oil to use in a new flathead

Alright, here we go again down the road of which oil to use and whatnot...

Basically I've just finished building my flathead and have been looking into oils to use. I've read that on these older motors you want to use an oil with a higher zinc content to give the oil a good "scuffing" property--protecting the older lifters in these motors better.

I've also been thinking about conventional vs. synthetic. Now, I'm not trying to start some huge debate about it, i've been down that road before, i'm just curious as to what people's opinions are on this.

I've been looking into using Amsoil synthetic 10w30 because of the higher zinc content and overall quality of the oil. Any thoughts?

thanks,
evan

 

My builder told me to use regular 10w-30 during the colder months and straight 30w during the warmer months (which is like year round here) and valvoline is a good name.

 

I second the straight 30 weight. Thats what I have always run in mine.
Donnie

 

I am getting ready to overhaul my F-Head and was doing some research on the zinc issue and there is a source of engine oil and zinc additive for vintage autos that I ran accross. www.motorheadoil.com I may give it a try.

There is some interesting links on their site to some articles about why the zinc has been slowly removed and why some of the oils for diesel/commercial use that we have relied on up to now may not contain it much longer either.

At the moment I am using Mobil 1 10 w 30 in my DD and Wifes van, I had a personal experience with Synthetic Oil that made me a believer. My 81 Cherokee with a rebuilt 360 has not had any cam and lifter issues in 100,000 miles of Mobil 1 use with no additives to date.

I Personally am a believer in the synthetics but I am also doing some research on zinc additives for them and who makes a synthetic lubricant that truly is suitable for the L & F engines

I will post my findings shortly as I am almost done harassing the Technical Departments of some Synthetic manufacturers.

There should not be any issues with the Amzoil 10 w 30, Will post what they tell me.

 

i read somewhere (maybe here) that synthetic is not good for these motors because it is loaded with detergents and such that are more suited for modern motors. I run 10W30 in mine all year round due to the change in climate with the seasons up here.

 

yeah when i break in a new motor i always use non-detergent 10w30 for the break in period, drain it and then replace it with whatever oil i'm going to run in that motor.

from what i can tell it should be ok to run a modern synthetic oil in one of the motors, especially if it has been rebuilt as modern piston rings are much improved over the originals. that sound about right to everyone?

 

i've been doing some reading on their site too. from what i can tell, that Motorhead Hi-Z oil is good stuff. I've also come across this website that compares modern performance oils (like Amsoil) and shows the amount of ZDP that is in each oil:
Oil Comparison of ZDP

it shows there that Amsoil has the highest amounts, which leads me to thinking about running Amsoil with the possibility of the Motorhead ZDP additive to keep the cam and tappets safe in the new flathead.

any thoughts on this?

 

Let me give a little insight into detergent versus non detergent motor oils. Detergent oil is designed to suspend the metal particles or dirt and soot deposits in the oil so they can be run thru the filter, non detergent oil is more like machine oil, its designed to let the particles settle out of the way at the bottom of the crank case or wherever.
As far as Synthetic it should be fine for any motor after the break in period.

 

The diesel oils have a higher zinc and phosphorous content. Look on the back of the oil bottles for a Cx rating. The gas oils have a Sx rating. It is all about emissions and what in the oils get burned and sent out the tail pipe. They have been able to reduce the oil qualities due to everything now having roller tappet cams and the highest load pressures used to be on the cam lobe. Rotella makes car weight oils with diesel ratings like 10w30. Older engines typically had more loose bearing tollerances so a 15w 40 would be ok too.
Due to the newer blends, I think it is valoline, that make a "muscle car" oil that is for flat tappet engines.
Another thing to consider is if you put an adative like Lucas or even the old STP you can use them as a zinc supplement because that is what they are loaded with.
Synthetics are fine and i've run Royal Purple a lot on my hot rods and I have no complaints but to be honest, with the extra costs, the synthetics aren't going to be worth the costs in a weekend play toy that will see low run times.

 

" I've never used synthetic but I've heard over and over not to attempt to use synthetic in a new engine because the rings won't seat."

I was surprised to hear this but a couple of weeks ago Horsepower TV built an engine and said the same thing, they added a petroleum base oil for the break in and then replaced with Royal Purple, a major sponsor.

For whats it worth I run Penzoil 5W 30 in all my vehicles and never had an oil related failure.


I personally synthetics are for high performance engines and long intervals between oil changes.

 

In porsches we use brad-penn or swepco as the recommended oil because they dont change the formula every 20 seconds. The latest CJ-4 / SM formulations have significantly reduced the anti-wear additive ZDDP (provides phosphorus and zinc). Per SAE papers approximately 1200 ppm of both phosphorus and zinc is needed to prevent premature wear of rotating parts like camshafts in cars that have flat tappets. I dont know about our jeeps but porsches have them. So if the label says it meets SM or CJ4, STAY AWAY

 

A guy on an IH board got this response from Castrol.

This seems to be the best recommended from Castrol of there oils at this time.

Castrol Syntec 20W-50 (Recent reformulation identified by "Recommended for Classic Cars" text on back label) (min Zn = 0.12 = 1200 ppm)(full synthetic) PREFERRED

 

"Valvoline Racing Oil" is a widely available high-ZDDP formulation. It can be obtained in single-viscosity or multi-vis.

The diesel engines have the similar issues with their piston pins that flat tappet engines have with the cam lobes. A diesel formulation should be better, though widely available products like Delo and Rotella have been reformulated recently.