ZDDP - Page 3 - PeachParts Mercedes-Benz Forum

JHZR2 · #31 11-25-2010, 09:27 PM

While I said that some adds can be OK, I would not add any old plain moly.

You do really need to understand surface chemistry. You will likely have one of two things going on - either the moly gets lodged in the filter, or else sits in the bottom of the oil pan. Unless it is stabilized correctly, it can not work as you would like, and worse, could agglomerate into larger particles and cause damage.

Something like lubromoly mos2 which is designed for the lube oil environment would be far superior to you playing chemist...

RustyBeard · #32 11-29-2010, 08:31 PM

Quote:

Originally Posted by Alastair

There is NO Doubt that these new Low Zddp oils DO cause issues with OLD engines with 'flat-tappets'.

Mercedes doesn't use flat tappets.

Quote:

You wouldnt use Mobil 1 fully synth in a Model T would ya!

No, the sole reason being the transmission shares the sump and the clutches will not grip with such slippery oil.

layback40 · #33 11-29-2010, 09:28 PM

MoS2 should never be used in an application that has combustion such as an engine oil. MoS2 undergoes high temperature combustion to form MoO2 (carborundum). You dont need that up & down the bore of your motor or around your rings!!
It is fine for certain gear applications, not Auto or LSD.

babymog · #34 11-30-2010, 05:29 PM

What is the breakdown temperature of MoS2? It is (according to my Detroit Diesel oil analysis) a common component in premium engine oils.

layback40 · #35 11-30-2010, 05:39 PM

Jeff,
I dont know an exact temp that it will start to oxidize. The temps and conditions that occur in combustion are more than enough to cause the oxidation.

JHZR2 · #36 11-30-2010, 06:31 PM

Quote:

Originally Posted by babymog

What is the breakdown temperature of MoS2? It is (according to my Detroit Diesel oil analysis) a common component in premium engine oils.

MoS2 is a solid, properly formulated motor oils use a solubilized form of moly.

69shovlhed · #37 11-30-2010, 07:49 PM

evil monkey, it is known that older flat tappet engines such as the v8's used by hot rodders and racers need additives that are not in modern motor oils. old style hydraulic and solid lifters will gall to the cam lobes without additives. it is possible that valvoline racing oil may have the correct additives; i will have to do some research before i fire up the chevy 409 engine i am building. but being a mechanic for 8 years don't make you an expert. still, you've chosen the right brand to specialize in. i hope your not one of those punk kids that drives around in a nip $#!*box with a bad sounding muffler.

layback40 · #38 11-30-2010, 07:53 PM

MoS2 was developed years ago as a replacement for graphite. It is used in lubricants in a colloidal form. It tends to coat moving surfaces & forms a slippery surface. The colloids will oxidize in a combustion chamber. This was a limitation that was identified when it was first developed. We use grease that contains molly, some gear oil & diff oil with it. Never in a motor oil though.

babymog · #39 11-30-2010, 08:44 PM

Hmm, the SAE handbook has Molebdenum, no MoS2. Now you're going to make me blow the dust off of the Marks book aren't you? Now where is that thing.

babymog · #40 11-30-2010, 09:02 PM

Okay, it's stable up to 350*C/662*F in oxidizing environments which covers it in most of the engine. It's use is in coating and bonding with the metal surface, which it should do and the thermal mass of the metal protect it somewhat from thermal breakdown even on cylinder walls, provided there isn't an excess of MoS2 or lubricating oil on the cylinder walls.

It is probably the reason my engine has those wierd crosshatch marks on the cylinder walls at 237,000 miles, causes crosshatching marks when used.

Anyway, you're obviously correct that extreme heat will cause it to break down, but I'm not entirely sure that Molebdenum Trioxide is harmful to the engine. The worst place I'd expect in an engine that has good rings would be the turbo if shut down hot / classic heat-soak. Seems that the Molebdenum Trioxide would just pass rather than bonding to the metals though. This is the reason that I never thought much of PTFE in engine oil, it's inability to endure combustion heat or turbo heat-soak so your point certainly has merit although (and I hate to say it) it has worked well for me for the past couple of decades, ...

layback40 · #41 12-01-2010, 03:35 AM

Jeff,
Fine carborundum particles from the combustion is about as bad as running without an air cleaner. you may be lucky with your motor. Who knows/
Put the stuff in your diff (not LSD) or manual trans. Just keep it away from extream heat.
PTFE is an interesting one, it may have a few good points, again we need to look at what happens when it is incinerated in the combustion chamber. You may find some interesting very corrosive products. When all is said & done, you cant beat good quality oil. I hope we all agree on that.
Every one has their favorite snake oil, if it makes them feel better, I best let them use it. Just not in my motors.

MTUpower · #42 12-01-2010, 06:41 AM

Quote:

Originally Posted by 69shovlhed

evil monkey, it is known that older flat tappet engines such as the v8's used by hot rodders and racers need additives that are not in modern motor oils. old style hydraulic and solid lifters will gall to the cam lobes without additives. it is possible that valvoline racing oil may have the correct additives; i will have to do some research before i fire up the chevy 409 engine i am building. but being a mechanic for 8 years don't make you an expert. still, you've chosen the right brand to specialize in. i hope your not one of those punk kids that drives around in a nip $#!*box with a bad sounding muffler.

Evil Monkey, Rusty Beard, Forced Induction are all the same person who has been banned here and other places many times. He does have a excellent knowledge base of MB's and he's a truck mechanic. However his ultra critical views of anyone that does not agree with him has been far too acidic for his own good, thus the ban. I have no doubt he'll try to rejoin under a different moniker, but you can pick him out a mile away.

Alastair · #43 12-01-2010, 07:12 AM

Quote:

Originally Posted by RustyBeard

Mercedes doesn't use flat tappets.

No, the sole reason being the transmission shares the sump and the clutches will not grip with such slippery oil.

Wow! Joined and Banned in the Same Day!--Thats gotta be some kind of record!

To MTU, Yup, His aragance and particular caustic nature have caused his banning from Many Automotive Forums, and he's on very thin ice over on STD, where he's lost his moderator rating--Not before time--You can spot him 10 miles off!...

Anyway,

Well aware that M.B dont use flat-tappets, They are curved!

As to the Model T, well-I have NO idea, Never owned one, Used it as an example, same could be said of an Austin Seven, which doesnt share its engine-oil with anything...

Surely the flat tappet however,is showing up an inadequacy in lubrication--even though it may not directly affecting our M.B. engines...

layback40 · #44 12-01-2010, 07:40 AM

We havent had lances protege 'eric' back under another name lately, maybe we have but Im not smart enough to realize it.

Many of the old push rod motors had flat tappets like the A & B series BMC/Austin/MG etc. I think the old toyota & Nissan (BMC copy) also had them.

Graham · #45 12-01-2010, 01:41 PM

Does anyone know of a website or any reference that lists ZDDP or Z & P concentrations in auto lube oils? Only one I have found is from Mobil.

I used to use Castrol Syntec in my '72 gasser, but am switching to Mobil because I have no idea where Syntec stands for use in old cars.

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

Always have used Mobil 1 15W50 in 300D.