Cams
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Re: Cams
The guy who runs this "site" is pretty good at doing what you need.
http://www.rmcompetition.com
Specialty engine building at its finest.
Specialty engine building at its finest.
Re: Cams
Marking B.S.
What they're marketing as cutting edge, is what we've been doing for decades.
"Low Shock" is their term for an inverse radius design. They don't want anyone to know that, because then you'd know they're 40 years behind.
Since 1979, we have been designing inverse radius cams, that allow for much more area under the curve, and an opening and seating velocity 2-3 times as gentle as normal flat flanked designs. The inverse radius design allows for a slow initial lift rate to take out the lash, and open the valve, then accelerate the valve to max velocity earlier then a flat flanked design, giving more time to slow the valve down towards max lift, to reduce loft. On the closing side it allows for a higher negative acceleration, to allow for a much lower seating velocity of the valve, reducing seat bounce.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Re: Cams
Funny, cuz I only recently read the articles on COMP's LST stuff and some of what they were talking about sounded familiar... So I dug out the measurements I'd taken of some rollers a few years back, one of which was a COMP endurance roller and the other was a Jones Racing Cams grind. It's not meant to be an apples-to-apples comparison of lobes w/ the same general specs (because they're not; the Jones cam is about 5 degrees shorter at .050" and has a little less peak lobe lift), but more of a way to see the differences in design approaches taken at the ramps and lower sections of the lobes
COMP measured w/ .810"-wheel diameter roller lifter: Intake w/ .018" lash (per cam card w/ 1.5 rocker)
Lift Duration Notes
.012 315 Seat duration @ .018" lash
.016 307 SAE duration @ .018" lash (.004" lobe lift above lash); Advertised 298
.020 300
.050 266
.100 232
...
JRC measured w/ .810"-wheel diameter roller lifter: Intake w/ .018" lash (per cam card w/ 1.6 rocker)
Lift Duration Notes
.011 323 Seat duration @ .018" lash
.015 307 SAE duration @ .018" lash (.004" lobe lift above lash); Advertised 308
.020 295
.050 261
.100 229
...
COMP measured w/ .810"-wheel diameter roller lifter: Intake w/ .018" lash (per cam card w/ 1.5 rocker)
Lift Duration Notes
.012 315 Seat duration @ .018" lash
.016 307 SAE duration @ .018" lash (.004" lobe lift above lash); Advertised 298
.020 300
.050 266
.100 232
...
JRC measured w/ .810"-wheel diameter roller lifter: Intake w/ .018" lash (per cam card w/ 1.6 rocker)
Lift Duration Notes
.011 323 Seat duration @ .018" lash
.015 307 SAE duration @ .018" lash (.004" lobe lift above lash); Advertised 308
.020 295
.050 261
.100 229
...
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Re: Cams
Do you know what you need or do you need the design as well as the finished product?
I would suspect there are only a handful of people that would be worthy of that job, and you won’t find them advertising in car magazines.
I would suspect there are only a handful of people that would be worthy of that job, and you won’t find them advertising in car magazines.
Re: Cams
I really have no idea what I need. Probably because this is my first sb2.2 build. It's a pretty good effort, but not a max effort build. It will have 15.5:1 compression. It's gonna run up to 8500 rpm plus, with around a 7500 converter. It'll have 2.18 or 2.20 intake valves. That isn't for certain yet, because we're having trouble finding titanium valves.
I know it will need a nice sized cam with a wider LSA than I'm used to, coming from building 12.5:1 sbc bracket engines for thirty plus years. Sure, I could come up with an intake and exhaust lobe in someone's catalog and guess at an LSA and have decent results, but I want the right cam the first time for the best results for the components I have and for the application.
Looks like Jones Cam Designs is a wise choice for sure.
I know it will need a nice sized cam with a wider LSA than I'm used to, coming from building 12.5:1 sbc bracket engines for thirty plus years. Sure, I could come up with an intake and exhaust lobe in someone's catalog and guess at an LSA and have decent results, but I want the right cam the first time for the best results for the components I have and for the application.
Looks like Jones Cam Designs is a wise choice for sure.
