Had my compression checked....

[gsr916]

hopefully CBURKE reads this as well heh. i used about 3/4 quart of oil in 600 miles, so i assumed my compression would be bad. last week i had a killer exhaust leak and i had about had it with my exhaust rattles and didnt feel like using my trunk jack to jack it up and get under there cuz its a pain in the ass so i made an appointment with a mechanic i kno to just let him deal w/ it and put on stock exhaust. well i fixed the leak anyway so instead of cancling the appointment i just let him do compression check. im glad i did because there are 2 numbers to the compression test. The first shows how well the rings are sealing, and the 2nd shows the actual compression. My test:

- -DRY - - - WET<---(teaspoon of oil added)
1-120/210 150/270
2-120/210 130/250
3-120/210 130/270
4-120/210 150/260

My compression is damn near perfect (215 is ideal)... but i have a lot of blow by, because the rings arent sealing as well as they could be. im still getting enough seal to keep compression, so that is good. What pat (mechanic) said was that he thinks someone used fully synthetic oil in the engine when it was almost brand new, and because of that the rings never set in (never will either). Mentioned something about being glazed over as well... so maybe cburke, maybe u had the same thing happen lol. sucks knowing the rings didnt set completely, but its nice to know my compression is that high and consistant in all 4 cylinders.

anyway, thought some of u might be interested, if not i dont care anyway lol

[kornflakes28546]

so do you plan to replace the rings or just leave them alone for now?

[gsr916]

leave alone to help aid in my quest for a CBR

[Tano016]

Why are there two results for each the dry and wet test, whats the diffrence in the method of testing?

[casperGSR]

the wet test is after you add about a capful of oil into each cylinder... it's essentially the 'real' number because when the car is running the cylinder walls are lubricated with oil and the oil helps the rings seal the compression chamber

[gsr916]

i dont kno too much about that first number, he just said it measures the rings ability to seal. i thought the 2nd number did that too... honestly i dont know. he just told me that he doesnt think my rings ever set in and that they are polished to a mirror finish instead of them being set and thats how i have so much blow by. i wonder wut my compression is at like 7K rpm

[kornflakes28546]

Originally Posted by gsr916

i dont kno too much about that first number, he just said it measures the rings ability to seal. i thought the 2nd number did that too... honestly i dont know. he just told me that he doesnt think my rings ever set in and that they are polished to a mirror finish instead of them being set and thats how i have so much blow by. i wonder wut my compression is at like 7K rpm

i thought they did comp. tests at WOT?

[Tano016]

It is done at wide open throttle, but when you crank your engine at WOT during a compression test your engine only reaches about 250rpm, idealy your compression should be the same thoughout the rpm range. BTW if you read my previous question carefully i was asking why there are 2 Results for EACH the dry and wet test. It would be interessting to know, was a leakdown test done?

[gsr916]

yea i kno the first number in each he said measured the rings ability to seal i dont kno too much about that one... 2nd is the actual compression. no leakdown test done tho

[MODIFIED_GSR]

The Oil Does Increase The Compression Hes Right. Those Numbers Would Be The Real Numbers

[casperGSR]

the reason you would do the two tests is because if you get initial low readings during the dry test you can add a capful of oil and if the readings go up that generally indicates that the rings aren't sealing as best as they should.

[casperGSR]

however though if you add the capful of oil after the low readings and still get low readings with no real improvement then it may be something in the head like a bent valve... generally the purpose of doing the dry/wet test is to help establish if the rings are at fault for the low compression.

[gsr916]

well yea but there are 2 numbers for both dry and wet!

[casperGSR]

right because generally adding the oil will increase the compression numbers because it helps the rings seal