Box Stock

Lifters NOT flat

bomber315

bomber315

Member
so i am going over the 2020 Akra rulebook with a fine tooth comb. (still haven't managed to get thru to akra for a new version :rolleyes: )

i came across this part,

"BS lifters only, no modifications allowed. Over-all length of push rod 5.285" max, 5.230" min. Push Rod must be of 3 piece design (Hollow or solid tube with 2 solid ball ends). Lifter Head diameter .915" min with no visible modifications. Weight check lifters 18 grams min and push rods 9 grams min. Machining to bottom of lifter allowed. Bottom must remain flat. To be mated bottom to bottom at tech to a known stock lifter. No other machining to lifter allowed. Weight rule still applies."

well nevermind they say no modifications allowed and then go on to say how you can modify them... my issue is that the bottom of the lifters is NOT flat from the factory! at least none of the ones i have are... if you hold them up to the light you will see they look like this:

====|)(|====

all be it, very very slightly

What sense can be made of this???

EDIT: i understand why there is a slight dome, i am just curious if this is ever truly teched and how any many people get thrown out because they arent perfectly flat from the factory.... also i dont know how you could ever (dyi) "machine" weight off of the bottom of them and keep the dome. I was going to go to town with sandpaper, until i saw the dome. I cant sand a dome into them, i can only sand them flat. and then they wouldnt spin as designed.
 
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When the rule was written it was done with lifters that were coming through with the bottoms being flat. The rule allows for machining to meet weight spec. We haven’t seen any lifters as of yet that are not flat. Until we do it is in your best interest to get flat ones. I have put the word out to be on the look out for this issue and if we find out it is a problem from our sources we will address it at that time. We want to keep the bottom flat so foul play doesn’t begin.
 
DynoDon said:
When the rule was written it was done with lifters that were coming through with the bottoms being flat. The rule allows for machining to meet weight spec. We haven’t seen any lifters as of yet that are not flat. Until we do it is in your best interest to get flat ones. I have put the word out to be on the look out for this issue and if we find out it is a problem from our sources we will address it at that time. We want to keep the bottom flat so foul play doesn’t begin.
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You may not want to answer this, and if you don't I understand. What benefit is there to a not flat lifter vs. the flat lifter? Is there some form of additional lift or something similar? I'm not asking to argue the difference, I'm just intrigued as I would never think about reshaping a lifter.
 
jaymancds said:
You may not want to answer this, and if you don't I understand. What benefit is there to a not flat lifter vs. the flat lifter? Is there some form of additional lift or something similar? I'm not asking to argue the difference, I'm just intrigued as I would never think about reshaping a lifter.
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Think duration.

The way the lobe contacts the lifter, and acceleration rate.
 
no shocking the spring which may help by not introducing bad harmonics up through to the spring which may help stave off valve float which may help lead to that 300-400 rpm nobody has found yet or the ability to raise the ramp rate on the cam... the possibilities could be endless.... 🤓I’m getting engine nerd goosebumps just thinking about it.., lol
 
Make yourself a sample lifter. For this, chuck in drill press, and sand a taper.

Profile cam with degree wheel and compare to flat lifter.

Not earth shattering, but possibilities are there.
 
OVALTECH1 said:
no shocking the spring which may help by not introducing bad harmonics up through to the spring which may help stave off valve float which may help lead to that 300-400 rpm nobody has found yet or the ability to raise the ramp rate on the cam... the possibilities could be endless.... 🤓I’m getting engine nerd goosebumps just thinking about it.., lol
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goosbumps right, :) imagine if you could put a roller on the end of the push rod.
 
With the “compared to known to stock part” language put back in the book for 2021 it will help discover excessive modifications. I will work on language to solve the problem but until I get information back from my sources on this issue the current language stands. I will inform all certified techs of this issue. However we don’t have control of non certified techs that don’t have access to the tech forum to keep up on issues like this.
 
No that's not what I'm talking about. I would say (I haven't measured) that the center of the lifters is .001-.003 higher than the outside of them.

And I have some lifters from a junkyard engine that are the same, this isn't a new thing I don't believe. I truly believe the AKRA assumed they were perfectly flat when they wrote the rule. Or the rule is poorly worded and should read more like "guys, don't be machining domes on your lifters"

But the part about butting them up against a known stock lifter scares me. If that is done you are going to see light around the edges of 2 "known stock" lifters. At which point it will be a judgment call whether the dome has been increased or is stock.
 
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I just received lightweight lifters ( item: 131065LW ) from JCspecialty. I was told on the phone that they are AKRA legal. They ARE sanded FLAT. (hell I could have done that)

They also apparently didn't add the piston I asked for to the order and charged me $19.77 to ship a small, less than 1 pound, box. That's not good for repeat business. But that's beside the point.
 
bomber315 said:
No that's not what I'm talking about. I would say (I haven't measured) that the center of the lifters is .001-.003 higher than the outside of them.

And I have some lifters from a junkyard engine that are the same, this isn't a new thing I don't believe. I truly believe the AKRA assumed they were perfectly flat when they wrote the rule. Or the rule is poorly worded and should read more like "guys, don't be machining domes on your lifters"

But the part about butting them up against a known stock lifter scares me. If that is done you are going to see light around the edges of 2 "known stock" lifters. At which point it will be a judgment call whether the dome has been increased or is stock.
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If you get in trouble with that you have the tech man call me. I don’t care if it’s 2 am. I get those calls frequently and am ok with it
 
Stoichiometric; maybe you misunderstand the term? I've always understood it to mean an open flame. Once you add compression, and the effects of it, and the tuned exhaust, things change. I doubt any racing engine rooms at stoichiometric.

Not that I'm an authority on the this so look it up.
 
DynoDon said:
If you get in trouble with that you have the tech man call me. I don’t care if it’s 2 am. I get those calls frequently and am ok with it
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I don't actually expect my lifters to be teched, but you never know I guess... I'm just trying to put my engines together to the fullest potential of what the rules will allow. I like seeing my plain black shroud running with everyone's $700+ engines haha.
 
alvin l nunley said:
Stoichiometric; maybe you misunderstand the term? I've always understood it to mean an open flame. Once you add compression, and the effects of it, and the tuned exhaust, things change. I doubt any racing engine rooms at stoichiometric.

Not that I'm an authority on the this so look it up.
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What he said?????? Uh ok
 
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