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Without opening this beat-to-death discussion once again, could someone please give me their recommendation for a good engine oil for use in a rebuilt 1930's straight eight? 

I've searched and there's a whole lot on the internet about oils and how ZDDP is being phased out, but I figure any discussion more than a year or two old is outdated as oil manufacturers change their formulations.  What's the latest collective wisdom?

 

I interested in oil viscosity (10W-30 versus 10W-40, etc) and the brand which has the highest ZDDP ppm . . . . . preferably in an over-the-counter-at-Walmart brand that doesn't cost $10 per quart.  (I use eight quarts per change !) 

 

Thanks -- Scott

Troy, NY

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Hard to go wrong with Rotella 10-30, and its often on sale. Thinner is better if you can get away with it because it flows faster cold, and most actual wear occurs when the engine is cold. 15-40 is readily available if the particular engine requires something thicker than 10-30.

 

As far as I know zddp was not in use yet in the 1930s, so you have less to worry about than someone with a newer car with a more radical cam profile and stronger valvesprings.

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Hi Scott ! How many miles on the engine since rebuild ? Also , you have made me somewhat curious as to what '30s straight eight it is. My overactive imagination is conjuring up everything between simple domestic flathead , to exotic foreign OHC. (Or perhaps a 420 cu. in. domestic supercharged DOHC , for that matter - I hope you are so fortunate). In certain instances that might favor a particular oil. Forgive me if I am seeming too prying. Just trying to be as specific as possible for your maximum benefit.  - Carl

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Interesting point on early versus later engines...

I'd still prefer an oil with zddp rather than one without. But I've read that diesel oils are not good for gasoline engines. Something about how the additive package is formulated differently. 

The car is not all that exotic---1932 Packard standard eight

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Curti: Thanks for the reprint from Skinned Knuckles magazine. That publication is an indispensable asset for anyone in the old car hobby. Subscription rates are $28.00 for one year, $53.00 for two years. The subscriber address is P.O. Box 6983, Huntington Beach, CA 92615-6983. Zeke

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Firstly, do a search on this forum. This topic comes up about once a month.

 

If you want maximum zinc in your oil, use a diesel oil rated CI-4. I would like to know where you read that diesel oils are not good for petrol engines; is it based on science or hearsay? Of course the additives will be different: diesel engines are much dirtier so the additives are designed to handle that. They won't hurt an engine though. Thinking about it, the compression pressures are much higher in a diesel engine too, so maybe the additives are "stronger" to hold their viscosity under higher pressures?

 

To minimise wear, use a synthetic oil. Wear tests show pretty much ALL synthetic oils are better than ALL mineral oils in this regard.

 

For viscosity, your manual probably calls for SAE 30? To minimise wear on startup, use a multigrade oil with a low value for the number before the W. That refers to how it behaves at low temperature (W, I believe, stands for winter). So choose a 5 or 10W. The second part would be the 30. A good reference on viscosity and zinc is Richard Widman's paper www.widman.biz/uploads/Corvair_oil.pdf (attached below). He has also developed a tool to graph the viscosity of an oil at your local temperatures http://www.widman.biz/English/Calculators/Graph.html  . Clearly, we want the flattest viscosity curve we can get, without the high low-temp. peak.

 

I am running "Penrite HPR-5" 5W-40 CI-4 (i.e. diesel) oil in my 1930 Dodge Brothers 8. It is a little worn but leaks more oil than it burns and it doesn't leak much. The oil pressure is more consistent than when I was using 20W-50, which is far too thick (as I know now).

 

Corvair_oil.pdf

Edited by Spinneyhill (see edit history)
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Since rebuild, probably not much more than 300 miles.  That was 12 years ago because the car sat in dead storage for a long time until I got it . . .  got it back.

Long story, but I did the rebuild back then.  New connecting rod bearings, original crankshaft journals, rebored, new pistons, valves.   Original mains and camshaft.

