Worn valve guides?
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Joined: Aug 2001
Posts: 707
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From: Washington, D.C.
My '91 C2 has some valve noise, which is especially noticeable when driving next to a high curb or other reflective surface. My mechanic said that it's completely normal for a 911 (i.e, the price you pay for solid lifters). He also said that a little loose is better than a little tight, from an engine longevity standpoint. I read somewhere about 911 owners being "connoisseurs of clatter". I guess this is where it comes from.
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Joined: Jun 2001
Posts: 89
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From: Chicago
I always hear a clatter (or you might call something of a slapping sound) when I ride next to a reflective surface, especially with the top down. Doesn't bother my mechanic, but it does take some of the menace out of the rumble.
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Joined: Jun 2001
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From: Putnam Valley, NY
John:
Your oil consumption is within Porsche specifications (Melissa: I believe Automotion was only quoting the factory). I have never heard of someone that could identify valve guide wear by listening to the engine.
Kevin's method is the correct way for determining wear.
Valve noise is common in the 911 engine. Excessive chatter is not, but it only means you need them adjusted.
Now, if you had them done less than 10K miles ago and you just drive your car around town, you may have a problem - that could be caused by valve guide wear.
Let us know the outcome - make sure you are there when your mechanic checks the valves. Watching is a great way to learn.
Horst: you drop the engine to adjust your valves? If you can do it quickly, you can adjust the valves and do alot of other little things too - like cleaning, checking hoses, vacuum lines, cables, etc.
Your oil consumption is within Porsche specifications (Melissa: I believe Automotion was only quoting the factory). I have never heard of someone that could identify valve guide wear by listening to the engine.
Kevin's method is the correct way for determining wear.
Valve noise is common in the 911 engine. Excessive chatter is not, but it only means you need them adjusted.
Now, if you had them done less than 10K miles ago and you just drive your car around town, you may have a problem - that could be caused by valve guide wear.
Let us know the outcome - make sure you are there when your mechanic checks the valves. Watching is a great way to learn.
Horst: you drop the engine to adjust your valves? If you can do it quickly, you can adjust the valves and do alot of other little things too - like cleaning, checking hoses, vacuum lines, cables, etc.
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Joined: Jun 2001
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From: springfield, MO USA
JBH: I've been chicken about dropping my 90C4 engine. The hydraulics with the 60+bar pressure scares me, and I haven't totally figured out how to disconnect without opening a line. In any case, the exhaust valves are easy to do w/ the engine in, and the most likely to be out of whack. In my case only two were even slightly tight, and since I have no other issues with the engine, I decided to leave well enough alone. The intake side is the one that would be a bitch with the engine in.
Thread Starter
Intermediate
Joined: Jul 2001
Posts: 45
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From: Orange County, CA
Thanks everybody. I'll let you know the results next week. It's a relief to know that some valve noise is normal. I don't think it's gotten any louder in the last 10K miles so hopefully it's just me being paranoid.
Thread Starter
Intermediate
Joined: Jul 2001
Posts: 45
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From: Orange County, CA
Well, I brought the car in to another shop for the original problem (climate control related-saved $1500 in the process). The valve noise was perfectly normal based on the mileage from the last adjustment. A second opinion, even if it costs $75+, is definitely worth the trouble.
Thanks again to everyone who posted.
Thanks again to everyone who posted.
