Valve Guide Poll
03-10-2005, 06:03 PM
#20
Rennlist Member
Originally Posted by Rob993
For years I have been hearing about the "dreaded" valve guide, carbon build up issues on the 993's. 
What I am curious is how many of you guys actually have had them replaced and typically what did it cost? I know once a person does them, they tend to add a number of other toys that add to the total cost, but I am just trying to get a feel of what to expect on a couple of 993's that I am looking at in respect to the valve work themselves.
Search's showed tons of stuff, but not really a poll as to who has had it or needs it ..Etc
Thanks
Rob
What I am curious is how many of you guys actually have had them replaced and typically what did it cost? I know once a person does them, they tend to add a number of other toys that add to the total cost, but I am just trying to get a feel of what to expect on a couple of 993's that I am looking at in respect to the valve work themselves.
Search's showed tons of stuff, but not really a poll as to who has had it or needs it ..Etc
Thanks
Rob
You may want to start a poll (graphical) to give a snapshot of how prevalent the valve guide problem really is. As replies and descriptions are very helpful, a nice chart supporting it would be great imho.
Not sure if you can add it after the post has already started, but just a suggestion.
03-10-2005, 06:04 PM
#21
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top end rebuild was $6k for me here in the bay area. i got several quotes before i had the job done; the high price was $8.5k (which seemed ludicrous) and was going to take 1 month (don't ask me).
03-10-2005, 07:57 PM
#22
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I'm currently getting my top engine rebuilt, so final price is not for sure yet. But I'm having other stuff done at the same time. Not hot-rodding the engine, just longevity stuff. Mine has 110k miles on it.
Carbon build-up was horrible in my SAI ports. Just my perspective and what I've learned in the process, but I'm starting to think that the SAI ports make it seem valve guides are worn more than they are. Maybe instead it's just bad design of the ports. Anyway, time will tell on that. I'm starting to think the valve guide "problem" is a bunch of hype, as so many others have already posted.
What I think is the coolest is that, after 110k miles on my engine, the only major things they found were clogged ports and worn guides. Springs/retainers are fine, clutch okay, cylinder heads great, all valves fine. The guts of the engine are in great shape. How many other cars can make that claim after so much hard mileage? Getting my top engine rebuild has renewed my faith in Porsche's design and capability. It truly is an amazing car!
Carbon build-up was horrible in my SAI ports. Just my perspective and what I've learned in the process, but I'm starting to think that the SAI ports make it seem valve guides are worn more than they are. Maybe instead it's just bad design of the ports. Anyway, time will tell on that. I'm starting to think the valve guide "problem" is a bunch of hype, as so many others have already posted.
What I think is the coolest is that, after 110k miles on my engine, the only major things they found were clogged ports and worn guides. Springs/retainers are fine, clutch okay, cylinder heads great, all valves fine. The guts of the engine are in great shape. How many other cars can make that claim after so much hard mileage? Getting my top engine rebuild has renewed my faith in Porsche's design and capability. It truly is an amazing car!
03-10-2005, 09:42 PM
#24
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When I was in the trade, (back in the day) Porsche cars were THE most profitable car a garage could service in the repair business. Reasons being; 1. very good sources for parts through the aftermarket (= buy low, sell high). 2. Porsche owners typically want the best for their cars (protect the investment). Selling preventative maintenance is like taking candy from a baby. Now that I'm viewing from the outside looking in, I find many owners simply follow too religiously the advise of their repair shops. Many shops tend to sell services prematurely, the infamous valve guides a case in point. My advise; monitor your oil consumption, weight the cost/benefit of making the repair, wait until the car starts using oil excessively, get a couple of opinions on the diagnosis, cost and quality of the repair, and, most importantly, consult your forum.
03-10-2005, 10:37 PM
#25
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Thread Starter
Arrwin, good idea on the graphical poll. Problem is I don't know how to set one up on this thread.
Either way it seems the valve issues has approached "urban legend" scale, based on few actual rebuilds. When one has 100,000 + hard driven miles, and basically only some cars need a top rebuild, that's pretty good! Especially when one thinks of the Ferraris that are in the same class as the 993's, that have accumulated massive expensives to get to the 60,000 mile range
Either way it seems the valve issues has approached "urban legend" scale, based on few actual rebuilds. When one has 100,000 + hard driven miles, and basically only some cars need a top rebuild, that's pretty good! Especially when one thinks of the Ferraris that are in the same class as the 993's, that have accumulated massive expensives to get to the 60,000 mile range
03-11-2005, 03:24 PM
#27
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I thought you guys might find this interesting. I've been bugging the shop forman at one of the local dealers for info on 993 valve guides. We get into this debate on the local board also. Anyway, here is what he had to say.
George
George
Been sitting on valve guide survey I ran for quite a while. Really wanted to
investigate each repair and look at a number of things. Mileage, age, driver
habits, year model and production date. Most importantly to me, was to see
if repair showed additional items like; smog pump switching valve, check
valve, or check valve mounting block being replaced.
In any shop environment it's very possible to conclude guides are reason
for disassembly when in fact another factor can be involved that causes
incorrect conclusions to be made. It's been my personal experience that 1996
was the year that had the most problems.
