What's up guys I just recently purchased a 1jzgte from jdm engine zone upon arrival I tested the compression and got these numbers I personally think this is bad but maybe I'm overthinking it? CYL1-130psi CYL2-130psi CYL3-135psi CLY4-140psi CLY5-135psi CLY6-140psi I sent the results to jdm engine zone and they told me "These are great numbers for a cold engine" "Keep in mind this is a turbo engine and has not been run to achieve operating temperature Those numbers for a cold engine are great". How many of you would return it and or run it and see if the numbers change?

 

How many times did you let it crank?

I made the mistake of only cranking 3-4 times and got 150psi on a 2jzge and when I went back and did it correctly I got 185 when I did 6-7 cranks.

 

7 times iirc also the motor isn't good I just had a shop compression test it and cylinder 1 read 90psi then it maxed out at 120psi the rest of the cylinders were spot on

 

Ah, that's too bad. Are you going to rebuild it? If you have the funds might be good time to make improvements.

 

Nah I'm going to have the motor company swap it out for another engine that's actually healthy.

 

so I redid the test with a compression tester that has a shrader valve and I got better results only weird thing is cylinder 1 starts off low at 105 then after each retest it goes as high as 150 if I let it keep cranking it looks like it wants to go more higher but Im confused as what this actually means? I got Cylinder 2-170psi cylinder 3-175psi cylinder 4-180psi cylinder 5-180psi cylinder 6-175... Cylinder 1 is the only thing going low then high any help would be appreciated

 

Is the throttle body on the engine? If so did you have it propped wide open?

 

No it's not propped open while I do the test. But wouldn't that affect the other reading from 2-6? Why just 1? I'm genuinely confused because it starts off at 105 then as I retest each time it goes higher and higher. And that's letting it turn over about 7 times.

 

so I just retested it and it settled around 155 this time and that's a wet test

 

Have to let the engine breath when doing compression tests or you'll get inconsistent results. Wait awhile then do the test again don't add oil. If test goes up when adding oil on a particular cylinder there is probably a ring problem.

Other factors to consider are altitude and the compression gauge itself.

 

see that's the thing. All other cylinders are healthy it's just that 1 cylinder acting up. I went from using a harbour freight one to a tester that has a shrader valve

 

That's not a good sign but it could be one ring set has carbon and isn't seating properly. In theory anyway, with all my experience with Toyota engines (quite a few) I have yet to see a ring problem that went away after awhile. It was either good or bad.

Forgot to say, do a leak down test it's easy and revealing. Pressurize the cylinders and time how long the gauge drops. Also find out where air is leaking, into the crank case is rings into the exhaust/intake is valves. Some leakage past the rings is normal of course, past the valves no it should be very little and slow.

 

yeah cause after all it has been sitting for god knows how long. What would you do in my situation? I contacted the engine place I got it from and they are telling me they won't accept it back because I already "began working on it and I could have done something to cause it to have low compression" which makes no sense and I'm heated but could I end up replacing that 1 piston head and be good since the rest are technically healthy all reading 170-180..?

 

Do a leak down test first. If you have to tear down the engine that's a can of worms. Do you replace just rings on one piston? All rings? Also bearings? Valve stem seals? Refresh everything? I have heard of broken rings and ring lands on these engines but I would expect that to cause very low compression.

 

yeah see that's what I'm not worried about since the rest of the cylinders are already reading high compression that is within healthy readings it's just that one. Also Im already refreshing the motor aka seals and water pump cam seals basically everything also trying to figure out how true that saying is about japanese motors being low miles..