Upsetting Results Of Compression Test, Need Help

[9TalonNT6]

Hey i just did a compression test on the 1990 GST 5speed 248k (was told it was rebuilt at 180k but i dont think so) i just got picked up for 400.00, so here are the numbers:
cyl 1: 125 Psi
cyl 2: 125 Psi
cyl 3: 120 Psi
cyl 4: 8 Psi (did the test 3 times because i couldnt believe it myself)

car idles rough similar to alot of 1g's but drives decent out of first gear. How long do you think this motor has until its junk?

 

[95AWD6Bolt]

If you got it for only 400 and if its not your daily, I would just beat on it till it blows up and then either rebuild it or buy a new engine for it. However, this is why you always, always, always do a compression test before you buy a used car, especially a dsm. I had this happen to me also, only the results came back worse....70's across the board. I dont know how it will run but when I drove mine with 70 across the board it ran and drove fine. Just had a little idle issues. Good Luck.

 

[endeffect0]

Throw some oil in the dead cylinder and see if it's a piston ring if it is... well its kinda dead already but if the compression doesn't improve it might just be a head gasket leaking on that cylinder in which case you could just throw a new head gasket and get a long life out of it yet.

 

[Bmxr152]

also try a leakdown test to see if it might have something to do with the head since it migh be original. I know the motor was done but was the head done with it? Also make sure the car is at normal temp when doing the compression check.

 

[9TalonNT6]

thanks for the help, im going do a CLT on it tomorrow, and ill post my findings

 

[9TalonNT6]

So i did the test and it was the rings time for a tear down

 

[IslandTSI]

Ive seen engines be rehoned and freshened up with the block still in the car and then go on to last for another 50,000km. Its just a worn set of rings most likely. Pull the head, drop the pan. Pull out the rods/pistons. Rehone the cylinders, put on new rings reinstall and you're back on the road.

 

[9TalonNT6]

Thanks for the info man, Do you think i should do all the rings while im in there? Also about honing can i buy a tool for that or? Any additional information will help. Thanks

 

[Dream On]

http://www.aa1car.com/library/2002/eb110242.htm

 

[coryd]

how do u know its the ring for sure??? did u do that wet compression test?? what was the number after? what was you leakdown test results?? when u were doing the leak down test where was the air coming out?? if it wasnt coming out of you dipstick or oil cap then you rings are fine

 

[Bmxr152]

I just honed out my cylinders, put new rod bearigns, Wiseco pistons, Arp head studs, and the Mitsu MLS head gasket all with the block still in the car and have put around 25,000 miles on it, with no problems. One sugestion if your going to rebuild the motor i wouldnt slim out on parts. I kinda wish i would of spent $300 more and got some kind aftermarket rods.