SN oil in a 40 or 50 weight

Olds 307 and 403

Active member
Oct 4, 2018
169
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28
Melville, Saskatchewan
I did a post on Classic Olds but never really found my answer til my last search. My understanding is a ##W40 or a ##W50 weight oil is exempt from the 800 ppm zddp SN maximum which is just weird and doesn't really make sense. It does make me rethink certain oil I assumed were no good because of the SN rating. VR1 20W50 is available at Walmart in SN rating which is supposed to have 1300 ppm zinc and 1400 phosphorus, according to what I have found. To 10W30 is not in store and supposedly SL rated. I have some SL Defy in 5W20 and 5W30 and some SG, SL/SM motorcycle in 10W40 and 5W50. The only downside to motorcycle oil is no friction modifiers.
 

Matt69olds

Member
Oct 8, 2018
73
55
18
Kokomo Indiana
The last engine I built with a flat tapper cam I bought a quarts of break in oil made by Lucas. I’m guessing if you can’t find the grade in the weight you want, you could always add engine oil supplement with the added zinc
 

Olds 307 and 403

Active member
Oct 4, 2018
169
53
28
Melville, Saskatchewan
Cutlassefi sold to me 5 bottles of the ZDDP additive. I am planning on a roller cam in the stroker but still have a flat tappet in my 350 and 260. I plan on running the SM 5W50 full synthetic motorcycle oil in the 260. My question is what is zddp max in a SM 50 weight? The 260 is sludged up, low oil pressure and has some lifter noise, probably from the sludge. The 350 also has a tick, all the lobes were inspected as well as the lifters, they looked ok, I may have a lifter sticking internally. I have tried the factory non adjustable and aftermarket roller rockers, still have a tick. I will go through them before running it in spring. I may run 5W20 or 5W30 old Defy with one liter of VR1 20w50 to boost oil pressure, not that the oil pressure is bad, very good at 15 to 20 hot idle in gear and 40+ psi cruising. Not bad for a 40+ year old motor.
 

Matt69olds

Member
Oct 8, 2018
73
55
18
Kokomo Indiana
In my opinion, nothing breaks up carbon and sludge better than automatic transmission fluid. I wouldn’t run the engine very hard (no long highway trips) and change the filter a few times. It won’t take long for the filter to get filled up with crud.

Some rockets and cam profiles are a little noisy. If your sure nothing is worn out, and the noise isn’t due to excessive valve lash, there probably isn’t much you can do to “fix” the concern, other than to turn up the stereo.
 

Olds 307 and 403

Active member
Oct 4, 2018
169
53
28
Melville, Saskatchewan
I will probably mix in a concentrate Risoline additive with 5W50 after I flush the motor with Kleenflo flush, next oil change on the 260. I will make sure there is no play in the valve train on the 350 and live with if it checks out.
 

Olds 307 and 403

Active member
Oct 4, 2018
169
53
28
Melville, Saskatchewan
I use the US made Hastings LF222, much cheaper here and well made. This 260 is only getting so much attention, already flushed it and ran some ATF in it. The 350 will go back in the 88 once the 403 stroker is done.