Ultradyne olds solid roller

[rocketracer380]

Need help figuring out specs on this ultradyne grind where do I start

[CamKing]

Maybe by giving us the part/grind number ?
You could also call Bullet cams, since they bought all the Ultradyne masters.

[F-BIRD'88]

You might use The Wayback Machine site to look up the Old Ultradyne online Cam Catalog.
If its a catalog grind cam you'll find it.

[Elroy]

http://www.bulletcams.com/Masters/ultradynemasters.html

[midnightbluS10]

You might use The Wayback Machine site to look up the Old Ultradyne online Cam Catalog.
If its a catalog grind cam you'll find it.

That's a good idea. Let's see if this works. It should take you straight to Ultradyne's Olds mechanical roller cams as of 2003.

https://web.archive.org/web/20021230170 ... shafts.htm

Below is a link to the entire catalog from 2003, also.

https://web.archive.org/web/20030205002 ... atalog.htm

[BillK]

Not sure what year it is but I have catalog "Volume 8"

[6.50camaro]

The one ultradyne cam I had ,I don't know if it was a bullet made cam or a UD Harold cam had numbers like 287/295 05 on it which were the adv. duration and the LSA of 105 under that was R123 R117 which was the lobe profile number which are listed on the bullet site. Hope this helps . Dan

[Elroy]

I think it would be interesting to hear someone in the know' opinion(s) or analysis on the function and dynamics of the ultradyne lobes. They drew strong feelings back in the day both good and bad. Not sure if said person exists on this forum but there seems to be a wealth of knowledge here. Maybe a new thread..sorry if I derailed.

[n2xlr8n]

I think it would be interesting to hear someone in the know' opinion(s) or analysis on the function and dynamics of the ultradyne lobes. They drew strong feelings back in the day both good and bad. Not sure if said person exists on this forum but there seems to be a wealth of knowledge here. Maybe a new thread..sorry if I derailed.

Do a search for user UDHarold on here, then read everything you can.

We lost a genius when he passed, but there are still gurus here. CamKing is one of them.

[Elroy]

I think it would be interesting to hear someone in the know' opinion(s) or analysis on the function and dynamics of the ultradyne lobes. They drew strong feelings back in the day both good and bad. Not sure if said person exists on this forum but there seems to be a wealth of knowledge here. Maybe a new thread..sorry if I derailed.

Do a search for user UDHarold on here, then read everything you can.

We lost a genius when he passed, but there are still gurus here. CamKing is one of them.

I will do that thanks. I know his cams were well liked by some back in the day 80's 90's and definitely not by others. I would just be very curious how they held up or would hold up "dynamically" to some newer lobe designs. Maybe Camking will comment----that would be interesting.

[CamKing]

I would just be very curious how they held up or would hold up "dynamically" to some newer lobe designs. Maybe Camking will comment----that would be interesting.

IMO, they are harder on the valvetrain then they needed to be.
Harold didn't put a lash ramp on the opening side of the lobe. The lift curve just accelerated right off the base circle. This made for some short seat durations, but caused an extreme amount of force at the opening point of the valve.
When I would talk to Harold about this, he would say "You can float the valve on the opening side".
My comment to him was, "You sure as heck can flex the valvetrain on the opening side, and when that flexed valvetrain starts to straighten back up, it'll loft the valve over the nose, and bounce it off the seat.". This is something you see in Spin-Tron testing all the time. The loft over the nose isn't usually caused by the valve lift curve over the nose, but by the acceleration rates, off the seat.

[midnightbluS10]

I think it would be interesting to hear someone in the know' opinion(s) or analysis on the function and dynamics of the ultradyne lobes. They drew strong feelings back in the day both good and bad. Not sure if said person exists on this forum but there seems to be a wealth of knowledge here. Maybe a new thread..sorry if I derailed.

Do a search for user UDHarold on here, then read everything you can.

We lost a genius when he passed, but there are still gurus here. CamKing is one of them.

I will do that thanks. I know his cams were well liked by some back in the day 80's 90's and definitely not by others. I would just be very curious how they held up or would hold up "dynamically" to some newer lobe designs. Maybe Camking will comment----that would be interesting.

