ianellison

Just had a top & bottom end rebuild and have to decide which oil to use after first oil change/tappet adjustment at 1000 miles.

What do you use?

RonCT

One shop I do business with suggests Castrol GTX 20-50 High Mileage in order to get proper levels of Zinc and Phosphorus. Another suggests Mobil 1 Tri-synthetic 15-50. Right now, my 964 has a little of both - topped off with GTX and then discovered the last change (2k miles ago) was with Mobil 1... I asked if mixing and matching was a problem and the answer was absolutely not - so maybe I have the best of both worlds

ScottR

My garage puts Castrol Magnetec 10W40 in mine.

Henry964

i am using 5W-40 fully synthetic in my 964 with the engine untouched at 95 k miles, i am having a change of mind and maybe I will use a 10W-40 semisynt next change

RonCT

Both shops highly suggested 50 weight on the top end - these engines run very hot, especially on the track.

TR6

I recently had my engine built (top and bottom) by Buckley Racing and and after the initial startup oil was drained, he recommended Swepco 306 oil due to its anti wear additives (Zinc, phosphorus, etc). So I'm using Swepco 20w50. A lot of folks use Brad Penn for the same reasons (anti wear additives). It's fairly common knowledge (see many past posts) that the mass produced oils such as Mobil 1, Valvoline, etc, have reduced their zinc levels.

MisterRisky

brad penn 20w-50 in summer, blended 1 to 1 with 10w-30 in winter for a net weight of 15w-40 in winter.

Manny Alban

Castrol 20w50 in the race car and Mobil 1 15w50 in the street car. I change the oil in the racecar every other event.

velocitylover

Brad Penn 20w50(2600 mi on total rebuild).After brake-in did Castrol 20w50 but was told reformulated oils not so good for air cooled with tappets.Look up big oil debate on this forum ANYTHING NEW ON THE MOBIL 1 FRONT?on 993 forum.Good luck!!

RonCT

The change in formulation is why my shop said to use the "High Mileage" 20/50, which has the "old formula" levels of zinc and phosphorus for our air cooled engines.

MisterRisky

For your reading pleasure, the infamous "Anything New on the Mobil 1 Front" thread. Brought to you by the kind folks on the 993 forum:

https://rennlist.com/forums/993-forum/407224-anything-new-on-the-mobil-1-front.html

velocitylover

Got a little mixed up!! Thanks MisterRisky

MisterRisky

You're right on velocity. I just added the link. 'Cause I'm a nice guy like that.

JasonAndreas

Mobil 1 0w-40

dfinnegan

Zinc be damned!?

OT: Did you bring your car with you to your new location?