Factory 60k 4g63 toast?

[KrazyRob]

I have a 99 GSX with 60k miles.. It has some mild mods.. HMI EVO 16g turbo, Had a blown head gasket when i bought the car, had the head resurfaced and installed a Felpro head gasket and torqued to specs, put a new timing belt and water pump..... After the repair we did a compression test and it had 170 psi on all cyls.. I have drove the car as a daily driver for about a year now, i dont race the car pretty much baby it... Any way last night i went out to start the car and when i turned the motor over to start it, it would not start it sounded like the car had no compression and that maybe the timing belt broke or came off, all i could think about was bent valves.. I took off the timing cover on top of the motor and found that the timing belt was still on and tight i thought for sure that it had came off.. Then i went and did a compression check on all cyls and found out bad news.. The compression readings were 55psi, 40psi, 40psi, 70psi... The readings were steady at that pressure and didnt seem to fall...

I do not understand what has happened here.. The car was running perfect when i parked it in that spot a few days ago, you would think i would have noticed the car running poor as the compression was slowly getting low.. It went from running great with strong boost, to parking it for a few days to a dead motor. How does this happen? Im stumped.. I thought maybe it was a lack of oil issue that chowed the rings, or a head gasket leak around a cyl or 2 but not all. Lucky i have a spare car to drive to work, but this sucks.. what do you think has happened here.. I really dont want to tear this 60k motor down...

 

[silvreclips]

sounds like you did a cold compression test, numbers will come up on a hot motor but not that much. Add a capful of oil to each cylinder and try again, if the numbers come up significantly this tells you its the rings, if it doesnt come up any than the problem lies with the head or headgasket.

 

[Xit40]

Do a leakdown test and determine where the air is escaping. There are only a couple choices: Intake/exhaust valves, rings/cylinder walls and head gasket. That will go a long way to determining what happened and your course of action.

 

[black_eclipse96]

Have you checked to see if your still in time? Timing being off a couple teeth would cause low compression.

 

[KrazyRob]

I did not add oil to the cyl good point and it was cold.. It was like i turned the key to a different motor than im used to something mechanically happend when i turning the key.. It sounded different.. Im wondering if it did jump out of time cause that was the first thing i thought, that the timing belt had came off.. The car did not even try to start or stumble.. It was like i had the spark plugs removed and coil unhooked as i turned over the motor.... Its a 105 degrees today, when it cools down im going to go out there and put the motor on TDC and check the timing.. I really hope this is the issue now that you say off timing causes low compression...

 

[Xit40]

Definitely check your timing. I thought you did already, but you just said the belt was tight. Pray that your timing is correct or close to correct. If it's off more than a tooth or 2 valve to piston contact has probably happened. Please don't ask how I know.

Please also try to use good grammar. It is difficult to help when everything is crammed together in one paragraph with run on sentences.

 

[curt-s]

sounds like you did a cold compression test, numbers will come up on a hot motor but not that much. Add a capful of oil to each cylinder and try again, if the numbers come up significantly this tells you its the rings, if it doesnt come up any than the problem lies with the head or headgasket.

Oil will usually sit in the dish of the piston, not really doing anything but falsely raising compression because of less space. You have to be lucky or crafty to actually get it around the entire skirt.