Leak Down Tester?

[Hudson]

Yes i did the combustion leak test with the engine running for about 15 minutes. Was at operating temperature. Sucked about 4" of coolant out of the radiator fill cap, and put the tester in, and let it suck air. I even saw the steam or whatever was rising into the test tube. Didn't change colors or anything.

Is it possible that i have a bad intake valve on cylinder #1? If so, how do i check for this? I can't for the life of me get air to stop coming out of the intake. I have been constantly feeding air into the cylinder, and watching the gauge. I can see the gauge begin to rise in pressure, but at no time does air stop coming out of the intake.

I'm going to see if i have any better luck in the second cylinder.

Is the intake rocker the closer one to me, or the farther one away? I'm assuming when it rocks up the valve is closed, and when it's down all the way, it's open, correct?

Here's a picture of where i think the crack in the head is. Does this look like a crack to you?

I began removing parts from the jeep to make the head easier to pull. Am currently soaking the exhaust manifold in kroil so it gets nice and loose for me.

I just saw the crank mark. Should i line it up that little notch in the pulley at 4 (like in the picture) or at 0?

I feel dumb.

[ct67_72]

Cant tell in the pic. When the valve is open the valve spring will be compressed.
If both are even, set the mark on the crank to 0. That is 0 degrees before or after TDC. Or TDC. Set it there and see how much leakdown you have. If its still high but less than 90-95% or whatever you had than there probably is an issue with the intake valve or cylinder head.
From google images the exhaust looks to be the first port on the head. so on no.1 the rocker closest to the radiator is exhaust, the second rocker intake. You should be able to basically line up the port of the intake or exhaust manifold and the rocker/valve.

[Hudson]

Cant tell in the pic. When the valve is open the valve spring will be compressed.
If both are even, set the mark on the crank to 0. That is 0 degrees before or after TDC. Or TDC. Set it there and see how much leakdown you have. If its still high but less than 90-95% or whatever you had than there probably is an issue with the intake valve or cylinder head.
From google images the exhaust looks to be the first port on the head. so on no.1 the rocker closest to the radiator is exhaust, the second rocker intake. You should be able to basically line up the port of the intake or exhaust manifold and the rocker/valve.

That's a picture of where i think the crack is. Does that look like a crack to you?

Cylinder two worked A LOT better.

Put in 30PSI and it held 20PSI. That's 33.4% leakage. Which is still terrible.

Going to continue doing this down the cylinders and see what it's looking like. Cylinder #1 is not holding anything.

Lets say i get the same results for every cylinder. Does that mean my head is shot, or does that mean something worse? Possible to have a bad intake valve on cylinder #1? How would i check for that?

[ct67_72]

Sounds like your going to end up pulling the head. Did you try and air up cylinder #2 more than that? That isnt a lot.
If cylinder 1 is that bad it should have low compression too. Check it and see. If it is in fact low that would confirm your leakdown findings.

[Hudson]

Sounds like your going to end up pulling the head. Did you try and air up cylinder #2 more than that? That isnt a lot.
If cylinder 1 is that bad it should have low compression too. Check it and see. If it is in fact low that would confirm your leakdown findings.

I'm honestly not trusting myself. I'm going to go buy a vacuum gauge tomorrow and hook that up to my spark plug contraption.

That way when i turn the crank, if there is pressure it's the compression stroke, if it's the vacuum it's going down on the intake stroke. I just stop it right before it switches to the vacuum stroke, and i will have a true TDC.

That way i can actually tell if i am performing this test on TDC or not.

I think i hit TDC on the #2 cylinder, and i tried it up to 100PSI, and i heard this pop, so i instantly cranked off on the pressure. Put 30 pounds in the cylinder, and it went to 20, so i don't think i broke anything.

I'm just questioning the accuracy of my gauge.

I can't do a compression test. There is no oil in the jeep, and i have just about everything in the front of the engine removed. Radiator, serp belt, A/C compressor, a/c pulley, Ps pump, etc etc.

[ct67_72]

If you reference my earlier post its pretty fool proof. You can determine which stroke the engine is on by watching the valves open/close.
You can also put your finger over the spark plug hole. As the cylinder comes up on compression it will push air out. When you feel it pushing air out watch the crank for the mark to come up and line up the marks to 0.

