Thread: What's happened to camshafts?

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It seems to me we are hearing more and more about flat tappet cam failures than we ever did in the old days, even when the cam is broken in properly. I know we hear about oil today "not having the good stuff anymore", but sometimes cams fail even when additives are put in to replace some of those things.

Before I knew what I was doing (not that I know much more now) I remember installing a lot of cams in Pontiacs, Fords, Chevys, and other engines without even doing a breakin procedure, I would just install it, fire it up, and let it sit there and idle for a while. And yet, I don't ever remember one of them wiping out a lobe.

Are cams made of different metals now, or are we using higher spring pressures or more lift, which is affecting how they rub the lifter base? Just curious what our more educated members think is causing this to happen.

Don

Cheap construction, off-shore suppliers, cut-throat pricing, hecho en mexico, inferior metals. Some, all, or most of the above.

Years ago, I never had a cam fail. I did some rather radical (for the street, at least) cams from 6-cyl Chevys to Pontiacs, to SB & BB Chevys. Granted, I didn't do dozens, but I never had one take a dump.

Now, I wouldn't put in anything but a full roller.

I absolutely agree with Jack. I've had several pretty radical (for their day) engines plus many flatheads where I shoved a new camshaft in the hole in the front with a little bearing grease or some STP, finished up the engine assembly, started it up and drove away. Now steel roller camshafts are, IMO, the only safe way to build an engine

would it have something to do with so much of todays metals coming from recycled materials .. how much metal is newly mined and used now days

Originally Posted by Itoldyouso

It seems to me we are hearing more and more about flat tappet cam failures than we ever did in the old days, even when the cam is broken in properly. I know we hear about oil today "not having the good stuff anymore", but sometimes cams fail even when additives are put in to replace some of those things.

Before I knew what I was doing (not that I know much more now) I remember installing a lot of cams in Pontiacs, Fords, Chevys, and other engines without even doing a breakin procedure, I would just install it, fire it up, and let it sit there and idle for a while. And yet, I don't ever remember one of them wiping out a lobe.

Are cams made of different metals now, or are we using higher spring pressures or more lift, which is affecting how they rub the lifter base? Just curious what our more educated members think is causing this to happen.

Don

Don, as you know, the oil producers ceased adding extreme pressure lubricants to off-the-shelf motor oils because the additives were affecting catalytic converters and costing OEM auto manufacturers big money on warranty claims. These extreme pressure lubes were necessary because of the tremendous pressure generated at the lifter/lobe interface, some say the pressure there is in the vicinity of 250,000 lbs per square inch. So, that's strike one.

The second thing to come along is the extreme energy grinds, where the lifter edge is just short of digging into the cam lobe as it comes around to nudge the lifter up in its bore. This design adds tremendous pressure over the previous long-ramp designs.

Third thing is the increased use of higher ratio rockers. Even if an extreme energy design can be made to work with controlled spring pressures, oil additives and proper break-in, along comes Ricky Racer looking for that additional 1/2 percent increase with high ratio rockers. This adds more pressure at the lifter/lobe interface, the highest loaded area in the motor.

Fourth thing that I see is inferior materials, particularly from the Chinese. Their castings are not what we Americans are used to seeing and their machining operations are....less than ideal.

I see that Comp in particular is pushing nitriding of the cam before purchase at their store. I'm told this adds to the life of a flat tappet camshaft.

Personally, I will never again use a flat tappet cam in anything I build. I have reached the age of patience, so if it takes a little longer to save up for a roller cam, that's the way it will be.

Originally Posted by Itoldyouso

It seems to me we are hearing more and more about flat tappet cam failures than we ever did in the old days, even when the cam is broken in properly. I know we hear about oil today "not having the good stuff anymore", but sometimes cams fail even when additives are put in to replace some of those things.

Before I knew what I was doing (not that I know much more now) I remember installing a lot of cams in Pontiacs, Fords, Chevys, and other engines without even doing a breakin procedure, I would just install it, fire it up, and let it sit there and idle for a while. And yet, I don't ever remember one of them wiping out a lobe.

Are cams made of different metals now, or are we using higher spring pressures or more lift, which is affecting how they rub the lifter base? Just curious what our more educated members think is causing this to happen.

Don

well its some of this and some of that . oil now has more detergents in it and NO ZDDP and if you add that to you new oil there is a very good chance that it is just going to sit in the bottom of the oil pan never mix in the oil and if it will mix it will not bond to the cam and lifters as the detergent blocks the zddp from working.as for lifters not having the right radius ground on them or to coarse of a finsh or not the right rock well hard to say .thats why i do and have been putting in roller cams in for the last 20 years .i do build flat lifter cam engine any thing but a bbc. but i will not cover a wiped cam no way in hell .that is the first thing i get that out of the way if they do not like that they can fine someone else that will lie to them
.i do not like to wast my time by machining and build the best engine i can for the money knowing i building some thing that can fail on break in with a flat lifter cam

All of your answers make sense. I've wondered about how well those additives mix into the oil and if they accompish what the old oil forumas did. Roller cams are the way to go, for lots of reasons, but if someone is building an old engine, like a flathead, what are they to do?

