Hi All,

I have a 87 gl-10 with the turbo motor , it lost water and got pretty hot,enough to stop running, vapor lock i think. it did restart after cooling and sounded ok. compression test says around 50psi all cyl. and equal. that seems low to me even for turbo motor, is that near what to expect or what has been your experience on this . I found no sign of water in the motor, all had leaked from the tiny hose from block to water outlet.

Anyone know for sure what the pressure should be just cranking for compression test?

Happy holidays

Hi All,

I have a 87 gl-10 with the turbo motor , it lost water and got pretty hot,enough to stop running, vapor lock i think. it did restart after cooling and sounded ok. compression test says around 50psi all cyl. and equal. that seems low to me even for turbo motor, is that near what to expect or what has been your experience on this . I found no sign of water in the motor, all had leaked from the tiny hose from block to water outlet.

Anyone know for sure what the pressure should be just cranking for compression test?

Happy holidays

 

on 7.7:1 (oem) 145 psi at 350 rpm. 50 psi consistently is no doubt a guage problem (I would hope) , I do'nt know as the engine would even run that low.

should be higher than that, like he just mentioned.

was the car warm or cold when you tested it - it should be warm. remove all the spark plugs and prop open the throttle plate when testing - this will give you low readings if you don't. were those things done? i wouldn't suspect thsoe things to keep it down that much, but who knows. is your battery strong and firing the motor up without problems? a slow firing battery will reduce the readings as well because the psi measurements are based on a certain engine speed, if you're not reaching that speed due to a weak battery...readings will also suffer.

 

if the motor was blown, i wouldn't expect the same readings all the way around like that...50 on them all, very odd to not have some difference across cylinders. i'd suspect the gauge to be clogged with oil or something.

50psi, there's no way the engine would run. If it really is 50psi, you blew something (think, headgaskets). My XT Turbo tested out at 115psi when warm, which is just above the minimum (114psi).

 

Something's wrong, either your engine or your gauge.

Well, OK,

I thank you for the input I did have the throttle open, the battery up checked the belts for position. I came to the same conclusion, bad guage or bad engine, I'll check with another guage first, I knew that wasn't right.

Thanks again

Remove all the plugs, and disconnect the fuel pump when you are testing too. Unburned fuel will wash down the oil in the cylinders.

 

GD

Hot enough to stop running? That's frickin bad. you may have blown both head gaskets in which case you would get these numbers. put a little engine oil down the spark plug hole and test again, if it goes up you got bad rings. If it doesn't you may have blown the head gaskets. Possibly a stuck or burnt valve but that would be odd in all cylinders. But really if you get a motor that hot it's bound to be toast. Why didn't you shut it down before it got that hot is the question you should ask.