Anyone using a half-speed camshaft on a flathead??

I found an old double lobe, half-speed flathead camshaft in my collection of parts. Is anyone using one? Pros and cons??

Dan Marvin, Owner
Exeter Auto Supply

 

we need pics ASAP....

 

Is this one of the old Schaller quarter-speed cams ??

There were a few articles in Hot Rod in the early sixties about these, mainly talking about the SBC version.

From memory, the complete kit had a special timing setup, distributor drive and lifters to make it all work correctly.

 

Found some online info ...

http://www.my-creative.com/SchallerCams/Schaller stories.htm

 

Schaller 1/4 speed. I have the original 1963 Hot Rod article. 63 Hot Rod Annual

 

So what exactly did these double lobe cams do?

 

Not sure what the article says, but I supposed a cam running at half speed (one quarter the RPM of the crank) would be a little easier on the valvetrain, maybe made it possible to have a more aggressive lobe profile. The cam simply had twice the number of lobes, with the lobes for each valve being 180 degrees from each other.

 

A 1/4 speed cam allows the cam to run slower for the same pattern and so lighter springs can be used and lift rates per degree can be higher. I cant help butwonder now that springs can be had that will stand almost anything it may now be a loot point but back then it was not so. They even fielded an indy car with such a cam. I think Mickey t was involved in that effort. Schaller I seem to remember has something to do with Rislone additive too.

 

neato mindset

 

That seems to leave out the fact that the valves are still opening each intake and exhaust stroke, so how does this change anything. It seems that the lift rate would remain the same for a given profile, or am I missing something here?

 

I still don't see how this is supposed to work. Is the cam turning slower?

 

The cam is turning at half speed (compared to conventional) but the rest of the valve train is still experiencing the same cycle motion as a standard cam. It was one of those "better" ideas that turned out to not be better. You can be assured if there was any REAL benefit the rest of the industry would have lined up and used it.

Frank

 

Here is a little more info,,

http://www.hotrodders.com/forum/some-fun-technology-old-days-63413.html?

Lars

 

The cam is turning at half the speed so the valves are opening at the right time. If it were spinning at normal speed then you would have in. and ex. valves opening at the same time.

 

Dang fab32 beat me to it!

 

It was one of those "better" ideas that turned out to not be better.

Yup - part of a very long list.

 

My point exactly.

 

Maybe you should read the original article Apparently some benifit was realized. I read an interview with former founder of Cam Dynamcs when he talked about how cam design or ramps could make huge differences in what a valve spring would handle. Remember this is the guy who gave drag racing the 7000 RPM cheater stocker camshafts that would run 7000 on stock spec springs. Cams still have a lot of secrets. The Schaller 1/4 speed cam article (Hot Rod Annual 1963 about the mdle of the book) said a chevy would rev 8000 with stock style springs. Anyway i am just answering the question not promoting the idea. One thing though I do take very strong exception to is ""If there was any real benifit you can be rest assured the industry would already etc etc."" DONT think like that. I have disproved this so many times in my career. The status quo has for the most part nothing to do with what else might work. People are resistant to change, even me. Having tried a lot of different things I have discovered it just aint so. Sometimes the industry is just lazy. Sometimes engineers lack creativity.
Thomas Edison who was conceived in Canada and born in the USA once said ""Inventions are made by people who are too stupid to know they ""wont work""
There is a lot more to that statement than meets the eye.

 

I totally agree with you. I see it everyday at work... some process or invention has been created that would make things run smoother and work faster, but the red tape gets in the way. It'll cost too much... it'll take too long to re-train people etc.

Auto manufacturers are out for one thing. That is to make money. If a special cam made 25% more horsepower, but cost 50% more to make X a million units... what do you think they're going to go with? lol...

Good ol' business... how I hate thee...

On the other hand, if this cam really was great and made a noticeable increase, the after market would've embraced it. Even if it was more expensive. Interesting idea though. I like this type of automotive creativity.

 

Well, the 1/2 speed oilpump would take less power to drive (though, i don't remember that being a concern 'till 'bout '90, or so)
The tappet/lobe pressure must've been ferocious!
I think i'd relegate it to the 'conversation piece' collection.

 

Me I would like to try a constant speed oil pump. (Perhaps electric.) Life is so short it is hard to try all. No cavitaion, no pumping huge amounts of oil only to blow it out the pressure relief hole. Just a steady cool flow of solid slippery oil pumping continuously into the oil galleries.
Don

 

Comparing identical profiles, the half speed cam would have reduced friction from the lower velocity. Interesting idea. But the gains are so low that it’s basically not worth it. Modern roller lifters have substantially reduced the already small friction from the cam. There is no gain to be found here. The majority of energy loss (and efficiency loss) inside an engine comes from the inelastic collisions that occur every time the pistons and rods change direction and the low thermodynamic efficiency (maybe 50% at best).

 

The claimed benefits were indeed geometrical, ramps allowing less violent action, less wear, better following of radical profiles, etc. I have some of the articles out where I can find them---will try to locate. I think the guy got started on Harleys!
The FIRST big problem for it was that it really needed an engine designe for it...the cam drive, geared up distributor drive, and such made it too complex and expensive as an adaptation. I'm not sure howinhell it would be driven on a flathead, and of course speeding up the pump would be virtually impossible, unlike SBC where the distributor can do that part. Theink about distributor drive on a FH, too!

 

http://www.google.com/advanced_patent_search is Google patents...couldn't find anything, either under Schaller or using descriptive words... surely there are patents. Anybody have any parts with numbers or any clues on chasing this down?

 

Just when ya think you've seen/read it all , something like this pops up.

I have a built 304 cubic inch flatty with a 404 - A Isky radius lifter cam in it . This is the type that all lifter bores are drilled and pinned so they don't walk. I am wondering if i can try to run this on the street? Anyone ?

 

I'll try to post some pics of the camshaft tomorrow.

 

Ninth place finish in 1963 Indy. Car was fielded by Mickey Thompson and driven by Al Miller and sponsored by Harvey Aluminum. Article was by Don Fransico. Lots of us are old enough to remember that car and those people. I tried to photograph it but dont have a photo editor on this computer. If someone does I think even the text would be readable if darkened and constrasted if they would be so kind as to give it a try.
You know The fact the MT thought it reasonable and that it had a 9nth place finish at Indy with FINISH being the central word makes me wonder if we should be a bit hesitant poo pooing it completely. While i am skeptical about a lot of things sucess even partial sucess is hard to argue with. The fact that the car finished in the top tenand that it dd finish is pretty significant. I also agree to a cerain extent that since that time things have improved dramatically as far as lifters rollers etc go still we have BB race engines running 700+ PSI spring spressure open and you dont push that open with nothing.
Don

 

these are better

 

Amazing! It takes the same ramp acceleration to get the valve up and down, it takes the same horsepower to drive the valve, it takes the same valve spring pressures to get the valve closed, and it takes the same horse power to drive the cam!

You would have less wear on the cam gear, and more wear on the crank gear. and the cam and crank gears could be less strong as the forces on the cam gear are divided by two.

The forces necessary to spin a cam at 5,000 rpm is the same whether it is a 1/2 drive or 1/4 drive. As the forces resisting the cam do not change depending on the type of drive.

Confusing enough?

traderjack