Flat tappet lifter failure

[kansas stocker]

I'll bet if we went back to stock heights and poundage, camshaft and lifter problems would be 99% solved. Almost one of the easiest things to check but the whiners were heard, then new problems were created and the whining started again.
Just my 20 cents worth to account for inflation.

[Stan Weiss]

The whining has been gone on forever. I remember back in the mid "70s helping someone who was running a 302 Z28 with a Lunati stocker / dwell cam and he was always botching about hard on parts it was.


Stan

[Mark Yacavone]

Listen up,
No one want to go back and go slower, especially the "chaser" guys.

Anyway, I don't care what they do..The last two cars I've involved with, came with roller lifters. The next one will be a flat tappet but a soft spring rate..

But, I suppose this is as good a place in time to say "No mas"

( a little Spanish lingo for the folks in the big cities)

[Alan Roehrich]

It's not "just" any one thing.




It is oil, few oils are formulated to make flat tappets live. Finding an additive balance is tricky at best.


We're probably very close to seeing the end of cast flat tappet cores, especially the highest quality specialty cores used in Stock.


It is the tappets themselves, at most levels, the quality of machining has declined, tooling is wearing out, and the quality of base materials can be questionable.


If you're dealing with cast core cams, and iron flat tappets, realize that your government absolutely despises foundries. They hate anything that even looks like a foundry. They typically try to force out any foundry not making OE products, and they'd like to force out those foundries if they could.


Steel for billet cam cores and for tool steel lifters is in short supply. In the current political and economic climate, it is likely to remain so. That means you're going to see availability problems, and escalating prices. Honestly, if you try to buy a custom stock diameter steel billet cam, be prepared, you may wait months.


That's the state of the industry.


Now, understand, if you were to buy a steel billet, and grind it to a stock lift rule, you're grinding all the way through the heat treat. That means you're in for a second heat treat, and another grinding process.


Further, most all of the cam companies no longer employ a lobe designer on any sort of full time basis. That means there's actually not anyone there to even design you a Stock lift rule roller lobe. You certainly do not want just anyone doing that. Many of the good lobe designers are DEAD. Harvey Crane is dead, Harold Brookshire is dead, Jere Stahl is dead. I have not seen or heard anything from Steve Huggins in 10-15 years, no idea if he's even alive. Not sure about Darrel Hawkins, either. Comp Cams let Billy Godbold go. He's on a "retainer", you can bet mostly for mega dollar customers, like NASCAR, T/F, Pro Stock, etc. That's right, the number one cam company in the world does not have a lobe designer on staff. Isky hasn't introduced a new lobe in years, and they're not likely to be interested in Stock. Lunati is owned by Comp, Harold designed their last new cam lobes. Don Walthall may still be doing new lobes at Bullet.



Off the base circle, you cannot accelerate a roller lifter as fast as you can a flat tappet. It simply doesn't work. So, remember, you're dealing in most cases with low lift. under 0.530", in many cases, under 0.400". So the roller has no lift to "catch up" on, it's literally only going to just over 0.300" of tappet lift. This will require considerable development to reestablish the correct lobe profile, and duration. It may require a complete change of opening and closing events. That means you're not going to just go buy a roller, put it in, and your cam troubles will end. You may buy 4-5 cams before getting something that really runs well, and doesn't kill some parts. Bet on those cams costing you $700.00 or more, IF you can get someone to design lobes and grind cams for you. You MIGHT get ONE regrind on your expensive core.



So, NO, a roller lifter cam WILL NOT perform the same, nor will the valvetrain dynamics be the same. There WILL be a measurable change in performance, that may significantly alter the current balance of the class. If you think that you're going to just go buy a roller cam and some roller lifters, stick it in, go racing and be competitive, you're in for an expensive and ugly surprise.


And remember, like every other "enhancement" people have lobbied for, when you let this genie out of the bottle, it's out. It's never going back in. If it sets off another RPM increase, and more valvetrain damage (not to mention other parts) because of the changes, you're out of luck.


Stock is a very small market. I don't see too many cam grinders, if any, being interested in designing entirely new lobes, or multiple series of lobes, for more than a dozen different engine families to switch them from flat tappets to rollers. Especially given the amount of money most are willing to spend, and the amount of complaining most do. The return on investment is miniscule.



Roller lifters are not the solution. The most feasible solution is to work with some people to get some lifters and tappets that are compatible, and find some oils and additives that work. There's a possibility that some coatings and some surface treatments will help resolve the issues. The other thing that will help is getting the cam, block, and lifters in the exact correct positions in order to make the lifter spin correctly, and make everything stay there. Just getting the lifter bores bushed isn't enough anymore.

[Stan Weiss]

Has anyone talked with or had dealings with Mike Jones owner of Jones Cam Designs as far as developing new lobes?


Stan

[Alan Roehrich]

Originally Posted by Stan Weiss

Has anyone talked with or had dealings with Mike Jones owner of Jones Cam Designs as far as developing new lobes?


Stan

Mike is one possibility that I left out. His booth was substantially smaller at PRI this year, and he was busy, so I wasn't able to talk to him.


I was actually talking to Billy Godbold about developing some of his new Low Shock lobe technology for Stock, in hopes of getting the spring pressure requirements down, and increasing reliability. We passed each other three or four times at PRI, but had no time to talk. I'm not sure Comp would even be interested in paying him to develop new lobes. I was hoping to get some time with him and discuss materials and surface finish, there may be some possibilities there. And that's what his consulting business is about.


I have been wondering if technological and material advancements wouldn't make it possible to build a better Shubeck style lifter. But I have not found anyone to talk to about it.

[nickh]

On cam grinding has anyone tried Powell Machining, He recently quit grinding any flat tappet cam and lifters but is performing cam grinding on all other cams.