Single cat

I'm not looking to do anything bud. Was just merely looking to see how people feel about it.

getrdunn

iTrader: (7)

We've had a decent amount of valvetrain stability etc discussions. I'm assuming your going solid roller given the rpm your aiming for but one thing that has been proven to work with a billit custom grind hydraulic roller and run solids rollers with a tight lash Much easier on valvetrain with no hyd roller failure. Eliminates low hour spring and lifter replacement. Rather than 50-75 hour replacement you can potentially double it. Worthy of discussion with your builder anyway. He may be dead against it but I know several boaters and builders who've gone this route numerous times especially in endurance engines.

MILD THUNDER

iTrader: (3)

Most camshaft grinders don't recommend running a solid on a hydraulic. This is actually harder on things than a solid with solid.

solid roller camshafts have lash ramps designed to take up the slack in the valvetrain before slamming the valve open. Hydraulics do not.

I would discuss this with a cam lobe designer if that's something you are looking to do. Many don't understand the dynamics behind it. I had a buddy who had this setup, an engine builder in michigan thought it was the secret to sucess. Eventually it pounded his valvetrain apart.

getrdunn

iTrader: (7)

You ever done it besides the one budddy. Also what cam manufacture was it a cast core. Just curious. With the HP OT is going after he would likely end up with solid roller anyway. I was just trying to think of a way to eliminate heavy spring pressures while still making decent power. Nothing new as it's been going on for years. Call more power racing or Valako and have a chat with them about it sometime. I think jims going on a decade with his short duration high lift hyd roller cam still cranking 784 at 6k. When I called comp cams on my custom grinds from them they suggested to run solids. (I have bad luck with hyd rollers) I'm not suggesting for every build just an option.

Single cat

We will be running a big solid roller, And will most likely be a tool steal core with jesel .905 lifters with a .820 wheel witch will help some with the big lobe. Our boat it only a 32ft and has 2 speed Trans missions so it gets on plane crazy fast. And it's rarely under 3k rpm cruising

MILD THUNDER

iTrader: (3)

I see no good reason or advantage to a solid lifter on a hydraulic camshaft, over a camshaft designed for a solid lifter .

I know some guys have done it, and done it with good results. Back when there were very few if any hydraulic lifters that can rev high , , I could see the reasoning, in order to fix the issue. Today, guys are running hydraulic lifters to 7000+ rpm in big blocks.

My point here is endurance. If a guy wants to shoot for building a valvetrain that is easier on parts, likely he will find that a solid roller lobe with endurance goals in mind with lash ramps that are designed to gently take up the slack and gently set the valve back on its seat, will be better off than slapping a solid lifter on a hydraulic cam.

5050

everything I’ve been told is quite opposite, hydraulic lifters are heavier and just don’t have stability of solid roller. The reason a solid roller works and is so reliable on a hyd roller cam is ramps aren’t as aggressive as a solid cam therefore u can tight lash on them .002 to .004 cold and u don’t have spring pressure that u usually have on a solid roller lifter so there is less pressure on roller needle bearings which makes a very reliable set up and much easier on parts than an aggressive solid roller cam.

MILD THUNDER

iTrader: (3)

if that were true, why would any cam company , even make a solid roller camshaft anymore ?

all solid roller lobe designs, are not "aggressive" . What makes a cam aggessive is the the lobe design. A hydraulic design can be very aggessive, or very mild. Just like a solid.

the issue is, most guys discussing this on the interweb, don't really know what the acceleration rate at lash even is/measures.

there's some good discussions on this topic on speedtalk.com where some actual camshaft lobe designers (not salesmen) discuss this stuff .

MILD THUNDER

iTrader: (3)

let's say you have a 250 at .050 hydraulic , and a 250 at .050 solid. Both same max lobe lift, let's say .370 lobe . The solid has say a .014 lash ramp, and. 004 on the hydraulic.

at. 050 of lifter rise , the hydraulic will have lifted the valve .046 x 1.7 = .0782 of valve lift. The solid will have lifted it .036 x 1.7 = .0612 of valve lift. So, coming off the base circle , to .050 lifter rise , the hydraulic is opening the valve further than it would with a solid .


that is why, comparing a hydraulic grind to a solid grind, typically the solid needs more duration at .050 to hit the same rpm goal. Also why, they don't measure seat/advertised durations at .004/.006 on a solid.

a hydraulic simply doesnt need the lash ramp a solid does, because there isn't supposed to be any lash with a hydraulic lifter to take up. No lash, no gentle ramp needed. Put a solid on that ramp, and you have accelerated the opening. Certainly can be good for making power . As for longevity , not so sure I wanna be slamming my valves open and slamming them shut against the seat. How to you cure a valve bouncing off it's seat when it closes fast? add spring pressure. I don't know this for sure, but I doubt that a properly designed solid roller profile, with a solid lifter , will require MORE spring pressure than would a solid on a hydraulic lobe before things get out of control.

sutphen 30

mushroom lifters is where its at.