Synthetic oil in a Model A

[Ayers1]

I'm sure there is a thread on this somewhere but I haven't found it. Was wondering if anyone uses synthetic oil in their A's. Is there any advantages? I have a B model engine that I have apart to check/adjust the bearings and was thinking of putting synthetic back in it. It only has about 5k miles on it.. What are your thoughts?

Thanks,

[Jim/GA]

I don't, but sure, why not?

I change the oil pretty often and felt that the added cost of synthetic ($25/gal.) compared to conventional ($16/gal.) was not worth it. But now that I type that, it's not really that much more per year, in the grand scheme of things.

Other than cost, there's no real downside to synthetic. You will read all kinds of Internet stories about how bad it is. It's not.

[Ayers1]

Thanks Jim! I wasn't sure if it would affect poured bearings. I couldn't think of anything else it may bother. Since I use synthetic in my everyday cars I always have it on hand. I have to make a special trip to get standard.

[Synchro909]

I've heard that synthetic oil is more difficult to keep in the engine. Other than that, I haven't heard too much negative about it.
Personally, I run an oil filter and change oil at every 1,200 or so and the filter every other oil change so any additional cost would be little.

[Ayers1]

Thanks Synchro. I haven't heard that but I was losing enough out the rear main anyway. That's why I have the pan off. Hoping to at least slow down the drip!

[stickshift]

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It's a matter of preference. I've seen people go back and forth and swear by straight 30w or 10w 30, or 20w 50, or straight 40 weight. Synthetic, non-synthetic, etc. It really depends on where you live and what your engine runs best on. I have settled on regular 15w 40 diesel oil with a bottle of STP oil treatment. Why? because my engine likes it. I also have a rear-main leak and anything thinner would run out when going up-hill. The only bad thing I heard about synthetic is it's not good to run in a freshly re-built engine. Break in with a lightweight conventional oil then switch to synthetic.

I would like to add that I have a Toyota Prius with over 330,000 miles and no engine work ever done. Still runs like new and uses no oil. I only use synthetic oil in it.

[Pete]

I use because it makes me go faster.

[Ayers1]

Thanks for the advice stickshift. I've heard different recommendations too and thought I would get an idea what the Barn experts used!

[jeepguy1948]

I will throw out one tidbit for y’all (learned from personal experience). I use synthetic in everything I own with good success, except once. I inherited an old beat up atv that I knew burned some oil but otherwise ran fine, until I put synthetic oil in it. Constantly fouled spark plug, why? Synthetic oil wont burn, I had to switch to conventional oil and then once again all was good. Don’t tell the EPA once upon a time, long ,long ago, I might have, maybe, burned up my old oil on the campfire. Synthetic just put’s the fire out. So one thing I know for sure, it won’t burn.

[Pete]

Synthetic oil burns fine in vintage railroad steam engines. Makes lots of black smoke also if the fireman gets too generous on the firing valve.
Photo run by's look neat with a model A in the background also.

[ronn]

plenty of threads on this- I run it in everything. woulndt use standard again by choice.


basically the same cost either way here in NJ. around 20. for 5 quarts


even use it in the lawn tractor. will save your engine if you run it dry by accident.

[nkaminar]

I run Valvoline VR1 racing 20W-50 motor oil in my car. It has additives that protect the engine that are not allowed in cars with catalytic converters. They also make a synthetic racing oil if that floats your boat.

In the 60's when I started driving Model A's, I bought the cheapest oil I could find because it eventually ended up on the road through the rear bearing. The stuff looked like the oil I now drain out of my car when I change the oil.

Valvoline VR1 Racing 20W-50 Motor Oil

[Joe K]

The big advantage of synthetic oil is its "lubricity." It reduces moving part to stationary part friction, reduces wear in the engine because of this, and increases the available shaft horsepower.

It also lasts longer, i.e. more "consistent" friction properties over the life of its use.

The disadvantage for a STOCK Model A is that it keeps any wear particles in suspension: the whole synthetic thing revolves around having an oil filter. If you don't have an oil filter, all those wear particles stay in suspension - and may exacerbate wear.

The original Model A was designed for a non-detergent oil. Wear particles in non-detergent oil can settle out which in the Model A was planned to be the crankcase. There is a reason for the dipper tray - and that is to afford "cleaner" oil since it is away from the sump.

Don't ask me about the low level screen on the oil pump which lifts oil up to the tray.

If your Model A already uses an oil filter, you're probably already using a detergent oil. So a synthetic oil should be all of that - and even better.

(To be honest, most "regular" detergent oil contains some synthetic oil. Producers use this technology to "adjust" oil properties - and since synthetic is already being produced, they use it in adjustment because for them it is cheap. But the marketplace has universally come to a thought of 100 percent synthetic IS "synthetic oil.")

Joe K

[P.S.]

Originally Posted by Ayers1

I'm sure there is a thread on this somewhere but I haven't found it. Was wondering if anyone uses synthetic oil in their A's. Is there any advantages? I have a B model engine that I have apart to check/adjust the bearings and was thinking of putting synthetic back in it. It only has about 5k miles on it.. What are your thoughts?

Thanks,

Pros and cons discussed in video- https://www.youtube.com/watch?v=SnZKdhRevvU

After seeing the insert bearings in a Model A engine with 20,000 miles on it and zero signs of wear on anything that moves or rotates, and it has only had synthetic oil in it since rebuild, I was sold. Everything still looked exactly the same as when it was assembled. Usually, you would see scrapes and scuffs on everything by then.

[Ayers1]

Originally Posted by nkaminar

I run Valvoline VR1 racing 20W-50 motor oil in my car. It has additives that protect the engine that are not allowed in cars with catalytic converters. They also make a synthetic racing oil if that floats your boat.

In the 60's when I started driving Model A's, I bought the cheapest oil I could find because it eventually ended up on the road through the rear bearing. The stuff looked like the oil I now drain out of my car when I change the oil.

Valvoline VR1 Racing 20W-50 Motor Oil

Back in the 70's I worked in a service station. We sold a cheap "reprocessed " oil that was basically used oil that had been filtered several times and repackaged. That's probably what you used in the 60's!
Thanks for the advice on the racing oil. I'll check it out.

[Ayers1]

Thanks Joe K and PS. I have had no experience with older cars and synthetic oil. It's nice to know that I'm not doing harm! Engines are way to expensive to experiment with so that's why I am asking before I put it back together.

[JOES31]

The only draw back I could see is the lack of ZDDP. But I guess you could buy a bottle of
some and add it?

[mcgarrett]

For our old low compression side valve engines, no ZDDP is needed. ZDDP is needed for more modern engines with high valve spring pressure to counteract excessive wear on the camshaft.

[Pete]

Originally Posted by mcgarrett

For our old low compression side valve engines, no ZDDP is needed. ZDDP is needed for more modern engines with high valve spring pressure to counteract excessive wear on the camshaft.

Wrong.
It is needed anywhere there is hard metal to hard metal contact.
Valve guides, rings, cam and gears.

[Dodge]

Its getting real hard to find straight dynosaur oil in our neck of the woods. If you do
its more expensive than synthetic. There is plenyt of semi-synthetic.
I buy break in oil to break in the motors and seat the rings.
Then switch to semi or full synthetic.