did car manufacturers break in flat tappet cams?

[Kern Dog]

I did my first engine rebuild in the 90s, long after I started reading car magazines with articles stating that camshafts had to be broken in. I bought a Chevy 350 from some nationwide rebuilder in 1991 but I don’t recall if they advised it. I’ve done it on every engine anyway. I never lost a cam in a Chevy but none of them were as wild as the Mopar engines I’ve done. Mild cams, weak springs and I’d figure the cam could survive longer. Look how long 318s last…. They had .373 lift and usually peaked around 4400 rpms. The 340s looked radical in comparison with almost .450 lift. The 440 Magnum had what… .458 lift? Nowadays we push lifts to crazy numbers. The roller in the 360 I’m building is considered a mild to moderate grind with .544 lift. The roller I just bought for my 440/495 is .580/.578.
But back to flat tappets,
I’m running a Lunati solid that is also close to .600”. That cam has survived because of what….? I’ve been careful about using the right oil and avoiding extended idling. I have the right springs for it. The lifters are those EDMs that shoot oil through the hole in the bottoms. I followed the guidelines and this one survives. My last cam though… the legendary Mopar 528 solid: It was fine for years but suddenly shed several lobes about 10 months to a year after I switched to a modern oil.
Yeah, same oil for years and no problems then I thought I’d try a modern synthetic that unfortunately was a high detergent formula. In retrospect, I should have seen the outcome just by using common sense. The detergent wiped off any zinc the oil had in it so it just wasn’t properly protected. Once the lifters cut through the surface hardening, it was done. If you lose one lobe, you might blame a lifter that was tight in the bore. When ten of the 16 lobes are failing, you blame the oil.

 

[toolmanmike]

we have 30 minutes to get this running and to the line!! Start breaking in the cam!

They do start it in the pits but not to break in the cam.

 

[kiwigtx]

More than likely not. The oil had all the proper additives in it back then and the steel was real steel. I would think they did a test run. Saw pics somewhere in the factory doing this.

Come to think of it....I don't recall seeing a cam being broken in on any episode of Garage Squad.

I guess heavy show editing doesn't allow for such trivial pursuits.

 

[Budnicks]

More than likely not. The oil had all the proper additives in it back then and the steel was real steel. I would think they did a test run. Saw pics somewhere in the factory doing this.

Not sure about the OEMs do now...

I think (don't know the name) possibly something many had/have
run-in or break-in machines too, OEMs have too
mounting the engine to it, in a big tub like deal (one I saw)
& a shaft spinning it 'under oil pressure'
checking oil flows/pressures going where it's supposed to, at specific RPMs
also supposed to help rings seal, valvetrain diagnosed, harmonics etc. (Engine Nerds ****) etc.
that spin the engines mechanically (it's not started, not running, just spinning)
& they check cams & rotating assemblies etc.
sometime before they were completed, like intakes off, no exhaust
so they could se in, watch the oil flow etc., before they ever went into the cars...
A few of mine were on it/or on one of them during R&D...

Some of the quality engine builders/especially performance builder have them
CNC guys (brainiacs NERDs) I had as a sponsor, did R&R stuff for Pro-stock,
a well known guy/team checking, testing valve-springs & huge camshafts
custom CNC'd parts etc.
(not sure I want to mention their name, but this was the beehive style spring stuff,
long before it was a popular deal, now it's the norm, but used for other purposes)
The rotating assemblies, valvetrain, cams & engines/long blocks (IIRC)
he had one, I thought he called it a 'run-in' (or break-in ?) machine
I'm not exactly sure 'what it's really called',
that was 20-30+ years ago too
someone in the machine/automotive machinists 'tools industry'
may know what I'm talking about...

I tried to look it up & couldn't find the machines names/identity he used...
Just came back with the reg 'flat tappit' cams current break-in procedures...

 

[kiwigtx]

When the guys helped put my engine together and in the car, ...break-in time was exciting. First time I have ever been involved in that. Did the 20-minute deal with the cam, then cooled off a bit to check fluids and linkages.....then it was on the road.

My 1970 Plymouth Road Runner had likely never seen such action..... around 7pm in the middle of winter around the mean streets of suburban Howick. I was passenger while my friend Grant drove. He basically looked a lot like a smaller version of Peter Fonda from "Dirty Mary Crazy Larry", complete with glasses. Made a few short bursts, then a few decent burnouts.....ending with coming around a corner with a bunch of shops...... we were going sideways past a Fish & Chip shop that was packed.......people were looking ...and seemed to be in awe of the view.

I was pumped....that car was awesome the entire time I had it. Never any engine troubles....would go 150mph easily - although I wouldn't dare try that now. Cops would impound, crush and I would likely never see daylight again. Famous for the first and only ever quarter-mile burnout here in NZ.

 

[Budnicks]

Come to think of it....I don't recall seeing a cam being broken in on any episode of Garage Squad.

I guess heavy show editing doesn't allow for such trivial pursuits.

They did show on 'Fast & Loud' (Gas Monkey Garage) quite a few times
how they failed doing it right, ruined a few on camera, 2 cams on one car IIRC too
(Ford)
or something was really wrong or really bad parts, sometimes engine builder error too

 

[khryslerkid]

When the guys helped put my engine together and in the car, ...break-in time was exciting. First time I have ever been involved in that. Did the 20-minute deal with the cam, then cooled off a bit to check fluids and linkages.....then it was on the road.

