Flat tappet cam life
 

While there are tons of reasons why you can destroy a cam, one of the more recent hot topics has to do with zinc content. Having lost a cam myself while running Mobil 1, I have been thinking of a change. Nothing against Mobil 1... I have used it for years in my other cars with great sucess... but those cars did not have a flat tappet camshaft. My Cobra does.

I have been considering switching to Rotella T synthetic 5W-40 partly because of the zinc content. Plus it is available at darn near every truck stop in the country and at $13 a gallon (Wal-Mart), the value is hard to agrue with. So, I contacted Shell, told them of our issue and asked them for their advise. Here is their response:

"The Rotella T oils, both the conventional 15W-40 and the synthetic 5W-40, are formulated primarily for diesel engines. Although exact additive concentrations are proprietary, the Rotella T oils have a robust anti-wear additive chemistry and contain substantially more zinc than a dedicated gasoline engine oil that must meet the ILSAC GF-4 requirements for concentration of metallic and phosphorous based additives because of their effect on catalytic converters. While we have no data exclusive to flat tappet camshaft designs, we would expect the Rotella T Synthetic 5W-40 to perform well in these engines."

If you care to see what the zinc content of the oil you are using is, a quick search on Google should give you the information you need.

I have also contacted Crane Cams to get their input and will post it here once received.

Comp Cams had a news letter on their web site a couple of months back discussing premature cam failure. They talked about proper startup and break in, etc, etc but also discussed recent changes to oil formulations, specifically the reduced level of zinc. I did some searching and the additive that has been reduced is referred to as ZDDP which is zinc dialkyl dithiophosphate. The EPA has mandated a reduction in this additive.

Most modern engines have overhead cams so there is a much reduced friction between the cam and the lifters, many of which are now rollers. Therefore this reformulation does not hurt OHC engines. However, high performance pushrod engines exert lots of pressure on the cam and the flat tappet lifters and this is where the ZDDP is required.

Comp Cam goes on to say that they recommend oils such as Shell Rotella T, as well as some of their own additives.

Simply out of curiousity, I contacted STP and was advised that the main ingredient in STP oil treatment is ZDDP. While I have not used STP for many years, I will probably now begin to use a can of it with each oil change.

A friend of mine who is an engine builder, has had several cam failures during the past year, which very rarely happened previously. He now will not guarantee an engine equipped with a flat tappet cam if the customer uses any oil other than Shell Rotella T. He gives a copy of the Comp Cam news letter to every customer so that they have a better understanding about the recent changes to motor oils.

Wayne

Good info Wayne. Having Comp Cams recommend and a engine builder that won't guarentee and engine without using Rotella T speaks volumes.

I have heard that STP has ZDDP and I have heard that it does not.

I do know that the GM EOS (extended oil service) additive is loaded with it. Also, so is the Crane Cams break in lube and I have heard some recomendations on running it on a regular basis, not just at break in.

The magic number for zinc seems to be > .11%. But, more is not always better, there are limits. Here are a couple of charts that I have found:

http://www.repairfaq.org/filipg/AUTO/F_oil_facts.html
http://www.micapeak.com/info/oiled.html
http://www.ford-trucks.com/article/i..._Negative.html

No guarentee the information in these links are correct!

I'm running STP for the additives it contains, specifically to protect my flat tappet cam.

The question MUST be answered conclusively, does STP have the additives or not? If STP says it does, WHO says it doesnt?

I will try to see if I kept their email reply. I will post it IF I can find it. :LOL:

Wayne

I contacted STP to be sure. Here is their reply:

"Thank you for contacting us about STP Oil Treatment. We always appreciate hearing from our consumers.

The oil treatment products do contain zincdialkyldithiophosphate or zddp. The amount or concentration of the zddp is proprietary information.
Again, thank you for contacting us. "

I found the email from STP yesterday but I couldn't get back into this site.

Here is their reply:


Reference Number: 4339163

Dear Mr. Maybury,

Thank you for contacting us about STP Oil Treatment. We always appreciate hearing from our consumers.

