L6 roller rockers ...

[JMortensen]

Mack is still running a stock cam. I think they're symmetrical, or closer to it than an aftermarket cam...

[jeffp]

After re reading your last sentence a couple of times, I think I was able to interpret your point and understood it as follows...

The roller bearings, by design and function, will allow the two moving parts to function with one another, (as compared to the flat wiping surface of say Datsun L-series tappets), at given loads with less heat being developed even with the roller bearings smaller overall contact area, and as such there is, overall, less heat generated which reduces the demands made on the oiling system overall. Did that make sense? If that is what you said, yes, I agree 100%.

 

So with the reduced heat, and friction being applied to the entire rotating assembly of the topend, one then can create a new design and operation Characteristic of the overall performance of the camshaft in relation to opening closing the valve.

The opening event then can be much more agressive, that will yield the engine increased flow per degree of piston orientation, or pisition to Top Dead Center on the intake stroke. This will in effect increase the cylinder filling of the desired air/fuel mixture. This will also increase the volumetric efficiency of the engine as the pumping action of the piston, and the inertia of the incoming air/fuel will aid filling as the pressure differential between the cylinder and outside air equilizes. Now just as the inertia of the incoming charge gets to or beyond the pressure of the outside world, hopefully greater then the pressure outside, the valve then SLAMS shut to capture the excessive filling and reverse pressure differential (more pressure in the cylinder then the outside world). What you have now done is to increase the efficiency of the pump, much in the same way that a tunnel ram does on say a SB ford or chevy, this is very good.

The exhaust pumping action then reacts very similar, only what you then do there is take advantage of the exhaust gases excaping at an accellerated rate because of the very fast ramp of the valve opening. So what this then enables you to do is to open the valve very fast, expell the spent gases at a faster rate, and then GET THIS, slam the valve shut so that you can run LESS overlap on the intake/exhaust valve that will promote an LONGER BURN of the air/fuel mixture in the cylinder. So with the longer burn time, more energy then is spent with the concern of pushing the piston back down the cylinder for a longer period, measured in degrees. MORE power for the same amount of FUEL/AIR for an overall gain in again efficiency, better power, better fuel economy, LESS emissions.

So in in closing what you are doing is to increase torque, increase fuel economy, decrease emissions utilizing the same quantities of air/fuel, and infact you use less fuel/air to obtain the same amount of power. Decreasing the friction, that then decreases heat, and that is what enables you to increase the ramp time of the opening and closing of the valve to a higher rate to MAINTAIN the same constant of the factors involved.

You improve the pump, and aint that what all of us want to accomplish by building "performance" in the first place?

[Tony D]

The funny thing is the Rotary Valve People were not interesting in building a head for a Z-Car, nor with converting an existing example. They are hellbent for election on converting every metropolitan Diesel Bus in the country into a CNG Burning Rotary-Valved powerplant, and simply don't have time for us Hobby-Guys with some coin to experiment...

 

The DEVAS people, on the other hand, more that happily provided a quote, and given the tradeoffs between using a preexisting head, and retrofitting the actuators to it, or redesigning the whole head to use the rotary valves, the retention of current technology is somewhat more palatable as the rotary valve scheme is still fixed and static with regards to the power you get from the thing---the Variable Aspects of the DEVAS system and it's ability to retrofit to the existing cylinder head makes for an interesting conversion. The shutter system you discussed IS EXACTLY what the DEVAS system can do with the EXISTING poppet valves! There really is no reason for a throttle valve when you can control lift, opening time, duration, and rate of opening!

 

Even more interesting is the possibility of using a Modular Headed KA-24 conversion with the DEVAS system giving us better port flow, as well as a crossflow head without the hassle of re-lineboring the cams after sweatbrazing the head sections together....

 

But we digress.

 

BTW, the Aspin Rotary Valve is a very old concept, still 20th century....

 

Computer controlled vavles on a pseudo-desmodromic valve arrangement is a modern application of an 18th century idea.

 

Get RID of the cam! (insert photo of red circle with line through it superimposed over camshaft)

 

http://www.profuelmanager.com/camless.html

[jeffp]

I got to talking about my new Accel coil today with a few engineering buddy's at work and wanted their take on the size of the part in comparison to the electrical specifications. The convential coil configuration would dictate a much larger part then the part I have. We talked about how it would be possible to make a coil with it's electrical properties in this size. Ok so where is this going, well Karl and I got to talking about coils and a design that AGAIN was developed a few hundred years ago by Tesla, now aint that interesting. We went through a configuration of a coil that would literally knock the crap out of you, have much more efficiency then the standard coil configuration. Very col stuff, very cool indeed.

Then I thought, well Tony has been harping on the concept of electrically controlling an engine and you know who I am speaking of. So I posed my thoughts to Karl on the matter, and since the new coil design is so much more efficient in regard to the delta factors. I felt that a relay configured the same way would be much more efficient in opening and closing a plunger, and not only that it would be able to handle a heavier mass because of the electromagnetic properties would also follow the response time to actuate a plunger.

