Re: Engine oil

Posted by Owen_Dyneto On 2015/6/26 22:16:56

Most any oil you chose to use will be an improvement over the oils of the era of your car. IMO the only times a diesel-rated SAE15W-40 would be a poor choice is (1) for use in cold weather and especially for cold startups and (2) in freshly rebuilt or low mileage engine with clearances like a fresh engine. Rislone is primarily a detergent for sticky valve guides and rings and will not increase oil pressure - not that it's use might not be beneficial once or twice though if you do so, change the oil & filter more frequently.

40+ psi at road speed is an adequate pressure that engine, IIRC 45 psi at road speed was considered normal for the 356 engine. If you want to get to 45 psi you might consider adding a thin shim behind the oil pressure relief spring. No adjustment will change the hot idling oil pressure though a heavier oil might boost it a bit but even so I wouldn't be concerned with that reading.