Mixter

I've noticed that going through many ads and threads, that it seems quite common for 964 motors to be rebuilt with less than 100k miles. Buyers and owners seem to have an expectation that if it's not rebuilt it will need one soon. There's a lot of talk and or worrying about the condition of our 964 motors. How many times do we hear "Before you buy you must get a PPI!".

It seems important for sellers and buyer to advertise that the cars had a full rebuild and usually at much lower mileage than 100k. This seems to bring value; however, if it needed such an early rebuild, what does that say about how the car was maintained or driven by the previous owner(s).

Yet, the 964 is often touted as the most reliable and trustworthy sports car money can buy; "Bullet Proof" it is often said. If this is true, I'd expect to see rebuilds being more common at around 200k at least, rather than under 100k miles.

Am I missing something here? There seems to be very few examples of higher mileage cars without a rebuild, or even the expectation that this would be more common.

sc

Great question...and will be interesting to hear comments. Mine is less than 100K and runs strong!

crg53

Valve guides and clutches are the weak links in the 964 power train. My engine had a top end rebuild at 90 000 KM (bad leak down numbers on 2 cylinders), and I replaced the clutch at the same time with the RS LW unit. I think the bottom end and the piston to cylinder fit is bullet proof and should last 300 000 km if looked after.

blackbull

The aftermarket always finds improvements on an original design given enough time.

mike9186

Is it possible to replace the valve guides without removing the heads? I seem to remember in Ardnans 100K tune up PDF (which is excellent BTW) that he removed the rockers and changed the guides prior to his valve adjustment.

ras62

Head stud breaks are another fairly common reason for top end rebuilds but I would say the vast majority are initiated due to owners wanting to cure oil leaks rather than the engine being worn out.

Goughary

In my case. I bought the car with the underbelly trays on, didn't take it off, and in Summer dead stop commuting traffic, everything ran too hot and I ended up with burnt valves.

Further, these are not hondas. If I drive my car the way I drive it, from now (top end rebuild and suspension sorted, etc) until 20 years from now...my car will need much more service and attention than your average Honda in the same period...and further to that, if it's me doing the service or having the service done, in 20 years my C4 will be in exactly the same shape it's in now, and the aforementioned Honda will be a total bucket and lucky if it's still driving. Our expectations for maintenance are higher than most...gotta keep that in mind too. I have a 25 year old "perfect" car. Perfection requires a lot of attention.

STUARTQ

That's the conclusion I came to also.

And many often decide to do other work while the engines out as a safe guard, not because it needed to be done.

Mine has now covered 140k odd miles and seems to be holding its own.

I also noticed that the clutch is often done at the same time.

Steve Weiner-Rennsport Systems

Its impossible to replace the guides with the heads installed on the engine; guide seals, yes.

There are many reasons why these engines need some freshening before the 100K mark, but that's a long story for another time. All said, the 3.6 is really a durable engine that can last every bit as long as their (incredible) predecessors.

Navaros911

Because the owner can. It's peace of mind to reset the counter to 0 for maintenance. The smallest reason for me was enough to think about it when chasing oil leaks. My wife giving me the green light was the deciding factor.

Hey, if I can now, why not?

J richard

I'm surprised how quickly owners jump to rebuilding. Each series of engine has its issues, but with the exception of the early O-ringless 3.6 the motor (which was a limited percentage) the 964 shares the same robustness as the 3.0SC which easily goes 150-200k. Valve guides not withstanding I've seen rebuilds of perfectly serviceable engines for simple leaks which could be done for a fraction of the cost with no real benefit of longevity or performance. Properly serviced 100k is a mid life engine...

newsboy

Mine had a top engine rebuild at 57K and a clutch at 48K by a previous owner.

Paul284pt

This is a very good question and there is no single answer but the above sort of sums things up nicely for me, at 70k miles, although head studs weren't an issue. I found that when the oils leak were fixed (before the engine rebuild) it was still using oil.

It's could also be like asking why people climb mountains, it's because they are there and people can.

Cheers,
Paul

Paul284pt

This is a very good question and there is no single answer but the above sort of sums things up nicely for me, at 70k miles, although head studs weren't an issue. I found that when the oils leak were fixed (before the engine rebuild) it was still using oil.

It's could also be like asking why people climb mountains, it's because they are there and people can.

Cheers,
Paul

ThomasC2

I also think it is because on forums like this problems tends to get over represented because people ask about faults and problems. Transferring this to facts for all 964 running in the world isn't the same thing.

Thomas