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XtremeOverKill
11-30-2003, 07:54 PM
Who would be willing and interested to help out with a variable valve timing project for the AMC?

MC you have the machining skills

And from within the list , we can take our technical knowledge and create something great!

I have a few ideas already, and I would like to know who would be interested with me.


Mike M.

jeepsr4ever
11-30-2003, 08:34 PM
I think you are talking about a variable servo type valve...if so its already on my mind.....LOL gets rid of the lifters and rockers

XtremeOverKill
11-30-2003, 08:52 PM
Actually my ideas maintain the equipment that we have. Rocker arms, pushrods and lifters.

The idea of Solenoid valves is a great one, but where it has been successful in Japan the car runs on 72 volts.

Electric valves would be THE BEST! and hey if it works, I'm all for helping with that design.

I have also thought of useing rotating assemblies, instead of valves all together. - I'll explain that in a further post.

So...... the idea is of interest....

jeepsr4ever
11-30-2003, 08:55 PM
ohh yeah :?

XtremeOverKill
12-01-2003, 10:40 PM
Ok heres some thoughts on this issue

Solid lifters offer Zero variance from cam movement to valve - well lets assume the valve train is hot, and the lash was set corrcetly at 0.020 intake and 0.021 exhaust.

With hydraulic lifters, I have heard that there is sometimes as much as a 0.25 difference in the Cam movement and Valve movement. That little spring in there should only have to take care of the 0.020 lash, but heck, they go ahead and give 0.25 spring. The Oil tries to make for this difference, but lets ask ourselves. How many racers do you see running hydraulic lifters?? They're mainly solid lifters.

So I need the help of a Fluid Dynamics Person, and someone who knows Hydraulics.

What kind of pressures can Engine oil handle without turning into charcole.

What variations in Cam degrees would be 'effectively' experienced by valves from a fluctuation of the length of the push rods? Lets say if we take out a 0.035" out of the rod.... What will the effective lift and duration become?


Slowly, we'll get this
Mike
P.S. - I would really like to hear some thoughts from you guys. Thougths good or constructive criticisim. Every question is a beneficial one and furthers success.

XtremeOverKill
12-02-2003, 09:36 PM
HEY I'm moving up to 2 wrenches now!!!!

MC I sure could use some feed back.

The idea hasn't stoped here, but I would like to get some interactivity going.

jeepsr4ever
12-02-2003, 09:38 PM
i think a slight increase in duration or a coated or plated camshaft would help

XtremeOverKill
12-05-2003, 03:25 PM
OK here's the idea....

The idea starts with a Hydraulic lifter, modified such that it acts as a piston, as well as a lifter. Each respective lifter would have its own pressurized oil line going to it. Put the Intakes on one circuit, and the exhausts on another circuit. Each of these circuits would be pressurized oil fed, and regulated at a central location. The Standard method of oiling the hydraulic lifters would be eliminated, such that the only source of oil for the lifters, were their respective oil line. - I do not know what this would do to the respective oiling of the Main caps, but for right now I'm brainstorming on the Lifter idea.

The idea here is that we run a "larger cam" but complimented with lifters that would not follow EXACTLY the lobe of the cam, it would create a smaller lobe effect. However, when running at a higher RPM, the pressure to the lifters would increase, to give a more solid lifter effect.

Now here's the interesting part. I have heard of lifters on the market already that do what I have mentioned above - albeit I have no idea how it’s done. But the cool part about having the Intakes and Exhausts on separate circuits, is that you could have the pressures staggered, such that the exhaust stays open longer, or the intake respectively, would have a different profile, than the Exhaust. And all of this while under load, and RPM.


OK let’s hear critiques.
Respectfully yours,
Mike M

jeepsr4ever
12-05-2003, 03:37 PM
The rhodes Pump up lifters do some of that but i like the variable part, It does raise these questions

1. What would the pressure hoses need to be made of
2. Why even run a camshaft
3. What would be used for a pump and where would it be mounted

Lifted79CJ7
12-06-2003, 12:29 AM
OK, so how does Honda's VTEC engines operate? Aren't they basically the same principle as what you are thinking about, or am I smoking crack?
Jack

XtremeOverKill
12-06-2003, 11:55 PM
Dont quote me on this, but intuition tells me that the VTEC system and the DOHC engines that have the variable valve timing, will do something to "phase" the cams - one exhaust and one intake.

This is simliar to the idea here, with the exception that not only could we alter the lobe centerlines, but we could also make adjustments to the lift and thus duration as well.

The two may be alike, but I know 0% about the specifics VTECH, so if this appears that I'm copying them, then it is by mere coincidence only, for I have had this idea for a long time, but never knew anyone who might could make it come to life.

