How much lift with stock magnum roller lifters?

-
Cuda416 said:
Stupid question, be gentle...

What the aversion to hydraulic versus solid? Under pressure, the oil is damn near solid and doesn't compress right? I mean, I know it bleeds down but that fast?

I guess I think of it like the experiement kids do with corn starch and water. Add just enough water to a bowl of corn starch to saturate it, then poke your finger in. Goes right down to the bottom. now punch it, and it stops your hand acting like a "solid". In my head it seams similar in that the harder and faster you "hit" the oil, it's going to resist because of the viscosity?

BTW, with all of the talk I see about people wanting solid over hyd, I know I'm 100% wrong, but why?
Click to expand...

Well.....the thing is, at high RPM, they cannot bleed down fast enough, so they cause the valves to float and hang open. That's when bad things happen. Conversely, solid lifters don't have that problem. The lash takes up and room at high RPM that would otherwise cause valve float and prevents it.

You CAN use a traditional anti pump up lifter. Those have a faster bleed rate at high RPM and will not float the valves, however, they require an adjustable valve train with a setting from zero lash, to around .002" lash, like a tight lash solid.

So, since they require an adjustable valve train anyway, the best thing to do is just go straight to a solid and be did wif all dat, yo.
 
RustyRatRod said:
Well.....the thing is, at high RPM, they cannot bleed down fast enough, so they cause the valves to float and hang open. That's when bad things happen. Conversely, solid lifters don't have that problem. The lash takes up and room at high RPM that would otherwise cause valve float and prevents it.

You CAN use a traditional anti pump up lifter. Those have a faster bleed rate at high RPM and will not float the valves, however, they require an adjustable valve train with a setting from zero lash, to around .002" lash, like a tight lash solid.

So, since they require an adjustable valve train anyway, the best thing to do is just go straight to a solid and be did wif all dat, yo.
Click to expand...

Hmm, ok, so it has to do with lash and the ability to bleed down fast enough to not cause a problem? That's starting to make sense, I hadn't thought of it that way. I suppose it's been staring me in the face since for hyd you set "preload" which is negative lash. Am I tracking that right? Having the hyd bleed down slow is bad since the "preload" needs to go away?

Thanks
 
Cuda416 said:
Hmm, ok, so it has to do with lash and the ability to bleed down fast enough to not cause a problem? That's starting to make sense, I hadn't thought of it that way. I suppose it's been staring me in the face since for hyd you set "preload" which is negative lash. Am I tracking that right? Having the hyd bleed down slow is bad since the "preload" needs to go away?

Thanks
Click to expand...

Yes. There has to be some way to allow a little wiggle room for high RPM operation, due to the lifters wanting to "take off" off of the peaks of the lobes as they go by. A sort of shock absorber for the valve train. The lash in a solid lifter valve train acts in the same way, but there's no hydraulic function to have to bleed down, so they can RPM higher and make more power due to the more aggressive ramps they are able to handle as a result.
 
RustyRatRod said:
Yes. There has to be some way to allow a little wiggle room for high RPM operation, due to the lifters wanting to "take off" off of the peaks of the lobes as they go by. A sort of shock absorber for the valve train. The lash in a solid lifter valve train acts in the same way, but there's no hydraulic function to have to bleed down, so they can RPM higher and make more power due to the more aggressive ramps they are able to handle as a result.
Click to expand...

Got it, thanks!
 
Cuda416 said:
What the aversion to hydraulic versus solid?
Click to expand...

I think another big reason hydraulic are preferred is they are seen as no maintenance. Once setup, you shouldn't have to go back and adjust them. Some folks have an aversion to that. For a race motor, that should be a moot point. It should be getting regular attention. For a street motor owned by a guy that has trouble setting distributor timing, it is a big deal.
 
gzig5 said:
I think another big reason hydraulic are preferred is they are seen as no maintenance. Once setup, you shouldn't have to go back and adjust them. Some folks have an aversion to that. For a race motor, that should be a moot point. It should be getting regular attention. For a street motor owned by a guy that has trouble setting distributor timing, it is a big deal.
Click to expand...

I can certainly see that but I was focused around performance but didn't specify. Another post said they ran a .580 cam and ran to 6400 without problem so I'm assuming the problem kicks in a rpm's I'll likely not see without some crazy problem that unintentionally got me there.
 
You must log in or register to reply here.
-

Back
Top