cobalt

So if I am not burning any oil between oil changes every 1500 to 2500 miles do I have to worry? I have put just under 20k miles on mine with 66k miles now everything sounds and runs fine as far as I can tell and dynos at factory numbers. It is a late 93. Oil dipstick always shows to be at adequate levels. Should I consider opening the engine?

Schocki

No! Why would you open a perfectly running engine that is not burning any oil under normal driving conditions? I was out of the country once for six months and my wife drove the car every day to work. Round trip of about 20 miles on the highway at moderate speeds of about 130 km/h (80 MPH). The oil low light never came on in six months and after six months, the dipstick still showed 3/4 full.
My 92 GTS is the same no oil consumption between oil changes and I don't change the oil every 3000 miles, which is a waste of limited resources IMPOV.
My GTS runs on GT cams, X-Pipe and has been sharktuned. It runs very strong and with the modified R&P to an US S4 2.2 spec., I can hit 143 MPH in 3rd gear all day long. Still no significant oil consumption.
Why would I open the motor?

BTW if you would have the chance to drive it on the Autobahn in Germany and constantly above 4000 RPM. It will consume oil. My 944 turbo, 944 S2 and now my GTS are no exception to this rule. There is a reason for the factory claim of up to 1.5 liters per 1000 km. It is possible even on a healthy engine!

SwayBar

Cobalt, you are golden, no need to open that engine up!

Petza914

WOW, that is impressive. Must be a unicorn and the only GTS able to do this.

cobalt

I'm assuming you meant to type 143 MPH?

Believe you me I wasn't seriously considering it. There seems to be this dichotomy of opinions regarding the GTS engine. I know of several and I don't hear that many issues if well maintained they seem to be like any other nearly 30 year old car. I am a die hard air cooled 911 specifically 964 guy but the GTS is a special car and I feel privileged to own one.

ROG100

My GTS has circa 170k miles and is a DD for me. Oil consumption, IIRC, was about a quart every 800 miles when I first bought it with circa 60k miles.
Once the car had covered 100k the consumption got better at about a quart every 1000 to 1200 miles (also depended how hard I was flogging it). I added a vacuum pump for the crank case and it further improved.
With 170K miles it is even better but I have not been recording the consumption lately - oil is cheap!!!!
My car has GT ++ S3 cams, lightweight lifters, X pipe plus 2.5" cat back exhaust and a larger diameter throttle body. Shark tuned with 24Lb injectors the car is great to drive.
My biggest concern is the oil ingestion and the build up of carbon on the pistons. Maybe not as bad as it used to be I still feel that I am losing power as any knocks (pinging) instigate retarded timing.
So I have a pair of late heads with 968 intake valves to go on. So Sean is soon to remove the engine and give it the full Monty.
I ordered the stronger connecting rods to replace the "weak"ones and we will be checking main and con rod bearings - to be changed if required.
Pistons will be drilled to end the carbon build up - hopefully.

Schocki

Yes, I it's a mistake 143 MPH or exactly 231 km/h in 3rd gear selected in the automatic. I changed the number in my original post.

928cs

At 243 kn, this would have been a very low pass

Schocki

This is about maximum gear retraction speed . Very low passes in wing 67° are well above 500 kts

siscogts

What shocki said. If it is good as it is, no...