Correcting Mopar Valvetrain Geometry

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PROSTOCKTOM

PROSTOCKTOM

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Like most of us I always try to advance my knowledge to insure my engines are built the best possible way. While I am aware that rocker systems like a Mopar uses require shimming to get a correct sweep on the valve tips I wasn't fully immersed in some of the other aspects that also need addressing. I ran across a series of tech articles from B3 Racing that I think every Mopar guy should read and fully understand. The outcome from following the information provided would be increased performance, less parts breakage, and elimination of guys grinding on rocker arm bodies to clear retainers. Hope you all gain some knowledge from reading the articles.

B3 Racing Engines LLC - Mopar Rocker Arm Geometry Tech

Tom
 
Yup that's Mike. He's a member here. Get ready to hold onto something, cause there's two factions that always go after it regarding this. lol

I'm on the "it's a good thing" side. LOL
 
Mike was extremely helpful when I was putting my motor together. Now if I'd just get it in the car...
 
Id love to see some before and after dyno or drag runs after that 'fix' Seems like there is always a better way to do something but then there is the production cost and durability, etc.
 
I'm not sure it's something that adds power. Much like roller rockers, I think getting the geometry correct adds to overall durability and just "gets things right" and there's nothing wrong with that.
 
RustyRatRod said:
I'm not sure it's something that adds power. Much like roller rockers, I think getting the geometry correct adds to overall durability and just "gets things right" and there's nothing wrong with that.
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There is a lot to that statement that is dead on. The power loss on a messed up geometry issue can be seen when there is a dyno test done. I’m sure there’s some to be picked up. Like the roller rockers, the correct dead on ratio shows a few HP over the not so correct stamped rockers.

When things run correct & right, the engine is now right, all the power you built it for is there and not missing because it is no longer a jenky mess, longevity ensues.
 
Power gains with the geometry correction are probably minimal, but the entire drive train is probably much happier & will live a long life span.
 
Got that right. Longer life and happy while at it. Your simply making sure your getting all the parts are worth correctly for a happy and smooth running engine for a long time. Just another part in the puzzle that should be right on the money.

If it’s really bad, you won’t get the rpm’s out of it.
 
Demonracer said:
Power gains with the geometry correction are probably minimal, but the entire drive train is probably much happier & will live a long life span.
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I could certainly see power gains if the valve train is not opening and closing the valves optimally, due to incorrect geometry. Enough to feel in the butt dyno? That's anyone's guess, but I'll say this. It's attention to details like that, that make the difference in some wins and some losses. All the little "gettin it right" things add up. There's no question about it.
 
RustyRatRod said:
I could certainly see power gains if the valve train is not opening and closing the valves optimally, due to incorrect geometry. Enough to feel in the butt dyno? That's anyone's guess, but I'll say this. It's attention to details like that, that make the difference in some wins and some losses. All the little "gettin it right" things add up. There's no question about it.
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I put a set of the B3 rocker shaft spacers on the built slant in my 68 Barracuda. The motor has valve stems .090 longer than stock and roller rockers. I did a before spacers and after spacers comparison of the roller travel across the valve stem tip and the reduction in travel was remarkable.
Having the load that is moving the valve centered on the valve stem tip will reduce side loading of the valve stem against the valve guide and that will reduce wear and that will keep valve seat sealing optimized. Having the roller at the rocker tip moving less also reduces wear.
It’s all incremental. But it also all adds up.
Moving the rocker shaft up over .200 induced interference with the valve cover. I was able to modify the existing VC to add clearance. But if you go the B3 route be ready for that.
 
my68barracuda said:
I put a set of the B3 rocker shaft spacers on the built slant in my 68 Barracuda. The motor has valve stems .090 longer than stock and roller rockers. I did a before spacers and after spacers comparison of the roller travel across the valve stem tip and the reduction in travel was remarkable.
Having the load that is moving the valve centered on the valve stem tip will reduce side loading of the valve stem against the valve guide and that will reduce wear and that will keep valve seat sealing optimized. Having the roller at the rocker tip moving less also reduces wear.
It’s all incremental. But it also all adds up.
Moving the rocker shaft up over .200 induced interference with the valve cover. I was able to modify the existing VC to add clearance. But if you go the B3 route be ready for that.
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Right! I don't know if you remember, but on this factory slant 6 closed chamber head I have, I used 318 valves. I did that by choice, because I wanted room for a good valve spring. The 318 valves are .300" longer than the slant 6 valves, so that necessitated Mike's B3 relocation kit. It turned out very nice.
 