[Hudson]

If you reference my earlier post its pretty fool proof. You can determine which stroke the engine is on by watching the valves open/close.
You can also put your finger over the spark plug hole. As the cylinder comes up on compression it will push air out. When you feel it pushing air out watch the crank for the mark to come up and line up the marks to 0.

That makes perfect sense now. Just figured it out and a lightbulb went off.

I'm going to record me doing every cylinder.

I know for fact i'm on TDC on #1, and air is just blowing out the intake.

[ct67_72]

Well, since you are most likely going to have to do it anyway. You can always just unbolt the rockers. Or loosen them enough to have no pressure on the valve. Then it doesnt matter where the piston is in its stroke. The valve will be closed no matter what. They are non-adjustable so if you unbolt them, its simply a matter of bolting them back down.
Just make sure to not mix them up. Rockers stay in their same original location, as well as the pivot washers.

If you still have leakage, than its definitely an internal problem. If it is still coming from the intake, than I would suspect a bad valve. Either way at that point the head will have to come off

[Hudson]

Well, since you are most likely going to have to do it anyway. You can always just unbolt the rockers. Or loosen them enough to have no pressure on the valve. Then it doesnt matter where the piston is in its stroke. The valve will be closed no matter what. They are non-adjustable so if you unbolt them, its simply a matter of bolting them back down.
Just make sure to not mix them up. Rockers stay in their same original location, as well as the pivot washers.

If you still have leakage, than its definitely an internal problem. If it is still coming from the intake, than I would suspect a bad valve. Either way at that point the head will have to come off

I have a video but i'll sum it up.

I'm positive i'm on TDC now. Put air into the cylinder, and it leaks out through the intake, and i realized it's also coming out of the 3rd spark plug hole. (Would that lead you to believe a cracked head or bad HG?)

I know i'm going to have to pull the head, i'm just trying to figure out what is actually wrong.

I think i might of mentioned it before, but if i didn't i'll mention it again.

I HAVE NEVER EVER REMOVED A VALVE COVER BEFORE. I know nothing about the internals of an engine. I'm trying to soak this up as fast as i can, and i really appreciate your patience here.

I just took a picture. Can you please dummy down instructions on how to close the valves permanently so i don't need TDC so i can see if it's still leaking?

Do i simply just remove the bolts i've circled, and the valves are now "closed"? Or is a bit more complicated than that?

[ct67_72]

No.3 intake valve is probably open, and your hearing the air coming back in through the intake. So yeah, sounds like a valve issue. Head will have to come off. If its that bad there should be some obvious signs. If you dont see any thing obvious than flip the head over and fill the combustion chamber with some sort of solvent and see if it leaks down through the valves. (valves facing straight up)
What does the spark plug look like that came out of no.1?

[Hudson]

No.3 intake valve is probably open, and your hearing the air coming back in through the intake. So yeah, sounds like a valve issue. Head will have to come off. If its that bad there should be some obvious signs. If you dont see any thing obvious than flip the head over and fill the combustion chamber with some sort of solvent and see if it leaks down through the valves. (valves facing straight up)
What does the spark plug look like that came out of no.1?

Will do. So next step is to pull the head off and go from there? No need to continue leak down testing?

Spark plugs look like this.

Farthest right is the #1 plug, then the number 2 plug to the left, etc etc.

Plugs were changed under 10,000 miles ago.

[ct67_72]

Is the gap on the no.1 plug smaller than the rest?
Oh and I missed your other question earlier. Yes those are the 2 bolts that need to be removed. Do yourself a favor now. Get a nice clean piece of cardboard. or a box and put it upside down. Mark FRONT on the box in relation to the engine. Remove the bolts and take the rocker arms off and lay them on the box at the front. Poke 12 holes in the box front to back. take the pushrods out and put them in the holes front to back in order.
You may as well do all of them now. You need to remove them to pull the head anyway.
This way when it comes time to put it back together everything will be in order, and go back together that way.

[ct67_72]

sort of like this, but inline

[Hudson]

You know, i was looking at that picture, and although it looks that way, it isn't.

Will do. I actually watched a youtube video of a guy replacing the 0331, and he did exactly that.

Would bad valves cause my coolant to just disappear? Or is it possible that my valves are shot and my head is cracked? I think my engine is falling apart.

[ct67_72]

Valves wouldn't affect the coolant loss. But with the sludge in the valve cover the gasket or head its self could still be bad.
Get it off. Have the machine shop check it. All you can do really.