Technical Synthetic Oil verses conventional motor oil.

I drove my '32 to the auto parts house yesterday to get some antifreeze for my daughters car and I got into a conversation with a old friend that works there and naturally we started talking about our cars, he was telling me he is building a new engine for his '55 Chevy and he is planning on using synthetic oil.

I'm from the old school, if my motor oil works why switch to something new?

Is there any advantages/disadvantages of these new age oils? HRP

 

More miles between changes......

Joe

 

Synthetic oil works just fine, but one thing that I have found to be true is that the way early engines are sealed they have a tendency to show leaks more with synthetics than then they do with conventional oils.

 

Break the engine in with a mineral oil then switch to synthetic. Rings may not seat with synthetic because it's too slippery. After break in Mobil 1 15w50 has all the zinc you need for an older engine, used it in my flathead without any problems for years.

 

IMHO, Run whatever has been run in an engine. I don't switch up unless it's a fresh motor. I stick with whatever it's had in it previously usually. I've never run synthetic in any of my old stuff.

 

My dad has been a "lubrication technician" for about 20 years now, and no its no a oil change monkey. He's been overseeing any and all lubrication in a factory, from hydraulic systems, back up generators, pickup trucks to small engine driven welders. He has to go to special classes about twice a year to keep up with whats new in the world of oil. I have had MANY conversations with him about oils, oil filters, oil change intervals and oil samples. Obviously he can be very technical with thw subject, but I can convey some of what he has told me. If you've been running conventional oil for 100,000+ miles, continue running it, if you have 10-15,000 on a fresh build, run whatever you want. The synthetic oil has a extended service interval, but he says it has added cleaners in it also. I do know that is the only thing he runs in everything he owns, tractors, lawnmowers, generators, cars trucks everything. If you happen to have a specific question, I'll be more then happy to ask him and get back to you

 

RAK is right. Definitely benefits to a quality synthetic, just don’t use to break in.

 

My experience with synthetic oil happened several years ago. I drove my 40 to a friends house about 30 miles away one Sat. During the next week I switched to synthetic oil. Just by coincidence I drove it the next weekend back to the same friends house. Both days 100 degree temps. After the synthetic the engine temp was 12 degrees less than the the temp with non synthetic oil.

 

New cars come with synthetic oil so I don't see ring break in a issue.

 

New cars use different ring materials, and also different cylinder surfacing than old school iron though.

Synthetic motor oil technically speaking is much superior to conventional motor oil, and it isn't even close. Use it if it makes you feel better, I've never felt the need in an ordinary stock carbureted engine with 20th century bearing clearances and the rest of it.

 

An advantage to 0w20 synthetics seems to be nearly constant viscosity with temp. Fast idle on a fairly fresh 21-studder, ~20psi cold, warm & hot. Better than 20w multivisc that flows and pumps like molasses when cold.

 

They seem to not have conventional house brand oil at walmart any more, and besides the cost difference was negligible...so I'm using synthetic in the old cars now, too. I've been using it in the modern cars since my wife finally stared buying modern cars just over 20 years ago.

I run it till the change oil light comes on in the modern cars, which is about 8k miles...and it's up to about 5500 on the last oil change in Plan II. I think I need to change it soon in that one.

 

What about synthetic in flatheads? I've never heard that discussed. No issues?

 

My Walmart still carries two types of conventional 10-30.

 

I remember reading an article (either here or online) it gave the pros and cons of each oil (for all cars, not just old) and I think the suggestion was to run synth blend...best of both worlds.

@Blues4U
https://www.jalopyjournal.com/forum...thetic-vs-conventional.1198883/#post-13655422

 

THANK YOU, Sir.

Ben

 

Calling @Blues4U !!

 

And here I thought it was another California took it away thing.
Well, just like Home Depot told me once. "If it doesn't sell we put something else on the shelf that will".

 

Look at how many people who have had flat tappet cam failures lately. The main reason for this is that they have been using modern Zinc free Synthetic oils.
One oil is not better than another, it is about choosing the right oil for the application.

 

All new cars come with aluminium blocks with sleeves. You can't compare that with an old iron block.

 

That's true! Most all car manufacturers around the world have been using synthetic oils in new cars for almost 15 years now, both gas engines and diesels....So the "break-in" quandary really isn't one!

 

Flat tappet cam failure reasons.
1: crappy made lifters.
2: crappy made lifters
3: improper adjustment
3: crappy made lifters
4: low zinc
Oil is good. I recommend using it.
Change it a time or two.
Avoid orange filters if possible.

 

Hard to find regular oil on the shelf here, its mostly "synthetic blend", whatever that is.

 

Maybe in Europe where the cars are typically smaller than here in the US. A lot of our car and truck engines are still cast iron.

 

The cylinder sleeves are made out of what ?

 

Had a similar experience in 2002 with my Indian (S&S engine). It's warmed up some, makes 97hp at the rear wheel from 88ci. Went to Mobil 1, and the oil temp dropped 10 degrees, and I actually had to lower the idle RPM, it idled faster with the syn. I also put Mobil 1 gear oil in the new 6-speed I installed, and it started shifting soooo smooth

 

that's odd, my car ran slower on Drag Week this year with synthetic, than it has in the past with normal oil.

perhaps there is more than one variable at play, here.

 

Indeed. Barometric pressure, air/track temp, tire pressure...

 

Stated a couple of times above but, yes, regular oil getting scarce in my neck of the woods too. "Synthetic Blend" and full synthetic is pretty much all I can find.

 

done a leak down test with both oils?