BBC solid roller lifter failures - a root cause analysis

[Wolfplace]

I am not going to argue with you Rick
I have no desire to prove you right or wrong

I am stating that the design that you feel is so bad has been working in real life for many years now both in the conventional & EZ roll versions & this to me is more important than your opinion.

I am stating again that these lifters (the standard version) have more than doubled the life in one endurance engine I do over another well established & excellent lifter that is "better engineered"

Could they be better?
I have no doubt they could.
You don't like the design, how about you call Richard or Ron & explain what you feel could be a better design
How about you redesign them to your standards & talk to them about an improved version.

I am quite sure you are correct that Isky could make improvements on the design, & perhaps you have good reason to bash them in your opinion, I don't know, don't really care.
What I can say is they have stood the test of time in endurance applications now without your help so as I said, being a backwoods dumb ole hillbilly machinist I will continue to use them as is with no whining until I have a problem

[CamKing]

let’s say we have a BBC Comp Cams solid roller cam, with their fairly aggressive Extreme Energy lobes, with specs of 266*/272* at .050, .678/.688 lift, that calls for .016 hot lash. So, let's say we want to run it at half that, or .008 hot lash, which works out to .002 cold lash. We have clearance, so nothing is tight. What happens if you do that, from a cam designer stand point? Thanks for you input.

You'll increase the seat duration by about 20 degrees.
In my opinion, it'll hurt the performance, but it won't have any bad effects on valvetrain stability. It'll either be easier on the valvetrain, or the same. It will depend on the cam design.

[kwillymac]

Could there be a difference between a Billet cam and a standard Roller? I know Billet is harder, but could it be harder on lifters. I would think the cam being that hard may cause the weaker lifters to take a beating. Unless roller lifters are Billet?

The reason I mention this is I have friends with Billet Cams going through lifters faster than with standard cams.

[stealth]

they all suffered from the exact same mode of failure, in the form of extensive surface pitting on the axles and needles, which is also called spalling ………..

Thanks 540,

did you check to see if there were any tiny flat spots on the rollers. I always wondered if it wasn't the roller getting "flat spotted" from lash and valve float etc, once they had these spots they would pound away a the axle..

Just wondering

This has NO merit? The tiny flat spots would account for the erosion of the axle and needle bearings. Might a rev kit be of more value then previously thought?

This post went astray somewhere; it would be nice to get back to trying to solve the problem.

[new engine builder]

Could there be a difference between a Billet cam and a standard Roller? I know Billet is harder, but could it be harder on lifters. I would think the cam being that hard may cause the weaker lifters to take a beating. Unless roller lifters are Billet?

The reason I mention this is I have friends with Billet Cams going through lifters faster than with standard cams.

Does the roller lifter and billet roller cam have the same rating on the "rockwell scale"??
Does the surface "hardening" go the same depth on the roller lifters as it does on the roller cam??

[kwillymac]

Does the roller lifter and billet roller cam have the same rating on the "rockwell scale"??
Does the surface "hardening" go the same depth on the roller lifters as it does on the roller cam??

Good questions...I wouldn't know anything like that. I am not even sure the roller lifters are billet. Or are you saying if the hardness is the same it doesn't matter? I don't know much about this stuff. I lost a solid cam once in a motor, I never had a Roller cam. I have seen a lot of my friends have problems. I know that the ones that didn't have a billet cam lasted quite a bit longer.

[Ron Gusack]

I put over 1200 runs on some Erson roller lifters without any problems. Seat pressure was 200 and we ran a rev kit. I asked an Erson tech how I got so many runs without a failure and he said the rev kit. According to him, a rev kit will double lifter life most of the time. Controlling the lifter on the base circle and opening ramp must have some value.

[new engine builder]

I put over 1200 runs on some Erson roller lifters without any problems. Seat pressure was 200 and we ran a rev kit. I asked an Erson tech how I got so many runs without a failure and he said the rev kit. According to him, a rev kit will double lifter life most of the time. Controlling the lifter on the base circle and opening ramp must have some value.

I guess I don't understand why you would even need a rev. kit if you have the right valve springs to begin with.

[TheEngineWorks.com]

I guess I don't understand why you would even need a rev. kit if you have the right valve springs to begin with.

It would KEEP the lifter on the camshaft at all times.. The next camshaft is gonna be designed to run very tight lash, we will see how that goes. My theory is that a lot of the failure is due to the lifter smacking the lobe as the lash is taken out.. Ever look at a roller camshaft w/ some running on it, many times its obvious that the lifter has impacted the cam right at the point where the lifter meets the camshaft at the start of the ramp, I feel thats from the impact effect.

[CamKing]

I guess I don't understand why you would even need a rev. kit if you have the right valve springs to begin with.

Because the rev-kit holds the heavy lifter on the cam, and keeps the lifter in control below the lash point.
The "right valve springs" only control the lifter above the lash point.
For longevity on a street engine, I can see where a rev-kit could help the lifter.

[TheEngineWorks.com]

[Because the rev-kit holds the heavy lifter on the cam, and keeps the lifter in control below the lash point.
The "right valve springs" only control the lifter above the lash point.
For longevity on a street engine, I can see where a rev-kit could help the lifter.

Obviously we are on the same page.. I think we may be on to something for solid rollers on the street.

[new engine builder]

Because the rev-kit holds the heavy lifter on the cam, and keeps the lifter in control below the lash point.
The "right valve springs" only control the lifter above the lash point.
For longevity on a street engine, I can see where a rev-kit could help the lifter.

Does'nt a mech. street roller cam have a ramp rate that is less severe as a full on race cam??
So why would a street mech. roller cam really need a rev. kit??

[CamKing]

Does'nt a mech. street roller cam have a ramp rate that is less severe as a full on race cam??

My street rollers do, but we're talking about guys running race roller cams on the street.

So why would a street mech. roller cam really need a rev. kit??

Without a rev-kit, the lifter has no pressure to keep it on the lobe below the lash point. This could have some bad effects that don't show up in valvetrain stability, but hurt lifter life.
Maybe the lack of pressure allows the roller to stop rolling, and then when it hits the lash point, the sudden acceleration of the wheel is too much for the needle bearings, and the skid inside the wheel.
That's just one possibility I could see taking place, and I can't think of any problem a rev-kit would cause on the street.

[new engine builder]

Does'nt a mech. street roller cam have a ramp rate that is less severe as a full on race cam??

My street rollers do, but we'retalking about guys running race roller cams on the street.

So why would a street mech. roller cam really need a rev. kit??

Without a rev-kit, the lifter has no pressure to keep it on the lobe below the lash point. This could have some bad effects that don't show up in valvetrain stability, but hurt lifter life.
Maybe the lack of pressure allows the roller to stop rolling, and then when it hits the lash point, the sudden acceleration of the wheel is too much for the needle bearings, and the skid inside the wheel.
That's just one possibility I could see taking place, and I can't think of any problem a rev-kit would cause on the street.

Am I way off thinking it may create a harmonics problem?
If the lifters are leaving the cam lobe won't this cause a shock to the valve springs.
Causing the valve springs/valve to want to bounce off the seat more???

[TheEngineWorks.com]

Man, who has a spintron and a high speed camera that we can test these theories with??

Come on, one of you guys MUST have one sitting around gathering dust that we can do some testing with..