Re: Cams
Goooollllleee (in my best Gomer Pyle voice) that sounds like the Isky 404-A and 505-A cams for Flathead Ford. Must confess I never heard of the 505-A before finding this in the link below, however did order a 404 from T-Willy for a speed shop customer about 55 years ago and had to also rent the Isky jig tool to drill the holes in the block for the 'staples' to guide the lifters so they wouldn't rotate. The Schaller quarter-speed cam was inverse flank too.CamKing wrote: ↑Fri May 07, 2021 10:29 amMarking B.S.
What they're marketing as cutting edge, is what we've been doing for decades.
"Low Shock" is their term for an inverse radius design. They don't want anyone to know that, because then you'd know they're 40 years behind.
Since 1979, we have been designing inverse radius cams, that allow for much more area under the curve, and an opening and seating velocity 2-3 times as gentle as normal flat flanked designs. The inverse radius design allows for a slow initial lift rate to take out the lash, and open the valve, then accelerate the valve to max velocity earlier then a flat flanked design, giving more time to slow the valve down towards max lift, to reduce loft. On the closing side it allows for a higher negative acceleration, to allow for a much lower seating velocity of the valve, reducing seat bounce.
https://www.jalopyjournal.com/forum/thr ... am.148794/
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Re: Cams
I am with Mike J and Walter
Comps mass marketing Technic's from the past was to cover every hot rod and race car publication with their hype technical BS making them sound like they are the kings of the cam world. They are not even close. They do market some good products in the valve train hardware section of their book but I will not ever again use any of there cams when selected others in the industry put out better products that make more power.
Its also about the ability to work with them not listen to a sales man on the other end go a huh a huh a huh then sell something you never needed in the 1st place that does not meet your current required needs.
Just one guys thought
Comps mass marketing Technic's from the past was to cover every hot rod and race car publication with their hype technical BS making them sound like they are the kings of the cam world. They are not even close. They do market some good products in the valve train hardware section of their book but I will not ever again use any of there cams when selected others in the industry put out better products that make more power.
Its also about the ability to work with them not listen to a sales man on the other end go a huh a huh a huh then sell something you never needed in the 1st place that does not meet your current required needs.
Just one guys thought
Real Race Cars Don't Have Doors
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Re: Cams
Certainly not new ...CamKing wrote: ↑Fri May 07, 2021 10:29 amMarking B.S.
What they're marketing as cutting edge, is what we've been doing for decades.
"Low Shock" is their term for an inverse radius design. They don't want anyone to know that, because then you'd know they're 40 years behind.
Since 1979, we have been designing inverse radius cams, that allow for much more area under the curve, and an opening and seating velocity 2-3 times as gentle as normal flat flanked designs. The inverse radius design allows for a slow initial lift rate to take out the lash, and open the valve, then accelerate the valve to max velocity earlier then a flat flanked design, giving more time to slow the valve down towards max lift, to reduce loft. On the closing side it allows for a higher negative acceleration, to allow for a much lower seating velocity of the valve, reducing seat bounce.
I just re-did a "Will St.Clair" 6 cylinder engine which had an inverse radius ground roller cam from 1921.
A whole century ago.
http://www.rmcompetition.com
Specialty engine building at its finest.
Specialty engine building at its finest.
Re: Cams
I just made a set of tool steel cams for a 1912 Packard. The original OEM cams were inverse radius.Walter R. Malik wrote: ↑Sat May 08, 2021 10:50 am
Certainly not new ...
I just re-did a "Will St.Clair" 6 cylinder engine which had an inverse radius ground roller cam from 1921.
A whole century ago.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
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Re: Cams
My impression if Comp’s low shock design came from them grinding a Harold Brookshire Comp design backwards, and it working better.
-Bob
Re: Cams
It wouldn't work better. It would have massive seat bounce.hoffman900 wrote: ↑Sun May 09, 2021 5:30 pm My impression if Comp’s low shock design came from them grinding a Harold Brookshire Comp design backwards, and it working better.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Re: Cams
Gonna send you a cam recommendation form as soon as I find out what size intake valves we have in our sb2.2 heads. Either gonna be 2.18's or 2.20's, whatever we can find first.CamKing wrote: ↑Mon May 10, 2021 11:03 amIt wouldn't work better. It would have massive seat bounce.hoffman900 wrote: ↑Sun May 09, 2021 5:30 pm My impression if Comp’s low shock design came from them grinding a Harold Brookshire Comp design backwards, and it working better.