my compression test results!!

Status
Not open for further replies.
Joined
Apr 28, 2011
Messages
3,894
Location
missouri usa
Here's the compression results on a cold 1.9l dohc Saturn engine . I did exactly by saturn specs crank it with fuel pump fuse out and coil unplugged, gas pedal at wot. And ten revolutions. My 1st: 196 2:196 3:194 4:195 my car has 192,000 on it. I didn't bother doing a wet compression test because those numbers seemed pretty decent. I'm not sure what they should be exactly but they seem decent. Thanks all any comments questions concerns are welcome.
 
Yea not bad for a pos plastic fendered tupperware car.
smile.gif
I wonder what they would be new.
 
WoW those numbers are very close. I dont think ive ever seen numbers that close. How long did it take to reach the highest psi? I cant seem to find any specs on it but they seem high enough.
 
I let it crank ten times because that's what Saturn says to do but it reached the highest around 4 or 5 times.
 
My 92 Aerostar tested (one cylinder) 135 psi when I bought it at 27,000 miles. Has run steady and strong for over 100,000 miles since, though used a quart of oil every 1300 miles. Your compression is excellent. Should be little oil consumption and no need to add during an OCI with your engine.
 
That's why I tested compression because It uses oil. Apparently the oil control rings are the problem and it can still have great compression . I changed my pcv to I'm hoping that was a lot of my oil consumption problem.
 
My recollection from the old days was that the compression should reach 90% of that cylinder Max by the 3d pressure stroke. Your compression results look almost to good to be real.
 
Sounds pretty good to me. I had a Saturn, and it burned oil too. Makes me wonder: if you are burning oil, then perhaps it is either the oil control ring being overwhelmed, or perhaps too much cranckase pressure?
 
It's the oil rings. I just scrapped a SC2 where the compression rings were still springy after an unknown catastrophe, probably serious overheating, warped everything else in the motor.
 
Hope you weren't scraping it for money by metal weight whole [censored] thing is plastic
smile.gif
yes that was mostly a funny but there is some truth. My pcv wasn't nearly as good as new so i do hope it helps. Is there any real way to know its the oil cntrl rings and not valve seals/ guides or pcv valve?
 
Originally Posted By: chevyboy14
That's why I tested compression because It uses oil.
What is the consumption rate? If no blue smoke at tailpipe,
then I would just keep topping up and run 'er hard.
grin.gif
 
I can do a compression test while changing spark plugs! Cold engine, etc. Perhaps even incorporate a piston soak (adding a day, letting it soak in there) to the procedure.
smile.gif


So you have all the spark plugs out when you do a compression test? Or do you have the other spark plugs IN? Im rusty on this.
 
Originally Posted By: chevyboy14
Hope you weren't scraping it for money by metal weight whole [censored] thing is plastic
smile.gif
yes that was mostly a funny but there is some truth. My pcv wasn't nearly as good as new so i do hope it helps. Is there any real way to know its the oil cntrl rings and not valve seals/ guides or pcv valve?


No. You can idle and oil will work its way up past the rings but idle combustion temps are low and it will just pool on top of the pistons. Then when you hit the gas it burns off in quite a smoke show and people will say "oh, it's your valve seals for sure, the vacuum was holding it back", but, nope, it's your rings. Think they use Viton seals. I tried doing seals once with the head in place and got nowhere with my consumption. But it's easy on a SOHC.

32.gif
The car I scrapped, I put on craigslist, and a father/son team responded. Son read the ad but missed the part where the cat convertor and some other parts were not included with sale. They loaded it up on their trailer and paid/ got the title then asked about it... sorry guys. Figure son had a nice quiet ride home in the cab of their truck.
 
All spark plugs out. About a quart every 1300 miles with 10w40 about half of that with 5w30 I was starting to get some smoke I think that my pcv was the Issue for that i changed it and it doesn't smoke now
 
Someplace, somewhere, I recall reading someone using Marvel Mystery oil to unblock the drain holes in the pistons. Apparently Saturn used small diameter holes whereas everyone else uses slots. The least amount of crud there causes the rings to not be able to handle the oil. Not sure how, maybe it was MM and ATF, idle at temp, then flush? Don't remember now. But I recall that theory (bad drain holes) as being a possible reason for so many Saturns drinking oil.
 
Status
Not open for further replies.
Back
Top