Variable Valve Timing

[XtremeOverKill]

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]

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]

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]

ohh yeah

[XtremeOverKill]

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]

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]

i think a slight increase in duration or a coated or plated camshaft would help

[XtremeOverKill]

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]

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]

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