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Bullet/Ultradyne Cams

General engine tech -- Drag Racing to Circle Track

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RAS
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Bullet/Ultradyne Cams

Post by RAS »

Freinds, do any of you know for certain if Bullet Cams is grinding any of Harold Brookshire's Ultradyne Cams. I understand they may have taken over the line. I was surprised to learn Lunati has the rights to the General Kinetics name. I wonder if Harold had anything to do with that.
Ks Fats
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Re: Bullet/Ultradyne Cams

Post by Ks Fats »

They do have the Ultradyne masters; I haven't personally had one ground from those masters in about 5 years so can't speak for their willingness to grind one now; I don't see why they wouldn't but as you know company policies change according to changes in leadership. Have no idea who the principles are at Bullet now.
hoffman900
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Re: Bullet/Ultradyne Cams

Post by hoffman900 »

Howards has most of the designs Harold did after Ultradyne (during his time at Custom Camshaft Company (Arrington)). Lunati has his last commercially available designs.

The Howards’ Harold’s stuff are all CNC profiles so it would just be a matter of loading it in the machine. You can see them here: https://www.howardscams.com/sites/defau ... 0-2014.pdf (scroll to ‘Harold Brookshire designs’).

The Lunati’s are the TL2 lobe family.

Harold said here himself that he made all the Ultradyne stuff obsolete, YMMV.
-Bob
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Re: Bullet/Ultradyne Cams

Post by F-BIRD'88 »

Yes you can get a Ultradyne cam from Bullet Racing Cams. Nothing obsolete about these.
Lunati shows these cams as "New". "Street strip"
and "new oval" solids etc.
You can find the lobe master specs in the Lunati lobe lists. You can get the off the shelf catalog grinds and any combo and lobe separation custom grind versions
from both Bullet and Lunati.
You can recognize a legacy UDHarold/Ultradyne cam by its (old) part number Eg: 401A6LUN or 401B8LUN
Others with similar part number structure are UDHarolds cams. The popular Lunati VooDoo cams are Harold's designs as well.
You can reference the old Ultradyne online cam catalogs by searching on the Way Back Machine online internet archives web site.
https://archive.org/web/
Remember you are not limited ti just the off the shelf cams.. Custom grinds are there for the asking.
hoffman900
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Re: Bullet/Ultradyne Cams

Post by hoffman900 »

F-BIRD'88 wrote: Sat Jan 15, 2022 2:24 am Yes you can get a Ultradyne cam from Bullet Racing Cams. Nothing obsolete about these.
Lunati shows these cams as "New". "Street strip"
and "new oval" solids etc.
You can find the lobe master specs in the Lunati lobe lists. You can get the off the shelf catalog grinds and any combo and lobe separation custom grind versions
from both Bullet and Lunati.
You can recognize a legacy UDHarold/Ultradyne cam by its (old) part number Eg: 401A6LUN or 401B8LUN
Others with similar part number structure are UDHarolds cams. The popular Lunati VooDoo cams are Harold's designs as well.
You can reference the old Ultradyne online cam catalogs by searching on the Way Back Machine online internet archives web site.
https://archive.org/web/
Remember you are not limited ti just the off the shelf cams.. Custom grinds are there for the asking.

Harold:
I don't make any of the old UltraDyne cams, I have tried to obsolete all of them.
My new family covers from 245* to 291* at .050, and are all 28* major intensity.
To replace the 288/296, I have a 279/287---251/259 at .050, matching the 288/296 at .200 with 176/183, and bigger above.
To better it, I have a 283/291--most popular cam right now--that is 255/263 at .050, with the same offset as the old 288/296, 180/187 at .200.
This family are all at .4163 lobe lift, to be legal in Hooter Cup cars.
I just did a 360 ASCS Sprint Car cam with the 283/291 at .020, 255'263 at .050, and .4544"/.4544" lobe lift. Except for requiring a little more open pressure, it has the same dynamics as the lower-lift version.
I have a 31* major intensity family, with BBC valve lifts of .725", .775", .825", .875", and .925". I use the .725" lift cams in a lot of street cars, as the 31* family close the valve like the old UD 304, which won the 24 Hours of Daytona in the mid-80s. All these cams are dynamically stable at 9300 with normal roller cam pressures.
I do have some .590" lobe lift stuff that take the 400 lb seat, 1400 lb open springs, but they're all 65mm-70mm cores.......