Now Karl's little brain is going right to town on that idea, and in fact has alreday come up with a design that he believes will have that abilities to control something like the weight of a valve, along with a return spring, in the event of loss of power to the coil, that would slam the valve shut, you know avoid hitting a piston. So Karl is getting some materials to test his design, so we will see here in short order what he comes up with. He thanked me for being such an ******* to mention the possibilities of electronically operating a valve in this fashion and how that then could be applied to the internal combustion engine. The efficiency of such an engine, in my opinion would increase by a factor of about 25% or more depending on the application. I also did mention to him that I know of a controller that could provide as much as 35 Amps to operate the relay, and that could be controlled on a per degree or greater of resolution. ree ree ree he is off to McFadden dale for some test supplies LOL, kinda like Tonie's evil twin brother does to me LLLLLLLLLLLLLLLLLLLLL.

[BRAAP]

...So with the reduced heat' date=' and friction being applied to the entire rotating assembly of the topend, one then can create a new design and operation Characteristic of the overall performance of the camshaft in relation to opening closing the valve......

The opening event then can be much more agressive, that will yield the engine increased flow per degree of piston orientation, or pisition to Top Dead Center on the intake stroke. This will in effect increase the cylinder filling of the desired air/fuel mixture. This will also increase the volumetric efficiency of the engine as the pumping action of the piston, .....

So in in closing ......

You improve the pump, and aint that what all of us want to accomplish by building "performance" in the first place?[/quote']

 

 

YES YES and YES!!!!!

 

What you stated, in my opinion, is the biggest advantage a roller rocker brings to the table over a flat tappet. … I stated this very thing in my second post… The ability for the cam manufacturer to grind the lobes with much more aggressive and diverse ramps to better meet the cylinder filling needs of a specific power plant design.

The bumnmer here is the domestic V-8 market has at there disposal a plethora of this awesome cam technology to choose from “off the shelf” of most cam manufactures, not to mention, custom grinds are not so extravagant that Joe Blow can afford to have his own ground. Now find one for the Datsun L-series… I’m sure the major cam manufactures such as Comp, Lunati, Crane, etc, all have the resources to grind such a roller rocker beast for our beloved L-series. If one was dead set on Roller rockers, he/she could always just give one of these manufacturers a call to get a quote for such a cam….

 

 

In short, those rockers are great “IF” and only “IF” the engine builder matches a cam to take full advantage of the rollers ability utilize very aggressive opening and closing rates. Those rockers when used with a stock or performance flat tappet designed camshaft, would be a poor choice due to the cylinder filling events not being optimized, but actually worse due the geometry of the cam lobe being “designed” for the flat wiper rocker.

[Jason Jarvis]

I got to talking about my new Accel coil today with a few engineering buddy's at work and wanted their take on the size of the part in comparison to the electrical specifications.

Then I thought' date=' well Tony has been harping on the concept of electrically controlling an engine and you know who I am speaking of. So I posed my thoughts to Karl on the matter, and since the new coil design is so much more efficient in regard to the delta factors. I felt that a relay configured the same way would be much more efficient in opening and closing a plunger, and not only that it would be able to handle a heavier mass because of the electromagnetic properties would also follow the response time to actuate a plunger.

Now Karl's little brain is going right to town on that idea, and in fact has alreday come up with a design that he believes will have that abilities to control something like the weight of a valve, along with a return spring, in the event of loss of power to the coil, that would slam the valve shut, you know avoid hitting a piston. .[/quote']

 

OEM's have been working on this for years, as recently as a few years ago it was too much of a task for affordable materials and computer controls. Within the last year, I think I have read about the first application, but I'm not sure if it was in a test vehicle, high end production car, or a race engine.... I can just see it now, in the spirit of MegaSquirt, a home built electro-mechanical valve system.....

 

Ahhh, looks like a few schools and Visteon are ahead of you....

 

http://www.visteon.com/products/automotive/emva.shtml

[jeffp]

I took a look at their page and it sounds good. I don't really have anything to worry about though. All I need to read was that the system uses a 2 Kw alternator and knew automatically they were going in the oposite direction. Same principle, but totally different hardware and electronics.

I was talking last night with my engineering buddy again about it and he has a basic design going for it. @KW what a joke, the alternator would be about half the size of the engine LOL to funny.

[jeffp]

I am going to have to look at their claims, and find out if they have a patent or patent pending.

[Ed260Z]

I read a lot of theory on this thread, but has anyone answered the question? Will these rockers work with a standard cut L cam?

[jeffp]

NO, they will not work on the standard cam. I do believe I went through the setup in my earlier postings. The roller cam configuration requires a much wider lobe due to the short contact point of the rocket to cam. This is also true American made engines, they also require a ground cam to run a roller setup.

[Tony D]

I read a lot of theory on this thread, but has anyone answered the question? Will these rockers work with a standard cut L cam?

That was answered pretty clearnly in JeffP's post dealing with the actual ratio they are, and the ramp shape and lobe profile.

