Synthetic oil use on flat tappet cam after break in

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moparmat2000

moparmat2000

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First off. Happy new year!!!! As I sit here waiting for the end of 2020 I am pondering an oily thought. Theres been other discussions about oil with ZDDP and zinc additives for these older V8s. Kinda curious if after a remanned break in you switch to a true synthetic oil if that negates the cam lobe wear and can be safely used in place of oils with ZDDP zinc additives etc.
 
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I wouldn’t use synthetic conventional oil has been used safely for 60 years
 
Plus, aside from the possible cam wear issue, unless the engine was specifically built for synthetic use, thin full synthetics don't play well with 60 year old specs for bearing tolerances and clearances which can play havoc with oil pressure, and gasket and seal seepage, among other things.
I figure they were designed around Dino oil, and just feel uncomfortable running synthetics in them. The additive packages in the current crop of fossil oils (with the possible exception of the elimination of ZDDP) is light years ahead of what it once was, so they're still a quantum leap forward...
 
Synthetic in the new musclecar, diesel in the diesel, old racing oil with lots of zinc in it in the old mopars, street car and bracket car. To each its own, as required.
No synthetic anywhere near my old mopars.
 
If you look at synthetic under a microscope, the molecular structure is all identical in size hence why it finds its way out of the old seals ,gaskets etc don’t recommend :popcorn:
 
I run synthetic oil in everything I own !! Have for years now ! Mowers, weedeaters, chainsaws everything ! Have not had one bad experience with synthetic oil in anything ! I’ve had two cams that tore up lobes ! Both were with conventional oil ! And both happened when they took the zinc out of the oil !
 
Biff said:
If you look at synthetic under a microscope, the molecular structure is all identical in size hence why it finds its way out of the old seals ,gaskets etc don’t recommend :popcorn:
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I'm assuming since he saying "after break in" this is a brand new build and doesn't have old seals...
I'm going on over 5 years maybe even 6 and no leaks drag racing and all kinds of torture.. :popcorn:... 30w penngrade break in oil and 15-40 penngrade ever since...
 
33IMP said:
Synthetic in the new musclecar, diesel in the diesel, old racing oil with lots of zinc in it in the old mopars, street car and bracket car. To each its own, as required.
No synthetic anywhere near my old mopars.
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This Concludes This Conversation...
 
My dad was an early adopter of Amsoil in his Dart. Somewhere in the early 70s he started using it and put in the neighborhood of 200,000 miles on the current engine and rear end.

Engine rebuilt once at about 150,000, currently has about 169,000 on that rebuild. And rear has about 319,000 miles on it.
 
My Lunati cam instructions say specifically do not use synthetic oil during break in or the first 500 miles! So I'm assuming after that it's ok. I was curious to see what you guys had to say on this topic. I don't have 2 cents to give as iv never done it. But this is a good thread topic !
 
In my stock daily drive 318s, I have used Mobil 1 for over 20 years.
Hundreds of thousands miles.
I suggest putting some STP in if it concerns anyone.
A high lift hot rod engine may differ.
 
The shop that built my engine suggests Lucas High Zinc 10W-30 non synthetic. That's what I'll probably use for the near future. Having said that before I bought my 71 Dart I used only Amsoil Full Synthetic in all my weekend fun cars but they were all late model cars.
 
Used Joe Gibbs mineral based for break in first motor 318 solid flat tappet, 2nd engine stroker solid roller both engines put around 5k miles than have switched to full synthetic Penrite with Zinc 15-40. I always inspect oil on change 3000 mile spotless no signs of any metal. When I removed sump to change a bad remain went with a better quality seal anyhow inspected main bearings while the sump was off and checked cam lobes no signs of any wear or marks I was quite impressed on how spotless everything was cylinders still had the cross hatch .
 
My dad still has his 1978 power wagon he bought new, 360.
First oil change back in 78 he switched to mobil 1 synthetic.
At 213,000 miles, it was leaking oil bad out the rear main seal, and soaked the clutch.
I pulled the engine, dad said re-build it. There was no wear on the bearings at all, cylinders still had cross hatch marks on them.
I just re-gasked the engine and put a new clutch in it.
It is still going strong with 240,000 on it now.
 
my mild hyd lifter (under .500 lift) 340 loves 15/40 shell rotella t6 synthetic.....plenty of zinc
 
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I can’t imagine how in 2021 some haven’t figured out the benefits of a QUALITY (that means group IV and/or V base oils with the correct formulation of additives) synthetic oil.

Once the rings are seated you can switch to a QUALITY synthetic as long as it isn’t something that can run in an engine that has cats hooked to it.

You cam, lifters, rings and bearings will thank you.
 
synthetic is fine after break in.Is it better than dino oil...somewhere at the bottom of the argument there is a grain of relevance.Is it worth the extra money? I have run regular dino oil in all and everything for 50 years.All went 300k and were running fine when sold.
 
I'm doing very frequent oil and filter changes on my classic, usually less than 3k miles, plus additional seasonal changes, after the winter hibernation.
Don't feel the need or benefit for the synthetic oil$.
Maybe if I had a fleet, or needed longer gaps between oil changes. But for me and my 1 classic? Whale oil will do. Lol
 
I used Mobil 1 synthetic in my 1975 boat with a Chevy 2 motor for more than 35 years. Never took it apart. Never used any oil, ran great till I got rid of it. Just one data point, but I have run synthetic in all my cars for years.
 
I kinda got turned off by Mobil 1 when it first came out. The shop I worked in also maintained a small fleet of rental cars. Changed oil every 7k miles or so.
That stuff 1 was like INK!
It was staining everything, no to mention your skin.
Couldn't tell you if it still does.
 
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