What's the best oil?

[PJ Grady Inc.]

I see no problem going to 5,000 miles or once a year, which ever comes first. Oils are made so much better now than in the past, the PRV isn't working all that hard, and the motor holds 6 qts so it never gets overheated and breaks down. Changing it more often is not necessary and wasteful. Always change the oil filter when changing the oil.

Ahh.....David wouldn't that be much closer to 7 quarts or have I been overfilling these engines for 35 years with no discernible problems? Synthetic is unnecessary unless you're doing the Delorean World Tour. What is important, and I'm surprised nobody brought this up, is the correct viscosity oil. The oil companies have been gradually reformulating their oils since the early nineties decreasing the amount of zinc and phosphorus to trace elements in the quest of increasing catalytic converter life and efficiency. Newer engines use better materials and design improvements to eliminate the need for these minerals. Earlier engines however will suffer premature wear without them. The only exception to this reformulation is 15-40W which retains these elements because diesels and turbocharged engines still have a need for it.
Bottom line is all engines made before the early 90's will last longer using 15-40W oil unless you use an additive with your favorite grade of oil.Now if you want the absolute best oils made my research indicates the Amsoil product line starts with the best base stock available from which they formulate their oils. A Delorean does not need an oil anywhere near that good and the typical $12- a quart price for their oils should be enough of a deterrent that most people will take a pass anyway.
Any good quality conventional 15-40W oil should provide all the protection you need unless you're running DPI's Stage Eleven, EFI fueled, dual liquid inter-cooled, sequentially twin turbo'd time bomb or similarly stressed PVR!
Rob

[Lou and "Boo"]

My "fastest naturally aspirated PRV" qualifies as a stressed engine .... No?

[PJ Grady Inc.]

My "fastest naturally aspirated PRV" qualifies as a stressed engine .... No?

If indeed it is the fastest...by all means yes!
Rob

[content22207_2]

What is important, and I'm surprised nobody brought this up, is the correct viscosity oil. The oil companies have been gradually reformulating their oils since the early nineties decreasing the amount of zinc and phosphorus to trace elements in the quest of increasing catalytic converter life and efficiency. Newer engines use better materials and design improvements to eliminate the need for these minerals. Earlier engines however will suffer premature wear without them. The only exception to this reformulation is 15-40W which retains these elements because diesels and turbocharged engines still have a need for it.
Bottom line is all engines made before the early 90's will last longer using 15-40W oil unless you use an additive with your favorite grade of oil.Now if you want the absolute best oils made my research indicates the Amsoil product line starts with the best base stock available from which they formulate their oils. A Delorean does not need an oil anywhere near that good and the typical $12- a quart price for their oils should be enough of a deterrent that most people will take a pass anyway.
Any good quality conventional 15-40W oil should provide all the protection you need unless you're running DPI's Stage Eleven, EFI fueled, dual liquid inter-cooled, sequentially twin turbo'd time bomb or similarly stressed PVR!
Rob

What you're talking about is Zinc Dialkyldithiophosphate (ZDDP). It's an anti wear additive oil companies started adding in the 1960's (API SB). Motor oils were typically about .15% ZDDP through API SL. Starting with API SM oil was limited to .08% ZDDP *MAXIMUM* -- it can have less, but not any more. Some SN rated oils have .06% ZDDP.

Through API CI-4 there was no limit to ZDDP in diesel oil. API CJ-4 limits ZDDP to .12%. I use Delo 15W40 exclusively in all my vehicles, which currently is .11% ZDDP. Chevron also uses a proprietary refining process that introduces less paraffin into the oil.

Modern engines don't need ZDDP because their rocker arms have ball bearings riding on the camshaft lobes. Older engines use "flat tappets" -- either lifters or rocker arms riding on the camshaft directly. It's the difference between roller skating across a floor versus dragging your feet.

Bill Robertson
#5939

[DMC-81]

I also use Castrol GTX 20W-50 as recommended, but...

I had read about the presence of zinc being good, and saw the flat tappets during my valve adjustment last year (see pic). My question is, what percentage or PPM of zinc is required in our specific version of the PRV, and does somebody have an oil analysis of Castrol GTX 20W-50 or a link that shows the amount of zinc? I can't find it on the Castrol website.

