Thread: ZDDP additive needed?

Originally Posted by milld

I've been reading a lot about the quality of oils and levels of ZDDP which is essential for earlier engines like the RV8. Does anyone bother to put in an oil additive like this;

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Putting in Penrite 15w40 this afternoon has got me a little worried as to the levels of ZDDP that are put in oils.

New API standards reduce ZDDP levels in oils for environmental blah blah reasons + not needed as much in modern day engines.

There are many articles about this but maybe we all should be using an additive?

Well essentially the additives were removed to protect the cats in modern engines.
Nevertheless I still use it under various circumstances where flat tappet lifters/followers are involved.

If we take the Landrover V8's & the Buick family of engines (its predecessor) as and example, there are a lot of aftermarket parts available for them. Having a durable camshaft that will last at least 200,000 miles is essential for engine life and no comebacks!

The stock camshaft for the LR 4.6 variant has a known shorter life than its 4.0 cousin, due in my opinion to the more savage lift and duration of the 4.6 "grind", combined with infrequent oil changes.

Equally I can get 3.9 and 4.0 family camshafts of unknown origin in the aftermarket, made in places like Turkey/India etc. The quality varies enormously and the hardness levels vary as the same amount.
Normally I won't use them prefering to use a OE part or a cam ground by a machine shop I use who can guarantee the grind from a blank and provide the certificate of harness required. In all cases I use the same lifter as the Buick for all applications being the same level of quality as OE but a 1/3rd of the price per 16 off in a box.

Now the use of the additive!
I always use it in new engine builds, it prevents scuffing of the lifter. If you check the lifter face even after a short run when the cam lobe harness is suspect/below parr you will observe random scratches/scuffs on the lifter face as metal is spun off the lobe cutting through the case hardening even when premium regular lubricating oils are only used.The OE cam by the way never seems to do this as it is encouraged to spin when in service by the cam grind profile.

A case to argue the need to invest the $400US for genuine versus $150 for aftermarket!

Inspecting a used lifter even after a high mileage teardown will reveal a very smooth pronounced circular register on the lifter face.
For these reasons I add a qrt to the initial fill and leave it in there until the first change. It will at least help with the run in/bed in process.
I do recommend a customer use it for a more prolonged period if the engine is built with an aftermarket camshaft, just in case.
In 4.6 applications I will often recommend a diesel engine lube oil permanant fill like a MB229.5 for 4.6 engines after a rework due to their camshaft wear issue experiences.

So in short I use it when I feel it is necessary yes on a 4.6 initial break in, and more often if the cam is not OE.
Hope that helps
Dennis
zedcars

I use a bottle of this with every oil change on my flat tappet engines (added via the oil dip stick hole)

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5 bottles of ZDDPlus Engine Oil Additive US$40 plus $10 shipping