How certain is valve guide failure in 3.2s?
 

Ok this is really becoming an issue for me as I look at cars.

I am considering 87-89 Carreras. A number of them are
selling locally for betweeen 55 -83k miles for about $24k
-25k. Then there some around $15k with 150-160k miles
but a top-end or complete engine rebuild with better
valve guides in place. There are also some cars for above
15k with NO engine rebuild and/or no history.

I don't want to be stuck with a bill of $8-10k on this car
since I need to take out a loan to buy it. So I need to know
just severe is the valve guide issue, how certain is it, and
when does it typically happen. What people are saying is--
and I know that some of this may be untrue but people
(sellers) are saying this to me, any/all of the below
assertations:

the PRO-"yes it is an issue people"
-it is a certainty that a top-end is needed because from
factory the valve guides are guaranteed to fail.
-it could happen say < 100k, but you need to start worrying
about it between 100-150k, and esp. as you get to 200k.
-unless you want a bill for 8k, make sure to buy one that has
been done.
-there is no way to predict it from leakdown/ compression
-some indicators (but not guaranteed) are fouled plugs,
and the same car suddenly burning more oil than usual

the NEGATIVE "no it is not an issue people"
-I switched to synthetic oil say and it hasnt
affected me, and probably never will,
because of the ligher, synthetic oil
-It only affected a small number of cars (not mine).

I'm confused. Please help. It will help me decide what to
do with my buying decision....

THks Marvin

Sounds like you have done a good deal of research already and have a pretty clear picture of the issue.

My take is that every model have their weaknesses, but most cars are sound. One can only take so much precaution - then the rest is up to faith/luck.

With a proper PPI done on a car that does not smoke excessively and does not drink large quantities of oil and the history reveals a good maintenance schedule - it is anybodies guess what is going to happen.

This probably does not help, but it is my humble opinion.

Good luck!

There are several simple visual tests that can make you aware of a valve guide problem. The 1st would be to have someone start the car up and you stand behind it to look for the tell tale smoke blowing out the exhaust. The motor will smoke MORE if it's cold. The next is to check the exhaust tip for ANY oil residue. Do this before you start the motor up cold if possible. The exhaust will be black and should have a some what chacky feel if the motor is tight. If you feel just a little oil film than take a look at the motor up on a rack and look for the slightest weepage of oil from the gaskets. ALWAYS get a PPI from a Porsche shop that deals frequently with the year of car you're looking at. I don't prefer the newer dealers because they usually deal with much new cars and they generally don't have the people that know older cars.
The last 911 I bought was an '86 and it had 135K on the clock and here's what I based my purchase on. The owner had a 3-ring binder that had complete records from day one. He had eveything from the original stamp manual through the last service that was done to the car prior to my purchase. I put it on a rack and looked it over for my piece of mind and than drove it pretty hard for about an hour. I drove in traffic on the highway and even took it to a mall parking lot to check out reverse. I promptly stroked the check and drove it 2,200 miles in 2-1/2 days without a hic-up.
Do your homework, drive the car untill you're convinced that it's right for you and don't get caught up with your emotions.
Happy hunting,
Steve Ed

I think it would be best to buy the car with the assumption that it will need the job done, if it has not already been done. Also, there is a difference between replacing the valve guides and a rebuild. Just having the valve guides done and replacing some/all of the valves will NOT cost 8-10k. Also, if you remove the engine, take the heads off and take them to a mechanic you'll save a lot of money.

not sure how much I can add....
I bought an 89 3.2 and didn't really know that much about this issue or any others...but I do now.
there are several ways to check the car re. valve guides, pull the headers and look to see how much oil has or is being burned, get the motor hot and listen for ticking noises assuming the valves are adjusted properly, have a mechanic lift the valves and check for movement....
if all of this checks out and the oil consumption is low e.g. <1qt/900miles then you should be ok....start a savings account of $300/mo.

I got my car with 47k miles and it already had the issue, no maint. records...

depending on the knowledge and skill of the mechanics that have been in the engine before now...you will probably have to do a valve guide job at some point unless it has been done before..

I completely rebuilt the top end along with clutch and just about everything that could be done without splitting the case at 70k miles.

the car runs great now..I feed it 15-50 M1

I would agree with 889911coupe, assume any 911 will need some valve/engine work if it hadn't been done and documented by the PO. Even cars with low miles. Some get lucky around here and have bought cars with no problems for years but I would also take into account the other extreme as well.

In my search I looked at a lot of cars with 80-130K miles and a few had no head/valve work but drove well and had no smoke. A few even had decent leakdowns. After spending $$ for PPI's and getting nowhere I ended up negotiating down on an '88 that needed a top end but had perfect paint, interior and a new clutch etc.

In the end I'll still spend towards $20K (they all cost that anyway), but I will have a car that has all the work done by a reputible shop that I know and should be good for another 100K miles.

I thought they fixed the problem later in production. Nevertheless, my advice would be to buy one with higher miles that obviously was cared for and has lots of records. You save so much money over a low-mileage car. If I had a do-over, I wouldn't pay a premium for "low" miles.

