NHRA Stock Elimnator Guys

[B3RE]

Is anyone having valvetrain issues since NHRA allowed roller rockers in Stock Eliminator?

 

[Shorty Thompson]

Interesting . Why ?

 

[cjd1963]

I will be building a small block stocker over the winter and am curious as to what problems you're having. Craig

 

[Locomotion]

Just like with any other adjustable rocker, you have to double-check the actual lift at the valve because the actual ratio isn't always 1.5. The difference will have to be made up at the lobe when the cam is ground. May also require slightly different length pushrods to optimize things. Make sure the contact pattern is good at the tip and you should be set. At least that's all I can think of at the moment. I've had Harland Sharp roller rockers on my IHRA crate motor Stock combo for a few years now.

One may have some clearance issues (retainer to rocker) because of the thicker bodies, but I've gotten by with beehive springs.

I didn't have an opportunity to do back-to-back testing as my first roller combo was on a new engine.

 

[B3RE]

The reason I asked is because I have had a few f body guys, as well as others, have issues. It's because roller rockers really screw up the geometry on all Mopar shaft mount rockers. Lift rule classes like stock eliminator are the worst because the smaller lifts have a more dramatic problem. I have a solution to that problem and know it would be especially helpful to the lift rule classes, or to anyone with shaft mount roller rockers on their Mopar.

 

[B3RE]

If you're using roller rockers in your build, it is worthwhile to correct geometry at that time. Pushrod length is determined once geometry is corrected, so it doesn't make sense to buy another set of pushrods when you have valvetrain issues down the road. Oh, when it comes to rockers, you can buy whatever you want, but Harland Sharps are the absolute worst to get right.

 

[B3RE]

Just like with any other adjustable rocker, you have to double-check the actual lift at the valve because the actual ratio isn't always 1.5. The difference will have to be made up at the lobe when the cam is ground. May also require slightly different length pushrods to optimize things. Make sure the contact pattern is good at the tip and you should be set. At least that's all I can think of at the moment. I've had Harland Sharp roller rockers on myi IHRA crate motor Stock combo for a few years now.

One may have some clearance issues (retainer to rocker) because of the thicker bodies, but I've gotten by with beehive springs.

I didn't have an opportunity to do back-to-back testing as my first roller combo was on a new engine.

Even if the rocker ratio is correct, you will lose some lift at the valve due to the 14-15 degree pushrod angle on small blocks.

Pushrod length doesn't have an effect on geometry with a shaft mount rocker, only on stud mount rockers.

Having the roller tip centered on the valve doesn't mean geometry is correct. It just means the roller is centered on the valve. There is much more to it than that.

Clearance issues are usually due to improper geometry caused by an improper rocker shaft location.

A lot of guys like Harland Sharp rockers, but the design is not very good to achieve proper geometry.

 

[MiradaMegacab]

Geometry 101

 

[B3RE]

Geometry 101

I must have gone to the wrong school

 

[kkritsilas]

As the old saying goes, she's got the curves, so I've got the angle.

Kostas

 

[JSALeBaron]

Enigne Builder said DON'T

I am just one guy, but my engine builder (Gary Herche) told me (360 4bbl LeBaron) and my cousin (74 Buick Apollo 350 4bbl) not to worry about buying anything new. He said not to do it if your lift is small (mine is small, my cousin's is even smaller). He told us that if you're not running a lift higher than .500 to not worry about it. I listened to him (partly because I didn't want to spend the money on it) but my cousin didn't. He didn't gain anything, on the track, then on a dyno. We both run .7-1.? under the index. I run the 273 rocker shafts and Comp adjustable rocker arms and they are great!! Good luck though on the new rollers....hopefully it will be worth it. I can't tell you how many times I've thrown money at this stocker to not see any benefit!!:eusa_wall::eusa_wall:
Wayne

 

[JSALeBaron]

Just to add, every one of my Comp shaft mounted rockers were dead on.

 

[B3RE]

(mine is small, my cousin's is even smaller)

I'm sorry, I couldn't help myself.

I run the 273 rocker shafts and Comp adjustable rocker arms and they are great!!

I didn't know Comp made non-roller tipped adjustable rockers. Do you mean Crane ductile irons?

 

[B3RE]

Just to add, every one of my Comp shaft mounted rockers were dead on.

Dead on what? Ratio, Geometry, Arrival