Comp Cams Break in

[Ricko1966]

I think a lot of people with cam failures aren't using break in springs or break in rockers. Yea GM didn't use them new, but GM wasn't running as much spring pressure,or as aggressive of cam profiles. I screen shot this from comp cams, it says on line 6 of page 4 always run break in springs. It doesn't say always use break in springs,but skip break in springs if it's not convenient. At the very least,use a set of worn out factory springs as breakin springs but don't try breaking in your new cam with a ton of seat pressure on new springs.

 

[dd1990]

No one used break in springs in the past, radical cams are not knew, they've been around for decades, I believe the problem today is quality control on materials and fitment.

 

[xm20k]

No one used break in springs in the past, radical cams are not knew, they've been around for decades, I believe the problem today is quality control on materials and fitment.

Yes, however now adays people are grinding cams with roller profiles that are on the verge of too radical for flat tappets. A lot of them are really close to roller race cam specs. My roller for example is a @50 252/252 .600/.600 bracket race cam 4000+ there are flat tappet cams available now with all the same specs but more duration upwards of 256. I'd never attempt a flat tappet on a cam like this, and I've built some radical engines over the years and drive them on the street.

 

[YakkoWarner]

I have to preface this with the fact I have never built an engine from zero. I have never heard anyone mention or even reference specific break in springs and rockers before. I've always known about break-in oil and procedure for how to run the engine when new, but this is all new (and potentially useful) information to me so thanks for bringing it to light!

 

[Ricko1966]

Yes, however now adays people are grinding cams with roller profiles that are on the verge of too radical for flat tappets. A lot of them are really close to roller race cam specs. My roller for example is a @50 252/252 .600/.600 bracket race cam 4000+ there are flat tappet cams available now with all the same specs but more duration upwards of 256. I'd never attempt a flat tappet on a cam like this, and I've built some radical engines over the years and drive them on the street.

Right. Back in the 80s we ran rollers because the profiles were too much for flat tappets. Not because the factory went roller. If you were fast you were running roller. It's because we went beyond what was practical for flat tappet. .510 292 flat tappet on ancient ramps use to be huge now it's MEH. Yes we had flat cams back in the 80s and 99s too but we knew for really rowdy grinds we had to go link bar roller.

 

[Rustisbest]

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^^Looks like a Comp part number to me. From what I understand a lot of the popular cams are just being ground at the core supplier and slapped in the manufacturers box. He's got several videos up on the subject and i think hes quit fooling with flat tappets all together.

 

[dd1990]

Yes, however now adays people are grinding cams with roller profiles that are on the verge of too radical for flat tappets. A lot of them are really close to roller race cam specs. My roller for example is a @50 252/252 .600/.600 bracket race cam 4000+ there are flat tappet cams available now with all the same specs but more duration upwards of 256. I'd never attempt a flat tappet on a cam like this, and I've built some radical engines over the years and drive them on the street.

I would agree with you but people are wiping lobes on mild cams, and even roller cams have their issues. Quality control, IMO, is the problem, especially with lifters. Have to stick to good company like Howard's or Crower

 

[xm20k]

I would agree with you but people are wiping lobes on mild cams, and even roller cams have their issues. Quality control, IMO, is the problem, especially with lifters. Have to stick to good company like Howard's or Crower

I agree there are quality issues as well a lot of copycat chinesium. I've never purchased anything other than Melling lifters (flat tappet) they are typically the supplier of the majority of the aftermarket.

 

[Ricko1966]

So if you know theres an issue and one preventative measure is break the cam in for 300 miles on light springs, just break the cam in for 300 miles on light springs. Don't rely on,we didn't use to have to do that, well now we know there are issues,so take all steps to prevent them.Yep an extra afternoons work for a little preventive medicine. But a flat cam is a lot bigger deal than changing valve springs sometime next month,knowing you have to do it. A flat cam is SURPRISE!!!!! change me right now.

 

[xm20k]

Note the line around the bottom of these that is how you know you have ones that are not knock offs. Also note the color variance between the body and end that means these are more than likely correctly hardened. If the lifters, you get are one solid color and don't have the line at the bottom they might not be what they claim to be.

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[fast 99]

Note the line around the bottom of these that is how you know you have ones that are not knock offs. Also note the color variance between the body and end that means these are more than likely correctly hardened. If the lifters, you get are one solid color and don't have the line at the bottom they might not be what they claim to be.

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Am old school machinist told me good lifters have Rockwell peen mark on the bottom. Not sure if that means anything today.

 

[Rustisbest]

Looks like Comp sells 2 different versions
812-16 like in the video

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And the pro magnum 858-16

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[xm20k]

Looks like Comp sells 2 different versions
812-16 like in the video

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And the pro magnum 858-16

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Some do and the bottom ones are the better lifter they also tend to cost more. Take a look what the AC Delco lifters look like.

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[Old Guy Bill]

It's been many years since I've built an engine, but I seem to remember taking one set of springs out for break in...
The best lifters I ever used.

Rhoads Lifters

 

[vr1967]

Right. Back in the 80s we ran rollers because the profiles were too much for flat tappets. Not because the factory went roller. If you were fast you were running roller. It's because we went beyond what was practical for flat tappet. .510 292 flat tappet on ancient ramps use to be huge now it's MEH. Yes we had flat cams back in the 80s and 99s too but we knew for really rowdy grinds we had to go link bar roller.

Comp Cam burned a bunch of us (close to a dozen) in the late 80s and early 90s with bad (soft) BBC cam cores. They always claimed improper break in, yet, we all went to different manufacturers, and never had another issue.

The issue with Comp led me to meeting Harold Brookshire. Harold was a cam designer, and on street engines, never mentioned break in springs.

He used to grind us some pretty aggressive flat tappets, even by today’s standards. (We may have been his R&D team, and didn’t know it, as he always wanted feedback) We just always used moly lube, and a can of EOS.

His company was Ultradyne Cams, but also designed cams for Bullet Cams, Isky, General Kinetics, designed Comps Hi-Energy line, Lunati’s VooDoo and several others.

Sadly we lost him in 2014, and Ms Linda, 5 years later. Since then, I’ve lost track of his two children.

I think around 2000, we lost some of the companies making lifters, which hasn’t help. Seems to be only a few now making them for many name brands. QC seems to be a lot lower than it used to be.

Sorry for the ramble.