Best Oil for Classic Car with Flat Tappets

Status
Not open for further replies.
Joined
Jun 29, 2014
Messages
7
Location
Texas
I have a question regarding the best type engine oil for my wife's 1974 AMC Javelin that was just recently rebuilt. The engine is a 360 V8 and was rebuilt back to stock, and the car is only going to be use for normal type driving. Since the rebuild, the engine has about 200 miles and I plan to change the breakin oil at around 500 miles.
I am unsure what oil is best, but I have been told I need to use an oil with a good amount of ZDDP. I was thinking about either: Shell Rotella T 15w40, or Mobile 1 20w50, or maybe even Lucas Hot Rod and Classic Car Oil 10w30.
I would appreciate replies on what is recommended by those on this forum.
My email is: [email protected]
 
Amsoil Z Rod oil. Really a lot of oils would work OK. Do you really want a 50 wt oil though? I would think anything over a 40wt is pushing things.
I guess if the motor was built really loose..........maybe.

I really like old cars like the Javelin that you don't see very often. I hope you guys enjoy it.
 
You are correct, I am sure that a good 10w40 oil would be ok. I was just worried about the ZDDP issue.
 
Mobil 1 High Mileage 10w40.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2330033

If your really concerned you can add some Redline break in additive to get it up a few PPM, but IIRC anything over 1400-1500 PPM gets too corrosive.

http://www.redlineoil.com/product.aspx?pid=121

The stock 360 should hold 5 quarts of oil, so 3-4 oz and boost your ZDDP from 1000 to 1400-1500 ppm.

1200 PPM is the minimum to shoot for but anything over 1500 ppm is probably not ideal unless your draining the oil more frequently.



Look at these last few posts by Molakule.

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3133666/2








Originally Posted By: MolaKule
Originally Posted By: Michael_P
Question. If too much zinc can cause corrosion, why is zinc used as sacrificial anodes to protect marine metals such as aluminum and steel? Zinc would be the least noble metal of any metal found in an engine. What about the phosphorous that accompanies zinc, or the dithiophosphate compound? I have seen cam surfaces with rust pocks on them where the mechanic called it zinc poisoning. Furthermore, zinc corrosion seems to be magnified in a marine environment, or at least that is what I have been told. I am by no means a chemist, but know enough to sound dumb. My boat with over 2500 hours on it had zero internal corrosion on a teardown and it has seen 1600PPM zinc oil since day one. I have gone as far as 220 hours on an OCI as well.


Cathodic protection is due to an electro-chemical effect and can hardly be compared to surface interactions in tribology.

Here is a good explanation of cathodic protection and sacrificial anodes:
Cathodic Protection

But you're right Michael, it the concentration of phosphorous and sulfur in the ZDDP molecule.

Zinc Dialkyl Dithiophosphates or ZDDP (or Dithiophosphoric Acid, O,O'-Isobutyl Amyl Ester, Zinc Salt ) is an ester which is used as an Anti-Wear agent and an Anti-Oxidant agent (a multifunctional additive) in oil additives and is composed of the elements of zinc, phosphorous, and sulfur.

When concentrations get above approx. 1200 ppm, and when under high moisture conditions and extremely high temperatures, there is the potential for the ZDDP molecule to split apart (via hydrolosis) and form acids attacking the metals as acids of sulfuric and phosphoric acid.

Marine oils, both gear lubes and PCMO's, as well as classic car and HDEO oils, have a higher level of anti-corrosion agents which tend to combat any acid attack. Most Marine engines also tend to run cooler, only to expel moisture at WOT when hot.
 
What about Mobile 1 15w50, or is this too heavy an oil for a newly rebuilt engine?
I do live in Texas with high temperatures.
 
Highly doubt theres any need for a 50 grade oil. The specs for the oil pressure are as follows if you have an oil pressure gauge and my data is correct.

13psi @ 600rpm; 37 to 75psi @ 1600rpm

You should be able to achieve that with a 10w30, so the 10w40 high mileage is already overkill in case you have fuel dilution with the carb.
 
My friend had a built 360 in his rock buggy. Pushed about 380HP. After break in, he ran Mobil 1 5W30. I run M1 5W30 in my solid lifter Chebby drag car.

Sometimes the recommendations here blow my mind. Race oil in a 200HP stock engine from 1974? 50 wts? Jeebus. Get with the times. If you want ZDDP (because that's the ONLY anti-wear additive used in motor oil theses days...) then try Quaker State Defy 5W30. Monitor your oil pressure. If it's fine then there is absolutely no need for 40 or 50 weights.
 
Originally Posted By: Miller88
No reason for a 50 grade oil.

HM 10w-40, Rotella T5 10w-30 or Rotella 15w-40 (or pretty much any diesel oil)
Absolutly! I would run the T-5.

Wayne
 
Originally Posted By: dltowers
The engine is a 360 V8 and was rebuilt back to stock, and the car is only going to be use for normal type driving.


10w30 Defy has all the zinc that engine needs. If you just HAVE to use a diesel rated oil, Rotella makes a very nice 10w30
 
Cams still wore out in under 100K with high ZDDP oils in the 60's and 70's - so the cam wear in during the first 10 hours will be most critical. Since you are running a stock cam and hopefully stock springs, the tappet loading should not be excessive. A synthetic (EURO SPEC) API SL ACEA A3-B4 should be fine, and if you want to save some dough and buy something at an autoparts store for around 3 bucks a quart, 4T motorbike oil (10w40)are usually rated with an obsolete API SH/SJ service cat that had allowed high levels of ZDDP.

This aint a BB Chevy L88 running solid cam and tappets with 400+ lb open spring loading
smile.gif
 
Last edited:
Really not sure if there is a BEST classic car oil. I think it all depends on your engine/condition and how many miles you drive it... I have used plain jane Rotella and also Valvoline VR1 with good success. I also have tried all the expensive oils and found zero difference in performance. Just make sure you change it yearly in the Fall and at least every 2K miles. Carbs and fuel dilution... Good luck.
 
Last edited:
10W-30 Defy is fine, so is M1 15W-50. Maybe the 50wt will cost you a 10th or two MPG - big deal. I used to run the 15W-50 in my Suburban when I towed heavy trailers a lot. It started fine in the winter back then and I now notice no MPG improvements after going back to 5W-30 M1.

Phosphorous & Zinc
Mobil 1 15W-50 1200 1300
Mobil 1 Turbo Diesel Truck 5W-40 1100 1200
Mobil 1 0W-40 1000 1100
Mobil 1 High Mileage 5W,10W-30,10W-40 1000 1100

regular old
Mobil 1 5W-30 800 900
 
First, this oil should work for the application. Second, with modern multi-viscosity oils, it really does not matter where you live, the ambient temps are not going to effect operating temps that much, unless you have major cooling systems problems.
Another oil you should consider is Delvac Super 1300 15w-40. This is a dino oil, but it has a high level of zinc that will work well with the flat tappet application.
 
Status
Not open for further replies.
Back
Top