I had also heard that Castrol Edge is better for classic cars, but it would be nice to have these analyses to see for myself. All I can find is internet hearsay.

Also, I read that diesel oil in gas engines may not be good either, because although they have higher zinc, they also have higher levels of detergents. Does this cause concern?

image.jpg

[content22207_2]

API SM or SN is .08% (800 PPM) ZDDP max. It can have less, but no more.

Bob is the Oil Guy website has a bunch of oil analyses (search the forum).

API CJ-4 is significantly different from CI-4. Detergent levels are dramatically lower due to engine emission devices and low sulphur fuel. I believe API limits CJ-4 to .12% ZDDP max.

Bill Robertson
#5939

[David T]

ZDDP does not directly affect the viscosity of the oil. The PRV holds 6-7 qts more or less. There is a range of over 1 qt between full and low. I put 6 1/2 qts into mine when I do an oil change. Puts the level right in the middle between full and low. I am not sure how applicable that Volvo TSB is to our engine, there were a lot of variations of the PRV.

[DMCVegas]

Can we put this thread back on topic?

How about we just list what weight and brand of oil we use?

10w40 is the best all around weight for most owners. Unless you're running in constant triple-digit temps, then you switch to 20w50. Colder temps, perhaps 10w30, but most people avoid winter driving. This info is clearly, and completely listed inside of the Owner's Manual.

Brand is not important per se, despite what you will hear. As long as you're using a proper name-brand oil such as Castrol, Valvoline, Pennzoil, or something like that.

Generic, non-detergent oils are BAD! Don't be a dumbass and use garbage oils like these morons:

http://www.chron.com/cars/article/La...#photo-9150104

[content22207_2]

Generic, non-detergent oils are BAD! Don't be a dumbass and use garbage oils like these morons:

http://www.chron.com/cars/article/La...#photo-9150104

Private label oil (ex: NAPA brand) is not inherently bad. If it has a certain API rating, it meets the same API criteria as brand name oil.

SAE rating refers to viscosity only. It ensures all oils of the same rating are in fact the same thickness -- nothing else.

Detergent packages are proprietary and vary between manufacturers.

Both API and SAE ratings are on each bottle. Detergent packages are not.

Other oil ingredients, such as paraffin, can only be identified through an analysis.

Bill Robertson
#5939

[dmruschell]

I also use Castrol GTX 20W-50 as recommended, but...

I had read about the presence of zinc being good, and saw the flat tappets during my valve adjustment last year (see pic). My question is, what percentage or PPM of zinc is required in our specific version of the PRV, and does somebody have an oil analysis of Castrol GTX 20W-50 or a link that shows the amount of zinc? I can't find it on the Castrol website.

I had also heard that Castrol Edge is better for classic cars, but it would be nice to have these analyses to see for myself. All I can find is internet hearsay.

Also, I read that diesel oil in gas engines may not be good either, because although they have higher zinc, they also have higher levels of detergents. Does this cause concern?

image.jpg

The DeLorean is just one of several classic cars I own. After a lot of research and mechanic's recommendation, I was using Valvoline VR-1 20W50 conventional in all my cars (I preferred the 10W30, but it was never carried in stores).

I started using that after my mechanic rebuilt the engine in my 79 Vette and then realized why some of his other builds were wiping cam lobes and recommended it to me. So, that engine had about 6,000 miles on it before I started running Valvoline in it. It had already started burning oil, and it ended up being rebuilt again in October. It was probably due to the oil that was used before the VR-1, but there was definitely some premature wear in the engine (I say that because even racers have used VR-1 in their engines and the engines look fine at the end of the season). Not wanting to take a chance, though, we switched oil to Lucas Hot Rod oil 10w30. It's about as available as the VR-1, but it can also be ordered in 5 quart jugs. I'm using up my supply of VR-1 in my DeLoreans, but either one should be a fine choice. Both are high in ZDDP and are designed for flat-tappet gasoline engines.

I've heard that the detergents in diesel oil make them a bad candidate for gasoline engines that rev high. I run my DeLorean to its 6,500 redline, so it would not be a good choice for me. The 2 oils mentioned above meet my needs: readily available, relatively cheap ($6/quart for VR-1 quarts or for 5 quarts of Lucas), and will work well in all of my classic cars. I don't want to have to stock 5 kinds of oil.