I actually just came across a thread where Harold and others were discussing some things very similar to this, if not exactly. I'll see if I can find it again.

Edit: I think this might be it.

viewtopic.php?t=4793

[Elroy]

I would just be very curious how they held up or would hold up "dynamically" to some newer lobe designs. Maybe Camking will comment----that would be interesting.

IMO, they are harder on the valvetrain then they needed to be.
Harold didn't put a lash ramp on the opening side of the lobe. The lift curve just accelerated right off the base circle. This made for some short seat durations, but caused an extreme amount of force at the opening point of the valve.
When I would talk to Harold about this, he would say "You can float the valve on the opening side".
My comment to him was, "You sure as heck can flex the valvetrain on the opening side, and when that flexed valvetrain starts to straighten back up, it'll loft the valve over the nose, and bounce it off the seat.". This is something you see in Spin-Tron testing all the time. The loft over the nose isn't usually caused by the valve lift curve over the nose, but by the acceleration rates, off the seat.

Wouldn't that create some extreme violence if the lash got away from ya some? That seems like a somewhat artificial means of arriving at a shorter seat duration. How about the nose shape, asymmetry and other criteria? Anything you could add on that?

I know that the old Ultradyne literature always preached about how they claimed to be the only one's doing asymmetrical designs but I had witnessed non-symmetrical cam lobes from other suppliers while this was being claimed from UD. Maybe they were the first, and others followed and I just came into the industry late in relation to those events. Not sure. I'm thinking that subject contains some interesting history and disputes.

An extremely fast opening ramp during the time of much less rigid valvetrains than today. Their just wasn't as much knowledge or parts access back then in regards to valvetrain...possibly that is where the love-hate relationship I remember came from with UD. It either worked great or was a disaster.

[CamKing]

Wouldn't that create some extreme violence if the lash got away from ya some? That seems like a somewhat artificial means of arriving at a shorter seat duration. How about the nose shape, asymmetry and other criteria? Anything you could add on that?

I know that the old Ultradyne literature always preached about how they claimed to be the only one's doing asymmetrical designs but I had witnessed non-symmetrical cam lobes from other suppliers while this was being claimed from UD. Maybe they were the first, and others followed and I just came into the industry late in relation to those events. Not sure. I'm thinking that contain some interesting history and disputes.

An extremely fast opening ramp during the time of much less rigid valvetrains than today. Their just wasn't as much knowledge or parts access back then in regards to valvetrain...possibly that is where the love-hate relationship I remember came from with UD. It either worked great or was a disaster.

There's been asymmetrical cams, longer then I've been alive. Harold called his "Un-symmetrical". I studied his cams a lot, because he was really our only competitor. No one else was even close to what we were doing. If you looked at Harolds cams, they were symmetrical from about .050" on up. Below .050" on the closing side, they slowed down and had a normal lash ramp. On the opening side, they accelerated quickly, right off the base circle. The velocity at the lash point was about 4 times higher then what our similar sized designs were. I think the reason some people had issues with his designs, was all related to the stiffness of their valvetrain. Back in the 80's, no one had the money to spend time on the Op-Tron(predecessor to the Spin-Tron), and people were still under the misconception, that lightweight pushrods were a good thing.

BTW, it was because of Harolds "Un-symmetyrical" designs, I no longer look at max lift, as the lobe centerline.
When my customers were testing a UD cam to one of mine, and both cams were about the same from .050" up, and on the closing side, but mine was longer before .050" on the opening side, the UD cam always wanted the max lift to be earlier then mine did. They would move them all around in testing, and using Max lift as the centerline, the UD cams always wanted to be on a tighter ICL. This got me thinking, because the cams were pretty close above .050". The only big difference was the intake opening point. After sitting down, and calculating where the valves were actually opening and closing, I found out that if I used the mid-point between the opening point and the closing point as the cam's centerline, the UD cams were on the same ICL as mine.

[PRH]

We used quite a few UD cams from about 89 until they were more or less “closed”.

I was pretty happy with the results we got from quite a few of them.