 

In short, no. You need a custom ground cam to take advantage of the roller rocker.

[Tony D]

Anybody else shocked by the fact that with four hours to go on the auction, the bidding on those USED rockers has gone above $250?

 

Anybody know how much they were new from Malvern when they were being offered?

[Z-Gad]

Final price $415 !!

[TimZ]

Anybody else shocked by the fact that with four hours to go on the auction' date=' the bidding on those USED rockers has gone above $250?

 

Anybody know how much they were new from Malvern when they were being offered?[/quote']

 

I dunno - I called Malvern several years ago when they were advertising them on their webpage, and they were not interested in selling them at the time at any price, as they were having trouble getting them to last more than a few hours in their racing engines. I seriously doubt that anybody else has spent sufficient time and money to develop this idea further for the L-series, so to me the whole argument is a moot point. Ever wonder why you never see these things around?

[Twentyfourouncer]

methinks someone posting here may have ended up with them

[RB26powered74zcar]

methinks someone posting here may have ended up with them

 

That ones easy to figure out.... Jeff, Mr Jeff, lets see..... who here in this threads name is Jeff ????

[jeffp]

I asked the guy about them and he told me only after I bought them :

< Talk to Joe Schubeck, Schubeck Racing, 702-252-0577 (this is the last number that I have for him). It is my understanding that these were actually made for a special purpose motor that they designed. The rockers were of the same configuration as the Datsun. I do not know if this was on purpose or by a fluke. The rockers were purchased through Malvern Racing (David Weber). Malvern had theses roler rockers listed in his catalog (website) for a few years. I do not know how many he sold. I think he may have sold some to a drag racer in Japan (I am not sure). I have a complete report to send you on the entire project. >

 

So I guess I am going to jump off that cliff and go with it and see where it gets. I spoke to Ron Iskenderian today about grinding a cam for me. He had his doubts about the longevity of the cam, which I could understand. I did tell him about what we were doing at Sig Erson in 83 with the roller cams we were making. Just incase you don't know or remember, Don Garletts was running for Super Shops. Needless to say we learned very quickly what it took to get a roller cam to last more then two seconds in an engine without destroying itself. The first cam loked like a bunch of mushrooms after a 2 second run time. So I mentioned this to Ron and he commented about the turn around rate at Sig Erson at the time, and that it would be hard to find anyone that could answer how the cams were being made. I laughed a little and said I know exactly who to ask, and where he is. Bob Beatty, he is the guy to ask, of which I just happen to have worked with, and have a good handle on how to get in touch with him.

What we were doing is roughing out the cam, then grinding the center of the lobe with a 1/4" edge grinder about .200 deep, then the cams were sent out and welded, when they got back, they were then finish ground to specifications, they worked very well, seeing what they were doing and the kind of stress they went through.

So my cam will not have to be as agressive. The lift will be a maximum of .415 to get the .580 lift on the intake, and a little less to get the .540 lift on the exhaust.

Ron was thinking the cam duration would not have to be as long as a standard cam" is that what you were thinking?" you got it ron, very fast ramp, and closing of the valve, shorten the duration, decrease the overlap, decrease the lobe centers to get the same results. Sounds good on paper right, well keeping the cam lobes intact is the challenge. Then it is just a matter of having the rest of the head done, Nathan at B.C. Gerolomy told me he has 8 months left working there and he would be willing to do another head for me. Same setup as this new head, and were done. LOL all you got to do LOL. Thats the game plan anyway. I got to get in touch with Bob and pick his brain a little, I am quite sure he remembers what was done. So if I sell my first born ,and give them my right arm I will have a roller cam head to run for all it's got.

I have to think about this one for a while, I am thinking the lift will not have to be quite as agressive as the cam I now have, if I can get the ramp time shortened up enough, I will get the same if not better flow, but with the advantage of shorter overlap and duration. Get the valve open faster, keep it open at a higher lift longer, and shut it earlier, now that is the hot ticket. Longer burn time, better combustion, more torque, and since my engine is stroked, with a longer rod the engine is going to make some frickin power with less fuel consumption overall because more of the fuel will be burned. How does that sound?

Fortunately, I do have some good information on the roller and tappet setups. I made all of the tappets, and more importantly, got to do all of the rework on the tappets, the biggest problem was keeping the needle bearings from going bad, they did like to munch the needles. So I hope some good needle bearings were selected for the job. anyway lets see what comes in.

Any ideas are welcome if they are constructive.

[olie05]

Now that you have the roller rockers, have you considered taking one of them apart to perhaps try to spot the problem that malvern had initialy? The quote that has been going around is that these things lasted for a few hours of racing only. Either way keep us posted!!! I will be following this thread.

 

-Oliver

[Tony D]

"He had his doubts about the longevity of the cam"

 

Don't worry Jeff, those only have to last 23 miles, and afterwards, we can both wear our Red Jackets with pride....

 

Ssssssh! "Top Secret!"