OEM Rocker Arm Side Play

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12many said:
Keeping lifter preload within .050”-.090” will require 3 sets of pushrod lengths. No big deal, all three lengths available singular from Manley. Spacers and pushrod order come monday:lol:
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Did you put a straight edge across the valve stems? If it's the rockers... and it's a .0813 spread.. I would use different rockers and not order 3 diff lengths of push rods. Jmo
 
MOPAROFFICIAL said:
Did you put a straight edge across the valve stems? If it's the rockers... and it's a .0813 spread.. I would use different rockers and not order 3 diff lengths of push rods. Jmo
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Left head varies by .05625”, the right by .075” (Combined was .0813”) Straight edge across both heads, right head all exhausts were .030”-.045” lower than the intakes and the left all the intakes are .027”-.030” lower than the exhausts. Then add the rockers . Crazy! I’ve never seen “new” heads so uneven. Get what you pay for (Black Friday sale) Swapping around rockers worked on four valves, swapping a couple others saw no appreciable changes. Now that all the rockers are corrected they all at least fit the shafts as they should. The 16 pushrods are only $112 shipped
 
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PRH said:
I’m generally not a proponent of Chinese rockers....... but with what you have going on there....... I’d probably go with some PRW’s instead of having to rework stock replacement parts.
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PRW stainless is a decent rocker if they are setup right.
 
12many said:
Lefts vary by .05625”, the rights by .075” (Combined was .0813”) Straight edge across both heads, right head all exhausts were .030”-.045” lower than the intakes and the left all over the place, #7 intake was low as well. I’d have to check the left as I could tell it was just as uneven but didn’t bother to feeler gauge it. I’ve never seen “new” heads so uneven. Get what you pay for (Black Friday sale) Swapping around rockers only worked on two valves but swapping others saw no changes. Now that all the rockers are corrected they all fit as they should. The 16 pushrods are only $112 shipped
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Might be worth having the valve job redone by a machine shop that can get all of the intake seats the same and all of the exhaust the same. There will still be a difference between the two in height but by then it should be like .020 or less between intake and exhaust.
Other option is cut stems to equalize intake stem heights on each head then exhaust to try and end up in the spread or separate lengths per int/exh instead of 3 and a bunch of varied preloads/lifts.
Another option...5.011 vs 5.025...other words..+.050 vs +.100, .150,.200
Play with valves and cutting stems. If one was equip to do so.. could be attacked a few ways. Since we know the seat depths are all over the place but in a bad way..
how are the spring heights?
Sounds like shims or locks or both. I just used -.050 locks and .060 shims to bring in the height needed...
 
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MOPAROFFICIAL said:
Might be worth having the valve job redone by a machine shop that can get all of the intake seats the same and all of the exhaust the same. There will still be a difference between the two in height but by then it should be like .020 or less between intake and exhaust.
Other option is cut stems to equalize intake stem heights on each head then exhaust to try and end up in the spread or separate lengths per int/exh instead of 3 and a bunch of varied preloads/lifts.
Another option...5.011 vs 5.025...other words..+.050 vs +.100, .150,.200
Play with valves and cutting stems. If one was equip to do so.. could be attacked a few ways. Since we know the seat depths are all over the place but in a bad way..
how are the spring heights?
Sounds like shims or locks or both. I just used -.050 locks and .060 shims to bring in the height needed...
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All that is valid and an ideal approach, At this stage it’s mostly baked (heads bolted)
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funds are what they are so really no room to have gone that route. .....you know the story, other than disassembling the heads to check everything, swapping springs for the cam and setting the heights for the open pressure (not just installed, we shimmed as needed) The valve job ootb is well known, a 2-angle, but they seal. Why I didn’t check the valve heights back in late 2020 when we got them I don’t know......oh, actually I do. I was neck deep in my stuff and his heads got put on the shelf right away. With more thorough inspection and measuring earlier on we would have at the least gone Adjustable rockers instead of using these rockers. Doubtful we’d have had any corrections done.
Using six pushrods @7.325”, five @7.350” and five @7.400” and the least preload will be approx .050” and the most (1) will be .0875” most will be .0625”
An acceptable range I think most would agree.
 
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Ironracer said:
My older MP ones fit pretty darn nice...
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Do they really? Does anybody really have a KNOWN set of the MP "heavy duty 340" rockers to get some measurements off of? Anybody?
 
RustyRatRod said:
Do they really? Does anybody really have a KNOWN set of the MP "heavy duty 340" rockers to get some measurements off of? Anybody?
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All I’ve ever read about those is that they were thicker in the pushrod socket area to prevent breakthrough, but you’d think the whole rocker is thicker being a stamping. I can tell you these Mellings are heavier and stamped from slightly thicker steel than the old 78 factory rockers we have.
 
12many said:
All I’ve ever read about those is that they were thicker in the pushrod socket area to prevent breakthrough, but you’d think the whole rocker is thicker being a stamping. I can tell you these Mellings are heavier and stamped from slightly thicker steel than the old 78 factory rockers we have.
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And see....I've never seen THAT in print. All I've ever seen said "thicker cross section" and that is about vague as all heck.

I can attest to the lateral sloppiness. They were never tight on the shaft. Never. The biggest thing here to get things "equal" when using any rocker arm, stock or otherwise is getting the valve stem heights all correct and equal. When I had my slant 6 closed chamber head done, Richie got them all within .002" of each other. That's thanks to the badass Rottler he has.
 
RustyRatRod said:
And see....I've never seen THAT in print. All I've ever seen said "thicker cross section" and that is about vague as all heck.

