New motor oils are bad for Older Engines with Flat Tappet Camshaft

[Steve Paddison]

Hi All,
Just posted this because I thought this would be a very interesting topic to many of you.

Extract from "MTA NZ Radiator Magazine, July 2009"

- New Motor Oils Are Bad for Older Engines with Flat Tappet Camshaft<o></o>

"The lobes on this 289 Ford Mustang flat tappet [Pic Below]
cam suffered excessive wear because the motor oil did not contain adequate levels of ZDDP anti-scuff additive. If you are driving an older classic muscle car or hot rod that has an engine with a flat tappet camshaft, you should be aware of the fact that today's "SM" rated motor oils contain much lower levels of anti-scuff additive called "ZDDP" (Zinc Dialkyl Dithio Phosphate). The level of ZDDP in current motor oils has been reduced to no more than 0.08% phosphorus to extend the life of the catalytic converter. Phosphorus can contaminate the catalyst over time if the engine uses oil, causing an increase in tailpipe emissions.

The lower ZDDP content is not harmful to late model engines with roller lifters or followers because the loads are much lower on the camshaft lobes. But on pushrod engines with flat tappet cams, the level of ZDDP may be inadequate to prevent cam lobe and lifter wear. In some cases, cam failures have occurred in as little as a few thousand miles of driving! This is even more of a risk in engines if stiffer valve springs and/or higher lift rocker arms are used.

To avoid such problems, you should add a ZDDP additive to the crankcase, or use an oil that meets the previous "SI" service rating, or use diesel motor oil or racing oil that contains adequate levels of ZDDP to protect the camshaft and lifters."

 

[Rick Muck- Mark IV]

A friends Boss 302 v intage race car just wiped out a cam in less than 5 hours of running (4 on the street, 1 at the Glen) despite the additive! Three cam manufacturers told him the days of flat tappets are "over" and all recommend going roller.

The "Joe Gibbs" oil by Brad Penn in the US is highly recommended, but the manufacturers still claim life of a flat tappet will be short.

By the way, the cam lobe particles made it through the filter (probably bypassed) and found their way to the crank to imbed in the bearings. Number 3 rod bearing stuck to the crank and the lower shell slid under the upper shell to make a "one sided bearing" and the engine went "erk" and stopped dead.......lucky it was in the pits at idle so no "big bang" but a standard bore Boss vlock and standard crank now need machine work......

 

[Randy V]

As of a few years ago I went back to adding 2 bottles of STP (has ZDDP in it) to every oil change in all engines except my daily driver which requires 0w20 oil and no additives or void the warranty.
On the racing engines we use Truck Oil (like Delo 400) and EOS suppliment for Break-in and Dyno. Then STP / EOS afterward with Mobil-1.

 

[Larry]

I can relate. I had tappet failure on my 289 at about 2000 miles. After repair I now only use Rotella-T 30w Diesel oil.

 

[Ron Earp]

Three cam manufacturers told him the days of flat tappets are "over" and all recommend going roller.

I'd tend to agree. Why would you want to use a flat tappet lifter when high quality roller lifters are available for not huge money? Ford started using OEM roller lifters in 302s in 1985, twenty five years ago. I think GM started about the same time.

 

[Jim Rosenthal]

Well, if you already have a flat tappet cam and don't want to change it out, what do you do? I think this is useful advice- there are zinc additives, and I am going to put them in the oil in the Cobra and the GT40. Thanks for posting this.

 

[Steve26]

I thought that you could run at higher RPM's with a flat tappet cam compared to a roller cam? I was told this has to do with the steepness of the ramp angle on a roller cam. Anyone know for sure?
Steve

 

[Jac Mac]

This is not 'new' info to those of us who have had to find ways to make flat tappet cams live. I actually find it quite amusing that its taken approx 15 years for the MTA ( Motor Trade Assn of NZ ) to finally have the balls to acknowledge in public that the oils & removal of the ZDDP content has been the major factor. Go back a few years & have the tenacity to suggest that to them or the oil co's & you found yourself being quietly 'assisted' from the office.

Jim, either fit 'cool face or equivalent lifters' or do the lifter bore modification, use either the ZDDP additive & a good quality diesel oil, Run the cam in with 'soft' springs, Dont run your motor below 2000 or above 3000 on first start of the day until you see water temp begin to rise, prelube prior to start after extended periods of storage ( probably the 'only' good reason to fit an accusump system ), & let the rockers 'off' if not using the car for long periods of time . Been a long time since I have 'Lost' a lobe and I put this down to useing the above practises on engine build & initial start and '''trying''' to get owners to carry out the above procedures.... but many make their own rules up. its the old story...you can pay me now, or pay me later.....But you will pay!

As in Ricks earlier post the metal from destroyed cam lobes/lifters gets everywhere & in my book a lost cam lobe is a complete teardown . If it happens in a 'new' or race type motor there will be NO 'sludge' etc in the pan to absorb it & prevent it being pumped thru the oil system. Same thing can & does happen to a high mileage engine over time & does not cause anywhere near as much grief simply because the metal doesnt get pumped thru the 'dirty' conditions.

 

[Julian]

A google search for ZDDP levels in motor oils will bring up current information on which oils have sufficient levels of ZDDP and there are still a number of choices, especially in oils designated 'racing'

For instance;
Mobil 1 15W50 at last count had 1300 ppm Zn & 1200 ppm
Redline 10W40 has ~1700 ppm Zn & ~1700 ppm P
Redline 40W racing oil (non-detergent) has ~2500 ppm Zn & ~2500 ppm P
Brad Penn (all viscosities) typically 1500 ppm Zn & 1300 ppm P

Diesel oil is not an ideal choice due to the detergents it contains. Personally I use the Brad Penn (old Kennedy) green oil.

