Oil for the Nailhead

[kilkm]

I'd like to know what type oil people are using in the old Nailhead engines. The last oil change in my '62 401 I tried switching to Royal Purple 10W30 synthetic. The engine seems to have some clatter for about 5 seconds after start up then quiets right down and runs smooth. Also noticed increased oil consumption and blow by out the draft tube. I've read modern oils don't contain the additives these old engines need and thought synthetics superior lubricating properties would be the answer but now I wonder if it's OK for these older engines. I've read some people using oils for desiel engines such as Shell Rotella or adding E.O.S. assembly lubricant with a high Zinc content to conventional oil. How about adding E.O.S. to the Snythetic oil? I'd be interested in your thoughts.

[Centurion]

kilkm, I've been wanting to add a post about this subject.

My understanding is that Denny Manner, who was a Buick/GM engine designer/engineer from the 1960's to the 1990's, presented some technical tips at the 2006 Buick National Meet last July in Rochester, Minnesota. Manner has owned Buick collector cars for almost 30 years.

Among his comments:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">USE GM ENGINE OIL SUPPLEMENT (E.O.S.) GM part no. 1052367 in pre-1986 Buick engines. Flat lifters (pre 1986) and aluminum rocker arms (pre 1973) in our Buick collector car engines operate with very thin oil films and require zinc additive in the oil for wear protection. Unfortunately, today's oil designed for modern engines with roller lifters and roller rocker arms have lower quantities of anti-wear zinc additive. I recommend using a pint of E.O.S. (basically a zinc additive) with each oil change but don't overfill the crankcase. E.O.S. is also an excellent prelube to use during engine assembly of camshaft, lifters and rocker arms assemblies. Some of today's oils have adequate levels of zinc, generally racing oils and oil certified for both diesel and gasoline engines -- I choose to include a pint of E.O.S. with each oil change and be assured of wear protection.</div></div>

Interestingly, since reading Manner's comments, I have run across a number of articles regarding this very issue. There is currently a thread on a "Classic Lincoln" forum which is quite interesting:

http://www.thelincolnforum.net/phpbb/viewtopic.php?t=18359

I have seen similar threads on the forums of the Cadillac-LaSalle Club, and some of the vintage Cadillac owners say that the lifter noise has quieted dramatically since using E.O.S.

Some have noted that the E.O.S. containers specify that the contents are not to be used as engine oil additives, but my understanding is that GM is unable to market E.O.S. as an additive because zinc is destructive to the catalytic converters used on 1975-and-later model year cars. I've heard that some GM dealers are receiving numerous requests for E.O.S. on a daily basis.

Manner mentioned elsewhere that synthetic oils must be changed regularly because the additives are depleted over time, but he did not specifically indicate whether he thought there was adequate levels of zinc for the older cars.

I have read from one source that even those motor oils (like Shell's Rotella) that have higher zinc levels will be changed to reduce zinc levels during the coming years.

I'd welcome any further knowledge on this subject.

[Guest imported_Thriller]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Manner mentioned elsewhere that synthetic oils must be changed regularly because the additives are depleted over time, but he did not specifically indicate whether he thought there was adequate levels of zinc for the older cars.</div></div>

My recollection of this point from Denny's talk, and other sources, is that synthetic needs to be changed because, like conventional oil, it gets dirty over time. It is those impurities (combustion byproducts, etc.) that will damage the engine - changing the oil effectively flushes them out.

Time to give my GM service guy a call and line up a case of EOS.

Actually, somewhere (I'm so disorganized) I have a little notepad that I took notes from Denny's talk...he mentioned a number of things like this that were very much of interest.

[GMPARTSMAN]

We used to routinely add E.O.S. to oil changes in the early 70's. It was marketed as a supplement to boost the anti-scuff and anti-wear additives in the oils. I attribute the long life of my '73 Vega that I literally thrashed within a inch of it's life to the use of E.O.S. at each oil change. The only engine related failure I had in 80K+ of beating it into the ground was a rusted out head gasket at 45K. I stopped using it when I bought my '77 El Camino, and I wonder if it's use would have helped the camshaft last beyond the 35K it failed at with a flattened lobe which was a common problem from 75-77 small blocks.

