Here's a link to the Mobil1 web site, citing the levels of ZDDP in its 15w-50 motor oil. As you will see, it has levels high enough to work with flat-tappet cams. Nonetheless, I still recommend STP Oil Treatment for four cylinder engines in the red bottle for y-blocks.

Mobil1 15w-50 motor oil has 1200ppm of ZDDP

STP Oil Treatment for 4 cylinder engines

 

STP is just a thickening agent it doesnt contain the addtives that a thicker oil will have. If you want to use STP forget it just go up to the next thicker grade oil youll get the same effect but with the correct additives.

If you want ZDDP heres additives that replaces ZDDP

This is a Zinc replacement that contains no Zinc or Phospherous but is claimed to be better than regular ZDDP
http://www.hyperlube.com/ZRA_Spec_Sheet.pdf

If you dont want to run that you can run this with every oil change and be able to run an oil you want be it a specific brand you want or the correct oil weight for your vehicle.
http://www.compperformancegroupstore...Category_Code=

If not that and your not specific on what brand or weight of oil you want you can always look at oil for diesel engines they have higher ZDDP contents than ones for passenger cars.

 

Jeepers, Rusty, you're just full of misinformation. STP in the red bottle is a concentrated source of ZDDP. So is WalMart Tech Lube. So is GM EOS.

And the ZDDP in diesel engines is the wrong kind of ZDDP; Zinc Diaryl Dithio Phosphate vs. Zinc Dialkyl Dithio Phosphate. Don't use diesel engine oil.

If you search on Mobil's web site, you'll find that particular grades of Mobil oil are tailored for older engine and contain high enough levels of the right kind of ZDDP.

Mobil 1 motor oils and levels of ZDDP

Why do people try so hard to get this wrong?

 

why do people recomend very thick 20w50 oil for yblocks when the factory called for straight 20 weight. So I guess it goes both ways but as far as I am concerned the STP site didnt say anything about that oil additive containing pure ZDDP, not to mention Phosphate is the antiware additive and the diesel oi still has phosphate so it will work.

So I think you need to do alittle more research, cause first its 5w is designed for new car was your first claim even though 5w was used back to 56 in the Y-blocks in extreme cold weather and then went on to say that multigrade oil thins as it gets hot when the polmers thickens the oil then said that viscosity, thickness and oil flow are different even thoug thickness, viscosity, and flow are related as I stated in a previous post.

So good day to you and try not to spred disinformation to others cause some people here actually knows about some thing be it restoration, or what color different Y blocks were painted or oils.

 

Slow down, backup, and let it rest.

 

Yes, that PARTICULAR version of Mobil 1 contains ZDDP. My point was that synthetic oil alone, including the majority of Mobil 1 products do NOT contain this additive, thus will NOT allow for proper cam/lifter breakin or ongoing protection.

I think that the 15W50 is what they term TRUCK & SUV, but I have not looked into it.

 

Well, I suppose that you told me about not using diesel oil in a gas engine too late. I went for about 12 years with a 200 mile round trip commute. I had an old Mercury Zephyr for a work car. It was just a half ragged out old car that I got for cheap and rebuilt the motor and a few other things with the intention of running it to high mileage.

At rebuild time I broke in this engine with Delo 400 and ran NOTHING BUT Delo 400. The engine went ALMOST 300,000 miles when I finally sold the car to a guy for a giveaway price for his sixteen year old daughter. The engine was still running very strong and by that time oil consumption had gotten to the one quart per thousand mile level.

This engine never saw anything but Delo 400 with no additives of any kind and got an oil change once a month which was about a 4,000 mile oil change interval.

SOOoooo....... just think, if I had not used Diesel Engine Oil, there's no limit to how far the engine would have gone!


I am not doubting the validity of what you're saying, but just because it is a different type ZDDP does not mean that it doesn't work in a gas engine. If it didn't work, I just don't think that I would have had such success.

I STILL use Delo 400 in everything on my place with flat tappet cams. My newer cars have 4.6 Mod motors and in those I use Mobil 5000 changed on 3,000 mile OCI. All of my engines are healthy and go to high mileage.

 

I think that sometimes people want to use a heavier weight oil so that they can see a higher reading on their oil pressure gauge. Thicker oil will indeed accomplish this. The problem is that oil too heavy will not FLOW under certain conditions.

Flow is more important than the gauge reading. In fact most engines have more oil pressure than is necessary anyway. Many years ago Cummins started regulating their oil pressure to fifteen, yes 15 PSI. The reason was that they learned that this was plenty of oil pressure and anything beyond that simply wasted fuel to turn the oil pump.

In the old days, when oil was SOoo bad compared to todays lubricants, in really hot weather, there was indeed some gain to using heavier oils in the engines of the day, given the oil of the day.

My Dad had a '56 Customline Victoria, 272, 3 speed Overdrive that he bought new. We traveled alot to see relatives, so I feel like I grew up in the backseat of that car. He never used anything in it except 20-20W Havoline and changed it often. And that was in Texas.

