What is the Max HP on a sealed GM 604

[CamKing]

This stuff sounds like a JC Whitney catalog to me. Everything ads 25 more HP.

That's funny, because I just had that call today. Fuel "X" will add 20hp, Carb "Z" will add 20hp, Coating "K" will add 10hp, Valve Spring "Q" will add 15hp........ Pretty soon, he's got a 500hp 602 crate engine.

[sjvalleydave]

Mike, I know that hydraulic roller lifters are not the lightest things in the world...How do you control the float with those things?

[CamKing]

Mike, I know that hydraulic roller lifters are not the lightest things in the world...How do you control the float with those things?

That's just it, you don't.
Ask anyone that knows anything about hydraulic lifters: "what happens to the hydraulic system when you loft the valve?"

[novadude]

Mike, I know that hydraulic roller lifters are not the lightest things in the world...How do you control the float with those things?

That's just it, you don't.
Ask anyone that knows anything about hydraulic lifters: "what happens to the hydraulic system when you loft the valve?"

I don't know anything about hydraulic lifters, but my guess is that they pump-up and the valve won't set back down on the seat when you need it to seat. Can't see how lofting can possibly work with a hydraulic tappet?

[loudandproud]

Mike, I know that hydraulic roller lifters are not the lightest things in the world...How do you control the float with those things?

That's just it, you don't.
Ask anyone that knows anything about hydraulic lifters: "what happens to the hydraulic system when you loft the valve?"

I don't know anything about hydraulic lifters, but my guess is that they pump-up and the valve won't set back down on the seat when you need it to seat. Can't see how lofting can possibly work with a hydraulic tappet?

What if you set the preload to nill? Cant pump a lifter anymore...Then youre running practically a solid lifter and lofting the valve.

[CamKing]

What if you set the preload to nill? Cant pump a lifter anymore...Then youre running practically a solid lifter and lofting the valve.

With the ramp that's on the stock GM 604 cam, that would put the intake valve closing at 92ABDC

[novadude]

What if you set the preload to nill? Cant pump a lifter anymore...Then youre running practically a solid lifter and lofting the valve.

With the ramp that's on the stock GM 604 cam, that would put the intake valve closing at 92ABDC

Guess that'd be cool if 604 crate engines had a 16:1 SCR and turned high engine speeds.

[loudandproud]

What if you set the preload to nill? Cant pump a lifter anymore...Then youre running practically a solid lifter and lofting the valve.

With the ramp that's on the stock GM 604 cam, that would put the intake valve closing at 92ABDC

Can you explain the math on that for me? Im not sure how just going solid would do that much. How can you predict the closing point with loft considering it is rpm/valvespring/valvetrain wieght and geometry dependant?

Isnt this the theory behind setting a very light preload on a hyd lifter? It cant pump up anymore, therefore it wont hold the valve off the seat...?

Im not doubting you...I am here to learn... just would like to know where my thinking is flawed...

[novadude]

I've got a question on that... can you loft a roller? I would have thought that the line-contact loading of the roller wheel crashing back down on the cam (and the resultant high compressive stress) would wreck things in short order.

[rookie]

Mike, I know that hydraulic roller lifters are not the lightest things in the world...How do you control the float with those things?

http://www.google.com/search?q=minumum+ ... h=835&bs=1

[loudandproud]

I've got a question on that... can you loft a roller? I would have thought that the line-contact loading of the roller wheel crashing back down on the cam (and the resultant high compressive stress) would wreck things in short order.

oops... its a roller. I thought it was a hyd. Flat like the 602 crate... my bad.

Yeah lofting a roller wouldnt work out good.

[MadBill]

Mike would know, but theoretically, seems like it should be possible to loft a roller and have it touch down lightly on the flank like a ski jumper, rather than smashing onto the closing side ramp, like a skier "out-jumping" the hill and hitting hard out on the run out area.

Better yet, use a rev-kit that seats on the lifter OD (I suppose not permitted in this application) and let the push rod do the pole-vaulting.

[autodoctor911]

no one has mentioned that most of these classes require a rev limiter to 6200 rpm or something close to that for the 604. Are these motors for classes that have no rev limit, or are they able to cheat that also?

this idea of valve loft really intreagues me though. If I am running a cam lift rule, this seems to be a great idea. what if I do use a rev kit? would the pushrod need a guide sleeve or something to do the floating. that seems like the way to make it last. If the pushrod does the floating, if the point of reapplying contact is a hard hit, the hydraulic lifter could absorb more or all of the high forces. don't the physics involved in spring oscillation only allow doing this at a particular rpm, where the frequency of the spring matches the frequency of the valve event?

[sjvalleydave]

Rookie, those type lifters are not legal to run...We are talking about lofting a hydraulic roller lifter in a 604 crate engine...

[sjvalleydave]

The Crate DLM 604's in the West do not have to run a RPM chip...I just have heard that by 6800 or so they are pretty much done...I know Raceman14 has stated that he has some 604's running up toward 7400 rpm, but most I've heard say 6800-7000 tops