I can attest to the lateral sloppiness. They were never tight on the shaft. Never. The biggest thing here to get things "equal" when using any rocker arm, stock or otherwise is getting the valve stem heights all correct and equal. When I had my slant 6 closed chamber head done, Richie got them all within .002" of each other. That's thanks to the badass Rottler he has.
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I think I have read that in a really old DC catalog. I’ll look later today and see if I can find it because I’m pretty sure I’ve read the same thing 12many has.
 
Rat Bastid said:
I think I have read that in a really old DC catalog. I’ll look later today and see if I can find it because I’m pretty sure I’ve read the same thing 12many has.
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Could well be.....and it could be my stupid *** is remembering it wrong. I have the Ninth edition engine book, but I caint physically get to it right this minute. It makes sense though that the pushrod cup would be one area of improvement. I have seen several failures there through the years.
 
RustyRatRod said:
And see....I've never seen THAT in print. All I've ever seen said "thicker cross section" and that is about vague as all heck.

I can attest to the lateral sloppiness. They were never tight on the shaft. Never. The biggest thing here to get things "equal" when using any rocker arm, stock or otherwise is getting the valve stem heights all correct and equal. When I had my slant 6 closed chamber head done, Richie got them all within .002" of each other. That's thanks to the badass Rottler he has.
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Maybe someone here has an old damaged or worn out one they could cross section it so we could all see.
As far as the valve stem Heights go, you would think buying a new set of heads that that would be addressed. But it’s been well documented here about these Assembled speed master heads That they fall short in many areas, but they are still usable as is as evidenced by quite a few members here. Some have mentioned using factory style rocker arms but I don’t believe I’ve seen any mentions of the issue I’ve dealt with, or about the various stem heights being addressed. I think most of us would agree as has been mentioned here often, to buy the heads as bare castings and then have them set up properly. But by that time just buying a set of Trick Flows ....... yada yada,
yadda OOTB heads need going through. All that’s been beaten to death. You buy cheap heads assembled like these this is what you get, you can either spend more money to correct them or in our case do what
I’m doing to at least make the situation better.
There is no way I would just slap on without addressing the side to side slop, slid on these rocker arms as is, not taking the time to measure for each pushrod, etc. Do others? Maybe, maybe not.
Could be they’re running fine who knows.
 
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12many said:
Maybe someone here has an old damaged or worn out one they could cross section it so we could all see.
As far as the valve stem Heights go, you would think buying a new set of heads that that would be addressed. But it’s been well documented here about these Assembled speed master heads That they fall short in many areas, but they are still usable as is as evidenced by quite a few members here. Some have mentioned using factory style rocker arms but I don’t believe I’ve seen any mentions of the issue I’ve dealt with, or about the various stem heights being addressed. I think most of us would agree as has been mentioned here often, to buy the heads as bare castings and then have them set up properly. But by that time just buying a set of Trick Flows ....... yada yada,
yadda OOTB heads need going through. All that’s been beaten to death. You buy cheap heads assembled like these this is what you get, you can either spend more money to correct them or in our case do what
I’m doing to at least make the situation better.
There is no way I would just slap on without addressing the side to side Slop, or slid on those rocker arms as is, or maybe even took the time to measure for each pushrod, etc. Maybe, maybe not.
Could be they’re running fine who knows.
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Yeah, I don't even think the factory heads had even stem heights when they were new......as important as it was with non adjustable valve train, but "somehow" they still ran well. lol
 
RustyRatRod said:
Can you measure um in a few spots?
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Yessir I can! I just got back from work I'm Winter Haven, and my damn jaw is infected as heck from a bad tooth.. last week it was my ear.. the antibiotics seem to move it around for me. Lol. I'd have to pull em off the car. If you need em tonight, I'll do it for You.. just need what dimensions you need from What areas..hmm makes me wonder about that "disagree " I got when I was speaking of my own set up...
 
Ironracer said:
Yessir I can! I just got back from work I'm Winter Haven, and my damn jaw is infected as heck from a bad tooth.. last week it was my ear.. the antibiotics seem to move it around for me. Lol. I'd have to pull em off the car. If you need em tonight, I'll do it for You.. just need what dimensions you need from What areas..hmm makes me wonder about that "disagree " I got when I was speaking of my own set up...
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Not necessarily for me, but just for general information. To see how much they actually differ from stock non-heavy duty rockers.
 
RustyRatRod said:
Hell no.
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Thank You Brother Rob !!!!!!! Any I can take w/o pulling the shafts? Rocker cover is loose now... I don't mind going outside, but, I'm not wanting to get sicker ( just got outta shower, water in my ear). I'd imagine You would want the I.D., and the width ( at widest point?) Then maybe total length? But you .at want centerline of shafts to who knows? Let me know, and I Hope Kitty and You have a Blessed New Year!
 
Ironracer said:
Any I can take w/o pulling the shafts? Rocker cover is loose now... I don't mind going outside, but, I'm not wanting to get sicker ( just got outta shower, water in my ear). I'd imagine You would want the I.D., and the width ( at widest point?) Then maybe total length? But you .at want centerline of shafts to who knows?
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Take pictures if you can of one, zoomed and clear.
Here’s an oem rocker and one of the good Mellings (ootb ready) My digital caliper battery is now dead but I’ll get some measurements ASAP. Do you have a caliper to measure things?
The Mellings are slightly thicker as I’ve mentioned earlier. It be interesting to see how they (and any others like Elgin etc) stack up to the MP’s

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