And about the diesel oil, I now use that in my nailhead and my '67 Pontiac. The late model drivers are run on Mobil 1 though. So far, so good.

[kilkm]

Thanks for the info guys. I don't think I've ever let the oil get over 1500 miles on it before changing it in this engine and during that time I've added a couple of quarts due to consumption. I've put the car away for the winter now, but next spring I think I'll try the diesel oil and E.O.S. I'm a little uncomfortable with the snythetic in this old engine. Would a straight weight oil be perfered over a multi grade? I don't drive this car in cold weather.

[NTX5467]

A few points that I've discovered on this issue --

The OEMs drive the oil specs to a large degree. The new "SM" rated gasoline engine oils are the ones where the ZDDP (zinc additive) were lessened and (from what I've read) this is when some of the flat tappet cam manufacturers got excited. If you read the breakdown of each progressive oil spec rating, emissions hardware longevity are some of the concerns and that's one of the "SM" oils' orientations.

The "SL" rated oils, prior to the current "SM" oils are where the Shell Rotella T, Castrol Tection, and other diesel-oriented oils are rated (usually in 15W-40 viscosity ratings for the current breed of OEM diesels, as GM's Duramax). I found a discussion on the Shell Rotella website that said it was designed with diesels in mind (as stated by the site moderator), BUT the back of the bottle specifically says "Cars" and other vehicles can use it. The Chevron Delo400 notes some "ISO-Syn" formulation, which might indicate that it's a blended synthetic.

Further research (at WalMart and other chain auto supplies) revealed that, pretty much, the "SL" rated oils were still available . . . but not in the currently-used OEM 5W-20, 5W-30, 10W-30 viscosities, but in the 10W-40 and 20W-50 viscosities which are not currently recommended by the OEMs for their current-production vehicles. The oil that is used for the emissions and fuel economy certifications have to be what they recommend you use in the vehicles (understandable), but the oils that could have been used in earlier vehicles can still have the stuff they used to have in them. Whether or not the "heavier" oils are "SM" (as all Castrol gasoline oils for car-type use are) or "SL" can depend upon the brand. I've even found some 10W-30 oils that were "SL", plus some synthetic blends that were "SL" also. THEREFORE, you can probably find many oils out there, possibly even in a brand you're now using, that have an "SL rating without having to go to the diesel or fleet-type oils -- if that's a consideration.

So far, only one aftermarket cam manufacturer has raised the zddp issue. If they claim you have to have it to keep their warranty in place, that's their situation and the user will need to follow their recommendations. In other camshaft websites, I found no such concerns (at least, openly), but I didn't look for any instruction/installation sheets online from them. This issue was raised by them about three years ago. Since that time, it has tended to make the rounds of many car-oriented forum at one time or another, finding new audiences wherever it goes.

There USED to be TWO GM EOS formulations . . . the "quart" which replaced one quart of motor oil at oil change time and the "pint" that was added to existing motor oil. I believe these might have had two different functions back then, but the cans/containers read pretty much the same as to benefits of use. The smaller "concentrate" was a highly viscous liquid and that's the one that was recommended (generally) as cam prelube at camshaft installation time. GM also has a separate Cam and Lifter Prelube product now, which looks pretty much like what some of the aftermarket camshaft manufacturers have available from them (sticky and blue or green in color).

The GM EOS quart might have also had more detergent in it than the concentrate would have and was supposed to be (basically) a 30 weight oil. It could well have been the same end amount of additives as the concentrate had, but with a different "carrier". Back then, I felt like the quart EOS was a little suspect, but the concentrate had definite uses other than just something you put in the oil (consistency of STP back then).

By 1986, GM had started using roller tappet cams in many of their engines (notably the small block Chevy V-8), with more to come later. That's probably why the "1986" mention in what Denny mentioned.

The aftermarket cam manufacturer who recommends the Rotella T oil also has stated that synthetic oil of any rating can be used instead of the "SL" rated normal motor oils. It appears that the superior film strength of the synthetic will compensate for the lessened levels of zddp in that oil.

I know that everybody has their own brand preferences on motor oil, which is a "given". I also have observed that particular demographics of vehicle enthusiasts tend to favor particular brands of motor oil and lubricants (i.e., Valvoline with their long-standing involvement in drag racing has tended to have many racers that regulary use that brand of oil due the association with that activity). I know that Royal Purple has something of a similar situation from that brand being involved in certain types of motorsports and also some government contracts, plus a widening supply network to now include many chain auto supplies.

