Synthetic oil or not

[DonSTP]

Anyone have any suggestions about using synthetic engine oil?  I'm about to do the first oil change on my 68-RS 327 and I'm not sure if using synthetic on these older engines is a good idea. 

Any insight would be appreciated.

Thanks,
Don

 

[JohnZ]

There's certainly no financial justification for paying the premium for synthetics when you consider the care and low mileage accumulation our cars see between changes. The primary advantage of synthetics is their resistance to oxidation at high temperatures, which isn't an issue in non-racing usage. Use whatever makes you feel good, but don't expect to see any difference between dino oil and synthetic in normal street operation.

"Marketing, son, marketing - that's where the money is."   

[rich69rs]

I concur with John and I will also add that I have made the decision to use Mobil 1 in both my '66 Chevelle and my '69 RS which has a 327/210 hp engine.  Probably no advantage to doing so with the low mileage useage, but it isn't going to hurt either.  And I'm willing to pay the additional cost for the synthetic product for whatever advantage I may enjoy by using synthetic oil.

[DonSTP]

Thanks guys for the feedback. 

The owner of the auto shop store I spoke with said a real advantage of using synthetics is you don't get "cold starts" or said another way, synthetics adhere better and you get better lubrication at initial ignition vs traditional motor oil.

I agree marketing is powerful but as an engineer myself I look to the data and that's what I'm looking for here.  Perhaps I need to dig elsewhere to get the raw facts.

Thanks again!
Don

[Jerry@CHP]

Another note here, the synthetics will leak like a sive.  I use them in my race car (Royal Purple) and every time I take the car out of the trailer, I have to clean up oil droppings on the trailer floor.  The older engines were not designed for the new thinner oils. 

Also, do not use synthetics in a Muncie 4-speed.  Have had a few customers do it and it tears up the blocking rings in the gear box.  We will not guarantee any Muncie that we rebuild if the customer uses synthetic oil.

Jerry

[68Zproject]

Got a suggestion for non-synthetic oil for the Muncie?

[Jerry@CHP]

Yes, 75-90 or 80-90 Castrol, Pennsoil, Valvolene, Kendall, etc.  All of the major brands are good.

If someone chooses to use the synthetics in their Muncie 4-speeds, there will be problems.  Trust me.

Jerry

[GaryL]

Isn't there an issue with the newer rating vs. the older rating for the oil used in Muncies. My memory is a little fuzzy here, but I am thinking use GL-4 not GL-5? Something to do with damaging the syncros?

[68Zproject]

If someone chooses to use the synthetics in their Muncie 4-speeds, there will be problems.  Trust me.

Jerry

I was going to, thanks for the heads up.

[gro51]

I've never used synthetic oil.  I just had an engine built and my engine builder suggests that I go to synthetic.  I'm debating whether or not to use it.  The cost doesn't bother me.  But what got my attention is that he said it would add 5-7 h.p.  What do you think?

[X33RS]

This is an old thread.  A lot has changed in oils since this was started. 

To answer that question, I've never seen any advantage on the dyno with synthetics.  However playing with viscosities does make small differences in output. 

I concern myself more with how the engine is protected rather than worry about a few HP, unless I'm pure stock racing and looking for that little bit. 
   Most of the top engine builders in the country use synthetics nowadays, and each of them have their favorite "go to" brands.  I pay the most attention to the additive packages and what's in the oil that's going to do the best for my engine and it's intended use or purpose.  Every brand is vastly different so do your homework.  Oil analysis is the best thing you can do to make sure what you're using as far as oil and filters is doing it's job.

[Kelley W King]

I had a White Post master cylinder leak(lifetime warranty).He asked if I had my receipt and had I ever used synthetic brake fluid. I asked why and he said synthetic fluid voids their warranty. I had not and got a free rebuild.

[X33RS]

Next time someone tells you that, tell them all brake fluid is a variant of polyethylene glycol.  Since it does not occur in nature, all brake fluid is synthetic 

Only difference in brake fluid is Dot 3-4-5.1 are glycol based and Dot 5 is silicone based.

[joesauer]

I tried synthetic...worried about it causing leaks (too slick for my old engine).  Went back to real oil, using Joe Gibbs "Driven" oil which also has the right amount of zinc. 

[X33RS]

Joe Gibbs is good stuff.   Not sure why the old tale of synthetic causing leaks is still holding on.  Most of these engines have been rebuilt at some point over time.  Now with more modern materials used in production for seals and gaskets they should have no problem conforming to any oil you choose.

I've used synthetics for years in 9 different cars here and I've never had leaks on a properly sealed engine.