Break In Lubricant for Pistons & Rings
 

JE Pistons tech sheet suggests a light coating of an assembly oil (Marvel Mystery or similar)
Gibbs Driven HVL Hi Viscosity Lubricant (multi use assembly oil) reads piston skirts but may be a synthetic.
What is the recommendation for the rings, skirts, and Nickies cylinders ?

assembly oil
 

I would use a non detergent oil, or Gibbs BR break in oil is what I use on the ring pac assembly and engine run in as well.
Mike Bruns

I definitely agree with what Mike is saying and that is undoubtedly the way I would go as well, but I have to add that during a Mercedes during a tour I saw them assembling engines and lubricating everything with the same synthetic oil they recommend is always run in them. They must know something we don't.

He's thinking of preventing skirt scuffing and not ring sealing? The JE tech I am referring to.

I see two Gibbs' products for break in

Original: BR Break-in 15w-50
and BR40 Break-in 10w-40 -- within the BR40 product it lists muscle cars, European cars, and motorcycle engines

I'm thinking BR40 ?

Primarily I'm concerned with the rings seating against the Nickie cylinder.
Top ring is a very thin Nitrite ring

I am an old drag boat guy and am looking for the guidance from the experienced P-car folks.

A good coating of a good dino oil, like Gibbs or Brad Pen break in, is what you want to use.

Avoid any synthetics as they may not allow the rings to seat.

You are right to be concerned, these air cooled motors with the nikasil cylinders are unique and require special care for break-in.

Mike offered some excellent general advice that you cannot go wrong with.

I would add that ring seating and sealing depend on many factors that include ring material/coating, ring tension, cylinder wall finish (Ra, and this is critical!), oil type, and techniques used in this process.

Depending on the type of rings, ring tension, and cylinder wall finish, engines can be successfully broken in on synthetic oils, however this requires a specific set of circumstances and mainly for competition engines.

Use a GOOD break-in oil like Brad-Penn or equivalent and follow proper procedures for successful ring sealing in Nikasil cylinders. :) :)

Thanks to all for taking the time to provide guidance.
Prior to posting I think I read every break in thread until my head started spinning.
The guidance above helped.

Thanks again

Great advice provide above.

We used Brad Penn Break in oil for years with good success. Recently we have broken our last 3 motors in with Motul Break in oil. Very pleased with the results.

Jeff Alton
How long do you advice to run engine on the Motul Break-In oil ? Thats what I have in my newly built engine, and I now have some 350 miles on it but I now realize I did not think, until now on how long to run on it, except maybe until oil smell goes away and then change to synthetic. Grateful for any advice

Slight O\T but if pistons and rings have been retained, is any sort of break-in required?

New cams/rockers/crank/oil-pump