API SN rating

[Graymond]

I was at a speed shop the other day buying some oil additive for my hot rod, Chevy 350 Isky flat tappet 234 224 at .050. Need the zinc to keep the cam alive.

Normally I dump this in on top of my Castrol SM oil and so far it seems fine.

The owner warned me that I should never, ever use SN rated oil in a Gen I Chevy, even with the additive. He said something about it being manufactured differently than regular crude?

I have searched the forum and I cannot see where this issue has been mentioned or discussed.

Is this a real concern?

Ray

 

[Solarent]

Base oil manufacturing processes did not change much between SM and SN. However the concentrations of Gr II and Gr III basestocks have changed with certain finished oils may be different to accommodate the new additive packages that were designed to meet SN. The biggest difference in the SN changes relate to fuel economy improvement standards, not wear protection. I see no reason why you would have any issues if you were already using SM rated oil.

That said I don't have a hot rod, so some of our racing enthusiasts can probably make more specific recommendations.

 

[440Magnum]

Total mythology.

 

[brentalan]

+1, but IMHO, consider using one of the many oils already formulated with more ZDDP, so you don't have to worry about it.

 

[Graymond]

Wow, Thank you for the quick response.

Ray

 

[Graymond]

Originally Posted By: brentalan
+1, but IMHO, consider using one of the many oils already formulated with more ZDDP, so you don't have to worry about it.


That is the plan going forward. I have some SM that I am going to use up. I was thinking of Joe Gibbs, due to a local supplier. Any thoughts?

Ray

 

[addyguy]

Originally Posted By: Graymond
Originally Posted By: brentalan
+1, but IMHO, consider using one of the many oils already formulated with more ZDDP, so you don't have to worry about it.


That is the plan going forward. I have some SM that I am going to use up. I was thinking of Joe Gibbs, due to a local supplier. Any thoughts?

Ray


Probably more $$$ than you need to go.

A HDEO 10W-30, like Rotella 10W-30, will have all the goodies you need, and be a lot less expensive as an added bonus.

 

[Carbon]

Originally Posted By: 440Magnum
Total mythology.

If I cannot make sense of your comment, what does that indicate?

 

[Quattro Pete]

Originally Posted By: Carbon
Originally Posted By: 440Magnum
Total mythology.

If I cannot make sense of your comment, what does that indicate?

It indicates that the shop owner in question probably does not know what he's talking about. It'd be interesting to ask him to substantiate his claim.

 

[Gabe]

This is an interesting link: http://speedtalk.com/forum/viewtopic.php...c8559c4#p329715

It has a bunch of information on hot rod and racing oils in an easy to understand format.

 

[440Magnum]

Originally Posted By: Quattro Pete
Originally Posted By: Carbon
Originally Posted By: 440Magnum
Total mythology.

If I cannot make sense of your comment, what does that indicate?

It indicates that the shop owner in question probably does not know what he's talking about. It'd be interesting to ask him to substantiate his claim.


Right. The idea that SN oil is "manufactured differently" than SM oil is a complete myth.

 

[440Magnum]

Originally Posted By: Graymond
Originally Posted By: brentalan
+1, but IMHO, consider using one of the many oils already formulated with more ZDDP, so you don't have to worry about it.


That is the plan going forward. I have some SM that I am going to use up. I was thinking of Joe Gibbs, due to a local supplier. Any thoughts?

Ray


Probably overkill for that engine, and I don't know how good the detergent packages in racing oils are (my chief worry about using them in a street car or rod). HDEO (Rotella, Delo, etc.) would probably be my pick. Off the shelf among non-HDEO oils, M1 15w50 is still pretty high in ZDDP, and M1 0w40 isn't far behind Rotella. I'm currently using M1 0w40 in my old flat-tappet V8s.

Boutique oils can serve well- Royal Purple, Redline, Amsoil, etc. Lots of people here recommend Brad Penn oils, but their whole advertising campaign implying that its the source of the crude that makes their oil good rubs me the wrong way, because a refined product shouldn't depend on where the crude came from.

 

[abycat]

Yeah i doubt that billion doller refineries have switched the refining process to make sn oil. Ask the guy what oil makes wax in your engine. ha ha. I would throw in some Delo 400 in syn or conventional and call it a day. I have M1 HM oil in my flat tappet ford right now and its not dead yet.

 

[mechtech2]

Originally Posted By: brentalan
+1, but IMHO, consider using one of the many oils already formulated with more ZDDP, so you don't have to worry about it.


Good idea. Or maybe even a high ZDDP oil with a touch of your additive.
Be warned, cams and lifters will STILL wear!

 

[Garak]

Originally Posted By: 440Magnum
Probably overkill for that engine, and I don't know how good the detergent packages in racing oils are (my chief worry about using them in a street car or rod).


In fairness to Joe Gibbs oil (which I've bashed repeatedly here due to the price), a lot of their product line has appropriate detergent levels for street use. But, as you point out, there are many other options that are far more cost effective.

One can buy RP synthetic for less than the cheapest Joe Gibbs conventional - that says a lot about their pricing.