Synthetic Oil

[tfowler9]

I probably put 1000 miles on my car a year. I use Mobile 1 oil. Do I need to change it annually?

Thanks Tom 

 

[MKSpeedlab]

I have been told by a bunch of people to avoid synthetic unless its something specific for older cars. Older vehicles usually want more Zinc in the oil and synthetic doesnt usually have that. That said, Im going to be running Lucas Oil Hot Rod and Classics synthetic and it has more zinc and stuff to make it a bit better for older style engines. 

 

[Hemikiller]

For $25 at Walmart, yes.

 

[EBSTANG]

Is there any truth that allegedly synthetic oils can increase the potential for leaks, in our older cars?  Asking for a friend...

 

[droptop73]

That's an old wives tale. Synthetic will not cause leaks.

If an engine is already leaking what's difference?

 

[Kilgon]

I probably put 1000 miles on my car a year. I use Mobile 1 oil. Do I need to change it annually?

Thanks Tom 

Good question.   In a nut shell for that few miles once a year would be fine.   Does not mater if regular or synthetic. Beside mileage there are a lot of other factors that come into play when considering how often to change oil such as driving conditions and environment .  5000 miles of stop and go is harder on a motor than 10,000 miles of highway driving.  Hot climates vs colder ones.  Engine run time.  A lot of people are only driving short distances to cruise in's and the likes.   For these short trips you need to make sure that the engine gets up to operating temperature for a while to evaporate any moisture that occurs from condensation when first starting the engine and it also occurs when the engine is cooling  down.  This usually requires 10 to 15 minutes of driving.   This also applies if you "turn your engine over" once or twice a week to keep thing loose.  Make sure that you leave it run enough to burn off any moisture.

 

[c9zx]

Regular or synthetic, you need to buy the right oil with the a correct additive package for flat tappet cams. Modern, current certification oil does not have the right package. Chuck

 

[SteveO_71]

I was under the belief that zinc additives were more important for rebuilt engine break-in. Is it also necessary for an older engine that has been rebuilt in the past 10K miles? How does zinc additive apply to the other lifter types?

 

[c9zx]

This article may help. https://blog.amsoil.com/do-older-vehicles-need-high-zinc-motor-oil/

This as well. Chuck  http://www.lockhartmachine.ca/oil_study.html

 

[Carolina_Mountain_Mustangs]

I had my 73 Mach 1 sitting in an open pole barn for 37 years on a dirt floor in N.C. and we get about 100" of rain per year. Before I pulled the car into the shop to clean up I pulled a sample of the oil out using a tube in the dip stick tube. I sent to have analyzed there was zero water in the oil only high level of lead from the old leaded gas back then. 

Everyone said the engine would be locked up after not being stated for 37 years. I took to my shop and I took the car apart to detail and clean not restore. I pulled the engine and did not try to turn. I pulled the oil pan and valve covers. Everything looked brand new the car has 12,000 miles. I even pulled a rod cap off and their was still oil in the bearing. I have pics of it all. So I pulled the spark plugs. You could see the bottom of the cylinder walls and clean. You could see the wrist pins shiny. So I put ratchet on the crank and turned the engine over with one hand slowly and all the valves opened and closed so no stuck valves. I brushed new 10 W 40 havoline oil on the rockers, push rods and some on the crank and put the cover and oil pan back on. I put the engine back in. I did put a kit in carburetor but original fuel pump was still good.  I put the Lucas oil Zinc additive in with the havoline oil and did not try to start until the day I took to the Mustang Owner's Museum. This video was made that day, no smoke, no noise and engine was fine. 
I would never change the oil that often. I have not changed the oil in my 73 convertible in 4 years not. Why? I have put as much ad 467,000 miles on one engine with no oil failures. 305,000 on my truck that I bought new and I just drive until one quart low add a quart and drive until one quart low again and then I change. No idea how many miles that is way over 4,000 probably. 
I have driven over 2,000,000 miles in my life with no engine failures ever. I broke lots of transmissions, driveshafts, clutches, axles and rear gears so I drove hard. I never over rev an engine that is ridiculous to do. 

I would say never use synthetic oil in older flat tapped engines ever. Do not use synthetic gear oil either or if you drive much pinion bearings will go. Huge issue with new vehicles. 
I doubt that I ever change the oil in the Mach 1 again ever no need to with low miles each year. There is no way for water to get into the engine unless you pour it in. Yes when you drive a vehicle it will pull damp air in and yes there is moisture that is what the PCV vale helps with. 

In my opinion you are wasting your money on the synthetic and also on changing your oil. 

Couple pics of the engine that sat 37 years. Remember this was on dirt floor in open pole barn was not started for 37 years.

 

[Spike Morelli]

I'll respond. Keep in mind that I hold no PhD in any lubricant studies, rather just my opinion, or, observation here. I have tried a synthetic oil some years ago, and It did the job, no better but no worse than petroleum based oil. It did hold it's viscosity when the engine was hot, so oil pressure hot indicated better ( higher ) than with regular oil.

But I have a couple of cons to using synthetic. Firstly, cost......rather than buy oil 3 times more expensive than regular oil, I could just use regular oil and change it out three times as often and have cleaner oil. Speaking of changing oil, just because synthetic oil doesn't break down as readily as petroleum based oils, I still want to change the filter regularly to remove any combustion by-products, or minute metal particles, etc.        Secondly, if you leak any, or get some on your hands, it doesn't just wipe away with solvent like a petroleum based oil will.        Thirdly, as I hold an A&P license, I was made aware in school, that the FAA doesn't certify synthetics in piston engines. Something about combustion by-product contamination, If I remember correctly. ( Av-gas IS heavily leaded, even the standard 100LL blue fuel used in general aviation ), so that may be a factor in the FAA's testing. Synthetic oil IS used exclusively in aircraft turbine engines and synthetic greases in gearboxes, and hydraulic system fluid ( Skydrol ) where it never comes into contact with combustion.

Now, there are lots of people who do use a synthetic in their cars and are happy with it, lots of newer vehicles run it, but,  I'm satisfied with using a good brand of petroleum based Racing Oil, which has zinc in it ( I use Valvoline VR-1 ), but there's Castrol, Kendall, etc, there are a handfull of quality racing oils with zinc to chose from.  There you have it....my totally grassroots outlook on synthetic oil.