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Why are my valves grey in 1 cylinder and black in the others?

 
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Old 11-12-2010, 12:10 AM
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Why are my valves grey in 1 cylinder and black in the others?

The exhaust valves in the first cylinder are not like the others. They are grey and look like they have crystals while the other exhaust valves are black. The valves do not seal. Compressed air blown into the first 3 cylinder exhaust ports will leak around the valve seat. The first cylinder is the worst. The seal gets better until the last cylinder, which has no leak.

This is an H22A head from an engine running forced induction. I purchased the set up from ebay, and have found a number of problems. I'm not sure what symptom I'm seeing in these valves.

My guesses for why the first cylinder exhaust valves are grey is:
1. Persistent lean mix
2. Knock
3. burning accelerated by FI
4. ??

If someone has seen valves like these before, please let me know what the problem is.

Thanks
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File Type: jpg ex valves.jpg (125.8 KB, 35 views)
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Old 11-12-2010, 12:27 AM
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Re: Why are my valves grey in 1 cylinder and black in the others?

ive seen head gaskets do this before ... just enough to clean the build up off .. also a burnt valve thats leaking can cause them to looklike that but then there is usualy a crecent shaped patternt somewhere ( where the leak is the worst )
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Old 11-12-2010, 12:42 AM
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Re: Why are my valves grey in 1 cylinder and black in the others?

I don't understand how a headgasket would do it - like a head gasket leak?
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Old 11-12-2010, 01:11 AM
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Re: Why are my valves grey in 1 cylinder and black in the others?

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I don't understand how a headgasket would do it - like a head gasket leak?
yeah a leak . and if it had a leak and someone put stop leak in it it cristalizes as described ..
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Old 11-12-2010, 11:48 AM
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Re: Why are my valves grey in 1 cylinder and black in the others?

Thanks for the info. I knew a valve job necessary, just due to the leaks. I'm assuming that the guy who originally boosted the engine put his original head back on - no porting, -original valves/springs. Since they probably already had 200,000mi on them already, the extra stress of boost burnt the valves.

I don't know why cylinder 1 is burnt the worst, but it could be weak fuel pressure since it is farthest down the fuel rail. The leaking exhaust valves get worse as they move further down the fuel rail from the fuel pressure regulator.
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Old 11-12-2010, 10:57 PM
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Re: Why are my valves grey in 1 cylinder and black in the others?

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Thanks for the info. I knew a valve job necessary, just due to the leaks. I'm assuming that the guy who originally boosted the engine put his original head back on - no porting, -original valves/springs. Since they probably already had 200,000mi on them already, the extra stress of boost burnt the valves.

I don't know why cylinder 1 is burnt the worst, but it could be weak fuel pressure since it is farthest down the fuel rail. The leaking exhaust valves get worse as they move further down the fuel rail from the fuel pressure regulator.
f i had to guess prolly not enough fuel pressure in boost ..
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Old 11-17-2010, 03:04 AM
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Re: Why are my valves grey in 1 cylinder and black in the others?

When the guy added boost did he get bigger fuel injectors this might be your problem as the standard injectors are not delivering enough fuel and the forced induction is trying to force more air into the engine when the previous air didnt burn off which is causing stress on the valve seals, turbos and superchargers can be a hastle and can actually make your car worse and blow seals and such if not properly tuned, when you get your seals and everything tuned up, i would take your car to a dyno and take it easy and get it tuned. dont get on it on the dyno until your car is properly tuned otherwise you risk blowing more seals. Also you should check and see if your forced induction system has a relief valve(some turbos and superchargers dont have one) on it because if it has excess air it blows it out of the relief valve instead of into the engine which yet again, to much air can blow seals. Also your crystalization might be from a coolant leak and your engine burnt the coolant, or it could also be from as a previous poster said, that it was leaking and the previous owner put stop leak in there. and the different color valves, maybe the one has been burnt due to weird fuel/air mixtures or the previous owner replaced it. Hope i helped
-HondaDavid
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Old 11-17-2010, 09:45 PM
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Re: Why are my valves grey in 1 cylinder and black in the others?

Well currently the engine is fully disassembled (hence the picture of the combustion chamber side of the head). I think that we all agree that grey valves are probably due a to lean mix.

I'm going to take the head and block to a machine shop to repair the valve seats and hone the cylinders. Then I'm going to install boost quality top end to match the sleeved and forged bottom end. Only then will I put it back together and begin tuning.

Thanks for all of your help.
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Old 11-17-2010, 09:47 PM
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Re: Why are my valves grey in 1 cylinder and black in the others?

oh yeah, I'm sending the 780cc injectors back to Precision Turbo to have them cleaned and tested.
They said it would be $15/injector + shipping.
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Old 11-22-2010, 01:50 PM
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Re: Why are my valves grey in 1 cylinder and black in the others?

The stock injectors are good for up to 600hp I believe. Or maybe its the fuel rail I'm thinking of...
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Old 11-24-2010, 01:53 PM
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Re: Why are my valves grey in 1 cylinder and black in the others?

I that is misinformation. Stock injector and fuel rail are not capable of generating 600hp.

RC Fuel Injection has a rather simple injector/horsepower calculator. Using their calculator, an NA 200hp H22 would require 290cc injectors. The stock H22 injectors are 280-290cc.
RC Fuel Injection

780cc injectors will max out at about 375hp in a turbo H22 according to the calculator.

I don't have a fuel rail calculator but I don't think that a stock rail will sustain much more than the 200hp without substantially increasing fuel pressure. The tubes inside the stock fuel rail are only about 1/4in in diameter.

The following site indicates that 0.25in fuel lines with a 255lph fuel pump will have performance hurting turbulence. 0.375 or 0.5in lines would have been much better.

L&M Engines


My view on the H22 fuel rail with 780cc injectors:
At WOT 780cc injectors will require 2.75x more fuel than stock. I guarantee that the stock fuel pump and filter are not designed to tolerate a 275% increase max in flow. So if the fuel system fails to deliver sufficient flow, the injectors suffer from insufficient fuel. The problem increase as the injectors move down the fuel rail. So the injector closest to the fuel input on the rail could flow normal wile the last injector (closest to the return line) will flow the worst.

This is what I think happened to this engine because the cylinder closest to the transmission showed no exhaust valve burning (injector closest to the fuel line). Then valve burn worsens until the valves closest to the crank pulley are very burnt (last injector on the rail).
Any constriction in the fuel system would cause the problem. The fuel lines may be too small, the rail insufficient, the pressure regulator set incorrectly, the filter dirty or constricting.
The AFR may also fail to tell that there is a lean condition in one cylinder because the exhaust gas from all 4 cylinders are thoroughly mixed by the time they pass through the turbo and reach the o2 sensor. If the average AFR is ok, the engine tuner may have missed the fuel problem (he should have had tested the fuel pressure at WOT to confirm that he had sufficient flow).
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