Roller Cam and Lifters

[John]

Flash you might find this CNC link interesting as related to our discussion
http://www.cnczone.com/forums/showthread.php?t=41786
John

[Flash]

Flash you might find this CNC link interesting as related to our discussion
http://www.cnczone.com/forums/showthread.php?t=41786
John

John, thanks for the link........Vary good Read!!!!!

Flash.

[tirod]

I feel his pain- but imagineering his own cam profile? I believe his results will be not much better than if he hand filed the lobes. And its a four cam motor.

For the price quoted, I wonder if maybe Lunati couldn't grind a existing pattern for a AMC roller on the 4.0 cam, something along the lines of a RV grind. What's nice about strokers is that they can tolerate an incremental increase in duration, so it could spec out more than just for stump pulling.

[Flash]

So why don't they just heat treat our flat tappet cam and then there wouldn't be a problem with cams going flat??????????

or would it just cause the lifter to ware faster do metal differences???????

And what if they were to heat treat or Nitriding SIXPAK cam, would it have last it longer????????

Flash

The proferal grey iron is flame hardened for "heat treat", then parco lubrite treated. Of course we will have to keep it properly lubricated. We do really high shear wear to oil films at low rpm's and worst at start up. Zinc/phosphorous and high shear oil film strength.
The SIXPACK camshaft failure seems due to several things, he pointed out collision points with the base circle, less than choice parent material to run on a 52-55 RC roller, modification of surface hardening depth with unknown to me, follow up surface treatment. I think the life could have been extended, but the outcome would have eventually occurred.
John

John, i guess the real question here is, how long our stock cam with a special treatment and a roller designed would with same done to the roller(to keep simile materials waring agence each other )lifters.........How long would it last.........To bad SIXPACK has given up on the roller cam.......due to rule changes.

Having one of theses coating or treatment to one of his cams would definitely give us a much better life expectancy.

Even if we could get one of these iron/mod-to-roller decide to last 6 mounts.......It could sure give us some Dyno number(Real World) to compare and now whether the roller seen was worth it before we spend 1,300+ on a long life roller cam.

Flash

[John]

A quality roller profile selected for the regrind
Nitride the camshaft after regrind, polish
Quality roller lifters without chroming on the roller (too hard)
Lots of zinc/phosphorous oil

A few hours on a dyno, the parent metal of the cam materials will finally succumb.
John

[John]

The spring pressures for the rollers start around 135 and go up.....
You could daily drive one for a while, start serious testing and its life would be short.
John

[Flash]

The spring pressures for the rollers start around 135 and go up.....
You could daily drive one for a while, start serious testing and its life would be short.
John

so, in you opinion, even a small roller cam, say...............280 duration (seat to seat spec).450" lift with a short overlap.......Would still need 135 seat pressure? Or even a stock HO lift of .430 lift with more duration....... say, 260*




Flash

[John]

You might get by with a lower spring pressure, but what occurs is the increased mass of the roller lifter and inertia, bounce your valve train, really starts pounding your valve seats even on less aggressive grinds. Then the lifter lands again on your camshaft leaving chatter marks that wear awfully fast. If your Aunt Sadie drove it, it would last longer than if You or I drove it. RPMs, hard accel & decel....... I don't know just where the line in the sand for this would occur, A guess...125-128 psi seat on our motors.
John

[Flash]

You might get by with a lower spring pressure, but what occurs is the increased mass of the roller lifter and inertia, bounce your valve train, really starts pounding your valve seats even on less aggressive grinds. Then the lifter lands again on your camshaft leaving chatter marks that wear awfully fast. If your Aunt Sadie drove it, it would last longer than if You or I drove it. RPMs, hard accel & decel....... I don't know just where the line in the sand for this would occur, A guess...125-128 psi seat on our motors.
John

A Yeah, wasn't thinking of the extra weight of the roller lifter, as well as the much faster speed, the roller ramp will create.

And what good is a cam if ya can't flog the snot out of it ones in awhile

So I guess we're in a catch twenty-two here. More lift, and less duration would have a better chance of keeping the roller lifter on it lobe as more lift would create more spring pressure(as compared to a short lift long duration that could throw the lifter up and off the lobe at max lift)

Were as more spring pressure would cure the lifters "ski jump" affect.......but now will fail, do to excessive pressure's again, on a stock cast cam core.
look like this idea won't work, even on paper

[1bolt]

what I don't get is if a normal roller is just a heat treated cast iron cam, then why do we need a custom blank to grind the roller out of? Why can't we just get a custom roller grind heat treated? $800-900 dollars is a lot for a grind on a custom blank.

I still think there's merit to the idea of getting the cam CNC machined.

Did anyone ever explore the possibility of using a roller blank from another I6 engine?

It's really Hard for me to believe that the only solution costs nearly a grand...

The reason the Roto-phase blank never got off the ground, is that the entry cost needs to be cut in half (at least) before anyone will start taking it seriously. As it stands did anyone at all step up and comit to a blank?

[Flash]

I will comment on all of that when i get a momet..........the only cast iron roller cam are those, like Sixpack that know there life will be vary short, warned by the grinder before starting.

All roller cams are a.......what called a carbonized steel or billet. blanks

Flash

[Flash]

what I don't get is if a normal roller is just a heat treated cast iron cam,(It's not) then why do we need a custom blank to grind the roller out of? Why can't we just get a custom roller grind heat treated? $800-900 dollars is a lot for a grind on a custom blank.
Yeah thats what i was taking to John about......Hoping that having a cast crank heat treated or one of these fancy coating put on it......would be cheaper then getting a bar of billet and then making round lobe.......then turning them into actual lobes.....Cutting a Gear in it exc.....but it seam that it would fail in a short time, just like Sixpacks(all tho his wasn't heat threated or had one of those fancy coatings)
I still think there's merit to the idea of getting the cam CNC machined.
Elaborate a little on this,.........as i don't understand the difference between CNC and grinding a cam

Did anyone ever explore the possibility of using a roller blank from another I6 engine?

It's really Hard for me to believe that the only solution costs nearly a grand...
It cost's over a grand ($1,300-$1,400) for the final product!!!!
The reason the Roto-phase blank never got off the ground, is that the entry cost needs to be cut in half (at least) before anyone will start taking it seriously. As it stands did anyone at all step up and committed to a blank?

"Did anyone ever explore the possibility of using a roller blank from another I6 engine?"................. do you mean a different brand of i6........

I agree that if we could cut the price in half.......IT WOULD FLY but i don't know how to make that happen.

As far as people ready to step up to the plate YES! WE NEED 6 TO START THE PROSES.............and at the time we had a guy by the name of Mark, Delk, George T and Bill H
All were willing to buy one..........some could only afford the get the blank done and then would have had to save up for the rest.........but they were ready!!!!!!! what killed it was there wasn't "6" and the thought of the price going any high for a lower number of blanks produce.....WAS TO MUCH!!!!!
I contacted Joe to see if he would make a run of them with less then six.......he was willing to make one if that was necessary but would be a lot more. he said that he would figure it up and get back to me...............the plan that was hanging on by a thread..............................................................................collapsed

[1bolt]

Roto phase is going to cast a long special cam blank and hand machine a dist. gear fuel pump eccentric and round lobes that then need to be ground by someone else because Joe doesn't do grinds.

CNC machining is basically taking a length of billet nothing custom about it. in this case high carbon steel if that's what a roller needs, and having a computer controlled cutter (lathe or multi axis robotic mill) cut out a complete finished cam with the desired grind. Because it's a computer and it works from a CAD drawing there's no special super duper 50 years of experience $125 dollar an hour hand made custom race guy Joe "roto phase" premium.

Joe is a guy who fixes expensive race car problems, he's the one guy who "can do it" but he's also the last guy a Jeeper wants to do it because he comes with a steep labor rate.

The difference might be considerable.... model a cam in 3d and any CNC equipped machine shop could potentially carve one up for you. Now all that said I have no idea if an average CNC mill can do helix cut gears...

[Flash]

Aw OK, i see..............You really got my hope up for a split sec, with your first paragraph. as it sounded like you had called roto- phaze and was having a single cam blank in progress............then i realized it was a comparison

So who does CNC cam design?..........wonder what it would cost.

Flash

[gradon]

For me it seemed odd that a person could make a cam blank but couldn't grind a cam. I would've considered a $400-600 roller cam w/lifters but nothing like the $1200-1400 that it was after the grind. There has got to be a person out there who can do this for a lot less if only he knew of the demand and parameters.