Good quality 1.5 roller rockers?

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midnight340

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I know this has been asked a number of times, but wanted to find out what is currently a good way to go. I have a road trip plus 1/8 mile drags in 10-12 days so need to get this sorted!!

I am running the 740 Voodoo solid lifter cam with .526"/.546" lift in my 340. I am trying to use a re-bushed set of 273 factory units on new shafts. Geometry is good, but having trouble with one or two coming loose (even with lock nuts!) ...probably worn threads in the adjusters.

I am trying to contact Mike at B3 but haven't heard back yet. I can imagine it's a very busy time of the year for him. I have read his articles and know about his geometry kits.

I believe I have plenty of lift for my ported X heads so want to stay with 1.5 rockers.
I don't want to break the bank on these, but DO NOT want pieces I can't trust. Thinking about the Comp Pro Magnum units. Anyone using these with Mike's geometry kit???
 
go to the B3 website and read the tech reports- I think there are 3-4 of them
B3 can steer you right on the rockers
plan one of his kits if you want correct geometry
you are in the lift range where stock rockers are ok if not super spring pressure
and iron rockers are buletproof in your lift range and do not require the b3 kit
 
Mike at B3 posted in another forum that he is very busy right now before heading out to the Carlisle show, so anyone trying to reach him should please be patient.
Read through the thread titled TF 190 Heads in the Racers Forum, where he mentions rocker choices.
Sorry I can't post a hyperlink; my phone won't copy text any more.
 
Maybe I can stay with these factory units if I get it sorted. Gary at Rocker Arms Unlimited says they should have caught any wear in the threads so is sending me a couple more bushed and prepped arms.

Also I have a good local Mopar machine shop so I'll check with them to see if I could have these tapped for larger diameter adjusters?? I know that RAU can do this, but I do not have time before my summer events.
 
I know this has been asked a number of times, but wanted to find out what is currently a good way to go. I have a road trip plus 1/8 mile drags in 10-12 days so need to get this sorted!!

I am running the 740 Voodoo solid lifter cam with .526"/.546" lift in my 340. I am trying to use a re-bushed set of 273 factory units on new shafts. Geometry is good, but having trouble with one or two coming loose (even with lock nuts!) ...probably worn threads in the adjusters.

I am trying to contact Mike at B3 but haven't heard back yet. I can imagine it's a very busy time of the year for him. I have read his articles and know about his geometry kits.

I believe I have plenty of lift for my ported X heads so want to stay with 1.5 rockers.
I don't want to break the bank on these, but DO NOT want pieces I can't trust. Thinking about the Comp Pro Magnum units. Anyone using these with Mike's geometry kit???



I've seen this. It's usually (but not always) about 2 things. Geometry is off. Again, a centered sweep isn't nearly as important as a narrow sweep pattern.

The other is pushrods bending. Yep. They bend and then unbend. Over and over and over. I've seen some bend as much as .080! We knew how much they were bending because the witness marks on the heads. There was .080 clearance and you could see the rub marks.

Funny thing is, the pushrods were still straight enough to used.

What is happening is all that bending sets up a resonance frequency that does all kinds of wierd things. You see this on every brand of engine, it's not just a Chrysler thing. If you are running a roller it will also cause the rivets on the link bars to break and crap like that.

That's my thoughts. I could be wrong.
 
Mike at B3 posted in another forum that he is very busy right now before heading out to the Carlisle show, so anyone trying to reach him should please be patient.
Read through the thread titled TF 190 Heads in the Racers Forum, where he mentions rocker choices.
Sorry I can't post a hyperlink; my phone won't copy text any more.

Thanks, will do!!
 
I've seen this. It's usually (but not always) about 2 things. Geometry is off. Again, a centered sweep isn't nearly as important as a narrow sweep pattern.

The other is pushrods bending. Yep. They bend and then unbend. Over and over and over. I've seen some bend as much as .080! We knew how much they were bending because the witness marks on the heads. There was .080 clearance and you could see the rub marks.

Funny thing is, the pushrods were still straight enough to used.

What is happening is all that bending sets up a resonance frequency that does all kinds of wierd things. You see this on every brand of engine, it's not just a Chrysler thing. If you are running a roller it will also cause the rivets on the link bars to break and crap like that.