MC to answer your questions:
I have heard and done some primitive research on the Rhodes lifters. But where we differ is in the field of adjustability and reliability. With Rhodes I would be interested to hear from some long term test, to see what they will hold up to. After 10,000 miles, after 20,000 or 50,000 and some dirt, what happens?

I would like to use Rhodes, so don’t take it that I’m slamming them. But I would like to learn more.

With regard to the construction of the pressure hoses….my first thought would be for rigid and smooth bend hoses. But then Vibration? Ok so lets go with hydraulic lines, Northern Hydraulics – I think they are now known as Northern Tool and Equip. – Has lengths of 14” to whatever length. Their lines are rated for upwards of 10,000 psi and 20,000 psi. Granted we’ll probably not see these pressures, so perhaps some easier to manage Stainless steel lines would be preferred. And then an idea of a “Fuel Rail Like” design… with a rigid body, and only 1 hose per rail, would be the least moving parts, perhaps least susceptible to vibration. And then finally the options to eliminate vibration are to created whatever network of hoses or rails you want, and then make a tray of epoxy that would hold everything in place, much like electronics.

The options are many, which one suits us best is yet to be determined.

Why run a Camshaft….. A really good thought not to run one, but the reliability of timing becomes and issue, and then the “what if” this breaks approach comes in. With a cam and adjustable lifters you would at least have a fall back, to where if the lifters went to Zero pressure, the cam would take over – albeit not as well – but it would still cycle the valves. And then the timing of the valves, keeping them all in unison would become an issue if we were relying on pressure to actuate them 36 times a second @ 3000 rpm.

And then with regard to a pump…Power steering pumps develop some high pressures, and they are belt driven. So perhaps another belt routing idea looped around another pulley that would be the auxiliary oil pump. - I really don’t know, but that’s still in the brainstorming section –

My apologizes for the length,
But I am eager to hear responses, thoughts, and critiques.
Mike

jeepsr4ever
12-07-2003, 12:44 PM
In reguards to the Rhodes lifters they work great in theory BUT when you have a fluctuation of oil volume to the lifter they dont work so we see a progressive failing of the lifters pnuematic pressures. The idea of having a hydralic line to each lifter CAN be done, but we need to examine it a little closer.......

1. Is the amount gained worth the amount used?
2. Can we incorporate the dwell of the piston at TDC
3. Where is our biggest advantage gained
4. What about servicable parts
6. A pressure relief would need to be made

XtremeOverKill
12-07-2003, 02:52 PM
Help me understand what you mean when you say dwell of the piston? And what you are thinking of? I'll be the first to admit that I'm ignorant, and it seems the more I learn, the more I realize that I dont have a clue.
Oh well, ask more questions.

Amount gained.... I assume you mean in power created vs power taken to turn the pump. I wouldn't think it would take more than 10 hp to do the pump, and creat phenominal gains - across a broader RPM range.

We're still in Prototype mode

I'm eager to hear of your knowledge, and what you have to say...... although I am wondering why the rest of the board is remaining quiet on this one...... :-|

Look foward to your input MC

jeepsr4ever
12-07-2003, 03:02 PM
We need to get you a CAD system!

The dwell is the amount of time proportional to the rotation of the cranl that the piston sits at the top of the stroke.

I guess in my personal experience the hydralic line dont last forever BUT we would need to talk about the pressure we need here, lets say your valve springs are rated to a spring rate of 250-300 lbs (common double valve spring) how much volumetric pressure would we need without overkill

It raises alot of questions....hmmmmm

XtremeOverKill
12-07-2003, 04:06 PM
I have access to and have been trained in a program called Pro/E = ProEngineer. Only problem is, it's for educational use only. So if I were to design something, I could save it, but it will not convert to a professional file program. The best that I could do would be to take desk top pics, and/or send you print outs.

I have a good conceptual idea of things in a spatial orientation. Mathematically I can easily see how the piston moves at its maximum velocity and travel when the connecting rod is nearly perpendicular to the crank. As the piston and rod travel in the combustion chamber I can easily see how this motion slows down, ultimately reaching a zero point. But to calculate this, we would need to take a derivative with respect to piston movement, of the crank. This would tell us the EXACT position where the piston reaches TDC – I know duh – but then pick your allowable window of negligible movement, and that would become your dwell would it not?

I have access to Auto CAD, and ProE….. Benefits of being a college student ….. I’m only 21…a business student at UNC-Charlotte but with a passion for Mechanical Engineering, and AMC.

-Best regards,
Mike

XtremeOverKill
12-11-2003, 02:31 AM
MC,

What would you like to be seen on CAD, or Pro/E = a 3-D rendering model.

Model of the lifter?
Lines?
or Pump Location?

And if I can get an idea on paper, in design form, could you manufacturer "test" lifters for me, or who would you suggest going to to make a Prototype?

jeepsr4ever
12-11-2003, 07:58 AM
You draw it send it to me and we will discuss going forward

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