With oil so advanced now, can freshly built engines be broken in with synthetic?

[Nicasio]

Probably a dumb question, but I see a lot of newer cars are factory filled with synthetic. Would this be ok to do on a freshly built old school V8? I doubt I would ever do it, but just curious. Also, what is the latest info on properly breaking in a newly built motor. I’ve seen so many different opinions in the past.

 

[eljefino]

If you have flat tappets you'll want some more zinc. That could be supplied by the cam assembly lube though.

I think the 20 minutes at 2000 RPM is still the golden rule for breaking in.

IMO half the reason people used conventional was it was cheap. 20 minutes at no load is a pretty easy ask of an oil, then you flush it out and put something else in. Now the price spread is miniscule.

 

[tnt_motorsports]

FWIW I think this is an old wives tale and not relevant. IMO you can use either synthetic or conventional oil to break in an engine. Of course if you have a flat tappet cam you’ll probably want something with a little more zinc like a racing oil or HDEO.

Just my $0.02

 

[daves87rs]

Agree either would work…..

 

[kschachn]

Plus the past is not today. Most of the concerns in the past (regardless of whether they were valid or not) were about majority Group IV oils. Today nearly all synthetics on the market are majority Group III base stocks which are chemically similar to Groups I and II. The only difference is a superior VI, higher saturates and lower sulfur.

I can also say that I rebuilt my Mazda 626 engine in the late 80s and used Mobil 1 from the start. It worked fine, but who knows the exact composition of that brand at the time.

 

[lenjack]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

 

[Nesterenko]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

Must be some oil.

 

[Scott S]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

Never heard that one before..

 

[PontiacHO]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

They sure don’t die. This one about Ford engineers is actually another. Our fleet of Ford patrol cars in the 70s used Mobil 1 synthetic and ended up with wiped out main bearings. Ford honored the warranty claims with short blocks since they did initially approve the use of synthetics. It wasn’t at all the synthetic oil of today…

 

[ka9mnx]

Plus the past is not today. Most of the concerns in the past (regardless of whether they were valid or not) were about majority Group IV oils. Today nearly all synthetics on the market are majority Group III base stocks which are chemically similar to Groups I and II. The only difference is a superior VI, higher saturates and lower sulfur.

I can also say that I rebuilt my Mazda 626 engine in the late 80s and used Mobil 1 from the start. It worked fine, but who knows the exact composition of that brand at the time.

Did the same in the late 70's when I rebuilt my 58 Ford inline six.

 

[Jetronic]

Never heard that one before..

There's articles about it, not saying no wear, but no abnormal wear....

 

[PontiacHO]

To each his own…for older engine rebuilds I prefer conventional oil for initial break in. My thought is the rings will seat quickly. After cam (flat tappet) break in with high zinc conventional, change oil again to high zinc conventional for 500 miles then use whatever I want..synthetic or otherwise.

 

[kschachn]

They sure don’t die. This one about Ford engineers is actually another. Our fleet of Ford patrol cars in the 70s used Mobil 1 synthetic and ended up with wiped out main bearings. Ford honored the warranty claims with short blocks since they did initially approve the use of synthetics. It wasn’t at all the synthetic oil of today…

So was it just your fleet? And when in the 70s exactly?

What did Mobil say was the cause? Was excessive consumption (leading to starvation) the problem or was there a material issue with the oil?

 

[picklyrickly1073]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

Couldn’t do that on 0w-20, nope

 

[CumminsMech]

I've often used synthetic on personal engine rebuilds with no issues. Whether it be a flat tappet VW engine or a hydraulic roller engine, I wouldn't hesitate using synthetic. I've also never used a break in oil either in any personal or professional engine I've built.

 

[tolian21]

I have generator and manual recommends not to use synthetic oil for initial break in. I know its not relevant, but it is interesting why

 

[PontiacHO]

So was it just your fleet? And when in the 70s exactly?

What did Mobil say was the cause? Was excessive consumption (leading to starvation) the problem or was there a material issue with the oil?

Our county police fleet. Specifically the 400M engines. 2 years before I went to work there so around 1977. I personally didn’t negotiate the repairs however many of the cars were still active in the fleet with non-painted short blocks. The techs and fleet director told the story when I asked why we were using Valvoline All Fleet 15-40 in everything from police cars to motor graders. NAPA Wix filters. We stayed with that for the next 30 years…

 

[FCD]

Old wive's tales never die. For a good number of years, car makers have factory filled with synthetic.

In the early 70's, Ford engineers took a new Lincoln off the assembly line, and fed it Mobil 1. Then they ran it for 100,000 miles, without oil changes, only adding as needed. They then tore down the engine, and found absolutely no wear whatsoever.

Yup, it was in an article on Popular Science in 1976

 

[lenjack]

Never heard that one before..

True story. Read it in Popular Science, April, 1986.

 

[Kira]

'76...'86..what's the difference?
I have a can of Shell X-100 Zinc Additive.
What should I do with it; give it to my nearby engine rebuilder?