That's my thoughts. I could be wrong.

Wow! That's one I would never have thought of!! But I can't even imagine how crazy it gets under those valve covers at 7 or 8 grand!!!!!!!! I'm checking and do have some threads way too worn. I can feel the adjuster rock some in the arm with the lock nut loose!!!!
 
Wow! That's one I would never have thought of!! But I can't even imagine how crazy it gets under those valve covers at 7 or 8 grand!!!!!!!! I'm checking and do have some threads way too worn. I can feel the adjuster rock some in the arm with the lock nut loose!!!!


Yeah, it will eventually beat the threads out of the rockers too. Did you buy a correction kit form B3? What size pushrods are you using and what are your spring loads?
 
First, the geometry check out near perfectly with arms perpendicular to valve stem at 1/2 lift.

Still using some 5/16" Erson pushrods I got when I first built the motor way back. The springs are the recommended Lunati dual springs #73195 402# rate.

Listed as Seat Load: 115@1.700" Open Load: 336@1.150" ....but they are installed at 1.67 so I'm not sure what the loads would be.
 
First, the geometry check out near perfectly with arms perpendicular to valve stem at 1/2 lift.

Still using some 5/16" Erson pushrods I got when I first built the motor way back. The springs are the recommended Lunati dual springs #73195 402# rate.

Listed as Seat Load: 115@1.700" Open Load: 336@1.150" ....but they are installed at 1.67 so I'm not sure what the loads would be.


If you know the spring rate you can calculate the new load.

So... 1.70-1.67 is .030 X 402 is about 12 pounds.

That would make you about 127 on the seat, give or take because unless you verify the numbers with a spring tester you are still operating on faith that the spring is what the manufacturer says it is.


How wide is the sweep? I'm assuming 273 rockers correct? If so, with that much lift there is no way the geometry is right. Can't be. The shafts have to come up and move away from the valve.

You can't change one or more parts of the equation without correcting for it. That means the stand height and position relative to the valve, stem height, net lift, geometry of the rocker itself and I'm probably forgetting something.

IOW's, when Chrysler developed that system, it was for a certain stem height, with a known net lift using that rocker. You have changed the lift by a good amount. Now, that means you need to change the position of the shaft to get everything back where it needs to be.

There are two and only two ways to fix that. Use a kit from Mike or mill the stands off and use blocks and shafts with offset holes so you can alter the position of the shaft.

I never bought into the half lift deal, especially with shaft rockers. You want the sweep as narrow as you can get it.
 
I know this has been asked a number of times, but wanted to find out what is currently a good way to go. I have a road trip plus 1/8 mile drags in 10-12 days so need to get this sorted!!

I am running the 740 Voodoo solid lifter cam with .526"/.546" lift in my 340. I am trying to use a re-bushed set of 273 factory units on new shafts. Geometry is good, but having trouble with one or two coming loose (even with lock nuts!) ...probably worn threads in the adjusters.

I am trying to contact Mike at B3 but haven't heard back yet. I can imagine it's a very busy time of the year for him. I have read his articles and know about his geometry kits.

I believe I have plenty of lift for my ported X heads so want to stay with 1.5 rockers.
I don't want to break the bank on these, but DO NOT want pieces I can't trust. Thinking about the Comp Pro Magnum units. Anyone using these with Mike's geometry kit???


Problems with them coming loose ? Are the rockers machined were the lock nut sets or are you just tightening them down on the rough casting.
 
YellowRose, i appreciate your comments for sure. This is the pattern and also what they look like at half lift.

In my limited experience I didn’t think the geometry or contact patch was too bad given a stock set up and .100” more lift than they were designed for.
AEB12206-DF15-41E5-8D69-97BBB9EA07B5.jpeg
3897B172-8185-4729-A99D-A8435CD9F310.jpeg
 
If you know the spring rate you can calculate the new load.

So... 1.70-1.67 is .030 X 402 is about 12 pounds.

That would make you about 127 on the seat, give or take because unless you verify the numbers with a spring tester you are still operating on faith that the spring is what the manufacturer says it is.


How wide is the sweep? I'm assuming 273 rockers correct? If so, with that much lift there is no way the geometry is right. Can't be. The shafts have to come up and move away from the valve.

