I have decided to go ahead and buy a set of roller rockers for my motor. The rockers and valves that I had been running have about 30,000 miles on them, and since they were mixed up when they were dis-assembled and I don't know which rockers' wear pattern went with which valve stem, I decided to re-face the valve stems myself and don't want to run my used rockers on a fresh valve stem surface. No, I didn't mix them up, and at this point, it doesn't matter who DID- I just don't want to take any chances and want a fresh start with a new set of rollers (How's that for rationalizing?). Anyway, have any of you guys had any experience with the Scorpion roller rockers? How about the Curtisbuilt? These use a tongue and groove/shaft set-up, are adjustable, and also use Comp Magnum rollers in their kit for the actual rockers themselves. Any help would be greatly appreciated. I am sure that if money were no object, most of us would go with the Jesel's. However, money IS an object with most of us, and definitely me!! Thanks, guys.

 

 

Yella Terra 's here--the older heavy style--worked out great--luv them--so far no issues--revving it up to 6500--

 

Here's the shaft system I sell and it's very rugged, rev's high and are adjustable!

$525

 

I have seen a few broken Scorpion's. Unfortunately when they break, the person who posted the problem typically never comes back with an explanation as to why so you don't know if it was the rocker or the installation. I have used the Cranes and the Yella Terra's. They are both very high quality setups. Cranes are fully adjustable and the YT's are a pedestal setup with two rockers sharing one shaft. The Curtisbuilt you mention I believe are a different pedestal setup based on the use of the Comp rockers. They may the shaft setup and use Comp rockers.

 

I'm using the new Yella Tera 'ultra lightweight' rockers. I'm not a fan of pedestal rockers. I've had 2 sets so far. Harland Sharps, and the YT's. I have also used Jesel's and have had problems with them as well.

I don't like pedestal rockers for the simple reason that I can't get a repeatable seat of the pedestal. They aren't fastened securly when the pushrod starts taking up the preload and there is a tendency to move around. I found that I had to torque them down very incrementaly, if that's even a word, between the intake and exhaust or they would spin about the axis of the bolt I was tightening. Due to these factors I found that I couldn't get a consistent shim height to get a repeatable 'center wipe' pattern, or at least it didn't do much for my confidence level I had done so.

The Jesel's are a true shaft mount rocker with a mounting bar that you fasten in before the shafts are mounted. The bars fit snuggly between the webs on the head and are therefore always in the exact same spot after fastening. The major problem I had with my Jesels was I had to undercut the arm to clearance the larger than diameter retainers. I also suspect the retainers were a little higher out to the edge than stock. The other thing I found out recently was after I started to remount them on the bench I was setting up the shimming and found the maximum lift they would provide was ~ .570". There is a small 'knuckle' at the bottom of the trunion body that was hitting the mounting bar. Also, there is a spot in the center of that knuckle that was hitting the mounting bolt of the bar. Since I had already taken some material out of the underside of the arm and I am now running springs with greater spring pressure than before I didn't feel comfortable with taking more material off them. So I was kinda forced to go with the YT's.

Sorry for the long-winded answer, I thought you should know about the pitfalls I experienced using Jesel's and my opinion on my experience with pedestal rockers.

Those PRW's look really nice though.

 

ArKay99, nice write.

....I'll add a few thoughts and comments to the rocker arm discussion....

Shaft Rocker Arms

All the shaft mounts need attention to detail

1 - Pedestal mount area needs to be flat and carefully inspected for interference at both ends as well as any nicks, burrs, etc.


2 - Pedestal height is critical as it sets up the entire foundation for proper geometry - follow the installed instructions and use shimming/material removal to adjust

3 - Pushrod length is also critical to achieve the correct geometry and proper "wiping" of the valve tip - check this carefully!

4 - Pushrod clearance, as they pass through the cylinder head, needs to be checked and improved as needed.

5 - Whenever possible select adjusable rockers over non-adjustable.

Stud Mount

1a - Must be light enough in the right areas to avoid RPM robbing and valve train harming harmonics

1b - ....and that's impossible to tell from looking at the rockers.

1c - My best advice here is to view actual dyno runs that clearly display high RPM capability backed with long term, verifiable results on reliability.

2 - Flatness of the cylinder head mounting pad is crucial - check carefully for burrs and flash that will hinder the mounts ability to seat.

3 - Pushrod length is critical to this type of rocker system to perform - check it carefully and adjust for proper valve "wiping"

Stock Rocker Arms

1 - Have Harlan Sharp mod them for improved reliability in the trunnion area.

2 - Check the heads and mounting stand for burrs, nicks, etc...this is must for good mounting.

3 - Pushrod length - yet again this is critical to this type of rocker system to perform - check it carefully and adjust for proper valve "wiping"

that's it for now....I'll add more later

 

Thank you!! This is just what I've been looking for. Doesn't matter about long winded. As long as it is informative, and your post was!! I agree-those PRW's look good. I posted somewhere recently that I was curious why the aftermarket has NOT come up with a shaft mount system that uses a full length-of-the-head design. You know, one shaft per head, for all 8 rockers. It would seem that one long 16 inch shaft that ALL the rockers pivoted on would be stronger than having 4 shorter shafts that held 2 rockers each. It may not be feasible, or physically possible, but when I assemble my heads, I am going to look damn close at this possibility. But it does seem that if it was possible to do this, someone would have already done it, or maybe the increase in strength is so minimal that the increase in manufacturing expense, if any, and difficulty in the installation, if any, would make this a "not feasible" idea.

 

I am selling my 1.85 Curtisbuilts for $450...they were $1,100 new. let me know if interested. I ran them less than 1,200 miles before going to a XER cam.