--Scott

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O.K. That makes the way forward clear to me. An aspect of the following will not sit quite right with you , but lets have a civil discussion about it. With only 300 miles on a rebore and new rings , dump whatever goo is in there and replace with Amsoil Break in oil. It is a straight 30 weight formulated with plenty of zinc for your break in period. Your cyl walls will polish up correctly , and the rings will seat properly. Run this for about 1000 miles , and then change to Amsoil Z-Rod 10W/30. This has exactly the high level of zinc and phosphorus for your engine. It is also engineered to protect our engines from corrosion over the periods of non use , which your engine is a bit of a poster child for. We all let our old cars sit longer than the daily driver. Sounds a bit like stuck valve insurance. Which brings me to the hard part. I am currently using Z-Rod 20W/50 in my mid '20 Cadilllacs. These engines are original and untouched. The '24 has 63,000 miles , the '27 maybe 40,000 ? So therefore a heavier oil. I have gone from Valvoline 20W/50 full synthetic , to Mobil 1 15W/50 , and now the Amsoil Z-Rod. If a better oil is developed , I will happily change to that. I am wondering about this fairly new Penzoil Synthetic made from natural gas , but I do not have enough info yet. I am old , and getting rather short here , so I may just stand pat. If anyone has already travelled on this particular wheel , please do tell so I don't have to re-invent it. Anyway , the hard part for you to swallow , will be the price of treating your engine to the very best protection possible under all conditions , including accidental overheat. So let's see how much we might to sacrifice for the sake of our beloved cars. Maybe the cheapest oil change you can buy is $25. Let's say Z-Rod will cost $100. Is $75 or $50 extra every year or two worth it ? Think about it , and let me know if you need to be convinced. I think I can hold my own to your benefit. While we are talking Synthetic , please use Synthetic grease everywhere applicable. About 35 years ago I was talking to a group of farmers over at the feed store in Billings MT. They told me that after changing to Synthetic grease , wear ceased to be an issue in their heavy agricultural machinery. What , in the long haul is cheaper ? A properly engineered lubricant with every molecule lending a hand to the task ? Or some mixture of dinosaur lard which carries a bunch of molecular fragments which have a lower flashpoint and lesser shear strength ? If you have some doubts , I strongly suggest you read the 33 page paper Dr. Spinney' recommends. I took the "Professor"'s advice , and , as did he , learned a great deal from it. I have trouble concentrating and reading these late days , so I had to read it twice. But it changed some of my long held fiction. Let us know what your feelings are. If , after your studying , you still feel on the fence , please let me , and perhaps Spinney' , or even Richard Widman himself , let us have a last chance to convince you. Remember that Hot Rod Magazine test of synthetic oil about 35+ years ago ?  - Carl 

 

P.S. : If your oil pressure is not high enough with the 10W/30 , you can blend up , say half and half with the 20W/50 to get a 15W/40. But with a proper oil pump and pressure relief valve , assuming your gauge is working , I would think the 10W/30 should be perfect for a new engine.

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Hmmmm , interesting , Ted. This is a Synthetic break in oil. Amsoil says NO MORE than 1000 miles. The stuff is expensive , so maybe they are just letting the owner of a new engine get their money's worth ? Lots of people want to save money here and there when it comes to oil. I am the opposite. I love to be convinced I am giving my engines nothing but the best. I must admit that I still tend to throw money at things. But I'm getting better. There is not much left to throw here in this camp. Too much thrown too often already !  - Carl

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  • 3 weeks later...

I have a 1937, 1939buick  and a 1956 stude and a model aa ford,  all using 15/40 diesel engine oil ,citgo ,1300 ppm of zddp just for openers ,shell rotella is another good choice, have used for 20 years, no problems.

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You are going to get as many different answer as respondents to your question and anyone or everyone could be correct.

 

For my 1933 Chevrolet Master and 1962 Triumph TR4 I am using Valvoline Synthetic Racing Oil.  There racing oil comes in both Synthetic and Non-synthetic versions, but quite a few years ago I went with the synthetic since it had a higher zddp level than their Non-synthetic version, as I recall.

 

For most oil brands you can go to there website and get information on each oil if you go to the Product Information or PI Sheet.

 

I don't know if the zddp makes a difference or not, but I am using the higher level stuff and if you compare the PI sheets for each oil you will see the difference in Zinc/Phosphorus

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Valvoline R Racing oil is what we run in ALL our pre war cars. Duesenberg, Stutz DV-32, Rolls PI and PII, Packard 8 & 12, Cad V-16, Pierce 8 & 12, Auburn Supercharged, among a bunch of others........and the 1915 T. Pick your viscosity depending on application. We also run it in the Top Fuel dragster running in the 6's, and the shop pick up truck, which we use to chase parts and run to the sand blasters, and it runs in the 9's. ?

