Synthetic Oil

[SkiLew]

I got such good advise from my last post about a carb problem I thought I would ask the experts out there about this issue.

Is anyone using synthetic oil? I have a 1993 Ford 351 engine with the GT-40 heads. What is the recommended weight oil for this engine and is it ok to use synthetic oil?

Also need to know what temp. thermostat to use.

Thanks,
SkiLew

[itaxcpa]

I had the same question you did - found answer at http://www.pcmengines.com/faqs.html - here it is (snip):

Q. Can I use synthetic oil in my PCM engine?
A: Synthetic oils are not recommended for use in PCM engines. Synthetic oils may offer advantages in cold temperature pumpability and high temperature oxidation-resistance. However, synthetic oils have not proven to provide operational or economic benefits over conventional petroleum based oils in PCM engines. Their use does not permit the extension of oil change intervals.

Q: What kind of oil should I use in my PCM engine?
A: When the average temperature is above 50 degrees F., use a good quality SAE 15W-40 "SJ". Below 50, use SAE 5W-30 "SJ"

[DKJBama92Mariah]

I agree on the synthetic issue. However, i disagree on the weight issue. I think that recommendation is for the new PCM motors based on the Gen II Chevy block, i dont know if it applies to the older ford motors. The sticker on the cover over my carb on my '92 351 non-GT40 says to use 20W-50.

As far as the thermostat is concerned, i beleive that the spec is to use a 143 degree unit on raw water cooled motors.

Cheers,
DKJ