My 1970 Plymouth Road Runner had likely never seen such action..... around 7pm in the middle of winter around the mean streets of suburban Howick. I was passenger while my friend Grant drove. He basically looked a lot like a smaller version of Peter Fonda from "Dirty Mary Crazy Larry", complete with glasses. Made a few short bursts, then a few decent burnouts.....ending with coming around a corner with a bunch of shops...... we were going sideways past a Fish & Chip shop that was packed.......people were looking ...and seemed to be in awe of the view.

I was pumped....that car was awesome the entire time I had it. Never any engine troubles....would go 150mph easily - although I wouldn't dare try that now. Cops would impound, crush and I would likely never see daylight again. Famous for the first and only ever quarter-mile burnout here in NZ.




View attachment 1842171View attachment 1842173View attachment 1842174

Is that you! Looks like a Roger Mini Me!

 

[kiwigtx]

Is that you! Looks like a Roger Mini Me!

That's me....all of about 24 years old ...still have that Road Runner Superbird tee-shirt somewhere...doubt it fits now.

 

[Budnicks]

They do start it in the pits but not to break in the cam.

seat the clutch usually & check for leaks

crowd dig it too, smell of Nitro, in the mornings, smells like victory

 

[Unkle Krusty]

They had a lot of things, most of us do not have. Like six or more guys all working on you car.

 

[AR67GTX]

Come to think of it....I don't recall seeing a cam being broken in on any episode of Garage Squad.

I guess heavy show editing doesn't allow for such trivial pursuits.

Most of these car shows seem to have a lot of drama on starting a new engine up. I wonder how much of it is staged for drama. Either they aren’t getting fuel, or the timing is way out, or they don’t have spark, or something. And they grind away on it, testing this, fixing that, grind some more - big backfire scaring the whole crew - twist the distributor some more - more grinding the motor before it finally fires evenly and runs. The question is how do they not flatten the cam in every one of these shows.

 

[eldubb440]

Most of these car shows seem to have a lot of drama on starting a new engine up.

huge pet peve for me...... crank crank crank, backfire, commercial .......puleeeeze

 

[toolmanmike]

seat the clutch usually & check for leaks

crowd dig it too, smell of Nitro, in the mornings, smells like victory

We like to have someone bring a nitro car to our car club event. Even them running it in the pits creates excitement. Usually it's just someone sorting out a new car (new to them) or trying for their license.

 

[kiwigtx]

huge pet peve for me...... crank crank crank, backfire, commercial .......puleeeeze

It's almost like they get the engine running, then either drain the carb bowls, or move the distributor back a smidge to force a failed start.

Then they look like heroes when it magically starts with a few tweaks. All about building some drama.

 

[eldubb440]

It's almost like they get the engine running, then either drain the carb bowls, or move the distributor back a smidge to force a failed start.

Then they look like heroes when it magically starts with a few tweaks. All about building some drama.

they grab the distributor and start twisting while cranking.....like tuning a radio

 

[Budnicks]

When the guys helped put my engine together and in the car, ...break-in time was exciting. First time I have ever been involved in that. Did the 20-minute deal with the cam, then cooled off a bit to check fluids and linkages.....then it was on the road.

My 1970 Plymouth Road Runner had likely never seen such action..... around 7pm in the middle of winter around the mean streets of suburban Howick. I was passenger while my friend Grant drove. He basically looked a lot like a smaller version of Peter Fonda from "Dirty Mary Crazy Larry", complete with glasses. Made a few short bursts, then a few decent burnouts.....ending with coming around a corner with a bunch of shops...... we were going sideways past a Fish & Chip shop that was packed.......people were looking ...and seemed to be in awe of the view.

I was pumped....that car was awesome the entire time I had it. Never any engine troubles....would go 150mph easily - although I wouldn't dare try that now. Cops would impound, crush and I would likely never see daylight again. Famous for the first and only ever quarter-mile burnout here in NZ.




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The Old adage of;
"break it in like you're gonna' use them",
I did do the break-in for the cams, 2000+rpm full heat cycles hot & cold
then vary the throttle, the 1st 500+ miles on the road
I was never was real easy on my stuff, very heavy right foot,
I didn't have any problems
wiping flat tappet cams or old cast iron or moly rings etc. either
seemed the norm back in the day...
My street cars I was always trying something different...

My stepdad Bob used to break-in cams, usually a solid cam
or break-in new rings etc. on the open trailer on the way to the track sometimes
when we were running late, or just finishing up & needed to get on the road
we'd stop every like 10 miles & check it, for the 1st 1/2 hr or so
plenty of air going thru the radiator, wheels tied down & chalked
he'd set the idle screw at like 2200rpm, tell me to get in the truck
have me watch out the back, see if it was getting hot or smoke etc.
for like the 1st 30 miles...

It wasn't that strange back in the later 60's, to do that
I knew a couple of his buddies that did that too...
A friend of mine Pat Fulton from HS, his dad did it in his 68 Hemi SS/AH Barracuda
while going to the track too, I told him about my dad doing that also...
He thought he was the only one...