The main ingredient in our STP Oil Treatment is zincdialkyldithiophosphate or ZDDP for short. It is safe to use in all automotive engines. It is safe to use with both regular and synthetic oils. You may also use the product at a 10% treatment rate in gearboxes, manual transmissions, wet clutches and differentials.

Again, thank you for contacting us.

Sincerely,

Patti Copper
Consumer Response Representative
Consumer Services

So, there you have it! STP has got the goods. I don't use it because it effects viscosity... even though I don't think that is exactly a bad thing.

While STP would not say how much ZDDP is in their product, I did find a lab test that showed their various products have between 1 and 5% ZDDP. How they deal with the effects on catalytic converters, deposits and plug fouling from to much zinc is beyond me.

I will just go with an oil that already has it in the proper concentrations.

I think that I will go with Shell Rotella T in the Cobra but I have a couple of gallons of Gastrol GTX. I will probably use that in my '66 Mustang along with a can of STP just to be safe. ;)

Wayne

According to the links above, GTX has .12% of zinc. Just about right!

You know, if you send your oil to one of those oil testing companies, zinc is one of the things that should be listed on the results. :)

Thanks for that STP up-date, I'm feeling all better again! :LOL:

Just went through this
 

Use Brad Penn Racing Oil. It is the old Kendall product. They bought the refinery. It's about 40% less ash than Rotella and is the right formula for racing and flat tappet. So, why compromise with an oil that was designed for low revving diesels. You want Chinese food that tastes like pizza? Why not just get pizza?

Racing oils arent detergent and will lead to some nasty buildup of 'crud' in your engine unless you change it really often. We change it every race in the Formula Ford cars.

One guy ran the racing oil in his tow truck. Whew, what a mess it made of his engine!

I would contact one of the oil analysis companies, and present this scenario to them, and see what they say. They are the ones who know for sure, exactly what is in what. Plus they have you list your combo most of the time, so you never know the data they may have complied, and might have some pretty relevant info on this subject. They also aren't "selling" you oil, so their veiw should be unbias.

I use Blackstone Labs for my diesel oil samples every oil change.

Oil
 

The tech dept at Brad Penn will clear up the build up issues. They don't have them with their racing oils. But, they will save your flat tappet motor.

Actually you have identified the exact problem. If you look at that site, it states something like "based on current SH specs". Since then the spec has been changed to SJ, then SL and now to SM. It is the SM spec oil that has the reduced amount of ZDDP in it. Look at the label on the back side of an oil container and if it meets the API SM spec, you will also see a "sunburst" icon which I believe indicates that it is environmentally friendly, or whatever.

It is this SM spec oil that we have to worry about. :CRY: :mad: :(

Wayne

Damn...........as usual the advice here is all over the map. I was hoping for a miracle consensus. I've also been following the "zinc issue" and running a solid flat tappet cam.

:LOL: Excellent observation Clay.

Tow truck guy was using Red Line 50wt race oil, changed at the usual mileage intervals. 50K on the motor, I tore it down. WOW, unbelievable the amount of build up gunk in that puppy.

Perhaps the key to using race oil is 'change it often'?

GM EOS has about 6 times the ZDDP as Rotella, which has a good amount. Although it is a break-in oil, maybe half a bottle of it with the other oil of your choice would fill the bill for longevity.

Like I didn't have enough to worry about!! Will the STP muck up the engine and or leave deposits? There was an article in Circle Track Magazine talking about the same thing. They spoke with Comp Cams too. Comp is recommending the diesel oils such as Shell Rotella, Mobil Delvac, Chevron Delo and Castrol Tection. I looked briefly at the Rotella site. Rotella makes a syntehctic 5-40 that has all the Comp recommended API ratings: CI-4 Plus; CI-4 and CF-4. So it has the zinc, but how will it stand up to heat? I assume it would be OK being a synthetic, but what do I know.

EDIT I invited the Shell Guy (Rotella forum moderator) to visit us and share his knowledge about Rotella. With hope he will join the discussion. He posted the Comp Cam article a while ago on the Rotella forum. http://www.rotella.com/ubbthreads/sh...c=1&PHPSESSID=