Triumph Repair: Oil change for a 1970 spitfire?, triumph spitfire, mileage engine

Question
What type of oil should I use in my 1970 triumph Spitfire?

Answer
Hi Hap,

Oil weight should be matched to the engine condition and temperature in your area. Also, engine condition will dictate what oil should be used. In the summer and a high mileage engine you should use a heavier oil like 20w-50. If the engine was recently rebuilt you would use a thinner oil like 10w-30 and also that in the cold weather. If you don't know the history of the engine you can sometimes tell by the oil pressure. You want to see from 25 to 35 PSI at idle with hot oil and from 45 to 65 PSI at 2000 RPM with hot oil. If you change oil and put in 10w-30 and the oil pressure is low after the oil gets hot, you should use a heavier oil. Always change the filter every time you change oil.

As for what brand to use, that is a matter of choice and any name brand is usually good. What ever brand you decide to use NEVER add any other brand to it when it is low. Also don't keep switching brands back and forth.

I can't comment on the Syn. oils as I have not experience with them.

Howard