RustyRatRod said:
I could certainly see power gains if the valve train is not opening and closing the valves optimally, due to incorrect geometry. Enough to feel in the butt dyno? That's anyone's guess, but I'll say this. It's attention to details like that, that make the difference in some wins and some losses. All the little "gettin it right" things add up. There's no question about it.
Click to expand...

I can attest to the change in responsiveness (butt dyno?) The EFI 408 I had, did have some angle issues. I was already used to the launch characteristics of the car (street and track) After a consult with Mike, the obligatory paperwork (measurements), install and new pushrods (shorter). It was a very noticeable difference, with a much crisper idle and much faster ramp up, picked up another 500rpm (still pulling and now hit the limiter to fast). Dyno power? not sure, Drivers seat impression, I'll never do another traditional wedge again without it. As a side note it also negated the pushrod clearance work I had to do on my Eddy's since it moved the pushrods toward the center of the engine. This was with a comp roller cam, Mancini roller lifters and rockers.
 
Freakin A! You and me both. The car rpm’s & it’s acceleration is a bit better and smoother. When your geometry is really out of wack…. The correction is noticeable. If it’s only a little out, noticeable will be not as much.
 
I was in touch with Mike about getting a correction kit for my "Frankenstein" 5.9L Magnum short block with custom-grind hyd roller cam and stock Magnum lifters but with LA Edelbrock heads and valvetrain. He strongly recommended going to larger-diameter pushrods which would require me to pull the heads and open up the pushrod holes even more due to the weird angle from the taller roller lifters. Idk, I want to do it but that's a lot of time, effort and money (3/8" pushrods + rocker set + geometry kit) I just don't have at the moment. I guess I should have hit him up before I put the engine together lmao.

I do worry the stock LA stamped rockers at ~.540" lift are side-loading the valve stems and wearing the tips but... gah can't let that stuff get to me or I won't be able to sleep at night.
 
MopaR&D said:
I was in touch with Mike about getting a correction kit for my "Frankenstein" 5.9L Magnum short block with custom-grind hyd roller cam and stock Magnum lifters but with LA Edelbrock heads and valvetrain. He strongly recommended going to larger-diameter pushrods which would require me to pull the heads and open up the pushrod holes even more due to the weird angle from the taller roller lifters. Idk, I want to do it but that's a lot of time, effort and money (3/8" pushrods + rocker set + geometry kit) I just don't have at the moment. I guess I should have hit him up before I put the engine together lmao.

I do worry the stock LA stamped rockers at ~.540" lift are side-loading the valve stems and wearing the tips but... gah can't let that stuff get to me or I won't be able to sleep at night.
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You need to move up to those badass paired roller rockers Hughes offers for the Magnum heads.
 
^^^^^^I sold my cranes for the hughes, they're shorter and the oil band stays in the bore. I originally had to hog the bottom of the head with a .572 lift and 3/8" pushrod. The angles were crazy. After the lifters and b3 kit, the rods cleared as if I wouldn't have had to do anything. It did blow that every lifter change meant new head gaskets
 
This is the crazy angle with the taller crane retro rollers at full lift, I don't have a pic after the hughes and b3 kit, but with the shorter barrel and the rocker moved back, the pushrod is now centered. It doesn't take much. This all came to light with rocker to retainer clearance issues.

20151012_163800.jpg
 
RustyRatRod said:
You need to move up to those badass paired roller rockers Hughes offers for the Magnum heads.
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Those look awesome but I'm running LA-based Edelbrock heads so they won't work, fortunately there are more rocker (and intake!) options available for LA engines. I'm thinking to get some PRWs through Mike when the time comes.
 
Not sure, i think I still have them. I changed those to beehives .
 
Had I used the b3 kit with the big retainers I wouldn't have had to change the springs. As far as valve "float" and rev limiting issues......there where none. Durability was not an issue with 5000 miles and 27 passes in the low 11's . I've seen and been on the receiving end of the beehive hate.
 
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