Reworking the 273 Adjustable Rockers

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Jadaharabi

Jadaharabi

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I think there are some who might be interested in how I modified the oiling to stop the pushrod and valve stems from starving for oil at high rpm.

Something even more important that we all need to be aware of is EPA is after our race cars and off road vehicles.

Congressional legislation (H.R. 4715), the “Recognizing the Protection of Motorsports Act of 2016” (RPM Act) is to fight EPA

Checkout it out go to the SEMA web site.
https://www.sema.org/sema-enews/201...email&utm_content=50765031&utm_campaign=eNews

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Can you explain what the theory of what you are trying to do?

Why drill though the set screw area, then use a bolt to block it off. Is this to get oil from the shaft to the set screw and not let it squirt out of the end???

Is the hole on the opposite side to help oil get to the valve and rocker arm contact area?
 
At high rpm the oil is slung off of the top of the rocker arm so I tapped the hole on top part way down with a #6 tap. Then i put red locktight on a soft #6 screw and tighten it till it snaps in two. I then grind the stud down flat. I then drill a 1/8 hole under the arm that is pointing up toward the tip.
 
Jadaharabi said:
At high rpm the oil is slung off of the top of the rocker arm so I tapped the hole on top part way down with a #6 tap. Then i put red locktight on a soft #6 screw and tighten it till it snaps in two. I then grind the stud down flat. I then drill a 1/8 hole under the arm that is pointing up toward the tip.
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Ok, thanks. It's good to know how it all works. Nice job... :thumblef:
 
Why not drill it on the white line so the oil will go to the adjusting screw and pushrod cup? How much oil can get through the screw threads with it going through the screw hole? Would this give it more oil?

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The hole on the outside is from the machining of the pushrod oiling hole. What happens is the oil travels around the threads of the adjusting screws and is flung off. The hole is the perfect size for a #8 tap. I tapped it part way then put the adjusting screw back in. Next I screwed a #8 soft screw with red loc tight in against the adjusting screw untill it twisted in two. The screw will be lightly threaded by turning the adjusting screw in and out a time or two.
 
krazykuda said:
Why not drill it on the white line so the oil will go to the adjusting screw and pushrod cup? How much oil can get through the screw threads with it going through the screw hole? Would this give it more oil?

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The problem is not with the oil going down to the pushrod tip as it was designed. The problem is they didn't plug the access hole they made when they drilled the passage

By the way that adjusting screw tip in the picture is fried. But the picture doesn't show it.
 
So the access hole is there from the factory and you are just plugging it?

Does it matter, I wouldn't think that it would leak too much oil if any...

I would be worried that if I put the screw in too deep, it would interfere with the adjusting screw.... :violent1: :banghead:
 
I always thought that was where they drilled to get pressure in the adj screw, to keep it adjusted.
 
The reason they don't oil is because the oil hole in the rocker arm (on the pushrod side) does not line up with the oil hole in the shaft.

You MUST have the holes lined up so full pressure oil gets to the cup/ball when the valve is on the seat.

GenII hemi's had the oil hole timing off. ALL W-2/5 shafts and rockers are out of time. MoPar KNOWS this and they do NOT care.

If you are using heavy spring pressures, big RPM, then you need to assemble the rockers on the shaft (without the adjusters installed) and put all the valves in the head, preferably with soft springs if you have them. I should mention you need to blue the shafts first.

then take a small, sharp scribe and go through the oil hole in the back of the rocker and scribe a mark on the shaft. Do this for all the rockers.

Take the rockers off the shaft. Look at how far off the oil holes are. If doing a W-2/5 head, you will be STUNNED. they are off front to rear, and radially.
Take a ball of lead shot from a shotgun shell and pound it into the original holes. file it flat and smooth. Next, drill new holes where you scribed on the shaft. Make the hole a bit bigger than the OEM stuff.

Now when you put you shafts and rockers back on, they will get full oil pressure when the valve is on the seat. It will fill the cup up and you will not blue the rocker balls and cups any more.
 
