SS or Ti Valves
08-31-2003, 12:16 PM
#1
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SS or Ti Valves
My 500 mile Garrity Repta Head broke a valve yesterday. Suggestions on a SS or Ti replacement for the exhaust valves? I have had my fill of sodium stems.
I am not excited about doing this again so I prefer to change out the exaust valves.
When the Turbo is running, it is magnificent.
I am not excited about doing this again so I prefer to change out the exaust valves.
When the Turbo is running, it is magnificent.
08-31-2003, 05:27 PM
#4
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If the engine has 500 miles on it, and a valve seat came loose and broke a valve, what happened to the piece of the valve that broke off? How much damage was done to the piston, combustion chamber, and cylinder walls? (and the exhaust side of the turbo... which probably sustained damage with metal pieces going throug it).
What ever the case... valve seats don't just come loose. I'd take that engine and mail it right back to who ever built it.
That's the biggest bunch of BS I've ever heard (well... almost!)
What ever the case... valve seats don't just come loose. I'd take that engine and mail it right back to who ever built it.
That's the biggest bunch of BS I've ever heard (well... almost!)
08-31-2003, 05:39 PM
#5
Valve seats do come loose. Either because there was not enough interference or it was not seated down all the way. Do not use Titanium Valves on the exhaust side of a turbo engine. They will not take the heat. A really good stainless valve is good. Brand names buy quality.
08-31-2003, 08:07 PM
#6
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Wow. That makes me nervous about the Garrity head I'm ready to install. I thought that dropped valve seats were more of an "air-cooled" issue. I've yet to hear of a water-cooled engine having this problem - until now.
Wouldn't you be concerned just replacing the exhaust vale that the other seats might go after it's all back together.
I echo Tony G's concerns about turbine damage.
Wouldn't you be concerned just replacing the exhaust vale that the other seats might go after it's all back together.
I echo Tony G's concerns about turbine damage.
08-31-2003, 08:33 PM
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The head was the only rebuilt part. I bought this two years ago from Garrity and I have been gradually upgrading the entire car. I drive it rarely but I have a new turbo, jet hot coates exhaust, turbo cup with rear helpers, 17" wheels, etc, etc.
This is my last turbo. I will put a chevy engine in my next water cooled Porsche.
This is my last turbo. I will put a chevy engine in my next water cooled Porsche.
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08-31-2003, 08:45 PM
#8
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My point is that if the head is built correctly, you will not have a valve seat coming loose.
I've never heard of one coming loose on a 951 engine.
In fact, check the archives.... You probably won't find a thread there either.
I've never heard of one coming loose on a 951 engine.
In fact, check the archives.... You probably won't find a thread there either.
09-01-2003, 10:08 AM
#10
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I saw a head at Farlers with 3 seats loose and hanging under the valve head. Used to have a photo but I don't know what I did with it.
Alan C.
Alan C.
09-01-2003, 12:56 PM
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The "rebuilt" head in my car was junk too, but not sure who did it. The valves were loose enough to wear the keeper grooves down, which necessitated replacing two of the intake valves.
09-01-2003, 01:46 PM
#12
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"I saw a head at Farlers with 3 seats loose and hanging under the valve head. Used to have a photo but I don't know what I did with it. "
I guess the same mistake was repeated 3 times. What a shame.
I guess the same mistake was repeated 3 times. What a shame.
09-01-2003, 03:18 PM
#14
Valve seats coming loose could be from incorrect installation or if the oringinal seat, a problem of heat. stock seats coming loose this long after installation seems it would not be from incorrect installation, but from heat behind the seat. I'm told that sometimes seats that have been recut several times can become very small in mass and when cut down to get the proper seat angles can become a problem. Rare but it has been seen. Most of the times I'm told, the seat insert comes loose after the seat insert has been replaced. Improper interference from either improper measuring to gain the correct interference value, or improper installation are the typical causes. If done correctly, there should be absoluely no problems here.
If you have seen 3 seats loose, then further investigation would have produced the cause. Although this is a very normal procedure, if done wrong can result in catatrophic results. Pick your machine shop carefully. Once done, you cannot see a mistake.
If you have seen 3 seats loose, then further investigation would have produced the cause. Although this is a very normal procedure, if done wrong can result in catatrophic results. Pick your machine shop carefully. Once done, you cannot see a mistake.