Valve guide problem
 

I pulled my port exhuast manifold and valve cover to investigate a small oil leak. I then shone the light into the exhuast ports and found #4 port wet and had baked on oil. Upon further investigation I could see the bronze valve guide half way or better up the exhuast valve stem and the seal up under the valve retainer. Turning the motor over and watching verified the guide is moving with the valve. I did compression checks to see if a valve was bent, I had 165 to 170 on the whole bank.

What happened to the guide? Motor has less than 20 hrs since total rebuild. SS iconel valves/ bronze guides......

Is it an aluminum head?
Was it a shouldered guide?
What was the clearance between the guide and valve?
What type of stem seal?
What was the O.D of the guide and the I.D. of the guide boss?

can't answer many of your questions, as i didn't do the build. It was done by Goodwin Competition. They are the stock cast iron heads. I can also say the seals were not the umbrella type, they are p.c. valve seals

I know of Todd, I know Steve M, owner of Comp. Products & Howards. Todd, is Steve's guy. I would take that back to Todd, and let him look at it, before you start getting on here looking for answers. Is he willing to look at it?

Plan on it. Been working with Todd now for a year. I just came upon this problem today. I think i've been running it like this for awhile from the appearance of the exhuast port and valve stem. Don't know what would have happened if i didn't catch it. I'll be talkin to Todd tomorrow, but just wanted an idea of why this guide would have come out like that.

I have seen valves stick in the guides, usually they bend the valve. The bore could have been to loose for the guide, high exhaust temp would expand the valve and cause it to stick or low lubrication to the valve, someone else posted about the samething, but an alum. head. They said; something about the engine leaning out, they had more than one guide pull out.

It was the only one that I found that was like that. I did the compression check and figured with the good numbers the valve was not bent. But i could be wrong.
What would have happened if i didn't catch it and I kept running it?

I'm being told that due to the previous exhuast, and burning a bit of water due to reversion, it is causing the guides to loose press.....................

Assuming the previous water reversion caused the issue, shouldn't a relatively inexpensive guide been replaced when the head was reworked? Not sure what water reversion would have to do with a pressed fit guide. At this point, it will likely be hard to determine who shot who. It seems to me it would be worth asking for some consideration from your engine builder.

The head was reworked last year when the engine was overhauled. Bronze guides were installed at that point. But, the silent choice exhuast was reinstalled after the engine was done. Which if you were following my previous posts, was removed and longer risers and mufflers installed. But it was put on 3 hours too late. Engine builder is saying that the water heated and cooled the guide which made it loose it's press and/or the valve was rubbing the guide too much. He wants to look at both heads to make sure they are good. Also wants to look at the rest of the engine to see if there is any other reversion damage.............. He does plan on "helping" me out, but full warranty, he is not doing.

Water cooling a guide too fast will shrink it, have had it happen before. Todd,is correct on that. Did he know you had water in the cylinders prior to this? It's a good idea your looking at the whole engine.

Well, the verdict is in. Goodwin is replacing all the Iconel exhaust valves with new. All the guides will be replaced as well. Todd says he found evidence that the exhuast guides were rubbing or "quenching" as he calls it on the guides, and said he wanted to replace the valves so there is no chance of dropping a valve. He also found some staining in the cylinders from the water sitting in there over the past winter. One cylinder he said there is about 3 thousandths of electrolysis, so there may be a bit more blow by there. He left it up to me wether or not to tear down the motor to re ring and hone that cylinder. He didn't think it was crucial, and either did I. What i would like to know more about is this "quenching" of the valves and guides. I didn't think a SS valve and Bronze guides would have a problem with a little bit of water......................Can someone explain this better?

Maybe all the exhaust guides were too tight....?

I have seen valves stick in the guides due to clearance and lack of oil. Quenching,would be the valve and guide being hot then hit with cold water, causing it to shrink then become loose in the guide boss.