Rat Patrol
Well-Known Member
Fair point...but its close 1/8th of an inch you have to make up.....might be a deep trench? :mrgreen:
RHS head valve train geometry issue
- Thread starter Rat Patrol
- Start date
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Fair point...but its close 1/8th of an inch you have to make up.....might be a deep trench? :mrgreen:
OUTLAW MOPAR
New Member
Hi everyone I am new to this forum thing but not to lax heads. Alot of you guys mentioned geometry issues with comp crane and harlan, if youactually check the witnees mark pattern on OE. heads it is also not truly ideal. Most of these rockers are based on a generic motors design. Hughes and Indy build their rockers proper for mopars and you will find better geometry on OE heads as well. What makes lax heads look worse is the .308 diameter valve. But I agree with IMM the PRW are a good rocker choice with much better witness pattern and a fairly cheap $. To make matters worse if you call comp and ask why pattern is off on OE and lax they basically tell you MOPARS are only 13 % of business and otherwise dont care about our stuff. Just buy Indy, Hughes, or PRW, cus they seem to care, not to mention all of them are at leat a little cheaper than comp or harlan.
I have a set of harland sharp 1.6 shaft rockers that i had planned on using on my rhs heads but as said when i mocked them up the geometry is horrible, i do have .100 offset blocks for them as they were originally going on a set of brodix b1ba heads, would milling the pedestals and using the blocks correct this issue, has anyone done this combo?
D-mailman
Well-Known Member
W2 race heads use this set up primarily. You will be fine with the offset blocks. Make sure the machining is accurate on the pedestals.
moper
Well-Known Member
This is how I'd addres this issue anyway. Use pedestals but make sure your shop has a quality head guy and good equipment.
winstoninwisc
Taint easy livin free,season ticket ona 1wayride
I ,am expriencing the same problem with my Rhs heads ,the roller is at the razors edge of the valve stem , we saw it with my crane1.6 gold rockers and now I bought new comp cams roller rockers and the problem still exist . So what is the answer to the problem . my first guess was a lash cap also.iwill becalling comp onmonday march 21 2016 . I have been building this motor for 0ver 2 years now ,and thought I was doing some thing wrong
skrews
Well-Known Member
Rat Patrol
Well-Known Member
Why not just post your solution on here? Save people screwing around with lash caps or shims...neither of which will fix the issue.
moper
Well-Known Member
Mike's got some pictures on his website of the stuff he does.
some like to read these kind of article.
This one shows all 4 articles
Thanks skrews!!!
http://www.b3racingengines.com/techcorner.asp
This one shows all 4 articles
Thanks skrews!!!
http://www.b3racingengines.com/techcorner.asp
Vary nice articles would love to read #5 when it come out!
winstoninwisc
Taint easy livin free,season ticket ona 1wayride
I think the guys name was screws that put up the different rockers to show how far off standard meassurment ments were in the rocker industry, I had this problem also another problem was a stock valve coveror a mopar performance valve cover did not fit correct. milling on the head had to be done to let the valve cover sit down properly so I wasn't blowing oil all over, try to see if you valve covers sit down and cover all the way around . why indy would care I don't know ,but they are 4 hours from me brian at imm told me 4.925 to 5.1 valve , you do the math ,that's a huge difference , I did not buy mine from brian just called for help. hughes is sending me a roller rocker for $22.00 to try measuring and I can return if I do not like the fit yet . I donot understand why compcams shaft r rockers don't fit right on there heads . any1 gets any info can we please shoot out to every 1 .I went threw 1.6 crane gold rrockers , tried old flat mopar rockers and now comp cams , they said blbllblbldahi duno. So you are not alone , I think gr8 marketing sold us a load of chit . every 1 bombard compcams tommoro and make there day miserable as we can I'm out 2300.00 and NOT HAPPY ,iwill put up pics tomorro night
Lancair
Member
edlebrock 60175, Hughes 1.6 rockers 570 lift solid roller Lunatti cam
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1 shim under rocker shafts , everything lines up
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1 shim under rocker shafts , everything lines up
I have posted my solution here, but only people who are open minded can be saved from the valvetrain hassle.
Those who have children will appreciate this analogy. You tell the child, "Don't tease the dog, or he will bite you". They don't listen, so you tell them again. How many times do you tell them before you shut up and let the dog bite them so they learn their lesson the hard way. Now, do you get mad at the dog because he bit the kid, or do you tell the kid he was warned and that was the consequence of his actions?
