ZDDP, Flat tappet motors, and catalytic converters

[cadfaeltex]

I asked a while back about an oil for my 'new' 1994 Jag with 4.0L slant 6. I've read elsewhere that a higher ZDDP level is needed because it is a flat tappet motor and most modern oils have too little not to increase wear with this motor. However, others say that ZDDP will ruin my catalytic converter. I suspect both are true and I'm leaning toward the cat being easier to repeat than the motor.

What are your thoughts? What are some good oils with higher ZDDP levels? Any dino?

Caveat: just getting in to understanding how oil effects things so please dumb down any technical discussions

 

[JHZR2]

If the car does indeed have a flat tappet setup, then otherwise obsolete ZDDP technology is a good bet.

There are plenty of good HDEOs in 5w-40 variety that would be excellent. Unless youre modded or have really high spring pressure, I cant see how that wouldbt be high enough. Even then, Id consider just adding a bit of ZDDP additive or equivalent.

 

[oggb]

Run Rotella T6 or Mobil 1 Turbodiesel & Truck. Both will do you just fine.

If you're running during the summertime you could always opt for 15w-40 or some such diesel oil.

 

[mechtech2]

A broken in cam/lifter has different requirements than a new ones that are mating.
Also, normal street cars don't have fast lift rates and high spring pressures.
So you are probably just fine with modern oil of the correct viscosity.
Another option besides HDEO is to use Lubro Moly additive - it is good for all sorts of stuff. I use it.

 

[Gokhan]

Originally Posted By: JHZR2
If the car does indeed have a flat tappet setup, then otherwise obsolete ZDDP technology is a good bet.

ZDDP is anything but obsolete. ILSAC GF-5 requires a minimum of at least 600 ppm phosphorus (ZDDP).

There is no ZDDP maximum limit on SM or SN oils without the starbust and Cx spec -- that is there is no ZDDP maximum limit on 10W-40 and 20W-50 SM or SN oils.

The ZDDP maximum limit on CJ-4 oils is 1200 ppm phosporus. GF-4/GF-5 oils have 800 ppm limit. Again, those without GF-4/GF-5 and without Cx have no limit.

For older flat-tappet engines, you can use a CJ-4/SM oil or 10W-40 or 20W-50 SM or SN oil (without ILSAC GF-4/GF-5) for good wear protection, as such oils have at least about 1000 ppm phosphorus (ZDDP) or so.

ILSAC's primary goal is to increase fuel economy and catalyst life as much as possible and oils with GF-4/GF-5 sacrifice wear protection somewhat to achieve these goals. Unfortunately with engine oil, it's always a sacrifice between fuel economy / catalyst life and wear protection and the research focuses on optimizing the best balance between wear protection and fuel economy / catalyst life for modern oils.

 

[artificialist]

It is my understanding that SOHC and DOHC flat lifters don't require as much ZDDP because the valve spring pressures are significantly lower than those found in an OHV engine.

Also, newer oils often contain AW additives that are used to make the reduced ZDDP more effective.

Do you have smog testing where you live? ZDDP tends to make the catalyst less effective by covering up the rare metals, however, it doesn't lead to cat clogging, unless you are burning significant amounts of oil.

 

[Trav]

This is a DOHC engine, i don't believe there is flat tappet issue as in a valve train using rocker arms,slippers and other types of high stress mechanisms.

 

[A_Harman]

I say go with the oils that have high zddp. It is easier and cheaper to replace cats than it is to rebuild an engine. Since it is a pre-OBD engine, you won't get a fault code even if the cats are bad, which they could be already.

Since your car is a 1994, it was designed to work with SH oils, which allowed up to 1200ppm of Phosphorous in 30-weights, and had no limit for 40-weights. It would be good if you could stay close to the 1200 number.
Mobil 1 0w40 has 1000ppm of Phosphorous.
M1 TDT 5w40 has 1100ppm.
M1 15w50 has 1200.
Shell Rotella T6 5w40 has 1200.

Maybe you don't want to run 40 or 50 weights, or expensive synthetics?

A commonly available conventional oil that has the required zddp content is Valvoline VR1 10w30. All of the Brad Penn oils have sufficient zddp, but they are not as available.

 

[Torrid]

T6 has 1200ppm phosphorus? I didn't realize that. I might start running that in my GTO.

 

[Blaze]

I believe out of the various diesel oils John Deere oil had the highest additive package when I researched diesel oils for my older Ford 460 motor. I run the Deere 10w-30 in the 460 also in 2 lawnmomers and a Deere tractor.
--------------------------------------------------


THIS IS ON JOHN DEERE OIL UOA.