Many years ago, a car club associate complained that when he put Castrol GTX in his engine, the valve cover gaskets leaked . . . but when he put Pennzoil in instead, the leaks stopped. I asked my machine shop associate about that and his reply was that the Castrol "leaked" as it was getting into all of the small spaces within the motor, which Pennzoil obviously was not doing. We laughed. At that time, I was using Castrol and had no leak issues in any of the vehicles it was in (for comparison).

I do know that when I did an oil analysis on a vehicle that I'd been using Castrol GTX 20W-50 in since it's first oil change at 3000 miles, the analysis sheet indicated a large amount of (a) zinc additive (which reminded me of the "STUD" oil additive from the early 1970s, with ZDDP in it). So much for that. When I changed the cam (1977 Chevy 305) at 92K, to upgrade it and the timing chain, the cam showed minimal wear on the lobes . . . pretty much what I expected, all things considered.

In an engine, the period during initial cam "break-in" is highly important to later camshaft life. This is where the additional zinc from the EOS Concentrate comes in. I suspect that once the various cam lobes and lifters "become friends", the need for the zddp can diminish -- just a hunch -- without causing any problems down the road.

A key thing is that, unlike what we might have suspected, the "SL" grade oils (in many name brands) are still readily available at this time. "SM" did replace "SL" in the ratings, but I suspect the reasons for "SM" being around would not really apply to many of the vintage collector vehicles on the road today (and tommorrow). Therefore, it might be well to shop around for "SL" oils and learn to read the oil bottle to see what is supposed to be in it. Plus, the use of GM EOS Concentrate can't hurt anything either! I'm not sure about whether or not it would be advisable to add it to a "full" synthetic oil, though, but using it with a blended synthetic could be an option.

In the www.bobistheoilguy.com forums, I've seen some comments (over a long period of time) that mention that when changing from one brand of oil to another, the engine ran quieter or had more power. This CAN happen, but it can also be dependent upon how long the oil that was changed was in the engine (depending upon various factors of use and/or engine design, oil viscosity can decrease with time and extended use intervals, and the engine can become noisier as that happens). Finding those particular posts would be worse than finding a needle in the Monahans Sand Hills State Park, but I've seen those comments in there.

In theory, an oil of a particular viscosity should have a particular flow characteristic and lube the engine according--whether normal oil or synthetic. Yet I know that when I started using synthetic oil after an engine rebuild, it poured out of the bottle so quick I thought they were 1/2 empty to start with -- which is generally a synthetic oil benefit (easier flow in all temperatures), but it would also appear that an oil that flows easily will also vacate the engine's oil galleys sooner when the engine stops running.

In the early 1970s, some Chevy Big Block V-8s were prone to trap air in the lifter galley after the engine stopped. Then, upon startup, a random lifter noise could happen. The "fix" was to drill a .030" hole in the front lifter galley plugs in the block -- later, the existing solid plugs were upgraded to ones with the holes already in them. This let the air bleed out of the galley and also put more oil on the back of the cam sprocket and timing chain.

If you've got an oil consumption issue, I think that I'd go back and "baseline" everything with a change to a straight weight 30 motor oil (IF that will fit the oil viscosity recommendations for the ambient temperature ranges where you're located). Check the oil pressure and see how the consumption goes as that was generally what the engines typically "ran" back then. From that point, then you can try a 10W-30 or 10W-40 oil and see what might change (consumption, noise, etc.). Then, when you get that research completed, with the same oil brand, you might venture off into synthetic territory and see where things "go".

I really don't think you'll notice too much difference, but it's possible that the combination of a particular engine and particular oil might not work or might work great together. It might take some time and miles to find that "sweet spot", but it could be worth it (or at least getting an improvement from existing situations).

I don't know that the gauge of blow-by out the road draft tube would be a good indicator of the oil's performance. That particular flow would be more related to engine condition (rings and the cylinder wall interface, including ring end gaps and such) than the use of a particular motor oil -- but it could be that a particular oil (or viscosity thereof) could lessen, but not eliminate, it.

Just some thoughts and observations,

NTX5467