LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Valve Problem?

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Old Feb 5, 2011 | 11:59 AM
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Exclamation Valve Problem?

So I have a light ticking coming from the window side of the drivers bank. I am pretty sure it's a burnt or sticky valve. That would explain the misfire and light shake, wouldn't it? Question is, what's the cost for fixing that and how much labor is involved to pull the heads, intake manifold, valve covers, etc??? Any ideas?
Old Feb 5, 2011 | 01:11 PM
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Re: Valve Problem?

How do you know its not a lifter, or loose rocker?
Old Feb 5, 2011 | 02:37 PM
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Re: Valve Problem?

Would that cause a misfire/gentle shaking? If nothing else, it would result in compression loss in that cyclinder. Just enough to cause a gentle shake. That would also be why it goes away under load. Correct? The more I drive it the more I realize that it is definitely not normal. It could definitely be a lifter or loose rocker. But the click is very distinct, for sure... Thoughts??
Old Feb 5, 2011 | 06:58 PM
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Re: Valve Problem?

Yes, all of those problems could cause a misfire and "slight shake".

A burnt or sticky valve would probably show up in a leakdown test. A loose rocker would be easy to find, simply by removing the valve cover. A stethescope could then be used to locate a ticking lifter.
Old Feb 5, 2011 | 10:27 PM
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Re: Valve Problem?

Sweet. I might be able to pinpoint this after all. I am just getting this pretty loud clicking by the valve covers. It is present on both sides, but the driver's side is pretty darn loud. Here's the deal, if I remove the valve covers, can I reuse the old gaskets or do I have to get new ones? :-/
Old Feb 6, 2011 | 12:24 AM
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Re: Valve Problem?

Originally Posted by FastandBlue
Sweet. I might be able to pinpoint this after all. I am just getting this pretty loud clicking by the valve covers. It is present on both sides, but the driver's side is pretty darn loud. Here's the deal, if I remove the valve covers, can I reuse the old gaskets or do I have to get new ones? :-/
I actually just did this yesterday, and reused my valve cover gasket, but it cam off nicely and clean. As far as the clicking and shaking it seems like what i had and fixed by adjusting the valve lash.
Old Feb 6, 2011 | 01:41 AM
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Re: Valve Problem?

Were you getting a misfire/engine shake?
Old Feb 6, 2011 | 09:51 AM
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Re: Valve Problem?

Originally Posted by FastandBlue
Were you getting a misfire/engine shake?
only at idle, but it seems like it was one cylinder and it was getting a little bit of compression.
Old Feb 6, 2011 | 03:07 PM
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Re: Valve Problem?

Okay sweet. I'll take a look and see what I can find. Thanks!
Old Feb 7, 2011 | 08:26 AM
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Re: Valve Problem?

The valve cover gaskets are reusable..by design.

Why would a burnt valve cause a ticking noise?

Color me skeptical that this is your problem.....especially if you have done a leakdown test and it is OK.
Old Feb 8, 2011 | 03:21 PM
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Re: Valve Problem?

No leakdown test yet, so I am not positive. But something is kinda clicking in there, so I'm curious as to what it is. I might as well take a look, right? I am still getting engine shake, I have spark, and I have fuel. What is a good leakdown test tool to buy that won't break the bank?
Old Feb 9, 2011 | 04:38 AM
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Re: Valve Problem?

A leak down test is great for pinpointing a problem, but you dont even know if there is one yet. Save yourself some money. Go to harbor freight and buy a vacuum gauge for $12. Take a look over here to see how to read it -

http://www.secondchancegarage.com/public/186.cfm

Scroll down to the "scenarios" click on 1,2,3 for what a healthy engine reads, and 5.6.7,8 for valve issues.
Old Feb 10, 2011 | 01:02 PM
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Re: Valve Problem?

But correct me if I'm wrong, a vacuum gauge is not a leakdown tester, right? I can get a vacuum gauge anywhere, but I really want something to do a leakdown test with and I am pretty sure that I will need a specific tool for that. I just am wondering if someone can recommend a good, cheap one (oxymoron)?
Old Feb 11, 2011 | 12:39 AM
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Re: Valve Problem?

You don't need a leak down tester, but it is a good tool to have. A vacuum gauge will tell you everything you want to know.

Here is a decent leak down tester that won't cost to much:
http://www.amazon.com/Star-Hoffmann-.../dp/B000Q6P7GU
Old Feb 11, 2011 | 06:09 AM
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Re: Valve Problem?

1 glaring problem with only using a vacuum gauge. If you know what level it is supposed to be and it's lower, how do you know what is causing it to be lower? There is literally 10s of feet of vacuum hose, connectors, canister etc that could be leaking.

If you were to use a leakdown tester, it would pinpoint a definite problem with valves, head gasket or rings.

But beware it's use if you interpret the results wrong.

One other thing, if you suspect a valve is leaking. It would show up on a compression test.

Both leakdown and compression testers are available for loan at local autoparts stores.



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