He changed oil regularly and the car went to 100,000 miles without the heads or pan ever removed and was still doing well when he traded it in 1963 for a car of blasphemous make as folks on this site would see it.

Even though Havoline was really waxy oil, by changing it often, it worked out for him, even in 20-20W. Had he been using a multi-grade oil of the day, I feel that he would have had trouble.

With todays oils, 20-20W is obsolete, but I believe that any good oil of reasonable quality and adequate ZDDP level would work out well in a Y-block WITH REGULAR CHANGES.

The other WARNING I would put forth besides ensuring proper ZDDP content is that you should not use a multi-grade, dino oil with a wide weight spread. An example of this would be a 10W40, a 30Weight spread. These oils have an inordinately high volume of Viscosity IndeVI) improvers. This high level is prone to producing lots of carbon around the piston rings.

Multigrade oils also put forth potential problems with weight breakdown. This is because the VI additive consists of molecules that coil up when cold and extend out straight when hot. When they are uncoiled, they thicken the oil. The potential problem is that under certain driving sequences and conditions these molecules wear out. When that happens, you think that you have a heavier oil than is effectively in the crankcase.

My multigrade warning is meant much more for those in warm climates. If you use a properly selected multigrade AND you change it on proper intervals for your conditions, it should not be a problem.

 

Yep, 10w30 changed every 2,000 - 3,000 miles is an ideal oil. Everyone I know and every local shop as well as local engine speed shops recomend and use 10w30 in their cars.

As far as my daily, I am sure I would break the oil pressure gauge with 20w50. Gauge goes up to 90 psi and im at the high end of normal around 70 - 80 psi at 1,000 rpm. At 750 rpm idle the pressure is around 45 psi. But with todays oils you shouldnt have to run a thick oil. I mean hell I know a guy that has a olds 442 that he runs nothing but 0w20 synthetic in his. I dont blaim him cause the most wear happens on start up. He also use it cause thats just what the engine likes. He tried 10w30 and the engine just didnt have power or performed right till h used 0w20.



I do know thats why alot of the "old timers" as we were told by a "old timer" tech from the tech courses I took that they would dump a bottle of STP oil treatment in a brand new car cause they thought it helped the car out by making the oilpressure higher. All it did was thicken the oil, dilute the additves in the oil and made the pressure go up.



Oil does wear out though and get thinner with age. Fresh oil is always 45 - 80 psi under normal driving condition. Around 3,000 miles at idle the oil pressure is around 40 - 45 psi still but when around 1500-2500 rpm the oil pressure only gets up to about 60 psi. Doesnt move over as far on the gage, thats an indicator its getting close to another oil change on mine.

 

With oil pressure like that maybe you should adjust the relief spring and drop it some. The high pressures put a lot of strain on the oil pump drive, cam gear and dist. gear. Also robs power.

 

why?

My factory shop manual says normal oil pressure is between 20 and 80 psi and the needle is never leaving the normal range.

 

Messed up. double post.

 

The high pressures put a lot of strain on the oil pump drive, cam gear and dist. gear. Also robs power.

For example, I chose a regular output oil pump over a high output, for the above reasons. You agree that high viscosity oil isnt needed, but neither is 60-80 psi pressures. I guess an option in your case IS to run a 20w oil, given the pressure. Interesting... Do you have an accurate oil pressure gauge installed?

 

well the engine has never been rebuilt, that oil pump is the factory oil pump. There is a high volume pump option if I were to replace it but any stock replacement oil pump woud be a 80 psi oil pump roughly.

But the problem is though I dont care to pull the engine out to adjust something the factory put in. Not to mention the engine runs great, rides on the N and O on the NORMAL on the temp gauge and today I just notice I went from F to 3/4 and the trip odometer turned over 102 miles. So I hit a new high of roughly 20 mpg city.

But High flow is not needed though, could "wash the bearing away" and no need for high pressure though, that is usually found on small clearance bearing cars such as V6`s and 4 cylinders as well as some 8 cylinders.

The gauge though is accurate, its the factory installed gauge, and during my tech classes, I did a oil pressure test on my own vehicle by screwing a oil pressure gauge into the sending unit opening and the gauge is right on.

But I am not too concerned with it though the oil pressure drops after awhile but it never goes below 45psi or the halfways point of the gauge. Get engine rpm to 1500 - 2500 (40 - 90 mph) and the gauge jumps back up to 60 - 80 psi or so.

 

Yes, back in the sixties STP was a popular additive. It was not so common for new engines though. More often it was used in an old worn out engine trying to nurse a few more miles out of it.

It seemed that those were the people that never or rarely changed their oil. When you took one of those engines apart it looked like someone had used a grease gun to force the entire valve cover full of tar.

The one thing that STP DID accomplish, was the funding of quite a few wins for Richard Petty.