Cylinder Pressure test How too?

[supraguy31]

Hey all,
Well, Ive finally realized that after 10,000 miles on my engine ive started to get alot of Blowby (Oil) that is coming up through the valve cover PVC and into the Accordian Hose.

Im assuming that the Piston Rings didnt properly seat so I need to replace them.

Instead of Replacing all the Piston Rings, Can I just do a Compression test on each Cylinder to see which ones are bad and replace that set of Rings. Im going to get the entire set but I really dont have the time to pull every Piston and replace rings that arent bad.

Im going to replace all the Rod Bearings but that is the Extent of it. Would doing a Compression test tell me which ones are bad and which arent?

Thanks
Robert

 

[Allan_MA70]

you will need to hone the bore lightly as well.... full strip down time!

 

[supraguy31]

I thought so but I wasnt for sure if that is something that I would have to do. What about the Compression test thing though. Will that Detect what ones are bad and all?

Robert

 

[Suprapowaz!(2)]

They have a compression tester loan a tool at Autozone. http://autozone.com/servlet/UiBroke...&Parameters=Compression+Tester+Kit$CP7827$ACM
You pay for it up front, and get your money back when you return it. It's easy to perform the test. http://www.cygnusx1.net/supra/library/TSRM/em/EM_21.html
If the pressure is lower than TSRM recommended specs then perform a wet test. Simply unscrew the tester, pour a couple of ounces of oil into the spark plug hole, screw the tester back on and crank over the engine. If the pressure goes up then it's said to be the bottom end. If the compression remains the same then it could be the top end.

I did a compression on my engine. It was reading low number on number one cylinder. It read somewhere around 20psi. Did a wet test and the readings went up to around 90psi. Did a tear down and found it to be broken ring lands on #1 piston.

 

[supraguy31]

I can do that. I was Hoping that I could solve a little bit of clatter problem that I have By shimming my oil pump. We shimmed it when the Motor was first built but the Shim was too Big, Took it out and ever Since then, Ive gotten a Small clatter between 2000 and 3000 RPMs.

Long Story Short, After Putting another Shaller shim in last week, and Initially starting the car up, My oil Pressure will go up to Half gauge, Rev the motor and it goes over to about 3/4. Once you start to drive it, The oil Pressure will slowly start to Drop down to about 1/4 on the gauge and at Idle Im sitting almost on the LOW line. Im assuming that the lack of oil Pressure is due to....

1. Bad rings
2. Bad rod Bearings

Im replacing the bad Rings and Im replacing all the rod Bearings. Will this take care of the Oil Pressure Problem as well?

Robert