UDHarold
The Lunati TL2 and TR2 are the last lobe families Harold designed:
https://tech.lunatipower.com/new-lunati ... race-cams/

If you do order any them, remember centerlines aren’t going to be like a symmetrical lobe.
-Bob
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Re: Bullet/Ultradyne Cams

Post by 1980RS »

The people at Bullet are great to deal with, get you what ever you want or need.
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Re: Bullet/Ultradyne Cams

Post by F-BIRD'88 »

You are mis interpetating "better" as being solely a shorter seat duration VS .050" duration
and or a bigger .200" duration VS .050" duration.
Making the cam lift curve more and more intense has mechanical costs. More spring force / rpm
More pushrod/ rocker deflection.
Faster cam/lifter/rocker arm wear.
The "older" UD Harold cams make great power
yet last a long time . On a street strip engine or a marine or endurance application this matters.
There is nothing obsolete about these cams.

Those TL2 series solid cams require a better valvespring and valvetrain and will have a shorter service life.
They are intended for RACING. (short term)
For street , street strip, bracket racing the "older" stuff
gives a better mix of performance and service life.
This is true of UDHarolds Street/ Strip solid street roller cams also ( .370" .390" lobe lift).. These make great power and last many miles longer than a all out race roller cam. They run on relative moderate spring force.
This is where many street/bracket guys go wrong, then whine about roller lifter service life.
DON'T use a strictly RACE roller cam on the street.
There is nothing obsolete about these cams.

Pretty much all of UDHarold's cam designs are asymetric fast open - slow close designs.
Use the .050" lifter rise open close events method to verify cam installed phasing.
Not point of max lift.
Harold used to recommend running tighter than cam card valve lash spec on stuff that you want to last longer.
Easier on initial opening (taking up the running lash)
AND easier valve seating allowing the valve more time to slow down and gain stability as it seats.
He knew his stuff and what will work on the street.
Last edited by F-BIRD'88 on Sat Jan 15, 2022 11:11 am, edited 1 time in total.
hoffman900
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Re: Bullet/Ultradyne Cams

Post by hoffman900 »

F-BIRD'88 wrote: Sat Jan 15, 2022 10:59 am You are mis interpetating "better" as being solely a shorter seat duration VS .050" duration
and or a bigger .200" duration VS .050" duration.
Making the cam lift curve more and more intense has mechanical costs. More spring force / rpm
More pushrod/ rocker deflection.
Faster cam/lifter/rocker arm wear.
The "older" UD Harold cams make great power
yet last a long time . On a street strip engine or a marine or endurance application this matters.
There is nothing obsolete about these cams.

Those TL2 series solid cams require a better valvespring and valvetrain and will have a shorter service life.
They are intended for RACING. (short term)
For street , street strip, bracket racing the "older" stuff
gives a better mix of performance and service life.
This is true of UDHarolds Street/ Strip solid street roller cams also ( .370" .390" lobe lift).. These make great power and last many miles longer than a all out race roller cam. They run on relative moderate spring force.
This is where many street/bracket guys go wrong, then whine about roller lifter service life.
There is nothing obsolete about these cams.

Pretty much all of UDHarold's cam designs are asymetric fast open - slow close designs.
Use the .050" lifter rise open close events method to verify cam installed phasing.
Not point of max lift.
I know all of that, I think I've shown that over the years here.

Harold said he got more lobe area with similar or the same dynamics. He improved his math resolution.

I'm not telling you not to use what works for you, but it's probably a disservice to Harold to think his designs stop in like 1990, because he seemed very proud of what he did up through the mid / late 2000s, and Bullet isn't the only place to find his designs.
Last edited by hoffman900 on Sat Jan 15, 2022 11:26 am, edited 1 time in total.
-Bob
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Re: Bullet/Ultradyne Cams

Post by PRH »

A friend of mine had Bullet grind him a UD roller for a BBM a couple of months ago.
No drama.
Somewhat handy with a die grinder.
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Re: Bullet/Ultradyne Cams

Post by Walter R. Malik »

Lunati has "some" but, Bullet has "all" of the Ultra-Dyne profiles. Bullet also bought the rights to the Lazer profiles when Bill Metzger died.
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Re: Bullet/Ultradyne Cams

Post by hoffman900 »

Walter R. Malik wrote: Sat Jan 15, 2022 11:31 am Lunati has "some" but, Bullet has "all" of the Ultra-Dyne profiles. Bullet also bought the rights to the Lazer profiles when Bill Metzger died.
and Howards has all the Arrington era Brookshire stuff as CNC ground profiles. Curious what condition some of those 40yo masters are like at Bullet in that balmy MS air. Dynamics are probably a lot better considering many times they've been polished over the years!
-Bob
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