Jagboi requested I open this thread. It is going to be basic & in layman's language and only contain major pointers.

Running in an XK engine in very basic terms after rebuild. I warned him this could trigger objections

Ignore Jaguar's run in procedure. It is no longer valid. Dead as a Dodo.

With modern lubricants this can take forever with negative effects.

Suggest run-in/break-in with a Petroleum based Monograde oil of Max SF quality. SE if you can find. You might have to go to diesel oils to achieve this. Diesel engines do not run aggressive camshafts & are rev limited by the combustion process.

SAE 30 or 40 is fine. SAE 40 in hot countries. Elevates oil pressure while asperities are worn off.

After the first 300Km's/200 miles give the car bursts at full throttle. Only once at operating temperature.

Always watch the temperature gauge. If it rises unduly back off the throttle as the engine is still a little tight.

At all costs avoid constant throttle running. You need to back off frequently to draw oil into the ring belt.

You can use higher revs than Jaguar suggest. Add minimum of 500 to 1000 RPM to the suggested

In plain English don't pamper the engine in it's early mileage or you will have an oil burner for life. (Due to cylinder bore glazing or polishing ~ Two different mechanisms).

Continually press the engine harder & harder always watching temperature.

Lubricants have come a long way since the XK engine was designed. Their engineers would love today's lubricants.

Once you have done 2000 miles or 3000Km (ultra cautious) Demand full performance from the unit.
On my car I intend doing this from 1500 miles or 2400 Km's

Change oil at 1000 miles or 1500 Km's leave filter until 2000 miles or 3000 Km's (it will be doing a better job of removing small particals & won't go into bypass) After that change oil & filter every 10,000 Kms or 6500 miles. This could be extended if running synthetic oils but I suspect these cars are not going to run up large mileage & we will change oil on time. i.e. every 2 to 3 years is suggested.

Once run in:

Change to synthetic oils from SAE 5W-30 or 10W-30 up to max 5W-40 or 10W-40 (Stay away from 15W-40 due to ZDDP restrictions) This will extend cam & follower life.

Remember these are SAE 30's or SAE 40's at operating temperature ~ not too thin.

Jaguar never specified above an SAE 40 and that only in Tropical conditions or Torrid zones. 20W-50's are out unless you have a worn engine & are trying to delay the inevitable.

Avoid so called Classic Car oils ~ they are generally rubbish & they have the cheek to charge a premium for them. They use cheap Base oils & Viscosity Index Improvers & shear out of grade i.e. become thinner with use.

Synthetic oils will extend engine life substantially. Don't fret about oil pressure if it's slightly below 40psi at 3000RPM although unlikely on a properly rebuilt engine. Suggest you Plasti-gauge every bearing.

If you want a Quality level to follow, once run in, use any product APPROVED against Mercedes Benz 229.5. (NOT meets the requirements of). They physically test each candidate oil prior to approval and have an arduous test regime. Many products to choose from.

https://operatingfluids.mercedes-ben...sheet/229.5/en

 

Thank you very much! This will come in useful for running in the engine I just built.

 

Thanks for posting this ! Good and needed info for me as my rebuilt engine has only about 100 miles on it.

 

Re-torque the head at what mileage ? I was thinking at 500 and again at 1,000. Perhaps this is overkill ?

 

Just do it at a thousand. Many don't do it at all.