273 Rocker Arm Oiling

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340inabbody

340inabbody

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How does the oiling of the pushrod ball stud work on the 273 rocker arms? I have inspected mine and don’t see any path that the oil can get through. There is a hole in the rocker arm yes. But the adjuster has some sort of interference fit with the adjuster screw. There is no channel relief in the threads creating a path for the oil to drip through. Is this some sort of thread that makes an mechanical interface fit while also allowing some oil to dribble through?

I am really curious about this…

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At rpm oil is flinging all over the place under the valve cover. Trust me… it’s wet
 
Still trying to understand this design. Looks like special threads that are interferenced or thread angle differential? The threads look straight not spiraled or canted….

I believe air can get through even though they are super tight.
 
Interference fit on the rocker body threads.
 
There are two holes in the rockers. The lower hole on the backside of the rocker squirts oil in to the pushrod cup.
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340inabbody said:
Yes I see that BUT how does the oul get past the adjuster screw? It’s got to be about the type of thread.
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It goes through the threads. Stop thinkin about it. That's how it's worked for decades. You're askin questions. We're answering them. Quit bein bullheaded and listen.
 
RustyRatRod said:
It goes through the threads. Stop thinkin about it. That's how it's worked for decades. You're askin questions. We're answering them. Quit bein bullheaded and listen.
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My curiosity isn’t being bullheaded. It’s how I learn. Without curiosity there is no knowledge…..
 
340inabbody said:
My curiosity isn’t being bullheaded. It’s how I learn. Without curiosity there is no knowledge…..
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I get it, but repetitive curiosity is bullheaded. Especially when you have multiple people telling you the same thing and you keep asking/arguing. We're not gonna steer you wrong.
 
RustyRatRod said:
I get it, but repetitive curiosity is bullheaded. Especially when you have multiple people telling you the same thing and you keep asking/arguing. We're not gonna steer you wrong.
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Question: How does the oiling of the pushrod ball stud work on the 273 rocker arms? I have inspected mine and don’t see any path that the oil can get through. There is a hole in the rocker arm yes. But the adjuster has some sort of interference fit with the adjuster screw. There is no channel relief in the threads creating a path for the oil to drip through. Is this some sort of thread that makes an mechanical interface fit while also allowing some oil to dribble through?

Response 1. At rpm oil is flinging all over the place under the valve cover. Trust me… it’s wet.
Response 2. Interference fit on the rocker body threads.
Response 3. There are two holes in the rockers. The lower hole on the backside of the rocker squirts oil in to the pushrod cup.

Doesn’t appear that multiple people are telling me the same thing. I don’t see any argument here with ANY of the responses. Been quite respectful as that’s who I am. Your last response confirms my thoughts about the path of the oil through the threads. In mechanical assemblies there is wuite a bit of science and engineering that os really interesting. Am just trying to better understand what type of threads these are as I need to also replace a few. Since its a special thread I really don’t want to **** up my only rockers as I rebuild my valve train. So if you think I am overthinking this then have a beer and chill out. Maybe tomorrow someone with knowledge of the type of threads might respond.
 
340inabbody said:
Question: How does the oiling of the pushrod ball stud work on the 273 rocker arms? I have inspected mine and don’t see any path that the oil can get through. There is a hole in the rocker arm yes. But the adjuster has some sort of interference fit with the adjuster screw. There is no channel relief in the threads creating a path for the oil to drip through. Is this some sort of thread that makes an mechanical interface fit while also allowing some oil to dribble through?

Response 1. At rpm oil is flinging all over the place under the valve cover. Trust me… it’s wet.
Response 2. Interference fit on the rocker body threads.
Response 3. There are two holes in the rockers. The lower hole on the backside of the rocker squirts oil in to the pushrod cup.

