So how many miles until you rebuilt your 3.2?
 

Guys,

I just bought an 84 911 with 115,000 miles on it. This is my third Porsche and I think the best one for my taste. I had a 67 912 which was a great little car and a 75 911S which wasn't such a great little car. This one is really tight and no leaks! It is a really fun car to drive. Back to my question... At what point did u decide to rebuilt the top end or the entire engine? I heard these cars run past 200,000. My car has great service records and I spoke to the second owner who was a fanatic about maintenance.

Thanks!

From looking at my records, it didn't see any engine work until the ~170,000 mile mark.

If the car is tight, strong and dry I see no reason to open it up anytime soon unless there's some pressing issue...

My car now has ~250,000 miles on it.

No plans to open my engine up! I like to hear from guys who have that many miles on their cars. Thanks!

Mine had the top end done at 110k. Notes from the previous owner (twice removed) indicated head gasket leaks on a couple of cylinders. Made me wonder about head studs. Main bearings, P & C's are all still original. Rings and guides were replaced. Case was not split.

Now 46k later, still runs like a champ, and not a drip of oil, ever.

Top end at 200,000 and passing through 250,000 with no issues...1985 driven frequently.

Jim - You will know the time when the numbers tell you it's time:
Compression, leakdown, oil pressure, oil consumption, etc.

AS usage, conditions, and driving habits vary; you can't count on mileage to tell the whole story........

Did my at about 170k but it was really just because the valve guides were wearing out and the teeth on the starter ring wore out so decided to go ahead. Internals in stunning condition, pistons, cylinders, etc. in spec along with cams. Replaced all wear parts of course but over all it was in great shape internally.

My experience
 

My top end was performed at 72K miles because it started to burn a quart of oil every 400 miles. I should mention that the car was well cared for and not a garage queen.

Mine had a complete top-end done at 88K miles. The dreaded valve guide issue lead to high oil consumption and smoke. She is now at 120K and no problems.

150K due to a broken headstud and low compression on one cylinder due to broken ring.

Mine had a top end done at 158k.

valve guides were toast.
They say the old materials were soft comparatively. Let's go another 200k.

Top end at 95K on my 88. Replaced dilivar exhaust studs with steel. Did not split the case. New sensors and clutch "while in there." Also did shift fork upgrade.

184k on my '87........needed a valve guide job so, while I was in there.......you know how that goes.

Incidentally I had not planned on splitting cases but we did it after a little fax pas on the initial re-install, and it has been a phenominal engine since....tracked 5 times, leak free, probably uses a little over couple of quarts between oil changes (3k miles, Brad & Penn)

My SC had a rebuild at 200K. Its now 240K.

There are many examples of cars going to 200k and beyond without opening them. It's hard to determine what is the secret of longevity in the ones that go so far. My car hasn't been opened up (at 95k) and shows no sign of needing it anytime soon since it goes 3k between quarts and pulls like a train...touch wood. Usually when an owner chooses to do a top end it's due to excess oil consumption, and this seems to happen, mileage wise, all over the map. Cheers

At 127,000 miles the top end was rebuilt due to smoke on deceleration. Oil usage was 1quart per 500 miles before getting the work done.

top end
 

134,000 top end done was burning oil, doing great at 154,000 and still strong

39,000 miles on my 84...no issues yet :-)

242,000 miles on my 1984 Carrera and still going strong. She's a daily driver so the miles just keep on coming.

My '88 was my daily driver and was just over 220K when I sold it. Motor was never touched and ran great.

Jim (chatas17),

I think you are getting some good perspective above.
Best is:
In its formative years, if your 911 had been “driven hard & put away wet”, it would shorten its life.

There are three important factors:
How it is (was) used (my above “…put away wet” comment).
and
How it was serviced.
A close third is your expectations – it takes regular service (top-ends &rebuilds) to maintain peak performance.
I have some race engines that I completely rebuild every 25 hours of green-flag on-track running.
My street 911 SC is a bit more extended.
My original ’68 911 doesn’t count as it had a fresh (test :rolleyes: ) engine too often to count.
Your question is “How close to ‘perfect’ do I want to stay?”
For a street 911, most of us accept something only slightly less than 100%.
I’ll leave the 100% to racing.

Bob S. (LakeCleElum)’s post shows you the ‘way’.
Maintain a history of cylinder leak, cranking compression and other.
This will guide you to when it is ‘necessary’ or simply prudent for a rebuild.

Best,
Grady

What is the average cost of a top end rebuild?

Mine has 118K miles on it. Never cracked open, burns about 3 quarts per 1000 miles. It's about time...................:(

124,000 on my 88 Carrera. No issues. No plans to do anything but drive and maintain. Runs excellent, even on top of the Continental Divide.

Karl
88 Targa

I bought a used 1986 3.2 engine with about 80,000 miles. It was obviously driven hard by the previous owner, noted by the fact it came from a wrecked car. It needed the guides done, everthing else was ok. I did the valve guides, exhaust valves, and rings. Bottom end was still good. It ran great and I ended up selling it to someone for his 914 conversion.