I guess I'm not sure I understand the need for this mod. At no time do the rockers get "full oil pressure" unless you change the method of oiling the top end. In factory oiling the holes line up to expose the shaft to operating pressure for a few degrees out of 360°. I'm guessing something like 15-20°? So what's felt is a pulse which is then dispersed over the whole shaft because the oil pressure is leaking out the shaft and the sides of each rocker.
I wouldn't use these rockers for "big springs" or "big rpm". And if I was building for those, I'd probably be swapping to pushrod oiling.
 
moper said:
I guess I'm not sure I understand the need for this mod. At no time do the rockers get "full oil pressure" unless you change the method of oiling the top end. In factory oiling the holes line up to expose the shaft to operating pressure for a few degrees out of 360°. I'm guessing something like 15-20°? So what's felt is a pulse which is then dispersed over the whole shaft because the oil pressure is leaking out the shaft and the sides of each rocker.
I wouldn't use these rockers for "big springs" or "big rpm". And if I was building for those, I'd probably be swapping to pushrod oiling.
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I have run this type of rocker with 280 on the seat and 750 over the nose. It is the W-2 rockers but other than the bushing, they are the same.

Once you get past about 2500 RPM, there is almost constant flow to the rocker shafts, because the time spent with the holes lined up is short. There are pulses for sure, but as the RPM's go up, the pulses get shorter. As long as there is pressure in the system, when the oil hole in the shaft and the oil hole in the rocker lines up with the hole in the shaft, it will pressure feed the cup and ball with full oil pressure. That is another reason to run a HIGH VOLUME, HIGH PRESSURE PUMP. You need all the volume you can get, and the pressure helps get the oil out of the shaft to the cup and ball.

I have successfully run 360 pounds on the seat, almost 900 over the nose and made power past 8500 RPM. And almost never hurt a pushrod. It cost me almost 20k dollars and several years but I got it. With ZERO help fro MoPar. I actually had a lawyer draw up a bill with documentation and pictures of the issues, and how (at that time) brand new rockershafts were incorrectly drilled. They used the "race only" clause to screw me but all I really wanted was a PUBLIC tech bulletin acknowledging the issue and the correction for it. But they don't care.

Most guys don't need pushrod oiling.

I was at PRI about a 15-18 years ago and I happened by the Jesel booth. There was well known engine builder there who I met in person a couple of times, and talked to him on the phone many, many times. After we all were introduced, I was let in on the conversation. And the discussion was how to ELIMINATE pushrod oiling in Comp and Pro Stock engines and trying to use a system (highly modified) that was close to what Chrysler had used. Those guys don't care for PR oiling but they are better with the devil they know.

AFAIK, they looked into the non pushrod oiling deal, but not sure what came of it. It's possible the whole thing was not worth the effort.


EDIT: I also wanted to mention that most of the time, in situations noted above, I put a fairly big groove in the number 2 and 4 cam bearing journals. This helps, especially over 8000 RPM to keep oil upstairs.
 
krazykuda said:
So the access hole is there from the factory and you are just plugging it?

Yes

Does it matter, I wouldn't think that it would leak too much oil if any...

I would be worried that if I put the screw in too deep, it would interfere with the adjusting screw.... :violent1: :banghead:
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It does matter once you get past 6000 rpm because the oil wants to shoot straight out instead of turning down to the cup. The oil coming out of the top is going up to the top of the valve cover stead of flowing down on top of the valve. That's why racers cook the tips and adjuster ball, they are not getting the oil they did at 4500.

As for the screw hitting the adjuster not a problem. If you have the adjuster in the rocker and screw the screw in the hole untill it hits you then turn the adjuster and it will cut grooves in the tip of the plug. This will also keep it from turning back out.

When you tap the hole you only put 4 or 5 threads in it that way you are forcing the screw into the unthreaded part and the resistance helps to lock it in place.

