the heck with cams how about lifters

[butchville]

we been playing lolng enought lets take a hint from rhodes lifters make a fast bleed lifter with .030 addition lift should change cam timing an pick up bottom end also the more oil pressure =more rpm = more lift =duration change in cam should be a cheap fix thonk on this one awhile.

[your_I.D.]

You wont get any additional lift with rhodes lifters. You will get less lift at idle and gain it back as oil pressure increases. They work great if you have a radical cam grind and want better idle quality.


from Rhodes web site.

At idle speeds, the result is an approximate decrease in valve-open duration. At idle speeds, the result is an approximate decrease in valve-open duration of 10 to 15 degrees, and .020 and .030 inch of lift. By reducing valve lift and duration, a radical cam can be civilized enough to improve low-rpm idle quality, increase vacuum for operating power accessories, and create the potential for improved gas mileage

[your_I.D.]

It would be easy enough for a machinist to modify our lifters. A high volume oil pump would be needed. Along with some oil drain back improvements. (smooth and slightly enlarge brainback passages) 24 lifters dumping excess oil may flood valve area. And differant cams to take advantage of it.

[butchville]

what about increasing the travel on the lifter .030 that would give .410 to .420 lift at high pressure. i run rhodes lifters in my 400 pontiac motor with a ra4 cam made it livable on the street. by adding travel over stock to .030 should work any body know how to open up the stock lifter i'll machine any thing once.

[RacerX11]

You can't add lift by changing the lifters. The only way to do that is by changing cams. Thats like adding stroke with different pistons...just doesn't work that way. To get 0.410" lift at the valve, you need cam lobes with 0.410" lift. Then you could do whatever you want to the lifters to bleed lift down at lower speeds.

Marty

[butchville]

if you can bleed lift down you can pump it up. your right though lift on cams the same as before. controled lifter pump up it can work just ain't had time to work it out anybody know how our lifters ar put together.

[RacerX11]

You don't understand how lifters work. Your total valve lift is limited by your cam profile. If the lifter pumps up at higher rpm to increase lift, it will hang the valve open on the base circle of the cam lobe.

Marty

[SappySE107]

There is no way for a lifter to pump up and add lift for the reason marty said. They make rocker arms that do add lift at higher RPM but thats not going to help us any.

If the lifter were to "pump up" the hydraulic button in the middle, it would have to be so accurate that it only pumps up when the valve is partially lifted, and then pump down right before it closed. Too bad oil pressure is all you get for pump up which is far from perfectly timed to valvetrain events.

[firechiken]

Uh, you posted twice just in case we didn't understand the first time?

[RednBlack]

With about 2500 lbs of hydraulic pressure, and 24 electronically controlled spool valves, another PCM designed strictly for the application, major plumbing and machining issues, power source for the pump that weighs about 150 lbs, (Probably a 50 HP electric). It could be done. Added Note: And one helluva long extension cord! 480 of course.

[RednBlack]

That was a joke BTW. Switching hydraulic pressure at those RPMs is not feasible in an automobile. Not impossible though.

[SappySE107]

It gave me an SMTP error so I submitted my post again:P Ill fix it.

[firechiken]

Little off topic, but I remember a few years ago someone was developing a solenoid system of operating valves. It couldn't control lift, of course, but it would allow for instant closing and opening and unlimited duration based on engine parameters. Anyone know what became of this?

[Q]

It's not solenoid controlled. It's servo controlled; it controls both both lift and duration and it's stilll being developed.

[firechiken]

Oh, OK. Last I saw, they had a running prototype, and like I said, that was a few years ago. Thought we would have heard a little bit more about it by now.