My 88 has 138k miles on it and burns no oil, still on first engine and runs really strong.
My neighbor has the same car but the 89 model and had to rebuild the engine at 80k miles (2 years go).
Even with all the miles my engine pulls stronger than his.

On my 87, was burning oil so did the top end at 190K. What I found surprising inside was the amount of build-up in the exhaust ports. They looked to be 25% blocked, been told thats from fuel. I'm glad its all done now and clean as a whistle inside. All the "misc" minor leaks are gone now also.

My compression and leak-down were great, but was consuming a quart of oil every 400 miles prior to a top end (guides, seals, intakes, rebush rockers, etc) at 90k. I ended up splitting the case to check everything out and replace the intermediate bearings. Re-ringed pistons too. Running great now.

Top-end done at 73,000 miles. I was burning a quart of oil every 300 miles. New valve guides, studs, rings, sensors, etc. - car runs great now.

110k and brought it in for a valve adjustment...two broken head studs fell out when the valve covers were removed...absolutely amazed at how much better the engine runs now 10k post-rebuild. The air-cooled sound is still there but it sounds so much tighter/better and the vibration level in the car is way down...of course it pulls much stronger now...best money I've spent on the car followed by the Griffith's A/C.

I was expecting mine to need it by 300k, but it still runs strong and pulls like a freight train.
Burns a quart of oil about every 6-700 miles these days, I'll wait until it loses power or starts burning more oil...

Chuck.H
'89 TurboLookTarga, 335k miles

196k and dry
 

I have an 84 with 196k. The bottom is dry and no smoke on deccel or accel. Quiet all through the rev range. Will need the chains replaced as I noticed stretch symptoms once on a really hot day. And love the Motronic over SC CIS especially with the addition of a Steve Wong chip.

135K on my 84 no leaks, smokes for a few seconds after it has sat for a few weeks. Uses about 1.5 quarts of oil on a 5K oil change.

My new to me '88 is smooth with plenty of power. Compression numbers are excellent -- BUT it burns oil. Get an occasional whiff of blue smoke at stop lights. I would estimate it burns a qt. every 500 miles or so. I knew when I bought it that the valve guides were showing wear, but I didn't know it would burn this much oil. It's got 113K and the (complete) records suggest that the previous three owners maintained it properly.

So what do you guys think: I can live with the oil consumption indefinitely, and I'd like to put off opening the motor until something forces me to (like a clutch replacement). I know that worn guides compromise the valves' ability to dissipate heat, and that in theory one could overheat and break. But that strikes me as an extreme case scenario -- or is it?

I was going to post my own topic, but it seemed relevant to this one.

Thanks!
Hugh

Bruce Anderson, "i have never rebuilt a 911 engine because it wore out"

Rebuilt the top end of my 87 at 100k miles, oil usage had climbed to 300 miles so it was time.
As noted on a previous post, my ports had very heavy deposits that likely choked the air flow 25%. Yours may run for years without issue, but if consumption is at 500 miles then it is just a matter of time. If you are motivated you can do most of the work yourself, will have to sub out the head rebuild to a shop but there is an abundance of documentation available on how to do remove and disassemble the engine. Start reading now and when you feel the time has come to make the leap you'll be prepared for the job.
Other good sources are Wayne's rebuild book, the Porsche service manual and the Bentley manual.
Cost to rebuild the heads will be around $1000, gaskets and other while in there items will add at least another $1000 to the parts total. Go whole hog and the while you're in there items can really add up so be mindful if on a budget.
Assistance from the forum is priceless.

My 85 911 has 140,000 on the clock. Never been opened up and runs great. Oil use is about 1 Qt per 900-1000 miles. Runs very well and passed Cal smog with ease. So that tells me it is in good shape. A well known San Diego Porsche mechanic told me that it should go 333,000 miles easy. Wow, these are super cars. Most cars our vintage have been crushed long ago. But when I see a vintage 911 it usually looks great! Inmside and out. Like mine!

110k on 89 3.2. It was smoking and using a quart per 350mi. I intended to do a valve job but that turned into a complete rebuild. I got curious about the bottom end and pulled it apart and I'm very glad I did. A couple of the main and rod bearings were worn and the intermediate shaft bearings were showing copper. This "valve job" has turned into a new set of Mahle pistons and cylinders, ARP rod bolts and head studs, new main and rod bearings, rebuilt rods, 964 cam regrind, rebushed and resurfaced rockers, etc, etc. I have a problem in that I can't seem to just do the minimum required with these car projects. :rolleyes:

When I swapped engines on my SC, I was told that the 84 3.2 engine I put in had 70k miles when it was rebuilt. I do not know why it was rebuilt so 'young'. I have since put another 5k miles of very happy motoring.

So why do these engines run so long? The geometry? The air cooled concept? Do the 996's last that long? Just curious. I'm amazed how much pull my car has with 115,000 miles.