Leak Down Test

[kimokalihi]

I just got my Matco Leak Down Tester from ebay and I'd like to perform my first leak down test. I have an EJ20 twin turbo JDM DOHC motor on an engine stand with the intake, exhaust, alternator, AC, PS pump removed.

How do I hold the crank still so it won't turn when I do the leak down test?

To find TDC for each piston do I just do number one first and then follow the firing order? If you can eleborate on this that would be great, I want to get this right the first time.

What should I set the PSI of the compressor to?

Any more tips would be great, thanks!

Kimo

[Imprezive]

At our shop we usually have the out-of-the-hard line pressure pretty high but the leak down tested should have a regulator on it i believe, maybe like 40-60 psi?

You wont need to hold the crank if the piston is at top dead center because the air pressure wont be able to push the piston down.

Oh and if its on a stand pull all the spark plugs out to make rotating the engine easier. Also a mechanic's stethoscope is great if you are getting leakage and need to find out where it is from. You can also spray brake cleaner in the intake valves to check leakage, and vise versa with the exhaust valves if you spin the engine around.

Sometimes if you are getting bad leakage you can use a wrench to SLIGHTLY rock the crank back and forth to try and get the rings to seat. Keep in mind your engine is dead cold, and its leakage will improve when at operating temp.

Start on cylinder 1 at TDC, and follow the firing order but rotate the engine 360* each time. This way you will know that they are all on their compression stroke and not their exhaust stroke.

for example: Test cyl 1 at TDC. When done, rotate the crank 360 degrees and then test cyl 3. Then 2 and then 4 etc...

[kimokalihi]

You only need 40-60 psi? I thought you'd need around the same psi that you would get from a compression test?

[kimokalihi]

Alright I sort of did a leak down test on cylinder number one. First off, what the hell is wrong with these engines? When all the timing marks are lined up, no piston is at TDC! Cylinder number one reaches the highest point in the compression stroke when the mark on the crank sprocket is 90 before the mark on the oil pump! Is that normal? When I had my 89 toyota pickup truck with the bulletproof 22RE motor it was right at TDC when the distributor and the timing marks all lined up.

Anyways, I tried putting air into it when the cylinder was all the way up but by the large amount of air leaking out of the valves, I decided that was not the right place to do it at. So I lined up all the marks and the cylinder had gone down a bit and I tested it again. At 60psi. I can hear a little bit of air coming from the exhaust valves and then the engine starts to turn and the leaking quickly becomes worse. I can't seem to hold the breaker bar still so I can't get a good reading. It would be much easier with two people.

To make things worse I think my compressor is causing things to be off. As soon as I hook up the gauge it reads 20-30% leakage and you can hear the compressor leaking somewhere around the area of the regulator/gauges. I don't know how to fix this. The regulator does not work. The compressor will get up to about 100PSI and then the valve blows open and air comes shooting out very loudly until there's only like 50-60PSI left.

Now I'm annoyed. I wanted to get this test done so I could see if this engine was in good enough shape to run well and then I could start putting everything back together and drop it in. But I don't want to put it in unless I know it's good because the repairs would be much easier right now with the engine partially apart and on the engine stand.

[Imprezive]

lol. Fix your ghetto-compressor.

Did this engine come from a running car? Is the timing off or something?

Another way to tell if the piston is at TDC is to screw in the hose for the leakage tester, put your thumb over the hole and rotate the engine, lift your thumb every once in a while to make sure its still compressing, when it stops you are at TDC.

That leakage tester also has an adjustment knob on it. When you plug it in you need to turn that knob to get the right dial to read 0.

[kimokalihi]

I don't think ingersoll rand sells parts for this compressor anymore. I contacted them to find out though. Waiting for a response.

I read the manual for the leak down tester probably 4 times. I turned the knob all the way clockwise like it said and it would only go to 30% at 60 PSI. Which I think(not sure)means that the compressor is leaking 30% or so. If I put the PSI at 80, it'll go to 20%. I have not tried anything higher than that.

This engine came from a guy who says he bought it from tiger japanese engines.

I believe he got it from here.

http://www.tigerjapanese.com/


Therefore I have no idea if it's any good or not. He never put the engine into a car so he didn't know either.

[93forestpearl]

The timing marks line up when the crank is 90 off from TDC. I believe it is that way so you can rotate the cams without any valves hitting the pistons. Its not an issue with 22T heads, but it is with any of the DOHC or phase 2 stuff.

[kimokalihi]

So I shouldn't do the test with the timing marks lined up?

If I hook the gauge up to the compressor hose and turn the knob all the way clockwise and it only goes to 20% leakage and won't go all the way to 0%, does that mean the gauge is leaking? Because it does this when I just hook up the leak down tester and don't even plug the hose in that is screwed into the cylinder.

The compressor is leaking somewhere at the regulator or relief valve. Does the gauge detect that as a leak even though it's on the wrong end of the gauge?

I have this feeling I bought a shitty leakdown tester. It's a MATCO and there's tons of matco testers on ebay for some reason...maybe they're all faulty and that's why there's so many for sale?

I hate people who sell things they know are bad but don't say it in there listing.

[glennda5id]

Does your gauge have two PSI gauges, or a PSI gauge on the left and a percentage gauge on the left?

[kimokalihi]

The Matco leakdown tester I have has the PSI gauge on the left side(the side you hook the air up to)and a percentage gauge on the right(the side you hook the hose for the spark plug hole to.

[kimokalihi]

Alright, got in contact with Ingersoll Rand and they told me to give them a call about my compressor having a recall. So I just called them and they told me that they have a problem that can lead to the tank exploding and they will come pick them up for free and give you $100 or give you $200 credit for purchasing a new one.

Sweet! I'm glad I contacted them. Could have just saved my own life there. I have always been paranoid to be around those things, especially this one since it leaks and it's old.

I talked to my step dad since it's his and I think he is going to get a new one, sweet! No more using that shitty compressor that I would have to manually turn back on every 2 minutes or less depending on what I was using.

They had a really nice one on sale a little while ago for $600 with free shipping and it was a 60 gallon tank! Really nice compressor.

[kimokalihi]

Uh oh, I just realized that was from northern tool, not from the factory. I wonder if they'll still give me credit to northern tool haha.

http://www.northerntool.com/webapp/wcs/ ... 284_158284

[Legacy777]

That's probably overkill for what you need it for....but cool non-the-less

[kimokalihi]

Well, yes but I would love to have one. It's a good deal though! I hate having the tank run out of air all the time so a 60 gallon tank should last a little longer.

[kimokalihi]

OK, bad news. I think.

I did the leak down test with my step dad holding the motor still. The gauge refused to go to 0% leakage until we put 100psi into it which happened to be the max PSI on the other gauge on the tester although the manual said to use between 45-150 PSI.

Anyways we tested each cylinder and they all had about 20-25% leakage and all of them leaked through the exhaust, intake and the rings. Although it wasn't much leakage, just a quiet hiss from each hole. Number 1, 3 and 4 were all about the same. Number 2 cylinder had a massive exhaust leak. It was 70%! Loud hissing from the exhaust ports on the head from number 2 cylinder.

I thought this might be because I didn't have the cams lined up right when I put the belt on. We pulled the valve cover and checked the cam lobes and they were not pushing the buckets in at all. So it's definately a valve seating problem.

My question is, what do I do now?

Should I take the heads off and have new valves put in and have them do whatever work they do to the heads done?

While this is being done do I pull the pistons and replace the rings or anything?

What do you guys recommend? Or do I just say fuck it and put the motor in my car and hope for the best? I doubt it. I don't like that idea.