Engine Never Started

You defiantly want the rings to seat
So just mineral based oil
Don’t think zddp makes a difference in 30 minutes of run time
I believe zddp ingrains into the metal over time but don’t quote me on this

Yes I want the rings to seat, but you really need to drive it to do that. Whereas the cam needs to run in right away without the car moving, IMO. The cam is where the lack of phosphorus in the zinc-phosphate compound makes the difference with a push rod flat tappet cam engine. The XK doesn’t have pushrods of course so maybe its not such a big deal. On the other hand it will not hurt. I don’t know about the absorption of the zddp into the metal, perhaps so. But I feel confident it functions as a boundary layer protector that keeps the impacting loads from squishing straight oil out and allowing metal-to-metal contact. And here we promised to not talk zddp! Sorry.

At what RPM? And with vacuum advance?

3000 rpm 28 degree advance with vacume disconected. Not saying that’s right but works for my setup.

Ok, I thought it may have been at idle.:scream:

Clive, I do indeed have the 4.2 flywheel. I have to verify if my starter is correct too, but I believe it is. So, that is a bit of a relief: the mechanic who did the work so many years ago did the conversion properly. I am assuming he did the internals right too. But when he put it in the car, there are bolts missing (motor mount) and some not tightened. I’m checking all as I move along.