Incorrect diagnosis can easily lead to valve guide repair if someone sees
secondary air faults in on board memory. Multiple other things can create
this situation.
I have only witnessed one car that had guides that were so bad, that
lifters were failing. It was a 1996. Mechanical symptoms are rare. Check
engine light generates most guide repairs.
Just came back from training in Reno for 987 and did take the time to
survey other techs that were there about this issue. Intro classes are the
best because dealers usually send their best people to them. Really
experienced, caring Porsche folk that understand the difference between hard
data and bad conclusions.
We all agreed 1996 was the year for guide problems as far as our experience
showed. Every one of us had seen a few 1995, 1997 or 1998 models, but the
ratio of that year to 1996 was overwhelming. And lastly we all agreed that
the years out of 1996 range we had seen were not 100% properly diagnosed, in
retrospect (hard to explain and would take 100,000 words to just get
started).
Guide wear is measurable and the ones that were out of 1996 range were
near, but not out of, wear limit tolerance according to everyone I talked
to, and that mirrors my own experience.
Porsche will never give us hard data on what happened here. I believe they
had a bad run of guides somewhere in the last 95 production, possibly into
early 1997 production. Vendor over there that supplies guides that just
didn't get it right for a long production run.
Maybe someday it will come to light. I could be completely off on this. All
I have to go on is what I've seen and what others I trust pass on to me.
Here is what we have done in our shop since 12-01-99; year model followed
by number of repairs.
1998 = 1 car
1997 = 2 cars
1996 = 10 cars
1995 = 1 car
I just do not have the time to investigate these cars individually to see
if any signs are there to indicate if guide problem may have been
incorrectly concluded. I find this most interesting, but day to day duties
just don't allow the time I need to properly investigate.
One thing is for sure. Every time someone in the shop comes to me with a
993 and possible guide repair; I immediately become very skeptical if not a
1996. Since my antennae has been raised to this a couple years ago we have
not found one out of 1996 range that needed guides. Again I find that to be
very interesting.
investigate each repair and look at a number of things. Mileage, age, driver
habits, year model and production date. Most importantly to me, was to see
if repair showed additional items like; smog pump switching valve, check
valve, or check valve mounting block being replaced.
In any shop environment it's very possible to conclude guides are reason
for disassembly when in fact another factor can be involved that causes
incorrect conclusions to be made. It's been my personal experience that 1996
was the year that had the most problems.
Incorrect diagnosis can easily lead to valve guide repair if someone sees
secondary air faults in on board memory. Multiple other things can create
this situation.
I have only witnessed one car that had guides that were so bad, that
lifters were failing. It was a 1996. Mechanical symptoms are rare. Check
engine light generates most guide repairs.
Just came back from training in Reno for 987 and did take the time to
survey other techs that were there about this issue. Intro classes are the
best because dealers usually send their best people to them. Really
experienced, caring Porsche folk that understand the difference between hard
data and bad conclusions.
We all agreed 1996 was the year for guide problems as far as our experience
showed. Every one of us had seen a few 1995, 1997 or 1998 models, but the
ratio of that year to 1996 was overwhelming. And lastly we all agreed that
the years out of 1996 range we had seen were not 100% properly diagnosed, in
retrospect (hard to explain and would take 100,000 words to just get
started).
Guide wear is measurable and the ones that were out of 1996 range were
near, but not out of, wear limit tolerance according to everyone I talked
to, and that mirrors my own experience.
Porsche will never give us hard data on what happened here. I believe they
had a bad run of guides somewhere in the last 95 production, possibly into
early 1997 production. Vendor over there that supplies guides that just
didn't get it right for a long production run.
Maybe someday it will come to light. I could be completely off on this. All
I have to go on is what I've seen and what others I trust pass on to me.
Here is what we have done in our shop since 12-01-99; year model followed
by number of repairs.
1998 = 1 car
1997 = 2 cars
1996 = 10 cars
1995 = 1 car
I just do not have the time to investigate these cars individually to see
if any signs are there to indicate if guide problem may have been
incorrectly concluded. I find this most interesting, but day to day duties
just don't allow the time I need to properly investigate.
One thing is for sure. Every time someone in the shop comes to me with a
993 and possible guide repair; I immediately become very skeptical if not a
1996. Since my antennae has been raised to this a couple years ago we have
not found one out of 1996 range that needed guides. Again I find that to be
very interesting.
03-11-2005, 04:27 PM
#28
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Thanks George A for that,
I’m using about 1 quart of oil every 1000 miles, and it really bugs me. My 95 does not smoke at all, it just passed Calif. smog with flying colors. She now has 67k, I got it with about 60K and my oil consumption seems stable. Could there be another reason for the oil consumption? The car runs perfect and has no other issues other than using oil. My local shop Hergesheimer’s says not to worry enjoy the car.
I’m using about 1 quart of oil every 1000 miles, and it really bugs me. My 95 does not smoke at all, it just passed Calif. smog with flying colors. She now has 67k, I got it with about 60K and my oil consumption seems stable. Could there be another reason for the oil consumption? The car runs perfect and has no other issues other than using oil. My local shop Hergesheimer’s says not to worry enjoy the car.