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On ‎6‎/‎12‎/‎2017 at 8:23 PM, C Carl said:

 

P.S. : If your oil pressure is not high enough with the 10W/30 , you can blend up , say half and half with the 20W/50 to get a 15W/40. But with a proper oil pump and pressure relief valve , assuming your gauge is working , I would think the 10W/30 should be perfect for a new engine....

 

Here's a thought....if you don't get good oil pressure with a 10-30 oil........what about FIXING IT !      The thinner the oil, the faster it can draw away heat.  The thicker the oil, the better it will be able to disguise the problems of a worn out motor...( but not for long....the thicker the oil, the faster the motor will self-destruct".)

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Consider the following:  Multi-grade oils were not available in the 1930s. Most cars' manuals specified 30 in summer, 20 or 20W in winter.  Bearing clearances from the factory were greater, usually 0.0015 to 0.0025.  Viscosities change once in the crankcase, both from miles and from time (oxidation). Given the greater from-new bearing clearances, it is my own opinion that SAE 10W-30 may be a bit thin if you maintain do a good deal of 45-55 mph cruising in warm weather.

 

For all those reasons, I run diesel 15W-40 in my fleet.

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On ‎7‎/‎1‎/‎2017 at 9:48 AM, Grimy said:

my own opinion that SAE 10W-30 may be a bit thin if you maintain do a good deal of 45-55 mph cruising in warm weather.For all those reasons, I run diesel 15W-40 in my fleet.

 

I sort of disagree......!    the "15W"  viscosity is a heck of a lot better for ANY engine than ANY traditional  "single grade" oil for a cold start - enables the oil to get thrown around on the vital internals fast.

 

I trust we all know, or should know...the worst thing you can do to a typical car motor...is START it !   ( once it has been running for a while,  it has lubricating oil splashed all over the internals).

 

What concerns me is the idea of a 40 weight oil in any liquid cooled motor - a bit thick - not convinced you are getting as much oil tossed around as would be achieved with a 30 weight.  True - under extreme conditions of heat and speed - yes, the orig. manufacturers did recommend 40 weight...but that was simply because the old "single grade" oils thinned out so much under those conditions.

 

I prefer a 10W-30 oil.  Living in the Arizona desert, I rarely have the opportunity to drive only 45-55 mph in warm weather....65-80 mph is more typical to avoid getting run over by a semi or even a garbage truck....!  Wish we had only WARM weather...was 112 the other day.

 

Which gets us back to the basic question.....if you aren't getting good oil pressure with a hot motor with a 30 weight oil (for example...like the 10W-30 I have been using in the same big engine pre-war car I have owned and driven since 1956..........)  my recommendation...is....FIX IT !

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2 hours ago, SaddleRider said:

What concerns me is the idea of a 40 weight oil in any liquid cooled motor - a bit thick - not convinced you are getting as much oil tossed around as would be achieved with a 30 weight.  True - under extreme conditions of heat and speed

Variables to consider:  (1) What's your bearing clearance, both factory (loose by modern standards) or known-at-present by your plastigaging them? (2) How long since the engine was rebuilt, and to what clearances?   (3) How long, what speeds/loads/RPM, what weather conditions of operation of the engine? (3) Flathead / T-head engines are subject to much more dilution by unburned fuel in service.

 

Carrying your premise to its logical extreme, Peter, why do you not use 0W-20 in your Packard 12 for Arizona cruises?

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  • 2 weeks later...
On ‎7‎/‎1‎/‎2017 at 9:48 AM, Grimy said:

Consider the following:  .  Bearing clearances from the factory were greater, usually 0.0015 to 0.0025. .....

 

The laws of physics, at least to my knowledge, havn't changed down thru the years.    Looking at SAE tables,  engine mfg. specs...I am unable to find data to support your above statement.   Let me qualify that - I am not familiar with bearing clearances spec'd out prior to the mid 1920's...

 

By the early 1930's,  engine mfgs. were well aware that the thinner oils, going thru a motor's vital bearing surfaces faster,  acted much more effectively in cooling, than thicker, slower moving oils. 

 

Just the other week, we had extreme temps. here in Arizona.    Took my "bone stock"  ( except for the rear axle gearing)   even has the original  "insert style" copper-lead connecting rod bearings for a drive up Interstate 40 ( what USED to be U.S. Highway 66).   10W-30 oil.    After  a hot, fast climb up to Williams, Arizona for a train club meet,  idle oil pressure 20 lbs. Anything over a fast idle,  oil pressure (factory spec)  50 lbs.

