The bottom rings scrape and the first ring holds the compression, so you might have good compression but are burning a lot of oil and that is due to bad oil control rings, not compression rings, so the compression test will mean nothing to you.
I had perfect compression on mine, but I was going through a quart a week, so it wasn't the first ring, but rather the 4 underneath it.
There are some exceptions to that rule, though. You have to keep in mind that there are two functions that the rings serve: compression and scraping the oil off the cylinder walls. The bottom rings scrape and the first ring holds the compression, so you might have good compression but are burning a lot of oil and that is due to bad oil control rings, not compression rings, so the compression test will mean nothing to you.
I had perfect compression on mine, but I was going through a quart a week, so it wasn't the first ring, but rather the 4 underneath it.