Did we ever figure out why diesel oil is bad due to excessive additives but oil designed for vintage gas engines with more additives than diesel oil is OK?
Four pages of information and remarks just to save $8 to $10 per oil change on a engine that will run on any oil you dump into it !
In 2009, I built the 354 hemi for my avatar roadster. I wanted a high detergent oil to help remove any and all contaminate left over and unable to remove from any machining done. I chose Shell Rotella 15/40 and Motorcraft FL-1 filter. I now have over 40k miles on the engine and have run it in all conditions. It still runs 72psi oil pressure and 180° coolant temperatures. Oil changes happen at 5k intervals and is always at the full mark on the dip stick prior to the change. I would not hesitate to run diesel oil in a new gas motor at all. The motor starts out clean and remains so with high detergent diesel oil. I would NOT change to diesel oil on an old motor. But to use it continuously from start up to many miles hasn't done any damage and my oil looks quite good when checked.
I run Schaefer in my GMC 6 at Bonneville…… good s**t. Beenin business a long time. Tech line is helpful.
Oh for sure. What sold me on trying it was I made a post asking about it in an SBC page asking about Schaefer oil. Over 300 people commented. EVERY. SINGLE. COMMENT. was praise on the oil. Not one person bashed it like what normally happens on any post about any product on FB lol
Based on similar oil pressure readings for cold, warm or hot engines, I'd guess 0w-20 viscosity doesn't vary much with temperature. Perhaps it flows almost as well on a cold start as a 20 weight flows hot. As Martha might say, this seems like a good thing.
OK......let's 'thank-aboud-it' just a minute !! What's a price for a re-built engine running these days ? Machine shop work...."speed goodies"...plus the gaskets...(labor if you farm-it-out) $2500-$4000 depending on the amount of "goodies"? And you're thinking about cutting corners and save a couple bucks by running diesel oil ? That's a tidy sum to gamble on a ..."I THINK it will be OK with Rotella T in it !!" I'd just go with leaving the same old oil in it and just change the filter every 5-7 thousand miles. I mean...after all ain't that s'what a filter is suppose to do ? I THINK it will be OK.... 6sally6
That’s not all of it. There’s oil purposely advertised as specifically engineered for older engines that has more **** in it than the diesel. I’d like to know which group of experts are correct Or is it all just hooey
I think "hooey" probably best describes the majority of the " I thinks" crowd along with most tech expert quotes , just like any good salesman .
I had a good friend who did my machine work for years start selling oil in the late nineties. In 02 I built the 289 for my Fairlane and broke it in with Castrol synthetic 10/40 and ran that afterwards. One day he asked me what I was using in it so I told him and I listened to him for an hour telling me how the cam was going to go flat. Well I put over 12K on the little engine running the hell out of it and the cam never went flat. Now it didn’t have a large cam only little over .500 lift and 225@.050 duration so it didn’t have much for springs so I’m sure that helps but no flat cam. I never did buy his oil for flat tappet cams.
Go order a quart of Penn Grade 10-30 and a quart of Rotella. You will quickly see the Penn Grade, which is made for old gasoline flat tappet engines, is a lot slicker and really hard to wash off your hands. It strings between your fingers and sticks to the internals so everyday start ups are easier on the engine.
If you feel that makes a difference , ok , keep in mind motor honey , STP & others are " stickier " as well , are they better ?
Manufacturer A says too much detergent and ZDDP is bad. Mentions diesel oils as bad Manufactures B & C says we’ll take the diesel oil detergents and ZDDP levels and multiply them by 50-100%. And brands it as vintage engine oil. how can the science be correct for both or it really doesn’t t matter.
If after experiencing the " science" touted during the recent infectious disease fiasco is any indicator , science is something often used for monetary gain & little else .
You've missed the point , it's about being able to make an informed decision while trying to avoid advertising hype ...
Good article. I think the main point is that there isn’t an absolutely definitive answer to ZDDP question. Modern SM oil still has some and all oils are supposedly backwards compatible. We do know the benefits of ZDDP. I stand by my machine shop and cam grinder’s recommendation of 1200 ppm of ZDDP for flat tappets. I also don’t buy the use of - fill in the blank - oil will ruin an engine in short order. I like your statement “oil is good” Dan
Student: “if detergents suspend wear metals, then the oil with less detergent should have less wear metals in it? referring to the lake speed video
Sounds like you've got at least some students who are capable of thinking through some of these kind of issues on their own. That's encouraging!
Personally I believe the enemy of flat tappet cams today are valve springs. If you have an engine that will never see 5000 rpm and spend its life at 2-3000 why would you ever need 130# springs good for 7000rpm. A 270 Chevrolet 283 had 70# springs. I’ve run my GMC 6 Bonneville record setting engines with a max of 110# and normally in the low 90’s. The key is lightening the valve train. Conical springs, smaller retainers, etc all allow this today.
Timely post. I put “z28” valve spring in my 283 build just cause that’s what we’ve always used. Looked up the recommended springs for the baby cam I’m using. 80# was listed. Basically a stock 350 spring. The z28s are in the 110-120 range. Swapping em out now. Will it make a difference? One less thing to blame a failure on I guess
I wish I could say that the recent conversations about oil have been educational. But they haven’t for me. The usual points of view seem to boil down to opinions rather than facts. No doubt the requirements for engines and products developed by oil companies have evolved and hopefully still work optimally for earlier vehicles. The points brought up include; too much ZZDP or not enough, non-detergent or detergent, multi-grade or single weight, And then are those who say it doesn’t matter what oil is used and no way changing to a different oil could cause an engine problem. In the end it reminds me of a line from the comedy group Firesign Theater: “Just remember everything you know is wrong”.
The Jalopy Journal
