Possible bent valves. Rookie mistake :(

[Stunn3r]

Here's what happened,

My freshly rebuilt cylinder head is torqued down to the block, no timing belt installed, no spark plugs installed. Both cams are pointing at 12 0'clock, with the cam caps hand tightened not even fully flush with the cylinder head, but there is some pressure on the valves. When I was removing the balance shaft pulley, I accidently rotated the engine. I heard a small pop and squeaking noise (engine has not been rotated for a while). I did not think much of it until dawned on me today that I might have bent the valves.

I guess my main question is with the cams pointing straight up are any of the vales open? If so, is it possible I could have bent them manually rotating the engine slowly?

Thank you.

 

[chrysler kid]

Nah should be fine. The exhaust cam doesn't want to stay at top dead center, you probably heard it slightly rotate. In guessing there was not timing belt hooked up?

At top dead center the valves are nearly fully closed on all cylinders.

 

[1990TSIAWDTALON]

I would test now to see if all cylinders seal. I bent a couple rotating a cam by hand. At some point, 2 valves are slightly open. The noise I heard when it happened was a slight "ping" and that's it. That was the sound of an intake valve touching an exhaust valve for me.

 

[Stunn3r]

I would test now to see if all cylinders seal. I bent a couple rotating a cam by hand. At some point, 2 valves are slightly open. The noise I heard when it happened was a slight "ping" and that's it. That was the sound of an intake valve touching an exhaust valve for me.

The cam was stationary, and the cam caps were hand tight. Let me provide you some pictures. From the pictures I provided do you think enough pressure is being put on the valves to keep them slightly open and can be damaged by an engine rotation?

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[CKOPOCT]

Agree that most likely no damage to the valves. However, it would be very easy to remove the cams and test each cylinder using compressed air to ensure sealing just to be sure. Better to spend a little time doing that than finish putting everything together only to discover a problem.

 

[1990TSIAWDTALON]

"Probably" not, but are those GSC3?s If your cams are high lift, they can leave a valve open further than a stock cam will.
I was amazed at how little it took to bend those little valve stems (I am used to SBC size valves). When you REALLY bend them, it is noticeable from the uneven height of the valve stems on the top side. If they are just barely bent, it won't be easy to tell. A leakdown test would tell you if they are sealing.

 

[Stunn3r]

"Probably" not, but are those GSC3?s If your cams are high lift, they can leave a valve open further than a stock cam will.
I was amazed at how little it took to bend those little valve stems (I am used to SBC size valves). When you REALLY bend them, it is noticeable from the uneven height of the valve stems on the top side. If they are just barely bent, it won't be easy to tell. A leakdown test would tell you if they are sealing.

They are GSC S1's with dual valve springs, hence a lot harder to compress, but as you pointed out the lobe is bigger than stock even if they are just GSC S1's.

Can someone here kindly provide a quick cliff note on how to do a compression/leak down test with the cams and timing belt uninstalled? Thanks.

 

[CKOPOCT]

A leakdown test is just pressurizing the cylinder with the valves closed so the compressed air can't escape... unless there is an escape route like a bent valve, worn rings, cracked head, etc.

If you remove the cams you would effectively close all of the valves. Timing belt not necessary as you won't have to rotate the crank to achieve TDC to ensure cylinder X's valves are fully closed.

Just push around 100 psi of compressed air inside the spark plug hole using a threaded adapter and see if the gauge holds at 100 psi. If not, check around to see if you can hear where the air is leaking (intake, exhaust, into radiator, etc.).

 

[1990TSIAWDTALON]

Go rent a compression tester (Auto parts stores will rent them for free or a deposit). It will have a fitting that will screw into the sparkplug hole then use compressed air as said. It shouldn't leak anywhere.

 

[Stunn3r]

Go rent a compression tester (Auto parts stores will rent them for free or a deposit). It will have a fitting that will screw into the sparkplug hole then use compressed air as said. It shouldn't leak anywhere.

A leakdown test is just pressurizing the cylinder with the valves closed so the compressed air can't escape... unless there is an escape route like a bent valve, worn rings, cracked head, etc.

