Technical Cam break in! Why all the problems?

I read about( it’s been a while since I built an engine) all the trouble with camshaft break in these days.... What has changed other than oil, and you can get “ good” oil for break in.
I’ve built a considerable amount of engines in my life and just kinda “ drove “ them, never had a problem. The OEM made millions of flat tappet cars that survived, with out “ any break in, per say” !
Now I read about changing to light springs, special procedures, special oil, the replacing the springs. We never did that in the old days. Or at least I didn’t and never had any problems. Ok maybe one! Lol






Bones

 

A group of BB Chevys were built & the cams wiped on start up. Suspects included bad brand new cams, bad off shore lifters, too much spring pressure (higher than "back in the day"), oil w/o zinc. Don't know if it was ever determined the exact culprit but not too many people were aware of the zinc going away.

 

Wiping a cam is a major setback. I think all the precautionary steps came about because people were looking for any possible way to insure that it didn't happen. Overkill..........maybe, but if I were installing a cam with higher tension springs, I would take whatever steps possible in order to be sure. That said, I prefer roller cams which don't seem to be as problematic and give a lot better results.

 

Used to be If you bought a cam in the USA or even bought a US made car. the camshaft core was manufactured by Crane Cams. Yep everyone bought their cores from Crane. cranes cores wher made from new metal not recycled junk. Crane eventually lost that" monopoly" and went out of business. At the auction the Crane Factory equiptment was bought and sent overseas to some other place. Isky at one time would cut a groove around each lobe and fill it with moly to prevent wear.

 

my dad bought a new 64 truck. 283. and it developed a flat lobe pretty quick. New chevy engines used to be test fired on LP. And broke in before they left the engine plant.

 

I lost 2 before I found out that the oil company's had removed zinc for there oil.

 

CWC Foundry (made blocks in the 50s) is, and apparently has been, the supplier to Detroit for a long time from what I've seen. Or were you talking aftermarket?

 

Lack of zinc seems to be the major factor. Overseas lifters and cam blanks also share part of the blame.
Even back in the 50's and 60's, camshaft break in was advised. Much the same instructions as today with the addition of leaving the radiator drain open and a garden hose stuck in the radiator.

Pete

 

One must ask... Roller , Hydraulic Roller ,or flat tappet?
Roller= little or no break in
The biggest two culprits of cam wipe out upon new installations of flat tappet cams granted it was installed correctly are inferior material and or no lubrication.
One can check the harness of the bump stick with a hardness file on a nonwear surface before installation . The lifters will be challenge to field test hardness.

 

It's not a big deal with stock or very mild cams. But these days a lot of folks are running a lot more cam than they used to.

 

Back in mid to late 70's GM 350's had an issue with cams going flat. As far as today, I'd blame it on inferior materials. Yes I agree, people run much more aggressive cam profiles these days then from back in the day.

 

If yer gonna get all fancy pants and show off using Latin phrases it's important to spell it right Gus! "Per se"

Here's an interesting read on motor oil engineering test data. He claims that the "zinc" thing is quite a lot of hooey, and that modern oils are light years ahead of old school motor oil. Not gonna say I agree with everything he claims, but it's worth looking over to see what oils are suitable (or not).

https://540ratblog.wordpress.com/

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In recent years there have been entirely too many wiped cam lobes and ruined lifter failures in traditional American flat tappet engines, even though a variety of well respected brand name parts were typically used. These failures involved people using various high zinc oils, various high zinc Break-In oils, various Diesel oils, and various oils with aftermarket zinc additives added to the oil. They believed that any high zinc oil concoction is all they needed for wear protection during flat tappet engine break-in and after break-in. But, all of those failures have proven over and over again, that their belief in high zinc was nothing more than a MYTH, just as my test data has shown.

 

By my memory it was the 307 that was known for having soft cams more than any of the small blocks.

 

Add zink,or be sure to use a oil that has it. the zink is not in most oils now. Cams in the 50s n 60s came with a brack in lub that you put on lobs to help/now day it's harder to find.

 

Showing off.... are you crazy? I didn’t even know it was Latin! I heard it from a Hillbilly! Lol


Edit: Truck 64... your jumping on me for my Latin.... or lack of.... while you are quoting verse on Snakes disturber problem!!! Lol

But! I’m going to defend myself by blaming spellcheck!



Bones

 

Actually, there has always been a percentage of all flat tappet engines that suffered failed cams, it has always been known to be the most common failure point of new engines. This is nothing new, and yes it was an issue way back in the day. The problem gets worse, as Squirrel pointed out, with higher lift cams with more aggressive ramps that open the valves faster, higher, hold them open longer, and slam them shut faster. There is a reason why OEM's moved to roller cams in almost all new engines. And the reduction in zinc levels in modern engine oils has had a negative impact on this, though it is not the only culprit and it gets the blame for many failures that have occurred for other reasons. I think there has been a huge lack of any controlled investigation into the mass failures experienced, or at least I can't find any info on it, and so we really can't say for sure. I suspect there have been a number of contributing factors, from improper hardening of cams & lifters to improper installation and breakin procedures, to poor lubrication at the critical start up period. But it's easy to just blame the oil, so that's what everyone does. It takes the monkey off their back. And it makes them look like their an expert, "oh, it was the oil's fault, not enough zinc, yada, yada, yada." No, it couldn't be that you or your company screwed up, it has to be the oils fault. Right.