 

In answer to your question about my own car's motor - I did pull it apart - had to do a re-bore - new rings, pistons,  stellated the valves.   Didn't have to do anything with the lower end.   Well..I take that back - rod clearances were in the two thousandth range - so --yes...I know..i know...violation of SAE recommended shop practice....I put a thousandth shim under each rod'cap's "insert".   How wise a shop practice...?  Well..."so far...so good"....did that at Charlie Last's shop in the mid 1960's....50,000 + miles of "hot dog" driving....so far...so good !

 

For factory spec. rod bearing clearances on Pierce Arrows - you got me - I cant find that "call-out" in my "MOTOR'S  AUTO REPAIR MANUAL".   Remember - the high limit in the 1-3 thousandth spec. for a typical crank-pin diameter of that era  is a MAXIMUM  ACCEPTABLE RUNNING clearance.   I would be surprised if Pierce has governed by a different law of physics, and thus had a different "call out" for connecting rod bearing clearances.

 

Your question about why not use a ZERO-20 in my Packard V-12?  Good question.   May I respectfully suggest you are taking my comments as to viscosity  out of context.  You are forgetting that bearing journal diameter and stroke should also be considered in the spec. for oil viscosity.    The general rule is - the bigger the rod journal, and the longer the stroke,  the heavier/thicker the oil call-out should be. 

 

 

Edited by SaddleRider
I promise to learn how to to type (see edit history)
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Yes, Peter, my 1935-46 MoToR Auto Repair Manual specifies .001 to .003 as clearance limits for Packard Super 8s and 12s for both rods and mains, and that same manual does not list clearances for Pierce 8s or 12s of the same vintage.  Note, however, that those are in-service clearances, not as-delivered.  Other Pierce documents buried in my files reflect that manufacturing clearances are .0005 to .0015--and I am sure Packard's carefully-built engines used essentially the same.  Do not extrapolate those high-end standards to all other manufacturers!

 

Pierces beginning in 1933, and Buicks of 1934-35 (and perhaps earlier), used Oil Temperature Regulators (OTR) in which oil passed through  a "mini-radiator" containing engine coolant, to thin the single-viscosity oil during warm-up, and to stabilize the oil temp during long runs--all in the absence of multi-vis oils.

 

I do indeed use multi-vis oil (Rotella 15W-40) in all my fleet, for the reasons you address.  My point to which you seem to object, was that acceptable in-service clearances probably exceed--substantially--those specified for manufacture.  I'm delighted for you that you've had such longevity from your regimen, although I would have followed your own maxim to "just fix it", rather than to shim your rods when the engine was being rebored.  It works for you--good!--but by NO MEANS is that a Best Practice.

 

Nor is high oil pressure necessarily itself the Holy Grail:  Volume is more important than psi, given a minimum usually shown in owners' manuals or factory shop manuals (note: Pierce never produced a factory shop manual).  Pierce specified through 1928 what we would consider today as "low" oil pressure.  Through 1920, at least, the Pierce T-head engines' oil pressure is, by design, responsive to rpm--the more rpm the higher the oil pressure.

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Add Franklin to that list of engines with oil coolers - starting in 1932 with their v-12 and the next year with their 6 cylinder.  It allowed them to use slightly lower viscosity oils without loss of viscosity during times of high engine temps.

 

Shortly before that, Franklin engineers presented a paper to the SAE of their tests showing how using higher viscosity engine oils raised the engine operating temperature.  Proved the old mechanic's advice of use the thinnest motor oil that will stay in the engine.

 

And their oil pressure spec was also low by modern standards - 40-45 pounds at about 1500 rpm with warmed-up 30w oil. Hot idle it can get down to where the oil light would come on in modern engines. Panics many new owners. But the main and connecting rod bearing surface areas are so large for the loads on them that volume is what's important, not pressure.  

 

Paul

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I am going to toss in a curve ball. "Racing oil" is made to run at high revs and high temps for a short time. It is often changed after every race.

 

How does it perform long term? I read somewhere, perhaps Bob is the Oil Guy,  that they may not last so well for a long oil change interval before the additives are used up. I would read up on it before using it for ordinary running. It does appear to meet the requirements though.

Edited by Spinneyhill (see edit history)
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