i'm in the process of building my motor slowly.

i have a cc. ex 224/236 cam, pro mag 1.6 rr, matching springs, ported intake, ported stock heads, custom monoblade and may do some forged pistons if i can and want to add a rev kit.

so i bought some crane solid roller lifters to take the give out of the lifters. but since these rely on the oil pump for pressure to push oil to the upper end, what should i do??

options i see are several.
1- try to make changes to the block to allow more oil into the upper end

2- switch to a high volume pump and add an extra quart

3- change the spring in the stock pump for more pressure.


in the future i want a supercharger but in the meanwhile i intend to spray.

so anybody got any advice from experience?

 

oil is moved up in the lifter bore from the movement of the lifter, not by the core. Leave the oil in the bottom end where it belongs. DON'T use a HV pump either.

 

i'm talking about the oil that has to move throught the pushrod to the upper end, yes is does need oil up there!! i've already polished all the oil gallies so the oil will flow down quicker but i'm concerned that since the lifter itself doesn't help pump the oil up the pushrod and it's relying directly on the oil pump that there may not be sufficient pressure with the stock setup.

 

I know it's not an answer to your question. But why a SR lifter on a mild cam like that?

Rich Krause

 

I am a little confused. I hope that cam was designed as a SR and not a HR. The lobe designs are different. The SR lobe has a slight dip off the base circle to prevent the valve from slamming on the seat. After that the lobe is much steeper than a HR. (I believe all SR cams use billet cores also, but am not positive.) You would see no gain running SR lifters on a HR cam and may very well cause damage. If this is not the case, I just wanted to make sure you knew. Good luck with your build up.

 

ME TOO!

Bad idea to run SR lifters on a HR cam. Plus you should change the spring pressures too.

Bret

 

well it was my understanding that it was alright to run solid lifters on a HR cam, just not ok to run hydraulics on a SR cam. i know i won't see much of any gain but it's one less thing to worry about acting improper, although i realize it's rare for the HR lifters to go bad.

will it really cause that much of a difference on the valve seating? i know SR cams usually have steeper ramps but i doubt there is a significant difference between the intial lift. i thought all roller cams more or less snapped open and shut.
like i said, i was planning to run and rev kit anyway, which will help take pressure off the main springs.

so is it really that bad of an idea? maybe i should sell this cam and buy something steeper???!!! lol, not sure though, it will still be a summer driver.

 

Take Bret's advice.

Run solids on a HR lobe and you'll end up with broken parts.

Solid lobes have a gentle entry-ramp (don't know the technical cam term) to take up the lash slowly (accelerate slower). HR's don't have this and that means you are really stressing valvetrain parts. The one place you don't want to stress things.

Not good.

-Mindgame

 

Mindagame: I also don't think it makes any sense to use SR lifter with an HR cam. But a typical SR lobe goes from the base circle to 0.050" at least 20 degrees faster than an HR lobe. How is the HR lobe steeper in the initial portion? Obviously, that refers to the opening side. But from the cams I have looked at, the SR lobes look steeper on the closing side as well.

Rich Krause

 

Rich,

It's because the cam and lash differences of each design. It's mostly the .000-.020 range where the HR cam is faster where the SR cam is taking up the lash there. The .020-.050 side can be much faster for example the TK lobes from Comp they do that area in 28 degrees which is extremely quick, leaving you with a very large area under the curve and big .200 duration numbers for the corresponding .050 duration.

limige,

This idea is going to cause a big pile of money to fix.

Bret

 

Exactly what Bret said.

I'd sum it up like this...

Solid lobe = faster acceleration rates from .020 on

Solid lobe = slower acceleration from base circle to .020

Rich, I don't know about your findings but I'm curious what lobes you're checking?
Every SR I've seen is slower in this area.

Hydraulics are just the opposite, although some of the new designs are real close to SR's in .020+ acceleration.

Hydraulic lobe = slower acceleration rates from .020 on

Hydraulic lobe = faster acceleration from base circle to .020

So in limige's question, you've taken a solid lifter, which even in the most aggressive race cams accelerates slower in the BC to .020 area and made it even faster. The idea of slow acceleration as Bret mentioned is to take up the lash and reduce the impact seen once the lifter contacts the actual lobe profile. In our example, we've increased those loads significantly.

I experimented with this a number of years ago because after tossing the idea around with a few guys we thought it'd be a hot idea. To make a long story short, I couldn't keep valvetrain parts in the engine and eventually grenaded it with a broken lifter. This was a bracket motor by the way. So I wasn't necessarily worried about experimenting cause I didn't have a lot of dough in it in the first place.

Lesson learned? SR's and HR's while similar are very different and the engineers who design them know what they're doing. Want SR performance? Go with an SR, but don't try mixing the two. We all agree on that point and that's really all that matters.

-Mindgame

 

The 319X series lobes are about the most aggressive lobes out there and they will probably beat a SR profile at anything under 230degs of duration. After that a SR is the way to go.

Comp has some Cheater HR lobes that can be run both HR and SR, but it's because you shim the HR lobes up to limit the travel of the plunger to about .015"

They are for Mustang classes that make you run a HR lifter and turn 8000rpm.

Bret

 

thanks guys, i'm looking at a few cams, right now the idea is high hp NA being nitrous friendly as well.

i'm looking at a
256-263 @ 50 658-663 lift on a 113 LSA

or
244/244 .611/.611 112LSA

i do still plan on driving this in the summer on the street but i also want to put a two stage 50/150 shot on it.

can you guys tell me more about the attitude of these two cams, can i go with the bigger one on the 113 and still idle decent and have brakes?

 

We need some more info from you.

What displacement, transmission, gearing, weight (stock or gutted), the-more-the-merrier....

That 244 cam is about as large as I would want to go with a hydraulic. Even then, I'd probably just opt for a solid cause I don't mind setting lash every once in a blue moon but that's just me. Forget anything larger than that on a hydraulic. Then again, I don't know what you plan on doing?

The engine should be built around the cylinder heads. The cam choice is based around the cylinder head and these other unknowns. So let's hold off on specifics til we get some more information.

-Mindgame

 

As Mr. Mindgame posted, hard to be too specific without more info. But I will say that you are talking some huge cams for a street small block. And, as also previously posted, with that kind of lift and duration a solid roller setup is clearly the way to go.

Rich Krause