James Reeves - Reeves Racing
World's Fastest 8 Valve - 146.88 mph
86 GLH-T 9.99 at 143.78 mph
86 GLHS #169 Mom's - complete Super 60 car
87 Shelby Z 14.16 Dad's - mostly stock, no sh*t!
88 Shelby Z 13.5 - been in storage for 15 years
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Originally Posted by 22mopar
Steve
'90 VNT competition package Shadow - T-III SC6262 conversion/restoration
'91 Spirit R/T - white
'91 Spirit R/T - white
'92 IROC R/T - red
'67 Barracuda 273 now, 440/727 awaits....
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
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry
Bad laws are the worst sort of tyranny.
- Edmund Burke
1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
2004 GSW TDI, 5 speed, fully loaded, modified.
Aurora ignition wires for sale. Link to info
Super60 roller cams or custom/billet cams. Link to info
Originally Posted by 22mopar
Steve
'90 VNT competition package Shadow - T-III SC6262 conversion/restoration
'91 Spirit R/T - white
'91 Spirit R/T - white
'92 IROC R/T - red
'67 Barracuda 273 now, 440/727 awaits....
1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
2004 GSW TDI, 5 speed, fully loaded, modified.
Aurora ignition wires for sale. Link to info
Super60 roller cams or custom/billet cams. Link to info
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry
Bad laws are the worst sort of tyranny.
- Edmund Burke
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.
Originally Posted by 22mopar
Steve
'90 VNT competition package Shadow - T-III SC6262 conversion/restoration
'91 Spirit R/T - white
'91 Spirit R/T - white
'92 IROC R/T - red
'67 Barracuda 273 now, 440/727 awaits....
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?
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
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry
Bad laws are the worst sort of tyranny.
- Edmund Burke
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.
Originally Posted by 22mopar
Steve
'90 VNT competition package Shadow - T-III SC6262 conversion/restoration
'91 Spirit R/T - white
'91 Spirit R/T - white
'92 IROC R/T - red
'67 Barracuda 273 now, 440/727 awaits....
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.
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
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry
Bad laws are the worst sort of tyranny.
- Edmund Burke
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.
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 ----------
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
"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests." - Patrick Henry
Bad laws are the worst sort of tyranny.
- Edmund Burke
Would that be Hughes. http://www.hughesengines.com/Index/index.php