Would these 2 be related? I.e. Could the crack be causing the low compression?

Truck is a 90 p/u 22re auto 4x4.

My motor bit the dirt so I picked up another truck that was wrecked which had a motor from Toyota 2 yrs prior to me picking it up.

When I went to check out the motor the guy dropped in a battery. Let me know it had been sitting for 4-5 months and if it doesn't crank right away. That's why. Well it fired right up. Spunded great. No valve tick (suprising huh?) so I asked if he could run a compression test just to be sure. He said no problem checked it and compression was from front to back

150-120-150-120 I think that's what it was

Well I talked him down a bit and got the whole truck. Drove it onto a trailer.

I was hoping that with it being a new motor not smoking amd being suprisingly great running it was just a little carbon build up in the valves and a little run time it would be good to go.

Well I got the motor installed and ran it for a few weeks. The motor runs so good. Idles great so I was hoping for great news this afternoon.
Well hooked up the compression tester and 120-60 and I stopped there.

I'm stumped. With compression like that you would think it wouldn't run. Or have the power to spin 35's in dirt. But it does. It runs great but yet is 110 psi off.

The timing cover is cracked along the side. And will drop a drop of oil every 5 seconds while ruNning.

Could valves be so far out of adjustment its that low? Losing compression out of the timing cover?

HELP PLEASE! What do I do?

 

First thing you gotta do is get yourself a new valve cover.

 

Valve cover or timing cover?

 

Timing cover.

 

Could be carbon build up on the valves from it sitting too long and keeping the valves from fully closing. How many times are you cranking the engine before checking the compression. IIRC it should be about 2-4 turns from TDC? It's also not 110 psi off. But that could have been a typo on your part. A stock engine shouldn't be any more than 171 psi, and I think the lowest spec is actually 142 psi according to the FSM with no more than 14 psi between cyls.

 

Hey Xxx I didn't do any tdc check before checking. Screwed in tester and gave it 4-5 good revolutions. Both with throttle wide open. Partially open and closed. It didn't change anything.

 

no need to do any TDC stuff, if you gave it a good 4-5 revs then that isn't causing an issue. maybe a faulty gauge?

 

Well I considered that but if its off on one reading it would be off on the other right?

So regardless if I am 50 psi off I'm still WAYYY off in the other so I assumed it would be more to it.

I never get off that easy. Ever lol.

Honestly could a combination of carbon build up and valves out of spec be causing that much loss. And if it does why does it have enough power to spin the 35's. Or run as seemingly flawless as possible?

 

That's a good question. I have no idea. lol.

That's like me, how can I have 170+ PSI across all cyls and still have what I consider excessive blowby without having high compression pistons and a brand new (well 10,000 mile new) fully assembled cyl head.

 

Just ran a WHOLE can of seafoam through brake booster line. Half can at once half can second time.

Smoked a good bit, runs a little better, but cyl 1 showed a whopping 120psi...again.

Didn't go any further with the comp. Test.

What do I do?

 

Oops meant timing cover

 

put about a teaspoon full of oil through the spark plug hole and take another compression test. If compression goes up then your rings are bad, if it stays the same then its a valve not sealing or a headgasket.

 

could it be the headgasket even though im not mixing any coolant vs. oil?

cyl 1&3 are the same cyl 2&4 are the same.


could the valves not sealing make up for 110PSI?

 

110psi? The highest you should see is 170 psi your seeing 150 and 120. I doubt it's a head gasket since your not getting other signs. I would say it could be if it were 1 and 2 or 3 and 4 that were the same, but all 4 are low. But the chance the headgasket is bad between 1 and 2 / 3 and 4 at the same time is very slim.

Now if it does go up it can be an intake or exhaust valve. The only way to tell that is to get compressed air into the cyl through the spark plug hole and use your ear, if you can hear air escaping through the exhaust then it would be the exhaust valve, if you hear it though the throttle body then it would be an intake valve.

I'd like to add it's not a bad valve seal as a bad valve seal wouldn't affect compression.

 

i have 60 psi in cyl 2 (Assuming cyl 4 has 60 as well becuase initial test showed 2 & 4 the same, and 1 & 3 being the same)

 

oh ok, yeah I see that now, missed it the first time. I only seen the 150 - 120 - 150 - 120. Sorry for the confusion. I do that sometimes. lol.