Doesn’t appear that multiple people are telling me the same thing. I don’t see any argument here with ANY of the responses. Been quite respectful as that’s who I am. Your last response confirms my thoughts about the path of the oil through the threads. In mechanical assemblies there is wuite a bit of science and engineering that os really interesting. Am just trying to better understand what type of threads these are as I need to also replace a few. Since its a special thread I really don’t want to **** up my only rockers as I rebuild my valve train. So if you think I am overthinking this then have a beer and chill out. Maybe tomorrow someone with knowledge of the type of threads might respond.
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Ok. Fair enough. In some of your other threads though, this is the case. Sorry if I confused them. That said, are you going to question and argue with post #5? It shows so clearly a blind man could figure it out, yet you still question. The oil seeps through the threads. They are interference fit, but the interference isn't liquid or air proof. That's how they are designed. It's a good design, too. The only thing I would liked to have seen was Chrysler use non interference threads with non interference adjusters with a positive lock nut on top, but that's simple enough to remedy. I did it on my slant 6 unicorn head. Although the slant 6 rockers are not ductile iron (I wish) they did have interference fit adjusters. So I did away with those in favor of some good Crane adjusters and lock nuts. If I ever get that engine finished, they will be a nice addition. You can do the same to yours. It's a nice upgrade.
 
Am just trying to better understand what type of threads these are as I need to also replace a few. Since its a special thread I really don’t want to **** up my only rockers as I rebuild my valve train.
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they used an interference/tapered fit. if you need to replace a few, it's my personal opinion to replace the whole set with new adjusters that have lock nuts. it's more work, but i think it's a worth while upgrade.

here's a link to a kit:

PRW 9531808: Rocker Arm Valve Lash Adjuster Screw Kit for Mopar 273-440 [4135 Ball End] - JEGS

Get the Best Performance with PRW Rocker Arm Valve Lash Adjuster Screw Kit for Mopar 273-440 [4135 Ball End] 9531808 parts at JEGS. Shop Now at the Guaranteed Lowest Price!
www.jegs.com www.jegs.com

anyway, as long as the holes are clear, everything gets oil.
 
junkyardhero said:
they used an interference/tapered fit. if you need to replace a few, it's my personal opinion to replace the whole set with new adjusters that have lock nuts. it's more work, but i think it's a worth while upgrade.

here's a link to a kit:

PRW 9531808: Rocker Arm Valve Lash Adjuster Screw Kit for Mopar 273-440 [4135 Ball End] - JEGS

Get the Best Performance with PRW Rocker Arm Valve Lash Adjuster Screw Kit for Mopar 273-440 [4135 Ball End] 9531808 parts at JEGS. Shop Now at the Guaranteed Lowest Price!
www.jegs.com www.jegs.com

anyway, as long as the holes are clear, everything gets oil.
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Cool. I was trying to find those for him. All I found was Mancini ones for 169 bucks. I don't see what size the cup balls are on those though. Mancini sells both 5/16 and 3/8 balls for the same price. I didn't see what size balls the PRW has though. Maybe I missed it? I said balls. A lot.
 
balls, balls, said the queen; if i had two i'd be a king!

thems is 5/16 balls. 7/16-20 thread

they make several different flavors: 3/8 balls with 7/16-20 thread, 5/16 cup with 3/8-24 thread, and they sell all the components as loosies too. both jegs and summit carry them.
 
junkyardhero said:
balls, balls, said the queen; if i had two i'd be a king!

thems is 5/16 balls. 7/16-20 thread

they make several different flavors: 3/8 balls with 7/16-20 thread, 5/16 cup with 3/8-24 thread, and they sell all the components as loosies too. both jegs and summit carry them.
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Yeah then he needs the 3/8 24 thread with the 5/16 balls. I said balls.
 
RustyRatRod said:
Yeah then he needs the 3/8 24 thread with the 5/16 balls. I said balls.
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likely so. from a photo in another thread it looks like they may have already upgraded some of them... but then again i'll not make brash assumptions. they could be crane or isky, or erson or even old melling replacements.
 
340inabbody said:
Yes I see that BUT how does the oul get past the adjuster screw? It’s got to be about the type of thread.
Click to expand...
the oil obviously dribbles/seeps round the threads down onto the ball and cup. it's not rocket science, it's worked well for decades and doesn't warrant the amount of questioning you're giving it.
neil.
 