If you remove the cams you would effectively close all of the valves. Timing belt not necessary as you won't have to rotate the crank to achieve TDC to ensure cylinder X's valves are fully closed.

Just push around 100 psi of compressed air inside the spark plug hole using a threaded adapter and see if the gauge holds at 100 psi. If not, check around to see if you can hear where the air is leaking (intake, exhaust, into radiator, etc.).

Here is a picture of my setup. Basically, just a bare head installed. Do I need to install anything else to perform this test correctly?

Also, this is the compressor I will be using. It's a tire compressor. Is this adequate to perform this test?

Also, if you could you direct me maybe through Amazon, on what kit/connector I should buy to hook up the compressor. The ones I was looking at bolt directly the spark plug and reads compression from an engine crank which I obviously can't do.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

 

[CKOPOCT]

Nothing needs to be added to your setup. Bare head is fine. Missing exhaust manifold is a plus.

Don't think that compressor will do because you need to be able to control the output pressure from the compressor to the cylinder, though I am sure you could find an inline solution that would enable you to control the pressure moving through the line. Plus you'll need to have a quick connect adapter on the end of your air hose so you can connect to the test kit line that threads into your spark plug port. It looks like your air hose is specifically for connecting to tire valves with shrader valves.

Advance, Autozone, O'Riley's, etc. all have compression test kits that will enable you to connect a threaded hose into the spark plug port and will have a male quick connect on the other end that you can use to connect to an air hose.

Remember you aren't looking to read compression at this time - only integrity of the cylinder to see if it holds 100 psi of compressed air.

 

[Stunn3r]

Nothing needs to be added to your setup. Bare head is fine. Missing exhaust manifold is a plus.

Don't think that compressor will do because you need to be able to control the output pressure from the compressor to the cylinder, though I am sure you could find an inline solution that would enable you to control the pressure moving through the line. Plus you'll need to have a quick connect adapter on the end of your air hose so you can connect to the test kit line that threads into your spark plug port. It looks like your air hose is specifically for connecting to tire valves with shrader valves.

Advance, Autozone, O'Riley's, etc. all have compression test kits that will enable you to connect a threaded hose into the spark plug port and will have a male quick connect on the other end that you can use to connect to an air hose.

Remember you aren't looking to read compression at this time - only integrity of the cylinder to see if it holds 100 psi of compressed air.

My dumbass did not realize this, but this tire compressor does have a quick connect (picture included). So that should work. Please let me know.

The only thing I'm not understanding is "when you said being able to control the output pressure from the compressor."

The compressor has a built-in gauge. I'm thinking just connect the compressor quick connect to the spark plug adapter, pressurize it until the gauge reads 100psi, then look to see if holds the pressure.

Out of curiosity how do you tighten the spark plug adapter to the spark plug hole. Is hand tightening it adequate?

You must be logged in to view this image or video.

 

[chrisman287]

Not sure if you can make something like this but saw it in a video thought it was genius

You must be logged in to view this image or video.

 

[CKOPOCT]

Hand tightening is adequate. The quick disconnect on your compressor will work just fine. And, yes, you can just run the compressor to 100 psi. The only issue you might run into is if there is a leak you might not have enough air to figure out the source of the leak... but I doubt you'll have a leak anyway .

 

[DSMPT]

with the cams pointing straight up are any of the vales open?

If it was like the pics you uploaded above (The cam cap bolts were just hand tightened), No, all valves were closed.
But if the cam cap bolts are tightened down, Yes, Cylinder #2 exhaust, #3 intake and #4 intake/exhaust valves are technically open (How much open is depending on cams and the actual cams position)

 

[1990TSIAWDTALON]

I "think" the sparkplug hole hose should have a oring on it and hand tighten it.
All this test is for is to listen for any air leaks at the valves. Just about any amount of pressure will do if you have decent hearing (I don't). You will hear air escaping if any valve is open or bent. Unbolt the cams COMPLETELY so the valves should technically be closed.