As for the hole in the top you drill it 3/4s of the way through. Tap it 3 or 4 threads then screw the plug in untill it twist in two. A little loc tite on the threads doesn't hurt either.
 
moper said:
I guess I'm not sure I understand the need for this mod. At no time do the rockers get "full oil pressure" unless you change the method of oiling the top end. In factory oiling the holes line up to expose the shaft to operating pressure for a few degrees out of 360°. I'm guessing something like 15-20°? So what's felt is a pulse which is then dispersed over the whole shaft because the oil pressure is leaking out the shaft and the sides of each rocker.
I wouldn't use these rockers for "big springs" or "big rpm". And if I was building for those, I'd probably be swapping to pushrod oiling.
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Before NHRA changed the stock class rules these and the Isky look alikes were the only adjustable rockers you could run.
The cams with the full groove on the #2 and #4 journals have full pressure to the heads. At 6000 and above the hole in the cam an block are lining up so fast it has back pressure in the rocker arm shafts. That pressure is causing the rocker arm oil to blast out of the holes instead of flowing out an doing it's job.

This modification is not for a street car that sees 2500 to 4000 rpm most of the time an maybe gets run thru the gears once or twice a week.

This is not the W-2 rocker if you look at a W-2 there is no top hole and the hole at the push rod is welded shut. It comes from Mopar that way. The W-2 also have the hole for oiling the valve stem underneath the arm like I'm doing. I guess you could say I'm updating to the W-2 design only I'm not going to bush my rockers.
 
Jad, VG info! To clarify: (1) you are drilling a hole in the rocker (& the shaft) inline with the underside of the rocker arm/valve interface? (the drillbit photo?) and (2) you are drilling the OE hole in the rocker on the threaded adjuster side further inline into the shaft at the right clocking (with valve closed) then closing the outside hole used to access it (same one Ma used to originally drill it) but Ma did not drill thru to the shaft at that clocking and that is what we are adding?. Correct or not correct? thank you for your time bro. RR
 
Rapid Robert said:
Jad, VG info! To clarify: (1) you are drilling a hole in the rocker (& the shaft) inline with the underside of the rocker arm/valve interface? (the drillbit photo?) and (2) you are drilling the OE hole in the rocker on the threaded adjuster side further inline into the shaft at the right clocking (with valve closed) then closing the outside hole used to access it (same one Ma used to originally drill it) but Ma did not drill thru to the shaft at that clocking and that is what we are adding?. Correct or not correct? thank you for your time bro. RR
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RR Thank you for your post.

There is no drilling of the shaft. My shaft has the banana groves and 90 degrees from that on the pushrod side is a hole.

The only hole I'm drilling is the one under the arm on the valve side. it is 1/8 inch and is drilled at an angle to the tip.

No drilling on the push rod side. The hole is the correct size for the #8 tap. I do not tap all the way thru. I only cut 4 or 5 threads. I bottom out the plug against the adjusting screw.

To repeat I am not drilling into the shaft. On the push rod side I'm just plugging the outside hole to stop oil loss.

On the top I'm plugging that hole to stop oil spraying the inside of the valve cover top.
Then I drill one hole under the arm angling up to the tip of the arm.
As I have said this is how the W-2 rockers are setup from Mopar only they weld the hole closed.
 
Jadaharabi said:
There is no drilling of the shaft. My shaft has the banana groves and 90 degrees from that on the pushrod side is a hole.

The only hole I'm drilling is the one under the arm on the valve side. it is 1/8 inch and is drilled at an angle to the tip.

No drilling on the push rod side. The hole is the correct size for the #8 tap. I do not tap all the way thru. I only cut 4 or 5 threads. I bottom out the plug against the adjusting screw.

To repeat I am not drilling into the shaft. On the push rod side I'm just plugging the outside hole to stop oil lose.

On the top I'm plugging that hole to stop oil spraying the inside of the valve cover top.
Then I drill one hole under the arm angling up to the tip of the arm.
As I have said this is how the W-2 rockers are setup from Mopar.
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And as I have already posted at length, the holes in the shafts are in the WRONG location on W2/5 heads. They are off by a mile. You can groove all you want, but at a certain point (depends on spring load, cam lobe design, rpm etc) you MUST relocate the oil holes.

