Oil selection?

[remraf26]

I need some suggestions/ opinions on what the best oil to use is in my 1973 258 i6... Any takers?

 

[Jeepergeo]

10W-40 or 20W-50 (if you can find it). IMHO, the brand does not make that much difference. That engine was not designed to run of the thinner oils used today to boost mileage. Its not that older oil formulations are better or worse than today's formulations, they are just different.

 

[steady.foot]

Get some oil with zink additive in it or get some zink to put in your oil. I think they call it ZDDP They used it back when but took it out for emisions reasons. These older engines weren't desighned to run without it. It makes the oil stick to parts better.

 

[69jeepcj]

Yes, ZDDP. flat tappet cams need ZDDP (ZINC) to servive, most modern cars are running roller cams and dont need the zinc like the older cars did with their flat tappet cams. Valvoline racing oil has the most zinc that I have found, or rotella motor oil for diesel engines, either is about $5 a quart. I just put a cam and stuff in my motor last spring and comp cams recommended 5w-20wt, I have more engine than you but both are older engines and would benefit from the same. Without running the ZDDP you risk a high chance of wiping out a cam lobe quick. Modern oils dont have the zinc like they used to because the roller cams in newer cars dont need it.

 

[remraf26]

Thanks a lots guys. I had no idea about the zinc. I learn something new everyday on here.

 

[carnuck]

Delo 15W40 is what I ran for 240,000 miles. Now it's running 15W50 Napa synthetic to cut the blowby until I can build the stroker in my shed.

 

[remraf26]

Blowby?

 

[flatie46]

I think they quit putting zinc in the newer oils because if the car uses any oil when the zinc would burn in the combustion process it would clog the cat convertor.