AZ Targa

I don't speak for everyone, but I have put on most of the miles on my Cab, I started with 11k miles and now its at 75k. (Just as a reference)

TJ993

I would like to hear the Update - the cause.

My motor was rebuilt at 42,000 due to Exhaust Guides, it seems.

I did not own her at that time, but I did drill out the Exhaust Ports and that improved my Oil Consumption = Less.

Oil type is also a factor.

Best of Luck!!

TJ

berni29

Hi

I did my top end at 185k miles, not because of oil consumption or smoke, but because of a broken piston ring. The exhaust valve guides were shot, but the valves themselves were in spec. They were too far gone for k-lining, so I had them replaced.

Berni

kjr914

Before I bought it (and partially, WHY I bought it ), my car had a top end rebuild (valve guides) at about 45k miles due to CEL, but this was before the SAI clean out was known and it was under warrantee by a selling dealer (I"m sure lots of pressure by owner to fix it right).

M. Schneider

Nearing 100,000 miles since the October '97 delivery of 11 miles. No SAI issues, M1 V-Twin used, dry engine, oil used measured via dip-stick 1Qt every 4K to 5K miles. Typical OCI @ 7K to 8K miles-both filters; provides opportunity to have a look around . . .

The 3.6 runs strong-never apart, original clutch, etc. Great coupe.

IainM

I wonder how many top end rebuilds were a result of folks topping up the oil to 1/2 way on the dipstick and thinking the engine was burning a qt every 500/600 miles due to valve guide wear?

TJ993

Yes keith
My engine was rebuilt by Dealer at 42000 in hands of 1st Owner.
I believe there was Some Pressure or Persuasion involved. LOL

I wonder what Dealer knowledge there actually was Available in 2000???
What Oil was Being Used by Dealers??

My car came from L.A.
I wonder how much time the car SAT on the Freeway?
RETAINED Engine HEAT
I figure based on maintenance, the car was not driven hard enough.
CARBONED UP = Exhaust Valves Replacement??
Thirdly- Wrong Oil ? Maybe Viscosity ?

Correct Assumptions? What do you think? I do not want to alter or steal the thread i will send you PM.

I believe in my case the cause was all of the above.

TJ

kjr914

PM replied to.

Mark in Baltimore

Approx. 57,000 miles and no top end work needed. Burns little to no oil, even under track use (have used Redline 10W-40 full synthetic for years based on the ZDDP level).

solomonschris

I've yet to hear a good explanation as to why 993's might need top end work from mileage as early as 25k, or might go 150k plus...or any where in between. My NA 993's were sold in mid 50k with perfect leakdown. The 97' TT failed leakdown at 23k. One bad guide caused the problem. When a 50k NA could be had for $30k or thereabouts, and a TT of similar mileage for $70k, $6.5 to $8.5k was a big issue. With the prices these cars are bringing now, it's a much smaller issue.

race911

Because the guides are bad? While sub-50K jobs are the outlier, you guys would be shocked to see valve stem taper, and guide wear on the inner bore almost from the time they leave the factory. These things run clearances in another dimension, compared to anything "water" cooled and even boat anchor (VW) air cooleds.

As I've said numerous times before, if they were as easy to change out as brake pads (even if costlier), as soon as you guys had above zero reading on the bore gauge and micrometer, you'd be stumbling all over yourselves to replace them.

We've got one expert shop owner here who's been giving with his time, and very directly has stated the only way to check the above in the car--search is your friend.

race911

And my 4S had it done at 75K in the hands of the second owner, when it failed a smog check in 2001.

I have every receipt from new. It was dealer serviced only with the first owner, and in the hands of (probably) the top independent nearest to where the second owner lived. It was driven 15K miles/yr. consistently, probably with a decent mix of freeway, rural, and in-town driving. I know the car didn't see any track duty, at least anything more aggressive than beginner/lowest intermediate.

(Got your email with the invoice. Pretty much matches up with my car.)

tonypai

The first owner had a rebuild (bad valves) at 3 years and 40K miles. I just did a second rebuild at 99K miles.

kjr914

Why a 2nd rebuild? That would be very very rare, as the soft valve guides (is that what you meant above?) are the known weak point...

tonypai

As Steve Weiner put it, "it was the worst valve job I've ever seen". They weren't shimmed, all were bent and the SAI port was clogged. It was time.