I have done roughly a dozen Gen II hemis and EVERY SINGLE ONE OF THEM HAD THE OIL HOLES CLOCKED WRONG. Every one of them had OE rockers and shafts.

And depending on the rocker, the oil hole is off on Pcar heads too. I just had to fix my personal shafts. They are drilled for hydraulic valve gear. So there is no oil hole in the correct location.
 
Mopar Tim said:
I always thought that was where they drilled to get pressure in the adj screw, to keep it adjusted.
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Correct on the first part. but the oil is for the pushrod tip and not to adjust anything.

The oil in the lifter is doing the adjusting, once the rocker is adjusted, that has nothing to do with oiling the valve and pushrod tips.
 
Looks like good execution to me. If it works good for you, do it.
 
yellow rose said:
And as I have already posted at length, the holes in the shafts are in the WRONG location on W2/5 heads. They are off by a mile. You can groove all you want, but at a certain point (depends on spring load, cam lobe design, rpm etc) you MUST relocate the oil holes.

I have done roughly a dozen Gen II hemis and EVERY SINGLE ONE OF THEM HAD THE OIL HOLES CLOCKED WRONG. Every one of them had OE rockers and shafts.

And depending on the rocker, the oil hole is off on Pcar heads too. I just had to fix my personal shafts. They are drilled for hydraulic valve gear. So there is no oil hole in the correct location.
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These rockers don't work on W-2/5 heads or Gen II hemis either. I am sorry your having so much trouble. Maybe you should try some X or J heads with the 273 rockers modified like I'm doing.

The grove in the bottom of the rocker arm shaft is to spread the oil out over a larger area than just a hole provides because ALL the force of the valve spring is against it at that point.
 
Jadaharabi said:
Correct on the fist part. but the oil is for the pushrod tip and not to adjust anything.

The oil in the lifter is doing the adjusting, once the rocker is adjusted, that has nothing to do with oiling the valve and pushrod tips.
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I meant the hole was drilled to keep the adjuster from turning. I have noticed when screwing in the adjuster, it got harder to turn when it went past that hole. Did not think oil would come out of there.
 
Mopar Tim said:
I meant the hole was drilled to keep the adjuster from turning. I have noticed when screwing in the adjuster, it got harder to turn when it went past that hole. Did not think oil would come out of there.
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I always thought the rockers were tapped with a interference fit so the adjusters won't back out and without a lock nut. I am a long ways from my rockers right now. Anyone have one handy? Is the adjuster threads tapered or are the threads in the rocker interferenced?
 
I had to check and make sure I wasn't in the race part of the forum as this mod seems to be concerned with sustained rpm's over 4k. I used 273 rockers on my stroker motor last season (damn budget!!) and noticed no oiling problems. It's been discussed many times the seemingly inconsistency in the 1.5 ratio of 273 rockers? With this said a car sustaining over 4k rpm's is likely a competition car? 273 rockers are a great durable stock unit. Personally at my earliest (budjetable) convenience I bought what I believed to to be a much more proformance oriented rocker. I feel happy leaving my 273 rockers in their original condition with standing a little bit of clearancing for the springs and stop adjusters for the next guy or the next motor I have.
 
Jad, ok, NO drilling into the shaft. plug the top rocker hole (weld or setscrew). setscrew in the access hole in the adjuster side per your directions. drill .100" hole on valve side clocked just right to shoot a blast onto valve tip. All good so far? I have a bunch of shafts to choose from & some if not all (never noticed) have the banana grooves that would be on the bottom toward the valve side with the notches orientated correctly. (down/pass rear and down dr front). Good so far? is the OE oiling hole/banana groove enough for the adjuster/cup AND for the added .100" hole on the other side for the valve tip we wanna add? EDIT I reread your response again & I think I got it as in the OE shaft hole/banana groove DOES provide enough oil for the added valve side hole (or you woulda commented). Always a good day when you can answer your own questions!. Thanks again bro. this is gonna be a high RPM circle track 360 & I dont wanna leave anything on the table nor the embarrassment of a DNF!
 
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