Re: Flat tappet lifter failure
 

Both pounds...LOL!

Re: Flat tappet lifter failure
 

Re: Flat tappet lifter failure
 

Sorry who is this guy he is amazing

Re: Flat tappet lifter failure
 

What a thorough but concise answer to the problems we in Stock Eliminator have had! This person makes perfectly good sense. It seems that the word of the day here is variables, in that, some people can build a motor and it breaks in and goes the long haul for season after season, and other times the same engine builder builds one that can't get past the initial fire up and break in interval without killing the camshaft. Cast iron is a material that has variables within it by nature of how it is, with softer spots in some places than others, the items like core shift and an unevenness in how things may move around as the engine is running, as well as possible un evenness in thermal expansion rates. add to it that blocks made starting in the early '70's were thinner than their predecessors which didn't help in that area. The fact that the lifter hardness varied so much won't help, as well as quality control issues in the machinery that surfaced the face of the lifter adds to all this. He is right in that the answer to all this is to use a roller camshaft as a replacement for the older flat tappet set ups.
Back in the mid/'70's, it seemed that OEM Chevy motors, both big block and small block, had an unnatural spike in camshaft failures. I remember seeing cars still with half their warranty left having cam and lifter failures as a rather common thing. In 1980, I took a job with the county mechanical department which included both LA County Sheriff's cars with 350 and later on 305 Chevy Novas,Malibus and by 1986 the big Impalas, as well as all kinds on Chevy/GMC trucks, and scarcely a week went by that we didn't have at least one cam and lifter failure hit the shop. There didn't seem to be any obvious answers back then, but by 1990 or so, the steel camshafts with hydraulic roller lifters came along and that seemed to end it.
The answer that seems to be the simplest solution is to go to a steel cam and roller lifters in the basic Stock Eliminator engines. Since the only spec currently being looked at in a tear down is valve lift, it would seem that some kind of a rev kit that would minimize modifying the block to any real extent would be a good answer.
Some of the problem, one that they might not be able to fix, would involve locating the block in some kind of fixture where the lifter bores could be fixed and replaced with some kind of a bushing. Any of you guys with bushed lifter bores having cams go flat? A properly bushed lifter bore could be installed more accurately and may alleviate a tendency toward an improper angle of the lifter bore that would negatively affect the contact pattern of the cam and lifter.
Maybe the thing to do is confront the fact that the restraint on max valve lift has pushed the design limits to the max, and the solution is to use a roller cam with OEM lift and duration specs.We already have roller rocker arms allowed as well as the ratio is the same s the OEM ratio in regards to valve lift. Maybe its time for NHRA tech to allow for conversion to roller cams as well as OEM lift is maintained. Just a thought, but it seems like a possible answer to eliminate the quality control issues we're all facing right now.

Re: Flat tappet lifter failure
 

GM had a cam core problem in the 80s...
That was the source I'm told of the woes they had with cams going flat back then.

I don't think you will find a warm welcome to the roller cam solution on here, judging by previous posts.

It is a pandoras box, as far as tech. or lack thereof is concerned.
I don't know how far the limits on duration are on current flat tappet cams is, it sounds as they may have found it.
I don't know if a roller has anything to add as far as duration or profiles go that would increase performance, Stan or someone who is more up to date on current technology than I would probably be able to elaborate on that.

At this point I think tech. would be the major problem to allowing more loosening of a rule regarding this.

It seems like its partially a quality control issue as far as the lifters go.
everything I see or read says the lifter hardness hasn't changed, but that the finish of the face is inconsistent.
I feel like (no, I know) the additive package in the oil has changed due to EPA and such, which is why OEMs have gone roller.

With that in mind there is little motivation for anyone to continue making flat tappet components.
Like many of the parts used in "stock" this is a small market and at some point the parts will be unobtainable, as the bean counters won't allow these low volume items to continue being made.

Just some ramblings...

Re: Flat tappet lifter failure
 

A roller cam may let you have more area under the lift curve for a given seat duration than a flat tappet cam. Max velocity for a flat tappet will vary with lifter diameter. So a flat tappet Chrysler with its .904" lifter can have a greater max velocity than a GM .842" lifter diameter.

It would be interesting to see what these cams which will not live look like on a spin tron.


Stan

Re: Flat tappet lifter failure
 

Alan R. Sent this to me..
Eye opener.




https://youtu.be/NYtMCZYnF7I?si=3FFbDLZB1KlzoaN9

Re: Flat tappet lifter failure
 

I find it humorous that even after 14 pages of arguing and complaining, some don't understand that if you want a roller cam, either build a car that came with one, or run Super Stock. A close friend often jokes with me that Stock Eliminator is going to morph into a class where engine rules will be as follows: Bore and Stroke, compression, cam lift, stock castings with no welding or epoxy. It's always a good laugh, but the sad part is that if this class does last long enough, I wouldn't be surprised at something like that happening. First it's "I can't get a flat tappet cam to live, let me run a roller." Next it will be "I can't get .8,.9,1,1.2mm rings and spacers for my approved pistons with all the grooves moved around, so you should let me run a piston designed for a thin ring." So on and so forth, until it becomes even more of a joke than what's allowed now.

Re: Flat tappet lifter failure
 

I found the podcast to be very informative. It’s getting very hard to get quality metal and coatings. We are loosing venders ( bought up) then there goes the one on one handshake for parts.
I’m not pushing for rollers. I’m sure you understand that.
I have a small pile of flat tappet mechanical cams…not because they are damaged, because we found a better cam.

Re: Flat tappet lifter failure
 

Barry wasn't asking for rollers. He and I have been discussing cams, and the problems associated with flat tappets. I have talked to a few people about trying to get racers some help getting better quality flat tappet stuff. The point of the video was how much of an uphill battle we are facing. The industry isn't too terribly interested in helping us.


However, that is absolutely not an excuse to just change the rule. We remain opposed to changing the rule. I refuse to simply give up.