To mlpankey

Nascar left the hydraulic lifter because the rpm's against the lift durations would work the oil pressure out of the lifters and allow the valves to not open. At least that's one of the reasons.

Brian Jasper co. Ia wrote: If I remember correctly, part of the discussion I was reading talked about the lifter diameter and too small of a lifter would have the edge of the lifter dig into the lobe. I still need to give Barry Rabotnik a call so I can decide which cam to use in the 445 FE...

That is the real problem with a high lift cam and a small diameter lifter.

He was makeing a lot of comments about spinning a 226 engine and he's been fishing for wi50 like alwayse after seeing the pictures.  It's pankey being himself. Next he will post about everyone being caught up in all things shiney like last time.

Please explain flank, in cam grinder terminology for me please, I have never heard that term used before. And thanks in advance panky.

Butch(OH) wrote: Since those with sense are going to talk about it I will add my two cents. If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.

  a .842 diameter solid lifter on a 230 duration @ .050 will lift a valve with a 1.5 rocker to .480 lift . use the amc .904 lifter same length as the gm just bigger in diameter with same cam and rocker net valve lift is .515   its worth getting a grip on . The lifter diameter is also taken into account whe a cam designer is figuring the intesity of the flank for another term pressure angle. Anology we back into a parking spot with a 14 inch tired toyota corolla when we roll up against it we drop the clutch car lunges hard up against it and dies due to the small diameter tires pressure angle. Now we back our 16.9/38 tired 40 hp tractor up against it at a idle drop clutch and where over the curb and in the space behind the curb due to the larger tire diameter having a less pressure angle .

Edited by mlpankey - 07 Feb 2012 at 8:01pm

the larger diameter decreases presure angle gives the designer a opportunity to design a more intense flank along  with  the increase the duration and lift the diameter increase does by its self. i can provide technical bulletins from leading cam designers butch to prove you wrong if you wish. or just ask garry  since your so wanting to prove me wrong. another whos joined the peanut gallery. 

SteveM C/IL wrote: WTF!  Same cam? HUH?

No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL




Edited by Butch(OH) - 07 Feb 2012 at 8:49pm

SteveM C/IL wrote: WTF!  Same cam? The tippy top of the lobe is at the same height no matter how big a drum you set on it.NO? How then can it give more lift than it has? Don't mean to talk over your head with technical jargon like "tippy top". Help me understand your logic. Large dia will accellerate faster on same lobe but raise higher? HUH?

take a cam use a standard 842 lifter then run a pencil eraser over the cam lobe. The diameter lifter change will affect e rise.

mlpankey wrote: Butch(OH) wrote: Since those with sense are going to talk about it I will add my two cents. If I remember the question correctly he asked what was to gain from increasing the diameter of the lifter and the answer is nothing given that the cam is at optimum and the condition Brian mentioned is met. If a cam profile is not at optimum and cannot be ground as desired due to the ramp being at the edge of the lifter then yes, gains could be had by increasing the diameter of the lifter. The cam grinder can reduce the base circle to accomplish the same thing. All in all it's one of those things that just plain isnt worth a whole lot of chat unless a person cant get a grip upon what is going on with the cam and lifter to begin with.   a .842 diameter solid lifter on a 230 duration @ .050 will lift a valve with a 1.5 rocker to .480 lift . use the amc .904 lifter same length as the gm just bigger in diameter with same cam and rocker net valve lift is .515   its worth getting a grip on . The lifter diameter is also taken into account whe a cam designer is figuring the intesity of the flank for another term pressure angle. Anology we back into a parking spot with a 14 inch tired toyota corolla when we roll up against it we drop the clutch car lunges hard up against it and dies due to the small diameter tires pressure angle. Now we back our 16.9/38 tired 40 hp tractor up against it at a idle drop clutch and where over the curb and in the space behind the curb due to the larger tire diameter having a less pressure angle .

Mitch, correct me if I'm wrong, but in the most simple terms what you're saying is in your first example with the small diameter lifter that .480 lift is the maximum the lobe and lifter combo will tolerate before damage. The larger lifter diameter can either lift higher or faster due to the larger contact patch between the cam and lifter. Just like the tractor tire vs car tire. All things being equal, the tractor tire will transfer more energy before spinning out vs. the car tire because the contact patch is larger.  

