28-04-2020, 09:37 AM
I know my engine is clean internally. I rebuilt it with a Phoenix crank about 10,000 miles ago and had it in pieces recently to fix oil leaks that had developed.
I was using straight 30 and had been thinking of looking for 5/30 for some time. I think keeping to the specified viscosity, ie 30, is a good idea and the 5/30 means that the oil pressure when cold is much lower. I also seem to have an improvement in performance, which I think may be down to modern oil technology.
I don't have a camshaft to hand and don't know what the lift is on a standard cam. However it is a slow revving engine so less of an issue.
I have a Citroen SM which has aggressive cams on flat bucket tappets. It is also high-revving for 1970. Zinc is essential and good used cams are very rare.
In the 1960's I used Castrol XL because I liked the smell. Some of the cheap oils smelt dreadful!
I was using straight 30 and had been thinking of looking for 5/30 for some time. I think keeping to the specified viscosity, ie 30, is a good idea and the 5/30 means that the oil pressure when cold is much lower. I also seem to have an improvement in performance, which I think may be down to modern oil technology.
I don't have a camshaft to hand and don't know what the lift is on a standard cam. However it is a slow revving engine so less of an issue.
I have a Citroen SM which has aggressive cams on flat bucket tappets. It is also high-revving for 1970. Zinc is essential and good used cams are very rare.
In the 1960's I used Castrol XL because I liked the smell. Some of the cheap oils smelt dreadful!
Jim