API SM -> SN Oil upgrade - pushrod / flat tappet beware

[pl510]

I posted up a thread on oldschool.co.nz about the new SN spec oils hitting the shops - though you A series fullas might find this of use:

Just a quick public service announcement:

Now that API SN oil is hitting the shelves, us with old pushrod type engines could have a bit of fun if we inadvertently put the two together.

SN oils are not permitted to contain more than 800 ppm (parts per million) of zinc. This isn't a problem for newer ohc engines or pushrod engines with roller lifters but engines with flat tappets there will be trouble. We have seen cams chew out in under 1000 km.

Most engine oils rated SM or earlier should still be ok.

I have a couple of products that perform really well in older V8s, sixes, ford fours and other pushrod engines. Feel free to pm me if you're after more info

Cheers
Shannon

[Bartman]

Thanks Shannon!
I saw the post at os, but didn't knnow it was you.
So SN oil is the stuff to steer clear of?

[pl510]

Yeah mate if you have a pushrod engine there's not enough zinc for ya. Progress doesn't care much for old engines unfortunately

[DAT620]

SN is just a rating, check the Data sheet on the oil to see what levels of Zinc/Phosphorus or ZDDP it has in it, you want this additive in a pushrod engine because older engines components aren't has hard wearing as the new ones, the new SN rating rules out the previous ratings need to have Zinc in it due to the fact it eats out catalytic converters and isnt good for the enviroment.

Most racing oils have ZDDP additive in them. I used Valvolene VR1 in my BMC Mini for this reason.
Im no expert this is just what I have been told.

[dennisg]

Oil has not been good for over a decade I used Rotella but after its zddp was lowered I changed to valvoline racing oil (silver bottle). We can also buy zddp additives, they are not all equal. Around 1500 ppm is the amount of zddp I like.

[Dattodevil]

Good thread Shannon, I Just add a bottle of Wynns Friction proof, turns any oil into Datsun oil What products are you selling?

[brocky41]

I'll do a bit of research at Work, I'm sure that's y our Fuchs GT plus is now Formula SL 20w50. Made for old beasts like ours.

Great work PL510 for putting that up.

[Dattodevil]

From what I've heard anything after SM is no good for push rod engines.

[brocky41]

From what ive heard too - its the same for GL-5 up Etc on syncros on old gearboxes.

Which is why i try to sell redline gear oil GL-4 to the guys with older cars.

Not because its expensive, it just doesnt wear out your parts as quick.

This is what the MTL oil has written in its specs

"Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage"