Custom roller rockers

[Reeves]

lookin for a upgrade for shaft rocker arms?????[/

You have info on this?

[Directconnection]

If you change the location of the roller that touches the cam you may change the rocker ratio, but you will also change the degree-in of the cam.

Think about it, the cam is now touching the roller in a different spot, it has to turn to a different spot to be at the same point on the lobe.

Exactly.... and if you change the diameter of the wheel, too. Then, you'll totally mess of your cam's profile and valve timing events and need a special designed cam just for the new rocker's geometries.

[zin]

Exactly.... and if you change the diameter of the wheel, too. Then, you'll totally mess of your cam's profile and valve timing events and need a special designed cam just for the new rocker's geometries.

I have to disagree, if I'm reading you right...

If the wheel is simply larger, it's effect would be limited to how quick the lobe reacts with the rocker, making the cam faster acting, but not changing the phasing as their respective contact points don't change, same for rocker ratio, so long as the center-lines of the roller/cam/lifter are the same, the ratio stays the same too.

I'll admit, a given cam with an aggressive ramp might require a redesign to be compatible (no metal parts crashing into each other), and definitely to maintain the valve action of that cam, due to the fact the roller will contact the ramp sooner and run up it quicker, effectively changing the duration a bit depending on how much larger the diameter of the roller is made. I haven't seen too many cams used in our engines who's ramps are aggressive enough to become unusable... Though they certainly would act "bigger".

Mike

[turbovanman²]

lookin for a upgrade for shaft rocker arms?????[/

For what?

[Directconnection]

I haven't seen too many cams used in our engines who's ramps are aggressive enough to become unusable... Though they certainly would act "bigger".

Mike

Just remember that bigger isn't always better

[turbovanman²]

Just remember that bigger isn't always better

Says who?

[zin]

Just remember that bigger isn't always better

No doubt! Can't just go to the bottom of the page in the cam book! That said, the larger roller would seem to "wake up" a mild cam with no other mods... Except maybe some better springs!

Mike

[Directconnection]

No doubt! Can't just go to the bottom of the page in the cam book! That said, the larger roller would seem to "wake up" a mild cam with no other mods... Except maybe some better springs!

Mike

I agree.... and it appears that it would "seem" to wake things up.... but I also think there's got to be some downsides by using the larger roller on a profile designed for the smaller one. Less roller rpms would be one benefit along with accelerated lift and timing events on the front and lengthened events on the backside of the lobe. But as you know, a cam is a very technical thing to create. I think for most purposes... it may be a good thing... but then again, it probably would be engineered into the profile in the 1st place if it was.

I talked about this with my cam grinder last fall, as he was telling me that the roller wheel on the T-III is too small for the cam. And, to back his opinion up.... the rocker assembly I sent him had evidence of the wheel "skating" across the lobe (wheel is too small for profile which induces this effect) This *may* be one of the reasons why the T-III lobes "flake" as I've seen this same flaking in a 3.5 OHC Intrepid V-6. He told me that I shouldn't just use a larger roller (if I was so inclined) as the cam needs to be totally re-designed for that wheel's geometry.

Larger roller vs. larger lifter analogy: I forget the name of the cam company, but many guys here on TM that also delve into the 440 Chryslers may have remembered the cam company that had claims of "Real Chrysler Cams, Not Chevrolet Re-grinds" That was a stab at the other cam grinders on the market that took BB Chevy profiles and ground them for the RB Chrysler. The Chevrolet uses a smaller lifter vs. the Mopar, and the larger lifter diameter is a major PLUS as you can now re-design the cam to give you more aggressive ramping as it's easier for the larger diameter follower (ie: lifter) to do.

[puppet]

Don't the T3's have issues with the needle bearings breaking down as well? Maybe a roller along the newer 'isky" design ... solid bushed bearing?

[zin]

I talked about this with my cam grinder last fall, as he was telling me that the roller wheel on the T-III is too small for the cam. And, to back his opinion up.... the rocker assembly I sent him had evidence of the wheel "skating" across the lobe (wheel is too small for profile which induces this effect) This *may* be one of the reasons why the T-III lobes "flake" as I've seen this same flaking in a 3.5 OHC Intrepid V-6. He told me that I shouldn't just use a larger roller (if I was so inclined) as the cam needs to be totally re-designed for that wheel's geometry.

No doubt this would be the way to go, the ONLY way to go if you wanted/needed to maintain the manners of the cam as installed before the larger roller.

In the extreme I could see an "inverse flank" kind of a situation. That would equal high side loads on the rocker/lifter, possibly spitting the rocker out... I think it would be fun to play with one to see how it would affect the "standard" cams offered for our engines... Though I'll agree, not the "right way" to do it!

Mike

[Directconnection]

Don't the T3's have issues with the needle bearings breaking down as well? Maybe a roller along the newer 'isky" design ... solid bushed bearing?

I have a few spares and a couple have issues with the pins. One pin is almost totally worked out of the side, and another pin has about .010 play in one end vs having a press fit.

It's funny... on an 8v, if the roller poops the bed, no real biggy... but it's different on the T-III.

[puppet]

Been lucky to never have a roller go out on an 8v'er yet. The worst part of the follower to me is the contact point with the valve stem tip. An improvement in that area would certainly be nice.

[puppet]

http://www.schaeffler.com/remotemedi...in_Comp_en.pdf
http://www.gtisoft.com/archive/confa...N-Cosworth.pdf

Found a couple very nice papers on wear characteristic and overall valve train geometry.
One link outlines the cam phasing options that related to another thread we had going here ... that section is for zin

[zin]

One link outlines the cam phasing options that related to another thread we had going here ... that section is for zin

Looks like mostly stuff I already know, but it's that bit that you don't know that really matters!

And it looks like it is very well done, I like the illustrations, they tend to clarify things much better than just the text.

Thanks!

Mike

[puppet]

Looks like mostly stuff I already know, but it's that bit that you don't know that really matters!

And it looks like it is very well done, I like the illustrations, they tend to clarify things much better than just the text.

Thanks!

Mike

I thought about you when I came to the VVT section in the Schaeffler pdf Mike. You were talking about that unit you snagged a few weeks ago. Thought that section might interest you in particular.

[puppet]

It occurred to me that a helpful modification to the 8v finger follower might be a simple counter bored hole over the valve stem ... a little like the oiling hole done on a rods small end for wrist pin oiling.

The finger follower shrouds the valve tip as it is now. Probably little to no splash lubrication gets to that spot ... the roller is rotating ccw throwing oil in the wrong direction for underside oiling of the tip .. but not for a top hole. The hole should be just on the outside edge of the valve stem tip, opposite the camshaft and shaped like an hourglass in section. As the valves opens the hole will move over the stems center. Between duration events, the valve tip should then see some oil.

[zin]

I thought about you when I came to the VVT section in the Schaeffler pdf Mike. You were talking about that unit you snagged a few weeks ago. Thought that section might interest you in particular.

You'd be right! AND, it so happens it covers the exact style of unit I have! I now know how they are controlling it! Pretty simple really, but might still prove a challenge to implement it... BUT, one step closer!

Mike

---------- Post added at 12:09 PM ---------- Previous post was at 12:05 PM ----------

It occurred to me that a helpful modification to the 8v finger follower might be a simple counter bored hole over the valve stem ...

If there you develop an excessive wear issue, either with the valve or the follower, I'd say do it and maybe even add a mini scraper to peel the oil off the roller and direct it to the tip/hole...

Even better? A roller tip follower! They don't need the oil so much and lessens friction (granted, not that much)...

Its been suggested that I take a look at the Ford modular followers as a possibility...

Mike

[karlak]

.

I forget the name of the cam company, but many guys here on TM that also delve into the 440 Chryslers may have remembered the cam company that had claims of "Real Chrysler Cams, Not Chevrolet Re-grinds"

Would that be Hughes. http://www.hughesengines.com/Index/index.php

[puppet]

If there you develop an excessive wear issue, either with the valve or the follower, I'd say do it and maybe even add a mini scraper to peel the oil off the roller and direct it to the tip/hole...

Even better? A roller tip follower! They don't need the oil so much and lessens friction (granted, not that much)...

Its been suggested that I take a look at the Ford modular followers as a possibility...

Mike

Stem tip scuffing can get pretty bad on the 8v. I know a roller would be nice .. too bad that would mean developing another follower.

[Warren Stramer]

It occurred to me that a helpful modification to the 8v finger follower might be a simple counter bored hole over the valve stem ... a little like the oiling hole done on a rods small end for wrist pin oiling.

The finger follower shrouds the valve tip as it is now. Probably little to no splash lubrication gets to that spot ... the roller is rotating ccw throwing oil in the wrong direction for underside oiling of the tip .. but not for a top hole. The hole should be just on the outside edge of the valve stem tip, opposite the camshaft and shaped like an hourglass in section. As the valves opens the hole will move over the stems center. Between duration events, the valve tip should then see some oil.

I think that would be a great idea..........Look very close you will see its been done. Drilled the lash caps too.