 

[Tim Kay]

I recently switched to Amsoil - Dominator 15-50. I had this concern regarding cam wear and was guided to this brand for that reason. Anyone else use Amsoil? Pro or con experience?

 

[Reed Herman]

I have been watching this same thread on many performance and collector forums. Motorcycle and cars.
I can only hope that small oil companies will continue to make additives that will allow us to run older vehicles. Many engine configurations (overhead cam acting directly on shims, etc) are not able to be modified for any type of roller application.

We get so worried that emissions, legislation, parts availability, etc are the things that may keep us from driving our old cars. It may simply be that oil stops us in our tracks.

 

[Ron Earp]

I thought that you could run at higher RPM's with a flat tappet cam compared to a roller cam? I was told this has to do with the steepness of the ramp angle on a roller cam. Anyone know for sure?
Steve

Nice graphical example of flat versus roller:

Flat Tappet Cams vs. Roller Cams - Lunati Power

Only reason I could see staying with a flat is if you have an existing motor with a flat tappet cam and don't want to change. With FMS selling SB roller lifters for $99 a set, brand new, you might be able to justify the swap to a roller as a money saving expenditure since you won't need to use specialty oils.

 

[John Fitzpatrick]

Six months ago I bought a '71 Le Mans convertible with a 350 2 bbl and 60K original miles. It's been missing under hard acceleration lately and I'm starting to get a little lifter noise for a couple of minutes after starting. I thought I was just needing a tune-up, but now I have this sick feeling that the hydraulic lifters have been taking up the slack as the lobes have worn.:stunned:

Is this likely, and is there a way to check without a tear-down? I've put about 3,000 miles on it and used Pennzoil 10W30 for the two oil changes I've made.

 

[Brett James-McCall]

So If I am building my engine now, should I sell my cam and lifters and replace with a roller cam and lifters? I have a 1970 block, so would need to retro-fit.

Brett

 

[Jim Downard]

When selecting a cam for my 289, I called Reed cams in Georgia and told them I was looking to build my motor to rev to 7500 rpm. I thought we'd be going roller, but instead he told me to turn that kind of rpm, I'd need to go solid lifter flat tappet. That's all I can add to the subject.

 

[Ron Earp]

Jim, sounds like to me that he had a flat tappet cam and lifters in house he needed to move on. The two builders I know well that keep busy in roundy roundy use solid rollers on anything they build with RPM in mind.

 

[Randy V]

Solid rollers for daily use on the street are not a good idea unless you have something called a rev-kit (I don't know of any available for Fords) which have springs that keep the roller in contact with the cam at all times (no lash)..

Here's what they look like for a Chevy engine - maybe Jac or someone else knows of one for Fords...

Air Flow Research Cylinder Heads

 

[Ron Earp]

Solid rollers for daily use on the street are not a good idea unless you have something called a rev-kit (I don't know of any available for Fords) which have springs that keep the roller in contact with the cam at all times (no lash)..

I've never had an engine with one of those kits but I thought these kits were for hydraulic rollers? Is the idea the steep ramp on the roller cams will throw the lifter off the cam?

If that is the case, at least with a solid roller, I would think you could either reduce the ramp angle and still have something better than what a flat tappet could do. Or increase the valve spring pressure.

I is confused now.

 

[Randy V]

I've never had an engine with one of those kits but I thought these kits were for hydraulic rollers? Is the idea the steep ramp on the roller cams will throw the lifter off the cam?

If that is the case, at least with a solid roller, I would think you could either reduce the ramp angle and still have something better than what a flat tappet could do. Or increase the valve spring pressure.

I is confused now.

Hi Ron,

Solid Roller engines just like solid flat tappet engines - have to have a lash clearance built into them. Usually something on the order of .024" on the Intake and .028" on the exhaust. This is to make up for the expansion of the components as they heat up and to make sure that once they are hot that the valves will close all the way when on the heal of the cam lobes.
With this clearance - all the components can become separated from their adjacent counterpart.
The rocker arm can have clearance to the valve stem.
The rocker arm can have clearance to the push rod.
The pushrod can have clearance to the lifter.
and finally
The Lifter can have clearance to the cam lobe.

It's the clearance to the cam lobe that can have a bad affect on the solid roller lifter. The followers are not made to have a clearance or to be hammer upon as the slack is taken up and the follower (roller) makes impact to the cam.
The Rev-Kits were not designed to make a solid roller engine streetable - instead, they were designed to negate the weight (inertia) of the roller lifter by keeping it constantly forced against the cam lobe - This allowed the roller cammed engine to rev higher (hence the name Rev-Kit)..

 

[Jac Mac]

REV KITS: Always had to make them myself for Fords & Holdens, even many of the USA kits require spot facing on the plate for spring seat plus clearancing on block etc.

That said I have had several USA ex Nascar motors that were retrofitted with solid rollers before shipping to NZ & did not & were never equipped with rev kits. One of these later demolished the cam due to either valve spring breakage or pushrod failure. Net result was lifter did 1/4 turn & milled lobe off when unrestrained lifter was literally tossed out of bore & when link bar reached end of slot & started the process off.

Ford 302 SB with 8.200 deck has very little room to actually fit a rev kit above roller lifters, in this case a limit bar bolted to head underside to prevents lifter upward travel beyond max lift would help.