 

Hydraulic roller cams have there own set of problems besides cost so I still use flat tappet cams. All of my cam's are solid and I have the cam nitrated for an extra $100. The last cam had stout springs and was started and broken in with full spring pressure. I've never had a flat cam, I use Joe Gibbs break in oil at startup.

 

And using a zinc additive...be careful, according to oil testing folks, a lot is worse than not enough.

Mike

 

In the blog link I posted previously, one of the interesting things he claimed, was that aftermarket zinc additives in a bottle made the motor oil worse, theory being motor oil additive packages are carefully put together by the manufacturer, don't use oil additives etc. Maybe. Too much zinc causes problems as well.

Maybe Squirrel has it right, eh? Wal-Mart Super Tech 5w30. Don't worry about it.

 

Lost 2 stock 150,000 / 50,000 mile flat tappet cams on my summer only drivers when changing them both over to full synthetic oil did this some time in the mid to late 90s, thought it would be better for them, all the talk about lubing quicker at cold start up ect and I agree that it is better oil for daily drivers that don't sit very long.

I could be wrong just a theory but the thin easy flow oil runs right off the cam lobes after a couple of weeks, causing dry start up on the ramps. Always wanted to dip a spoon in full synthetic v/s a mineral oil with zinc and see how long it clings.

Live in Wisconsin so they sit about 4-6 months, I use Mineral oil with additives on my old stuff and have not lost a cam since,

 

Another problem is most machine shops use the shot blast method of cleaning blocks nowadays....this tends to peen over the edges of the lifter bores causing the lifters not to spin in the bore. This kills a cam in nothing flat. When I build an engine I pay special attention to the edges of the lifter bores, and make sure every lifter spins freely.

 

Cam manufacturers provide a camshaft break in lube containing zinc. Apparently they feel that its helpful but not infallible. We don't know any of the possible causes in each individual camshaft failure. If the cores being sold are from "name" cam manufacturers (even if bought elsewhere), its logical that they will be aware of any quality problem and quickly get it resolved. They cannot however correct problems because of incorrect installation,incorrect parts, or incorrect break in. Even the highest quality biggest name brands have all had camshafts that "wipe" when amatuer engine builders get ahold of them. Rather than suspect the oil (proper break in oil) or the cam shaft, I would suspect the engine builder as the most likely source of failure. None of us like to admit we screwed up, but we all do.

 

Small block Chevy engines had massive cam wear problems back in the late seventies and early eighties, well before the zinc levels were reduced in motor oils, so this isn’t a new problem. All of the fifties SBC engines that I took apart in my youth had varying degrees of cam and lifter wear, as did my mid sixties Pontiac and early seventies big block Mopar.

The biggest factor now is the higher hertz stresses on the lifter to lobe interfaces with “modern” aftermarket cam profiles, coupled with the loss of domestic lifter production. Sealed Power, Rochester Products, and Eaton were the big Oem supplier’s back in the day, and supplied the privately branded aftermarket parts as well. These suppliers dropped out of the flat tapper market when the Oem switched to rollers and OHC, leaving the offshore sources as the only viable suppliers.

 

I have never had one go flat either. I fire a new engine and never let it idle . At least till my 15 or 20 minute break-in is done. As soon as it fires I take it to 2500 at least. Set timing and with a fan in front of the radiator, Run the throttle up and down periodically , I keep the RPM up to make sure it's oiling good. Not an issue with a roller but sure is with a flat tappet. Shut her down let it cool off, Change the oil and filter. Check timing again and set out for a drive. Usually smoking the tires in the process. . I have had people come in the shop when I'm firing a new engine and go whew!! That's really singing!! 3-3500 on a sbc is nuthin but with open headers in the shop it will get your attention. I love the smell of burning engine paint.

 

If you can't get the engine to start off right away, the break in oil can be wiped off the lobes before you even get it running.

 

I've been saying this all along around here. Don't use aftermarket zinc additives for the reasons mentioned above.

 

And it's not an issue with the camshaft itself, as much as it is the lifter axle/bearings that cause the bulk of the problems with roller type camshafts.

 

I've seen problems with the hydraulic parts of the lifter similar to the problems flat tappet hydraulic lifters are having. Also I've seen problems with the retrofit cam and lifters not holding oil pressure in the lifters. I've seen this in sbm and 460 Fords.

 

Also the 350 around 1974 had a run of bad cams.

I have never lost one, even the old Wolverine cams I used to buy came with a tube of lube. They gave them out when you bought the cam. I go conservative with the initial lash with a bigger cam, pre-oil the crap out of everything and do what the cam maker suggests.

 

I've never had a problem with one, either. Use plenty of pre lube, a quart of Lucas in the oil. Crank it up, run it up a few times, then test drive it. Never did a 3000 rpm cam break in either. But, it's been about 15 years since I last built an engine, so things may have changed since then.