I remember pulling out the stock cam in my 389 Pontiac, slipping in a 421 cam that we lubed with 50 wt oil and stp, and as soon as we got it running we went for a ride. No breakin procedures, and sometimes we would even let a fresh rebuild sit there and idle for a while, something we now know is a no no. Never had one fail though, which is why I wonder how 50 years later we are now seeing problems we didn't have back then.

Don

well i did a old nail head some sbc s and some fords and others as well as a 36 caddy i use break in oil or oil with no detergent and a zddp is how i would go or a race oil that has some zddp for the life of the engine and lots of luck. as for the flat head crower make s key roller lifters for them

I'm in agreement with the consensus - all of the above. Simply put, lead, Zinc, and tin are all very good surface conditioners, but are, sadly, eliminated from our modern lubricants by environmental fiat; without them, we are left at the mercy of the other factors such as the quality of the materials and the engineering designs. Did I just write that?? My brain is in a twist today!! If I ever build another engine, I'll use a roller cam; the days of "sliding" lifters are long gone, as far as I am concerned.

Don I am surprised too. It seems I've been hearing and reading the same thing. I think the numeber of companies making cams has dwindled too. Richard recommended a additive for start up that adds zinc and other goodies back in. I used it on the ford with good results, but it ain't cheap. Something like 32 bucks a bottle, but it goes along ways, and is cheap compared to the alternative. I'll go out into the shed in the morning and post the name of the stuff if anyone is interested.

The additive is Superior Friction Reducer or SFR
http://www.sfrcorp.com/product/sfr-1...oil-fortifier/
note it comes in quart sizes that run around 35 bucks, but you don't use that much at one time.

This product was recommended to me by Don Shillady, master chemist and unruly teenager.
If you buy a gallon, the freight is paid, so the first oil change will cost you $6.90 (7 1/2 ounces of the product added to the engine oil) and subsequent oil changes will add only $4.60 (5 ounces of the product added to the engine oil) to each oil change. Pretty cheap insurance, I'd say.

So techinspector1 are you saying if you had a Gallon of that Stuff . You could build a SB Chevy with a Flat Tappet Camshaft that would Last 100+K Miles ?

Tech1 Thanks for the nice comments. I am just coming up for air after I sent in my textbook manuscript last Friday. I recall starting the book about this time last year when the garage got cold and I missed all the good weather to work on the car! Now it is getting cold again and the car is sitting in the garage as I left it with the nylon speedo gear "mystery" laying on the work bench. Anyway you guys are scaring me about the flat tappet problem. I am planning to install 1.3 ratio rockers to start the engine which has been sitting for about two years and I recall reading about how you can add an extra pint or quart to increase the splash level up to the cam internally so I will add the pint of the additive Tech1 mentioned to the already filled crank with Joe Gibbs startup oil. I asked a young sales lady about which modern oils have ZDP and she said it is illegal EXCEPT for flat tappet engines. So if I ever get the engine started I will switch to AMSOIL which is available with ZDP and/or continue to use the additive mentioned above. Yes I know that additive will cure some horrible screeching damage in the "four ball test" so it is a good idea to add to regular oil changes if it is legal. Apparently it is legal if you have the flat tappet cam. At this point in my build it will be easier to do the initial miles with the 1.3 rockers and additive but what do you guys think about adding the whole pint of additive to make the total fill higher to raise the splash level in the engine for the first startup?
I just returned from my 55th high school reunion and found some of my H.S. buddies still have some flathead Fords, too bad I have gone down the fiberglass road but it is too late now. We rehashed some events that we did back in the 50's with rifles, rockets and hot rods and the conclusion was that today we would probably have done at least short terms in prison for those things today, so whew! One of my old buddies who I had not seen since 1955 told me he still has a '46 Ford deluxe coupe with a dropped front end, finned aluminum heads and dual carbs with headers on the block. I tried to almost give him the 4" Merc crank I have in my shed but he doesn't want to take it apart again to change the crank. Anyway I don't blame him. I would just wax and polish it over and over!

Don Shillady
Retired Scientist/teen rodder

Don---and others

You do not get splash to the cam by raising the oil level---the level of the oil is below the crank/rods and /or windage tray---even if you add SOME oil

Actually the cam gets oiled by oil slinging off the rod journals and by leakage down from the top of the engine---this is the reason for running the engine at 2000-2500 rpm for 20-30 minutes to break in the cam--more sling-----

Original rods and bearings had a hole so oil would be squirted up bat all the new rods/cranks don't have adquate side clearance or the squirt holes and the cam lobe and lifter bases suffer from too little oil