rocker arm geometry

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moparracer54

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Hey guys..I got Indy LA x heads from Hughes with stainless 1.5 prw rockers. I'm not happy with the wipe pattern on the valve as the pattern is toward the outer edge of the tip. I ordered some lash caps hoping they would help but I don't have enough valve tip for them to work...only about .085 hanging out. I dunno how machining my rockers stands down would help because i already had to clearance my rockers as they were rubbing on the springs. I'm out of ideas....I don't wanna run em if they are gonna whip my guides out right away.... also my rules state steel rockers only which leaves me with comp or prw rockers. All help appreciated as I am one frustrated guy!!!
 
http://www.forabodiesonly.com/mopar/showthread.php?t=224353

Above is a link to my rocker geometry thread I started a month back about the same thing. While the parts we used are different the problem was the same. You could go through it and see what advise was givin to me and what I came up with for the resolve (I settled with lash caps). It may not solve your problem but maybe help with some ideas to do so. From what you discribe your only option is to drop the coin for a different brand of rocker to only prey for them to line up better. Seems a little ridiculous I know.
 
If you have retainers that are not configured for lash caps - you need those to run them... So it might just be a matter of getting those and running the caps.
In my opinion - I would look closey at the sweep and figure out why it's what it is. Your class may say steel only - but that doesn't mean you can try something else just to see if it's the rockers or the valve job.
 
This is the problem. Your valves are for a MAGNUM setup, not an LA setup. The LA valves are longer than the Magnum valves. This has been an issue ever since they started making these heads. Comp Cams had the right valves for the LA setup, but when they stopped carrying the RHS X heads, they stopped carrying the valves. The PRW rockers work better with the longer valves, the Hughes rockers work better with the shorter valves. This is why you have to use rocker shaft shims on Hughes rockers when they are used on RPM or stock heads.

The lash caps will work, you just need to file them down so they are not so deep.
 
You may need to switch to 10* locks/retainer that have a lash cap recess, if you can not grind the lash caps enough to fit.
 
It looks like Indy has 5.02 LA length valves and 4.92 Magnum length valves listed in their catalog. If your LA X heads came through with the 4.92 length ( pull one out and measure ) get ahold of Josh at Indy maybe they'll swap 'em for you.
[ame]http://indyheads.com/images/price2012.32.pdf[/ame] The valves are the 5th-11th part# from the top of this list.
 
why would you have to grind them down ? .060" recess and .060" thick should work perfect ?
 
Hughes cut down the spring pads to get 1.80 springs to fit.....dont u measure stem heights from the tip of the valve to the spring pad? So how do I know what my stem height needs to be with my spring pads cut down?
 
There in lies the problem, so how much did they cut the spring pad/seat?
Knowing this would give some idea of which direction to go, cutting stems down or using lash caps, or getting over complicated and honing shaft saddles.
 
As Mike mentioned the 4.92 long valves that these heads are being built with, are too short for LA valve train. Couple this with aftermarket rocker arms that are probably too long and now things are messed up. LA heads need 5.0-5.02 long valves to get the geometry in the ballpark. And even then the scrub pattern may still be off. Most of the aftermarket rockers out there are poorly designed, leading to these kinds of problems.

7658068-4822786-rockers.jpg
 
Wow that picture is crazy!!! My ol man ground down an .080 lash cap today. He put one on and said the roller position and sweep looked better. He also said we gained a lot of lift back at the valve as we were losing a lot before. So the geometry must be getting better also! My caps are .080 + 4.92=5" long valves now. U guys are definitely right about this and I appreciate the help! Anybody got any good ideas of how to shave down 15 more lash caps without taking all day?
 
If any machine shops you use have a surface grinder, that will do it nicely. If not, try not to lose a finger grinding 'em down.
 
Great picture Skrews. One suggestion - if you could label them as to the manufacturer it might help some guys in initial buying.
 
The cat and the two cranes look pretty close to the eye. Never had any hughes rockers assuming that the grey one. They were out of them when I tried to buy them. And the harland sharps are for an all out race set up used with machined stands.
 
Has anybody used the Indy Cylinder Head rockers on an Edelbrock LA head? I bought a set from them at the Indy Mopar swap($325 w/o shafts) but haven't had a chance to mock them up.Just curious what I'm up against.
 
Yup, its always something when building a MOPAR. Thats why us MOPAR engine builders are the best there is. We have to constantly figure out ways to make things work. Not like a SBC where you have 1000 different part selections for just about every part in the engine, we are limited and we have to make it work. But when we do figure it all out, LOOK OUT BABY! They run better than the rest.
 
Are all of the rocker arms the same ratio?
They look different, like the red 'comp cams ?' Looks like a 1.6 or big block arm?? Offset pushrod long valve head rocker??

Figuring out certain issues when building an engine is only the difference between competence and Incompetence.
Ford's and other manufactures have issues with shaft mount valve train as well...and we know they aren't the best motors out there.lol
 
"Figuring out certain issues when building an engine is only the difference between competence and Incompetence."

Dead on Justin. And I'll add that's true for professional shops and hobbyists.
 
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