Engine oil

[stickandrudderman]

We use 10/40 on all of our customers' engines and have had no complaints or problems thus far.
We have rebuilt plenty of engines that others have been unsuccesful in rebuilding and many of them have covered many thousands of miles since without issue.

[Shvegel]

High ZDDP?  Why?  Are we wiping out cams? 

[dirkbalter]

High ZDDP?  Why?  Are we wiping out cams?

I am using it too. (VR1-racing oil).  May be its overkill but it appears to provide added protection, cam surface for example. I does not have any disadvantages as far as I can find?

Quote Summit Racing:


Zinc in Oil - Not a Myth
ZDDP was first used in mainstream motor oil in the 1940's, primarily for its anti-corrosion benefits. Zinc kept the lead-copper bearings of the day from oxidizing, but it was also found to significantly reduce wear. As a result, ZDDP levels in mainstream oil gradually increased up until the early 1990s, peaking around 1,200-1,400 parts-per-million.

Starting in the early 2000's, hot rodders, race teams and automotive enthusiasts began seeing an increase in camshaft and lifter failures, particularly with flat-tappet cams. Issues with flat camshaft lobes became common place. Enthusiasts began scratching their heads trying to figure out why these failures happened. Valve spring pressures were checked, lifters were matched to the cam, everything was put together correctly, and brand-name oil was used - but there was still a failure.

Significantly reduced levels of ZDDP in mainstream oil were to blame. Looking back, we know these things changed parts-store oil forever:

Addition of sensitive emissions equipment like O2 sensors and catalytic converters
Better fuel economy via more efficient engines (roller valvetrains, georotor oil pumps, thinner piston rings, etc.)
Introduction of ethanol in gasoline (first E10, now E15)
Increased levels of detergents, extending oil change intervals
Modern parts-store oil is engineered with all of these things in mind. Obviously, your Eisenhower-era cam-in-block engine has a different set of engineering challenges. It needs different oil.

Best Oil for Older Cars and Race Engines
Oil composition has changed greatly over the years and while a certain brand/type of oil may have worked great in the past, the reduction of ZDDP could now spell disaster for your engine. ZDDP levels have gradually decreased since the 1990s in ALL mainstream oils, including diesel oils. In fact, the APIs new “SP” oil specification, set for release in 2020, is the first to not have been tested on an OHV pushrod or flat tappet engine.

For certification, API oils are tested on engines with a maximum 215 lbs. (open) valve spring pressure. Typical performance engines are equipped with valve springs over 280 lbs. (open) pressure. If you have an engine with a flat tappet cam, you need to be sure that the oil you use has enough ZDDP in it to create that layer of protection between the cam and lifters.

[mdsalemi]

Change the oil after you warm up the car, i.e.: run it for a few minutes. The thinking behind is, that you want to suspend all the contaminants in the old oil and drain them out with it.

...and one more good reason besides what you mention...the oil flows easier when warm. So, more of it drains out, faster, when warm, than cold. I wish that I had a warm garage every time I had to change oil but alas it was not meant to be. Warming up the oil facilitated the process.

[Shvegel]

Literally everything I have read about ZDDP or "Zinc" in oil has specifically mentioned either cam in block engines or flat tappet engines.  Our engines have neither cam in block nor flat tapppets.  I would go further and say that our engines had among the least valvetrain load of any engine of their day.

[MikeSimon]

Pat: Our engines have sort of 'flat tappets" as opposed to "roller" lifters. The contact surface between cam and rocker is basically "flat" and the "Hertz Contact Stress" is the concern.
I rather be on the safe side. All the modern and recent oil specifications, that have reduced additives to accommodate catalytic converters and supplemental friction inhibitors don't do anything for the old engines.

[Shvegel]

Mike,
Granted but the ramp in the lifting direction pretty much mitigates the stress of the flat profile.  If you think about it the flat lobe / follower in the longitudinal direction actually increases the surface contact area and decreases the load on the lobes/ followers in any given area. 

The real question is will it help the ball studs?  Maybe?  The ball studs have been a wear point since the beginning of time when oils contained a ton of Zinc per litre.  I think we are just looking at a design issue there.  So often we still look at our cars like we are going to drive them for 100,000 miles.  I am guessing the vast majority of us will manage 2 or 3 thousand miles a year.  30 years from now your ball studs may thank you for seeking out a high ZDDP oil.  I am fairly confident I will have taken up worm farming long before then.

[MikeSimon]

Very good point, Pat. As it is not that much of an effort, it may be wise to tend to the ball studs every time you adjust the valves. Taking the rocker arms off and applying some MOS2 type coating or dry graphite could be a good maintenance.

[mdsalemi]

I don't think you can have "too much" lubrication.