Stock 273 rockers had a hole drilled right through the adjuster casting and into the rocker so oil would flow sound the threads and dribble down into the cup.

For higher rom operation one modification was to brace the back side opening so oil would be forced down the threads and into the cup. This helped keep the oil from flinging off at higher rpm.
 
RustyRatRod said:
Ok. Fair enough. In some of your other threads though, this is the case. Sorry if I confused them. That said, are you going to question and argue with post #5? It shows so clearly a blind man could figure it out, yet you still question. The oil seeps through the threads. They are interference fit, but the interference isn't liquid or air proof. That's how they are designed. It's a good design, too. The only thing I would liked to have seen was Chrysler use non interference threads with non interference adjusters with a positive lock nut on top, but that's simple enough to remedy. I did it on my slant 6 unicorn head. Although the slant 6 rockers are not ductile iron (I wish) they did have interference fit adjusters. So I did away with those in favor of some good Crane adjusters and lock nuts. If I ever get that engine finished, they will be a nice addition. You can do the same to yours. It's a nice upgrade.
Click to expand...
I haven’t read past this post as I have been busy. BUT I have to break it to ya you’re wrong here. I just figured out how the oil path ACTUALLY works. It’s because I was curious. Curiosity like what drove Richard Fineman to solve the Shuttle failures root cause.
As can be easily seen by my pictures the oil is not dispersed through the threads. So they are not part of the equation or oiling process. The ACTUAL oil relief hole is BELOW the threads. It simply seeps out and onto the ball.
Really a simple concept. Surprised that I found this on first inspection that I have ever done on these. As soon as I took it apart I had that ah ha moment.
Its not about oneupsmanship here. It’s about curiosity truth and learning or it is at least for me. Not putting anyone doen here. I am a novice at best working on stuff I never worked on before. So far I have learned of several mistakes the engine builder made. And I never built an engine before. I owe that to you guys helping me!
Thank you!

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IMG_2127.jpeg
 
340inabbody said:
I haven’t read past this post as I have been busy. BUT I have to break it to ya you’re wrong here. I just figured out how the oil path ACTUALLY works. It’s because I was curious. Curiosity like what drove Richard Fineman to solve the Shuttle failures root cause.
As can be easily seen by my pictures the oil is not dispersed through the threads. So they are not part of the equation or oiling process. The ACTUAL oil relief hole is BELOW the threads. It simply seeps out and onto the ball.
Really a simple concept. Surprised that I found this on first inspection that I have ever done on these. As soon as I took it apart I had that ah ha moment.
Its not about oneupsmanship here. It’s about curiosity truth and learning or it is at least for me. Not putting anyone doen here. I am a novice at best working on stuff I never worked on before. So far I have learned of several mistakes the engine builder made. And I never built an engine before. I owe that to you guys helping me!
Thank you!

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View attachment 1716254916
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Ok, so it dribbles over whatever threads are exposed on the bottom. The frikkin point everybody was trying to tell you is that IT WORKS.
 
RustyRatRod said:
Ok, so it dribbles over whatever threads are exposed on the bottom. The frikkin point everybody was trying to tell you is that IT WORKS.
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Welp mine wasn’t! Thats the fing point. I wasn’t getting crapola out of my top end when hand priming at 60psi. SOMETHING was wrong and I needed to understand what. I was in a debugging mode trying to understand how the system worked.
 
Make sure everything is clean from the oil passages to the shafts to the rockers, to the adjusters and out the back of the rocker. Things can get gummed up, ... over the years.
 
Rocket said:
Make sure everything is clean from the oil passages to the shafts to the rockers, to the adjusters and out the back of the rocker. Things can get gummed up, ... over the years.
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Thanks Pierre! Yes I am doing this methodically. The shafts look great. I removed the caps and cleaned them throughly in kerosene with bore brushes. Used fine sandpaper as well. The caps didn’t fit but I found some 5/8 freeze plugs that did Dorman555-011 that right. Thanks so much for your help and guidance on this!!

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