Delo 10W-30

[s2ms]

I have found a local source of Delo 400 10w30 CI4/SL that I would like to run in my 66 GT350 with a solid lifter flat tappet cam. I have been using Delo 15w40 CI4+ with good used oil analysis but it seems all I can find now is the CJ-4/SM stuff. Plus I think the 10w30 would be a better viscosity anyway.

Can anyone think of a reason to stay with the 15w40 and not switch to 10w30?

Thanks.

 

[MGregoir]

The 15w40 still has 1200 ppm of ZDDP, I really would not worry. The 10w30 is a good oil too, but there is nothing wrong with the 15w40 CJ-4.

I would change to the 10w30 because it is a better viscosity choice than the 15w40, not because of the 1400 versus 1200 ppm ZDDP.

The only SM oil worries are about energy conserving ILSAC GF-4 20 and 30 weight oils.

 

[s2ms]

Thanks for the reply, pretty much what I've been thinking. I was aware of the ZDDP levels in 15w40 CJ-4 but did flatten a cam in this engine about 8 years ago. Although not oil related, it does make me a little more paranoid to ensure I'm doing everything possible to make sure it doesn't happen again. The Delo 10w30 seem pretty hard to find.

I will give it a try, do a used oil analysis and report any significant findings.

 

[Rock_Hudstone]

Originally Posted By: s2ms
I have found a local source of Delo 400 10w30 CI4/SL that I would like to run in my 66 GT350 with a solid lifter flat tappet cam. I have been using Delo 15w40 CI4+ with good used oil analysis but it seems all I can find now is the CJ-4/SM stuff. Plus I think the 10w30 would be a better viscosity anyway.

Can anyone think of a reason to stay with the 15w40 and not switch to 10w30?

In a high-perf flat tappet engine you want all the ZDDP you can get.
1200 ppm is the minimum for flat tappet cam longevity.

The CJ-4 oil may start out with 1200 ppm but how about after 2000 miles or so when the levels are down to 1100 or 1000 ppm, additive packs get used up over time.

If you can lay your hands CI-4 or CI-4+ grades in either 10w30 or 15w40 use it. I'd suggest 15w40 for the summer months, 10w30 in the winter. If you want to stay with 15w40 but can only find CJ-4 grade I'd add a half to a full bottle of GM E.O.S. per oil change.

However, there are still some 15w40 CI-4 oils still available off the shelf, such as: Castrol GTX diesel, (1300 ppm zinc), or Shell Rotella heavy-duty straight 30 wt.

 

[Steve S]

I wouldn't add much EOS .Look at the used oil analysis to see how much the additives deplete with use.