Too bad he didn't get a TBN report to see how much additive was left.

oilscan through john deere
oil - 10w-30 plus 50 john deere CI-4
7,424 miles on sample
104,xxx total miles on truck
no make-up oil added

iron..........................................11
chromium.................................. nickel....................................... aluminum....................................1
lead...........................................3
copper.......................................1
tin........................................... silver....................................... titanium.................................... silicon....................................... 6
boron......................................170
sodium.......................................2
potassium................................ moly.......................................119
phos......................................1366
zinc.......................................1569
calcium..................................3992
barium.................................... magnesium................................16
antimony................................. vanadium.................................. fuel% vol.................................. t/s% vol.................................. .5
water% vol............................... vis cs 100`c.............................10.6


Another of his reports.

Well I recieved latest oilscan this morning so I thought I would share

OILSCAN through John Deere
07 F350 6.0
John Deere plus 50 10w-30 (CI-4)
miles on sample 7,476
total miles 119,864

iron..................................11
chromium.......................... nickel.................................1
aluminum............................2
lead...................................2
copper...............................1
tin................................... silver............................... titanium............................ silicon................................7
boron..............................191
sodium...............................5
potassium........................ molybdenum.....................129
phosphorus.....................1424
zinc...............................1648
calcium..........................4165
barium............................ magnesium.........................15
antimony.......................... vanadium........................... fuel% vol........................... t/s% vol......................... .5
water% vol........................ vis cs 100c.......................10.5

 

[A_Harman]

For 5w40 synthetic oil, RT6 has a lot going for it: it's a relatively lightweight 40, has high VI for a Grp3 oil, is widely available, economically priced, and has a good additive package. Shell markets it as a mixed fleet oil, so it can be used in gasoline engines as well. The only knock I have against it is the high Magnesium content, which is not desirable in a gasoline engine due to concerns of buildup of ash deposits in the combustion chambers over time. But if your engine doesn't pass a lot of oil through the combustion chambers, it wouldn't be an issue.

 

[cadfaeltex]

From all I've read I think I'm going for Mobil 1 Ow40 the first go round in the Jag. Only thing it doesn't have going for it is price. Interested in the Rotella T6 though - should I be worried about the Magnesium?

 

[Torrid]

Originally Posted By: cadfaeltex
From all I've read I think I'm going for Mobil 1 Ow40 the first go round in the Jag. Only thing it doesn't have going for it is price. Interested in the Rotella T6 though - should I be worried about the Magnesium?


If you are worried about the magnesium, one of the Mobil 1 high mileage oils might be a better answer. I'm really considering the 10w30 version which I'd be running in both my GTO and 2000 Jaguar 4.0. Right now I'm running standard Mobil 1 5w30 and ZDDP Maxx.

 

[A_Harman]

I hesitated to mention the Magnesium thing because it would take so long to become an issue in a gasoline engine. If your engine doesn't use a lot of oil, it would probably never become an issue. You could try the RT6 for a couple of oil change intervals and see what the oil consumption is like, then decide if you want to continue with it.

 

[Torrid]

I'm still learning, but isn't magnesium used as a detergent to displace the lower calcium in RT6?

 

[A_Harman]

Yes, that's the tradeoff. Calcium versus Magnesium.
Look at VOA's for high performance gasoline engine oils, and they will have all Calcium based detergents.
Or look at the UOA for the JD+50 in this thread: 4000 calcium, 16 magnesium. You don't need that much dispersancy additive for a gasoline engine.
RT6 has 750 calcium, 1200 magnesium.
M1 TDT has 1000 calcium, 750 magnesium.
So having less magnesium may be a reason to like the TDT over RT6, but RT6 has higher flash point, higher zddp content, and higher HTHS.

 

[cadfaeltex]

Bought the M1 15w40 today. Availability ended up being the determining factor, only had one jug of the Rotella and only 3 qts of the M1 0w40. I'm planning a fairly short OCI this time so we see how it goes.

 

[BBDartCA]

Its a Jag, shouldn't he be more interested in a stop leak product??

 

[cadfaeltex]

And why would you say that

Actually it's been pretty dry so far (knock wood).

 

[Torrid]

Originally Posted By: cadfaeltex
And why would you say that

Actually it's been pretty dry so far (knock wood).


Same here. Mine is post Ford takeover though.