I'm of the opinion that the Carrera worn valve guide issue is overblown. Certainly, some percentage (I have no idea of the actual number) of the Carrera's were produced with 'inferior' valve guides, but too assume that all of them fall into this category is short sighted. As others have stated, oil consumption is the primary indicator of worn valve guides, and although there are exceptions, most Carreras will exhibit this characteristic say in the 60-90K mile range. If you purchase a well kept example with say 100K miles, that does NOT mean that a valve job is on the horizon, it probably means that you're good for many, many miles of smiles. On the flip side, if you purchase a Carrera with say 40K miles on her, you might not have reached the point where the issue typically surfaces. In my case, my car had 46K on her when I purchased her (now around 65K), and doesn't use any oil to speak of, so I 'think' I'm in the clear :)...time will tell. Every era of 911s have their 'issues', but SCs and Carreras are as close to 'bulletproof' as you can get for 20+ year old cars.

Valve guides on any 911 motor will wear. There is nothing that can be done to prevent it. I have an 81 and the top end was rebuilt 25-30k ago and the exhaust vavle guides are already worn and the car is burning some oil. I'll end up rebuilding the motor again next year and doing some upgrades but I know later on down the road this process will need to be done again....

Very true, but the 'bad batch' that went into 'some' Carreras make this the topic of this thread...

Marvin, for what its worth, I'll share my experience with you on this topic. I bought a 1987 with 140,000 miles on it in July from a neighbor and spoke to the local mechanic (who worked on the car the past few years) at length before buying....no PPI or leakdown test....I just trusted the mechanic and felt I had enought cushion in my price ($8k) to cover future repairs without getting upside down. In any event, he told me that the valve guides are worn and will need to be replaced as some time, not necessarily right now. Valve guide wear is progressive (i.e. they fail/wear over time....not overnight). Smoke on start-up will get progressively worse and consumption will increase.....you have to determine when to pull the trigger and replace the guides. In my case, he told me that I could resonably expect to drive the car for another 50,000 miles before having to replace the guides and to expect a cost of $5,000. My oil consumption is 1 qt per 600-700 miles which concerned me at first but from comments on this forum I'm not so worried anymore. Some say that 1 qt per 1000 miles is "normal" for a newly rebuild engine but you'll see opinions all over the board. I have a little smoke on start-up and no visible smoke when warmed up.

Good luck.

If I recall Poly Bronze are the best material type for valve guides.... and yes you are correct I was making more of a general statement

It might be helpful if you were to indicate how much you plan to drive it. If it is a low mileage per year, why would you worry about it?

my guess is that around 20% have PREMATURE valve guide failure.
check head studs too.

Marvin,

some thoughts:

Yes, the problem will not show with a leakdown or compression test.

It will be apparent in oil consumption, yes, but you have only the seller's word on this. I had (as you know) a severe guide problem on one cyl, but my exhaust tip was not coated with oil.

Plugs will be a good indicator of this condition. Pull them and have a look. If oil is getting into the cylinder in any appreciable quantity, the plug will be black and fouled. Be as suspicious of brand new plugs as fouled ones. They should have a couple thousand miles on them to be a good indicator of the cylinder's condition.

Very experienced mechanics will be able to estimate valve guide wear by the amount of radial play in the valve, so it is checkable to a degree by the right shop.

I don't think running with synthetic oil etc. will help slow\control this issue to any appreciable extent. Not all Carreras seem to suffer from it, but even Bruce Anderson did not hazard a guess as to which years are more likely to exhibit it IIRC.

Best advice is a higher mileage car that's already had the top end done.

ianc

I think, although I may be wrong, that at least one of the contributing factors is the climate you live in. I own an 88 cabriolet, and up here in Canada where its cooler, it doesn't seem to be as much of an issue. My mechanic claims that its the cars in hot climates that seem to have the most probllems with valve guides. If he's right, than cars in the southern states would have the most problems. Just my two cents ...

I believe the 993's are having some valve guide wear problems as well. Just the nature of the air cooled Porsche beast, live with it or pass. I personaly would have passed on my '87 if knew. Maybe a Z06 Corvette?

Anyone close enough to kill the heretic? :)

I think the biggest contributing factors are heat and lack of maintenance. Cars from hotter climates will obviously run hotter, accelerating the issue. A good PPI will really only tell you if the car has been maintained. Leak-down #'s aside you should be prepared to spend the cost of a top end rebuild sooner or later. Another test for valve guide wear is to rev the car to 5K and quickly let off the gas pedal. This creates a high vacuum situation and worn guides will emit a puff of smoke from the exhaust. I have seen this myself on a 3.2. Not on my car (yet). I'm with Ianc - a higher mileage car with a top end already done is a good value.

Not trying to be a jerk or brag but, these are expensive cars. If you need a loan to buy one, make sure the loan includes enough cash to make inevitable repairs. I saved until I could pay cash and have carried out small repairs myself. When the time comes to rebuild I have cash.

Good luck in your search. I love my G50 car and will rebuild the motor when the time comes. Or maybe I'll get a 3.6

My previous car before my 993 was an 88 Carrera that I bought with 158K on the clock. A top end had been done @ 130K by the previous owner and by the time I sold it after 3 years it still was using a negligible amount of oil (about 1 quart/2K miles). I bought my 993 with 34K on the clock and am now approaching 60K miles after 3 1/2 years. I still haven't seen a CEL, but know it could come at any time. I am going to drive the car until it happens then deal with it. The problem seems to have come from a decision by Porsche to use softer guides. It is probably overstated to some degree because I know of 993's on Rennlist with over 100K miles and no CEL, but it will happen sooner or later on all 3.2 Carrera's and 993's with OBD II. The 95 993's don't see the problem as much because they don't have the dreaded Check Engine Light, but they still need to deal with smoking and excessive oil consumption eventually because of the guides. There are better guides available now and if my 993 needs a top end that is what I will do.