Butch(OH) wrote: SteveM C/IL wrote: WTF!  Same cam? HUH? No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL

SteveM C/IL wrote: Butch(OH) wrote: SteveM C/IL wrote: WTF!  Same cam? HUH? No different cam this time, same cam before, or was it something else?  Must be some bad 'shine in that part of the world, LOL I'm new to this quoting thing.....Butch your puncuation or lack there of has me even more confused.  Is it " No(comma) different cam this time". Or...." No different cam(meaning same) this time"?

Sorry Steve and everyone else I confused. Mitch deleted two posts that were a pretty outlandish read. The were only up for a couple minutes last night and you probably didn't get a chance to read them before he withdrew them. I posted that before he withdrew them and it was a tongue in cheek poke at his dodging back and forth on the base line facts.

I forget that people here don't know my personality and cant see my face when posting, apologies offered and following explanation offered,

We started out by trying to make the point that given any certain USABLE cam profile /lifter combination that changing lifter to a larger diameter only (again, replete, capitalized ONLY) isn't going to make one little bitty difference in the duration or lift at the valve. He countered that with a post that states a larger lifter would give "X" amount of extra lift based on computer generated numbers. Now I don't need a computer program nor does anyone else with a thinking cap on to know that is BS. I don't care of you set a 55 gallon drum on  top of that cam lobe it isn't going to lift it one little itty bitty bit more than a  sewing needle.  His latest post says I am FOS because the cam grinders say if you enlarge the base circle and lifter diameter it will give the grinder some freedom in is ramps which is absolutely true but not what I am contesting.

If this subject must be turned into rocket science we must separate lift, duration and ramp or acceleration of the valve from seat to open.
Lift and total duration is pretty easy to understand and I wont waste space here to explain them,
 Ramp or acceleration is not as easy but damned important as getting the valve open and closed quickly without creating forces that will destroy the valve train is the goal. I think this is what Mitch is calling "flank" but I don't know? The grinder must also keep the point of contact within the face of the lifter diameter. If it goes past the edge bad things happen quickly. The faster the cam ramps up the further the point of contact travels away from the center of the lifter. This is why a larger lifter gives some freedom to how the cam is ground, it allows for the pint of contact to be further away from the center-line of the lifter. Another way they do it is to reduce the base circle of the cam. So why not just get some huge lifters and smack them like a baseball bat with an aggressive ramp and be happy? Because there are other factors involved too, mainly valve train weights and acceleration rates. You can start and stop that valve train so quickly it destroys itself as fast as you can install new springs, push rods and rockers. Heavy parts and fast accelerations and decelerations  require heavier springs to stay away from valve train destroying float at hi RPMs.

Cam and valve train design is pretty interesting when talked about intelligently. It just isnt as simple as big lifters cure all evils and I guess that is my point off all this rambling.


Edited by Butch(OH) - 08 Feb 2012 at 7:37am

mark vaughn wrote: Do you tractor pull pankey? If so i hope its AC power. I saw the engine you posted pictures  of and it was pretty nice. It takes alot of time to put sleeves in a block like that!

Mark.  Don't let him fool you too.  He has tried pulling but his stuff never runs and blows up after 5 hooks.  Though he will lie, dog around and try to make us think otherwise.  It gets easy to see who knows what and who gets information from the latest magazine at the gas station.

Nascar definitely knows the advantage of larger base circles. wondering though with it being a dodge why the 904lifter wasn't used. Yes I have pulled tractors since 2000 and your right the bore and sleeves takes the same time that it would take to put 4 60 over big blocks out the door.

Lynn Marshall wrote: ALL this tech talk makes me think of this.

The bigger the lifter the more agressive the flank can be designed before exceeding the pressure angle that tends to cock a lifter in the bore . .904 is mopars lifter size . without knowing the engine and seeing the cam why they went to a smaller lifter one could only speculate. However its been proven by cam grinders that will grind the cam flank for the 904 larger diameter lifters  a horsepower increase can be found. In crane cams technical data their roller cam is desinged for a .750 wheel minimum and can be ran with a .800 wheel wich they recomend . In the tech.data they also give the duration change from the bigger lifter at each .100 of valve lift.

Edited by mlpankey - 09 Feb 2012 at 12:49pm