You can't change one or more parts of the equation without correcting for it. That means the stand height and position relative to the valve, stem height, net lift, geometry of the rocker itself and I'm probably forgetting something.

IOW's, when Chrysler developed that system, it was for a certain stem height, with a known net lift using that rocker. You have changed the lift by a good amount. Now, that means you need to change the position of the shaft to get everything back where it needs to be.

There are two and only two ways to fix that. Use a kit from Mike or mill the stands off and use blocks and shafts with offset holes so you can alter the position of the shaft.

I never bought into the half lift deal, especially with shaft rockers. You want the sweep as narrow as you can get it.

And thanks for the spring pressure info. I wasn’t sure how to figure that.
 
They might be backing off because the area of the rocker where they seat has not been dressed. If that area is left as cast, the nuts have very little area to tighten down on. It must be very flat there.

That said, that's the rocker I would suggest running. They are very strong. I wouldn't be afraid to run them on a .650 lift roller properly prepared.
 
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YellowRose, i appreciate your comments for sure. This is the pattern and also what they look like at half lift.

In my limited experience I didn’t think the geometry or contact patch was too bad given a stock set up and .100” more lift than they were designed for.
View attachment 1715362836 View attachment 1715362837


your sweep looks nearly as wide the valve stem if i'm seeing it right ,if so your geometry is way off . time for a correction kit .
 
YellowRose, i appreciate your comments for sure. This is the pattern and also what they look like at half lift.

In my limited experience I didn’t think the geometry or contact patch was too bad given a stock set up and .100” more lift than they were designed for.
View attachment 1715362836 View attachment 1715362837
With a roller rocker and a B3 Geometry Correction Kit this is what the sweep pattern will look like.

B8B1CB22-0855-4C39-8850-3EE90FCEBCE1.jpeg
 
Thanks for the comments re the cast surface. That explains a lot!! And it looks like these arms need more work if I want to use them.

I’ve now got less than 2 weeks till I need to be reliable. Yikes. With rollers I’d need pushrods too. Not sure what’s possible. Maybe my local Mopar machine shop can help.
 
your sweep looks nearly as wide the valve stem if i'm seeing it right ,if so your geometry is way off . time for a correction kit .

As compared to what? Keep in mind, these rockers have a different pattern than say a roller tip. The rocker contact pad is much flatter and has a much wider contact area than a roller tip.
 
Thanks for the comments re the cast surface. That explains a lot!! And it looks like these arms need more work if I want to use them.

I’ve now got less than 2 weeks till I need to be reliable. Yikes. With rollers I’d need pushrods too. Not sure what’s possible. Maybe my local Mopar machine shop can help.

I would use them way before I bought something else. They are very strong.
 
Yes and that looks good, but you cannot compare a roller tip pattern to what he has. His pattern does need centering up a bit, but that's about all.
Appreciate your position but the thread title specifically references Roller Rockers so the inference is that the OP is looking to change - hence my post showing what can be achieved.
 
Appreciate your position but the thread title specifically references Roller Rockers so the inference is that the OP is looking to change - hence my post showing what can be achieved.

I understand. I only mention it in case he decides to keep what he has as there's "not much" wrong with it.
 
FWIW.... You cannot and should not be looking at the scrub patch width on the valve stem with 273 or stamped rockers like you would for roller rockers. They are 2 different animals. The contact point of the 273 and stamped rockers 'walks' across the valve stem tip in normal use; they are designed to do that. (It reduces the amount of wiping/scrubbing action between the rocker and valve stem for one thing.)

Believe it or not, that actually changes the rocker ratio through the lift cycle, and compensates for the rocker to valve angle changes to some degree... up to some level of lift. (It is actually better than a roller in that particular way.)

You can see from the OP's pix at mid-lift that the rocker is already slightly 'over-center' (i.e., a bit past being perfectly perpendicular to the valve stem axis). Lowering the shaft, or moving it way from the valve without raising the shaft center line, is ideally needed to get the scrub pattern more centered than it is. But both of those require some machining, I think. I personally would not mess with it at this time; there is still a fairly wide contact patch at the far end of the scrub patch, and since the spring pressures are not massive at full open, then I would think the contact pressures are still within reason. (One contact patch DOES seem to be at the limit!)
 
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