Limits on Hydralic Rollers

[Sandman]

I have had a 400 sbc that is to go together when car is finished.
Combo is Dart lilM, 4.125 x 3.75. 6" rod, SRP flat top pistons, AFR 220 heads, Super Vic manifold, 950 ultra HP Holley.
Cam I have atm is Comp Cam, 264/272@.050" 106LC. 4/7swap, Solid roller. 1.6 rockers.

As the car it's designated for won't be a race car, more a Hot street, Maybe race it once or twice. It won't be a daily driver.
I was thinking of changing to a large Hyd roller, around 250@.050", just to make it more reliable. (I worry about solid rollers on the street)

What are the limitations on RPM, (or anything else I should worry about) with a Hyd roller. I've never run them before, or even flat tappet hydralic cams unless it was std engine.
Crane gives a rev range out to 7200rpm on the large HR's. But most other companies only show about 6500rpm.

What's all the pros and cons?

Anyone that wants to take a guess at HP is welcome. I was hoping for around 600

[Daniel Jones]

> What are the limitations on RPM, (or anything else I should worry about) with a Hyd roller.

To my knowledge, my buddy Marc Arnold had one of the fastest normally
aspirated, fuel-injected, hydraulic roller-cammed 5.0L-based Fox body
Mustangs in the country. He's a guinea pig for Anderson Ford Motorsports
and ran a series of AFM's "Hi Rev" hydraulic roller lobes and turning
nearly 9000 RPM through the traps with a hydraulic roller cam and
lifters (real hydraulic lifters, not modified internally to be solid).
The car started out as new street car and evolved into a 9 second drag
race only vehicle. He started out using steel valves and Ford OEM lifters
and dog bones, then moved to Crane link bar lifters and later to titanium
valves before moving on to a solid roller cam.

When he switched to the solid roller cam, I borrowed a set of his one season
old Crane link bar lifters to mock up an engine and some of the lifter bodies
were scored. Marc mentioned the seats in the heads were also showing some
wear indicating some valvetrain bounce when he ventured into the 9000 RPM
region. IIRC, he has some dyno data showing a pretty ratty curve after
about 8800 RPM. Everything was tested on Anderson's dynojet and Marc has
documented some of his engine combos and dyno pulls here:

http://the-arnolds.net/Cobra/index.htm

> Crane gives a rev range out to 7200rpm on the large HR's. But most other
> companies only show about 6500rpm.

In general, hydraulic roller lifters need some help to turn a lot of
RPM. Heavy valves and large rocker ratios only makes things harder but
there are several things that can help extend the RPM range:

1. Better lifters (e.g. Crane link bars)
2. Limited travel lifters
3. Special hydraulic roller oil
4. Better springs and lighter retainers (beehives with nickel
size retainers)
5. Lighter valves (titanium or Ferrea hollow stem steel)
6. High RPM lobe profiles

Anderson did a bunch of testing to find hydraulic roller lobes that are
stable at higher RPM and Marc ran a bunch of different cams in his engine.
Some cam grinders will note which lobes are suitable for higher RPM.
For instance, Bullet lists their master lobes by three letter prefix.
The second letter is either T for torque/low RPM limit or R indicating
the lobe is suitable for high RPM and/or high ratio rocker arms.

Dan Jones

[Orr89rocz]

Set of morel lifters will work well. With afr 220 heads assuming new eliminator series with the lighter 8mm stems you should have no issue getting to 7000 rpm. Cam lobe will make or break the rpm range but i doubt you will have issues with most typical cam lobes. Think around a 160-170 lbs seat and 400-450 lb open spring will control just about everything you'd run in a hot street setup

[bigjoe1]

Why go BACKWARDS ?? You should not have any problems with the solid rollers if you know what you are doing. Hyd rollers are for girls---Remember ???


JOE SHEREMAN RACING ENGINES

[bigcam406]

to the OP: I was wondering the same thing youve asked.ive seen great improvements in recent years with the performance of hydraulic rollers,guys i know that use them are running numbers alot better than when they were running aggressive solid flat tappets.they also like the low maintenance thing as well.the thing that kind of turns me off is the advertised seat timing numbers compared to the duration at 50 thou.some numbers make the cam look sooooo lazy.am i missing something or is that the norm?

[Orr89rocz]

Hyd rollers will almost always have less duration at .050 vs a solid roller of same overall advertised duration. Solids can run more spring and can get more aggressive with the lobes. I dont know how much power that will lose as some hyd rollers can be pretty big and have over .640" lift with a 1.6 rocker

[Sandman]

Why go BACKWARDS ?? You should not have any problems with the solid rollers if you know what you are doing. Hyd rollers are for girls---Remember ???


JOE SHEREMAN RACING ENGINES

Awww, C'mon Joe, I'm just being a bit lazy.

Running my engine through an engine program, it shows about 20-30HP loss with a HR over the SR I was going to use.
(I don't take engine program figures as gospel, but still a good guide)
If it only looses that much HP, that'll be OK. Because it won't be any serious race car.
One of the problems with engine programs is they don't see the shortfall in parts & assumes everything is ideal. They don't see a HR lifter going to mush at 6000rpm etc.

[bigjoe1]

You have to know I am just making fun here.. In 90 percent of the street engines I build I use a hyd roller grind too. There are going to be some really interesting things come about in the very near future from Comp Cams and their hyd roller cams. I have some prototypes I am testing right now,and I am going to have to stop bad mouthing them pretty soon.


JOE SHERMAN RACING ENGINES

[rookie]

Why go BACKWARDS ?? You should not have any problems with the solid rollers if you know what you are doing. Hyd rollers are for girls---Remember ???


JOE SHEREMAN RACING ENGINES

Or for men who know what their doing!

[Hanzeng]

I've always wondered why rev kits are not used or recommended with HR cams when approaching the upper limits of them? I'm not talking about the 9000 rpm experimental motor, but the commonly advertised 6500 maximum?

[67RS502]

I've always wondered why rev kits are not used or recommended with HR cams when approaching the upper limits of them? I'm not talking about the 9000 rpm experimental motor, but the commonly advertised 6500 maximum?

because you dont need them
just look at a good lifter, lobe design and spring pressure, these will get you 7500 on a mil SBC
why complicate thing more then they need to be.
gilry rollers

[bigcam406]

You have to know I am just making fun here.. In 90 percent of the street engines I build I use a hyd roller grind too. There are going to be some really interesting things come about in the very near future from Comp Cams and their hyd roller cams. I have some prototypes I am testing right now,and I am going to have to stop bad mouthing them pretty soon.


JOE SHERMAN RACING ENGINES

sounds interesting Joe.are you testing the new ones and comparing them to the XE line or?????????????? you probably arnt allowed to divulge that info right?

[Orr89rocz]

Be interested to see what new line they have... Newest was xfi line which was to be efi but they are fairly aggressive high lift lobes but the xe highlift stuff seems even more aggressive. Comp has a lot of newer lsx lobes that i wonder if they could somehow transfer over to sbc cores?

[cstraub]

SBC and Morel Ultra Pro Hyd rollers about 8200 is what we are spinning them.

220# Seat
Ti Retainer
.120" Wall Pushrods with restrictor ends

[Sandman]

The 2 HR's that I was looking at are
Crane HR-252/400-2S-8IG. 252/256@.050", 108LC, .600" on In & Ex with a 1.6rocker

Comp Cam XR300HR 248/252@.050", 110LC, .600" In, .619" Ex with 1.6 rockers

On the engine program it shows the Crane as slightly better, by 9ft/lb & 6HP average.

There might be something newer that might suit better yet. I'm interested in what Joe is saying about new Comp Cams HR.