I'm not equating anyone to a child, but rather pointing out a mentality that allows adults to make the same kinds of decisions. If the rocker arm installer is told " You can't just bolt them on without proper setup", and they do it anyway, then blaming the manufacturers when there are problems is like blaming the dog for biting. A rocker arm is nothing more than a pivot, and the roller rocker has different geometry than a standard rocker. Since the factory never used a roller rocker, why would anyone think that the cast stands are located for proper geometry with roller rockers? And, you are correct, lash caps and "shims", don't help, and many times make things worse. Longer valves are a step in the wrong direction as well
Another point that seems to have a hard time getting through, is that centering the roller on the valve stem when the valve is on the seat is absolutely pointless. Where does the roller go when the valve is lifted, as the OP found out? What good does it do to center the roller, only to have the roller fall off the tip of the valve at full lift? How do guys run over .800" lift on a 5/16 valve stem with no lash cap? With proper geometry, that's how. Not centering the roller, or even centering the sweep pattern, but minimizing the sweep overall.
The tech articles are far more detailed than I can be in a post here, and are always available to anyone who has a sincere interest in having proper valvetrain geometry. I recommend reading them, and I am always happy to answer any questions that may still linger.
Marcohotrod
Well-Known Member
we think that when we pay good $ for new made in usa roller rockers that we can bolt them on and be good, or if modifications need to be made then instructions can come with the new rockers we spent good money on, or we can call a tech person that gives a care
When i got my RHS heads from Brian @IMM and put my unknown brand roller tip adj rocker arms on. I had to shim the crap out of them to get the roller tip on center.
Took picture of the valve tip with and without the shims. Brian told me that the shims were causing other problem and that i should install it without them. Said that the tip being just off center would be just fine. and he was right Works just fine.
After reading on B3RE's sight, i begin to understand why Brian said what he said.
My Geometry isn't perfect but at 5800 rpm, it don't need to be.
Rat Patrol
Well-Known Member
I agree with most of what you say Mike..exceot for the presumption that people knew about this issue before I posted the pics that en engine builder here alerted me to. It seems a select few did....but nowhere on any forum had I seen this discussed till I raised it at the request of one of the top machine shops where I live.
They were not my heads....but he , like me, was staggered to think that a supplier would sell a product that only a certain brand of rocker would work on.
I guess it affected him more because being 8000 miles from Indy...the local Comp rep had issues is believing what we were seeing.
This is all old news now...but even the post about a 'hughes rocker and a shim' coukd mislead a lot of folk into thinking that shims will fix the issue....when in 99% of cases the geometry will still be screwed at high lifts.
Not saying anyone is misleading anyone...but a simple direct explanation of what IS required will prevent a lot of assumptions.
Rat Patrol
Well-Known Member
PS - Ill try to re-post links to the pics I was given...
Rat Patrol
Well-Known Member
What did Brian say about potential valve guide wear?
Rat Patrol
Well-Known Member
Rat Patrol
Well-Known Member
As you can see from the 2nd pic...shimming the pedestals will push the rocker tip further off the valve - so shims may only be a 'fix' for Hughes rockers.
Rat, I'm glad you are giving this serious thought. In your pics, the roller is pretty close to centered when the valve is on the seat, but rolls way over to the exhaust side during the lift cycle. Anyone can see that is no good. Shimming up the stands will move it further to the exhaust side, but up is the right direction. The Trig angle between the valve stem and the rocker stand requires that the shaft be offset when it is raised. Add in the fact that almost every rocker available is way too long, and it compounds the problem, requiring even more offset.
By the way, shims aren't a fix for anything. Usually, over time, the stands will crack from forcing a flat piece of metal between the shaft and the stand. Also no good. A spacer that raises AND offsets the shaft is a viable way to correct the problem, or have the stands milled off and new ones made. A word of caution though. The person milling off the stands and making new ones had better know what he is doing, or it will still have terrible geometry, whether the roller is centered or not.
Here are a couple pics to show what it should look like on the seat and at full lift. The total sweep across the valve tip was less than .030".
"Causing other problem" is pretty vague. I'd be curious to know what the specifics were.
I would have to argue that the geometry needs to be correct no matter what rpm the engine is running. I have had a valvetrain start to become unglued as low as 4000 rpm when the geometry wasn't right. Corrected, the same motor spun freely to 6000, and peak power was at 5200. Mild engines need proper geometry too.
I don't understand why the valvetrain isn't important until the motor sees 7000+ rpm. Drop a valve at 5000 and you will be replacing a lot more than just a valve.
Ironmike
Well-Known Member
I'm just kinda shocked to read all this. Mine are Indy/Rhs, 2010 Era and have run a .556 flat tappet all the way to a .681/.688 Solid roller and my geometry is about as good as a guy could want. Same Hughes 1.6 rockers....again 2010 era.
No shims, lash caps, just never had a problem. Did I just get lucky or is the newer ones the problem?
No shims, lash caps, just never had a problem. Did I just get lucky or is the newer ones the problem?
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