John McM

A few months ago I sold my 1993 Turbo 3.6 to a UK buyer. It's in very good hands and is getting a professional going over. Well actually more than a going over, it will have a bare metal glass out respray, refurbished wheels, repainted calipers and a top end rebuild.

The concept of a top end rebuild on a car that has done 105,000km or 63,000 miles still seems strange, especially as I had the car from 45,000 miles and I don't abuse my cars.

Here's what the heads look like. It looks like the valves needs a bit of work, as does one of the rockers.

MeanMachine

Well he wants to know what the overall status of his car and taking it up to new.

Some items are not needed but its his preference.

I have a similar mileage Turbo 3.6 and I have resprayed the car, refurbished my wheels "James Dorociak",repainted my calliper and a top end rebuild .

Metal Guru

Look carefully at the exhaust valve guide; it's worn out. Compare it to the intake guide and you will see the difference. You can also see the witness mark around the valve seat where the exhaust valve was snapping shut in an eccentric fashion; in other words, it was missing the seat and hitting the head.
Eventually the valve head would break off and destroy the engine, so it was a good catch.
John, did the new owner ask for a leakdown before buying the car? A leakdown would have caught that.
Pitted cams/rockers are fairly common and not a show stopper.

John McM

Yes, a leakdown was done, albeit the tester couldn't get a good seal on cylinder one due to a chip on the head and it showed some leakage. I suspect now that may have been an unfortunate coincidence. Luckily the new owner has a great Independent shop and is thorough. Amazing to think a relatively low mileage engine needed this.

John McM

On the plus side the body looks non accident damaged. It was great in my last photos of it. It will be perfect after

Metal Guru

Every now and then you hear about a 60-70k mile car that needs a top end so it happens.

rstarga

just curios, what oil where you using?

John McM

Mobil 1.

The car sat for extended periods over seven years, but I guess I'll never know exactly what caused it.

mel_t_vin

John, what viscosity Mobil 1?

And how long were these extended periods?

John McM

0W 40. Oil changes done by the local OPC. The longest period was 14 months between drives. The car was always garaged and in a temperate climate.

Metal Guru

0W40.
Is New Zealand a chilly climate?
Here in the Mitten (Michigan) we can be as low as -20F (while my car is sleeping) to 95F but I drive my car (when it's running, that is ) in early spring and late fall also when it's low 40's out. I use 15W50 Mobil1 V-Twin.
Nonetheless, I'd put that guide failure down to a material issue, not an oil selection issue.

John McM

Lowest ever temp overnight is 35F, so no not a cold place where I live. The new owner is mulling over a complete overhaul just to make sure there is nothing blocking oil galleries.

rstarga

IMHO that was caused by improper oil and infrequent oil changes. The 0-40w Mobil 1 does not have enough zinc and other additives for flat tappets. Only 15-50 Mobil 1 or other similar specification oils works in these engines.
Any 0W oil in an air-cooled engine is a recipe for disaster. Clearances are much larger than the current water cooled engines.
I doubt you have a blockage, but I'd still tear the engine down to check the bearings and cylinders due to the incorrect oil.

John McM

I still have a 964, albeit it's used frequently on the Track, not stored. I'm using Mobil 1 Racing 4T 10W 40 based on an air-cooled mechanic's recommendation. Is that suitable?

rstarga

It has enough Zinc and Phosphorous, but I still prefer the 15-50 for an air-cooled. Especially for race track or hard use. Here is the spec sheet.
https://mobiloil.com/en/~/media/7038...f94e12c89.ashx