Our Pagoda engines were designed in an era when motor oils had more zinc in them. Regardless of how many miles we put on them now, how round or flat our tappets are, or profiles of our ball studs,  I'll certainly feel more comfortable with more zinc and phosphorus lubrication additives in my oil than without. It's not as if this is breaking the bank in cost. Last 5 quarts of oil I bought was $24 or so.

I'll also feel more comfortable with a 20W50 oil rather than anything less.

I haven't done any significant mileage since returning from Charlottesville to Michigan after the PUB-Virginia event in September 2017. But that trip, like many other highway trips I have taken (to the various PUB events, and to other events, over 20,000 miles worth) had me consistently turning 4,000 RPM for hours on end. Six or seven hours on end at a stretch, to be exact.

I'll take a 20W50 with >1200 PPM of zinc and phosphorus, thank you.

[hansr433]

Ahh, another oil thread.  Rarely are people more passionate about a topic, whether they ride motorbikes, drive classic cars or are racing.  So entertaining and I love reading them at night with a glass of Scotch in my hand.

FWIW, use whatever brand you can find in the correct viscosity (W20-50) but change oil and filter at least once a year.  I change the oil in my car every 3000km and one last time before I store the car for the winter.  My brand of choice is Motul Classic Oil 20W50 for Classic Cars built between 1950 - 1970 SF / CF.  I prefer mineral oil to semi- or full-synthetic as fewer particles will be suspended in the oil.  I am also a big believer in having a magnetic drain plug which will attract any metal particles and acts as an early-warning system that something is not right in the engine.

[thelews]

I use Shell Rotella Diesel T4 15W40 (in all my vintage cars).  Cost efficient, higher zinc.  I change at least every two years before winter storage as I'm hard pressed to get 500 miles on the car in a year.  I also change the filter with the oil which seems like a waste (1K miles or less), but I do anyway.  In 14 years, never had an oil related issue with the car which I often drive at 80 mph.

[MartinK]

Please do not have a look only on ZDDP. The zinc complex is only one of the additions in a proper engine oil. I always recommend a modern engine oil and not those "classic" fluids. They are mostly poor quality. The 20W fluids are in most areas too sticky for a quick oil film in the engine. In California or Arizona in the US maybe. It is a myth that the sticky 20W50 keeps a lubrication film during cold start. It is important that you have a quick oil pressure  and a low viscosity from the first crank attempt. Have a look at the handbook. It recommends 10W30. London is quite not known as a hot area. But you can easily use a 10W40 with a modern and current technology. For example Mobil Super 2000 X1 10W40. Btw Mobil1 0W40 contains more Zinc-Complex than most "classic" lubricants. But lubricants technology  is more than zinc. Too much zinc leaves burning coal and ash.

[mauro12]

Guys,  I only use for my car Bardahl xtc60 15w50 semi  sintetic oil . Bardahl is the most popular oil here in italy and I’ve always used in all my cars with fantastic results . My question is, why my engine oil gets dirty almost immediately? I have a very rich running issue and for this reason I’m going to send my pump to Hans fritzsche in Germany for a complete overhaul . The engine oil of course smells a bit of petrol . Is there a correlation between mixing gas and engine oil and getting the oil dirty ?
Maybe the unburned fuel generates carbon deposits in the oil pan ?

[mdsalemi]

Have a look at the handbook. It recommends 10W30.

Exactly where is that handbook from?

The reason I use a heavy oil 15W-50 is because this M130 motor turns much higher RPM at cruise; 2X what my daily drivers do.

[MartinK]

Exactly where is that handbook from?

Hei, is is from the 1967 250SL handbook. It is very comparable to 230/280SL.

The most important thing is that you have a sufficient oil flush while cold start and a 10W-something is quite good for that purpose. Please keep in mind that the oil pipe for the drop oiler of the camshaft and the rocker arms are lubricated without pressure. It only falls onto the camshaft bearings and if the oil is too sticky from the begin on, you may have no good oil film. The same with the small end of the connecting rods and the cylinder surfaces. The lower the viscosity of the oil is, you have less wear in cold engine operation. When oil is hot, it is not so much important if you use 10W30/40 or 50. I use 0W40 Mobil1, but it is a new engine. I recommend absolutely a 10W-something to avoid wear at cold engine run. All current Lubricants have enough additions to avoid wear and do not have only a look at zinc 
Talk soon. Martin.

[MartinK]

. My question is, why my engine oil gets dirty almost immediately? I have a very rich running issue and for this reason I’m going to send my pump to Hans fritzsche in Germany for a complete overhaul . The engine oil of course smells a bit of petrol . Is there a correlation between mixing gas and engine oil and getting the oil dirty ?
Maybe the unburned fuel generates carbon deposits in the oil pan ?

Hei. Yes unburned fuel and carbon may color the oil dark. But a dark colored oil is no proof for the quality of the oil and says nothing about its lubrication capabilities. And you are right, if the engine runs with a too rich mixture all the time, this is worse than anything other issue. Talk soon, Martin