Subject: Re: V12 Engine oil
Dear petemick
Nice car, I have the same, do you have an image to post?
Get the repair instructions written by David Hine, join the club if you have not yet.
Very important with an engine with unknown history is not to use modern oil with many additives which can detach deposits having been sitting in corners of the oilways for decades. As the original engine has no modern oil filter all this stuff would circulate permanently around and create wear or plug the system somewhere. The system is designed for oil without these additives and the sump is the "filter" it should form sludge here
I think there are two possible ways to go:
1. You leave the engine as is, stay with classic oil and change the oil often. I do it this way. What you should do at least is to remove the old oil, remove the lower end of the sump (the large flat ribbed plate held with huge number of screws and clean out the sludge there. Open the double "oil filter" housing and have a look at the filters and clean them with fuel and see if they have no damage. It might be good to check the pressure relief valve in the oils system that it is not stuck open (see also what Mark and Jim wrote about that). I am driving less than 2000miles per year with the car, so changing the oil once per year is a bit a waste of oil but cheap (the manual for the car says change every 5000 miles) and you can not do anything wrong with a mistake in a conversion (it is a complicated system and every change here changes something there). I am running with cheap SAE40 oil from a local supply.
2. You do a conversion to modern oil filters (see also the above post from Mark and Jim, there are also other ways to do it, e.g. a conversion of the original oil filter housing with fitting modern filters there). This conversion especially makes sense if you have to overhaul the whole engine. After that you can run modern oil.
What you also should do is to open the water plates (at least one to have a look). Again many little screws and it may be very hard to loosen the water plate without damaging it. Remove the sludge on the water side.
Let us know if you have more questions, I am pure amateur but try to learn and do much myself.