Break-in Oil

[LDunville]

I've got a 68 911S Targa in the final stages of a full resto. Last week I started up the engine for the first time and it ran like is top. I read several places about Brad Penn 20W-50 and bought a case for the break-in.

Just this morning, I noticed it says "partial Synthetic" which concerns me. I've repeated read that synthetics should not be used in older engines.

Should I be using the Brad Penn in a newly rebuilt 68 engine for break-in and/or long term usage?

Thanks in advance
Larry

[37yrold911]

do it; don't worry

only reason not to for the 1st 500 miles is that it is spendy for such a short run

[Norm01]

I used Castrol GTX 20W50 for break in and then switched to Brad Penn

[gled49]

We always run our engines in on an engine dyno with B.P. 30 wt break-in oil.

[37yrold911]

good point - I'd forgotten about that special purpose oil they have - I'd switch to that for the next 2-3 changes

if you are curious about the differences, BP is very good at answering questions, but the guy does so by telephone even if you Email in your question - also don't expect them to give away trade secrets

[NeunElf]

The main objection to synthetic oils is compatibility with seals. From the Porsche Classic Motoroil Website:

Modern, high-additive engine oils based on fully synthetic base oils can corrode old
sealing materials and make them brittle. There is also a risk that the deposits which have
built up in the engine over decades may be dissolved. Both of these processes can result
in leaks and, in the worst-case scenario, engine damage.

I had a Series III Land Rover for many years--some of its seals were leather. I suspect the seals we buy today are fairly modern--even if they go into 50 year old air-cooled engines.

I attended a talk by Dave Maxwell (THE guy who formulated Mobil 1) some years back. He mentioned that the first Mobil 1 formulations, a long, long, long time ago, leaked a lot. The base they used on Mobil 1 didn't swell oil seals the way "dinosaur" oil does. This probably led to the misconception that all synthetic oils leak "because the molecules are too small."

Mobil added an additive to swell the oil seals, solving the problem.

Personally, I'm not too concerned that Mobil 1 will destroy my oil seals. My big concern is that oil will break down at high temperature causing a catastrophic failure of a matching-numbers engine. Granted, 1965 911s don't overheat, but my Microbus and 356A are less immune.

It's certainly your choice of what oil you put in your engine, but at least some of the warnings about synthetics are unfounded.

[Noah]

You want to use a thinner weight (30) dyno oil for break-in primarily to ease seating of the rings.

[jos.hall]

The main objection to synthetic oils is compatibility with seals. From the Porsche Classic Motoroil Website:

Modern, high-additive engine oils based on fully synthetic base oils can corrode old
sealing materials and make them brittle. There is also a risk that the deposits which have
built up in the engine over decades may be dissolved. Both of these processes can result
in leaks and, in the worst-case scenario, engine damage.

I had a Series III Land Rover for many years--some of its seals were leather. I suspect the seals we buy today are fairly modern--even if they go into 50 year old air-cooled engines.

I attended a talk by Dave Maxwell (THE guy who formulated Mobil 1) some years back. He mentioned that the first Mobil 1 formulations, a long, long, long time ago, leaked a lot. The base they used on Mobil 1 didn't swell oil seals the way "dinosaur" oil does. This probably led to the misconception that all synthetic oils leak "because the molecules are too small."

Mobil added an additive to swell the oil seals, solving the problem.

Personally, I'm not too concerned that Mobil 1 will destroy my oil seals. My big concern is that oil will break down at high temperature causing a catastrophic failure of a matching-numbers engine. Granted, 1965 911s don't overheat, but my Microbus and 356A are less immune.

It's certainly your choice of what oil you put in your engine, but at least some of the warnings about synthetics are unfounded.

Great info Jim. I appreciate that. The "molecules are too small" is what I was always told growing up and the main reason I never switched in my vw. I've switched in newer vehicles but may have to try in the ole beetle.

[72targa]

"Partial synthetic" historically meant that the product contained at least some Group 4 base oil (typically PAO or polyalphaolefin [chemically synthesized base oil] as lead by Mobil1). Then there was a legal decision in the industry to also call Group 3 and even some Group 2+ base oils (highly refined petroleum base oils) "synthetic" due to their PAO-like properties.

It would be interesting to understand which part of the Brad-Penn 20W-50 is "synthetic" as the base oils above typically only apply to SAE 5W and lighter grades.

[jerryg]

I had my 2.0 911S engine completely machined and supplied with new parts by Walt Watson as in Competition Engineering. Here is his break in recommendations for 4 cylinder engines for the first 500 miles, but the same approach for 911s (more oil of course).

"1- Your restored engine has been sent to you EMPTY!!
It is up to you to fill the crankcase with oil.
We suggest a non-Detergent 30 sae oil.
This oil will be left in for the break in period. Approximately 300 to 600 miles.
After this initial period you may use any oil you see fit to use.
We don't use any synthetic oil partially due to the fact that almost all camshaft companies' call their warrantees void if they are used.
And we are still living in the dark ages around here.
Fill your Crankcase with 3 quarts. Remove all the spark plugs and disconnect the coil wire so the engine can't produce spark.
Crank the engine over until oil pressure is shown on gauge or until the oil light goes out."

The rest of Walt's tips can be found on his web site. www.competitioneng.com