Valve questions

Noidea

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So took my head off cause left cylinder wasn’t firing and when I did leakown test I found that the left side I take valve was leaking. It’s all apart now I lapped the valves as well and cleaned the whole area. I put water On the valves let it sit for a bit. I come to check it and there’s leakage detected o the intake valve. I’ve lapped it twice now didn’t work. I have about 3 other heads in my garage this old dude gave me a bunch of xs parts. I switched the valves and spring itself and still leakage. So I have 2 questions. Is this the proper way to check for leaky valves? And what else can i do to besure the valve seats correctly?
 
Yes, the liquid test is a good way to test for leaks, but I usually use something like kerosene, not water. And I blow compressed air up into the intake and exhaust ports to really get a good check. If you have leaking with the liquid just sitting in there then you have a really bad leak. Have you checked the valve to see if it's bent? Chuck it up in a cordless drill and spin it. Does it wobble?
 
I was using regular gasoline but found it harder to find leak cause it doesn’t drip just soaks into the metal I was doing compressed air test as well but kept getting different results. The valves I didn’t even have a problem with would bubble up when I sprayed air into them. I just rolled the valve I had an issue with across a straight even surface and it was good. Also as I said I switched it with the other valve from another head same issue.
 
1. A "leak down test" is done on an assembled engine with compressed air and pressure gauges.
2. Click the "Tech" button and scroll through the menus until you find a link to a free download of the factory manual. For your purposes the year doesn't matter, specs and procedures for valve service will be the same.
 
I did a leakdown test when the engine was assembled that’s why I took it out and lapped the valve. I already have the factory manuals as well as haynes manual they don’t really help much in this situation
 
Don't know what else to suggest apart from checking valve-seat contact with dye (felt tip marker works too), but I guess you've been there and done that. Seat needing clean up with a cutter?
 
Yea prob gonna need th seat cleaned up considering I even put another known good valve. I don’t trust my ability to dothat without screwingit up sending it to a machine shop 2mm. Prob hard to see but this is the leakage I had with the water on top. Would this little leak cause a cylinder to not run at all though? That was my original problem would suck if I do al this and still have the same outcome.
 

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From what I can see, I don't like the looks of that valve seat. Is that light showing through along the bottom right edge? If so, I'd say that thing is trashed, lol.
 
Sorry, crystal ball reception has gone to shit out here in the sticks ever since the broadcasters switched to high definition. So:What did you have for compression, and what percentage of pressure was retained in the leak down test?
 
I had about 130 for compression but did a leak down test was coming out of my left intake side of cylinder. Brought it to a machine shop guy said that water test is a bad test to do. He resurfaced my valves and used some sort ofvaccumtest on the cylinder head and said it was solid. Now I’m putting everything back together gonna see what happens when I start it. One question I put my valves back in and the valve stem sticks out a little more than the others is this ok?
 

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The guy at the machine shop didn’t grind the valve down enough for it to be sticking out as it is**
 
Did you mix and match parts from one of your other heads when you put this together? I ask because there was a valve collet design change in '73. The shape of the locking ring and the corresponding groove on the valve were changed (square to rounded). Mismatching collets to valves may account for that valve sticking out the top more .....

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Or maybe you just haven't seated the collets into the valve properly. How much the valve was ground wouldn't effect how much the stem sticks up above the top washer and spring. That would be controlled by how/where the collets lock into the groove in the valve. Once assembled, you're supposed to give each valve spring top a couple good raps with a big rubber mallet to insure the collets are seated and locked in properly. Try that, maybe the problem will right itself.
 
Upon further study of your pic, I don't think you have the collets installed and seated properly. Notice how they stick up above the top of the washer a little bit. Look at the other valves and you'll see the collets sit into the top washer deeper and are a little below it's top surface.
 
Interesting. I was going to switch it with the other valves I had and didn’t do it. These are actually exhaust valves I purchased from mikesxs a while ago so I don’t think they should be doing it but i everything seems right. I even tried to see if t was maybe the retainer if I accidently switched them but that’s just the way they sit. If that’s the way it is it shouldn’t hurt anything right the rocker arm still pushes down on the valve as it will I assume so I should be good. ¯\_(ツ)_/¯
 
Well, if it's an aftermarket valve, maybe the collet groove is located farther down on it. You'd have to compare it to an original to find out. But, if both exhaust valves are replacements, how come they don't both sit that way?
 
it looks seated properly I took it out a couple times and put it back same thing here’s another pick
 

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The one on the right side of the photo is the same mikesxsone but doesn’t stick out as much gonna keep lookin at it see what I can do
 
Whatever you decide to do, be sure you run that rubber mallet "test" on any valves you had apart. That bounces the valves open and closed and makes sure the collets are locked in OK. Better to have things come flying apart on the bench during the test than when you're running down the road, lol.

The only difference I can see it making is that valve spring will be compressed a little more. I don't think that would hurt anything.
 
The "mallet test" was required testing everywhere I've worked. Lay a heavy rag over the spring first. Otherwise, if a keeper does come out, it might wind up in NYC.
 
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