Reworking the 273 Adjustable Rockers

[Jadaharabi]

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.

No the hole was drilled so they could drill the oil passage for the pushrod cup to get oil.

The thread and rocker have an interference fix on these rockers. Yes it got harder to turn because you were getting more thread contact as it went in. The Isky rockers in my motor use a lock nut arrangement.
You could tap that hole all the way to the adjuster and then use a set screw to lock the adjuster. If you were having trouble with them backing off.

Mopar Performance written 1978 page 32 tells about the oil leaking past the screw an out the hole.

 

[toolmanmike]

No the hole was drilled so they could drill the oil passage for the pushrod cup to get oil.

The thread and rocker have an interference fix on these rockers. Yes it got harder to turn because you were getting more thread contact as it went in. The Isky rockers in my motor use a lock nut arrangement.
You could tap that hole all the way to the adjuster and then use a set screw to lock the adjuster. If you were having trouble with them backing off.

Moper Performance written 1978 page 32 tells about the oil leaking past the screw an out the hole.

Or does the oil puddle in the hole and run down the threads into the pushrod cup?

 

[j par]

#-o wait a minute, I get it. This is for some kind of stock race class ops:

 

[Jadaharabi]

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.

I'm just trying to help anyone that might need better oiling of the 273 and isky rockers.

I collected parts for years to build a 73/74 Duster 340/360 NHRA stocker. At the time i got them you could run the 273 or Isky only now you can use anything you want. I'm going with my Isky's upgraded to the W-2 improvements minus the bushing. Yes there is a lot of inconsistency with the ratio. i think the Iskys are a little better about it. Plus I prefer the lock nut.

 

[Mopar Tim]

#-o wait a minute, I get it. This is for some kind of stock race class ops:

I am just learning something I did not know. I just went thru alot to put a solid lifter cam back in my SB. Using these rockers. I just want to understand what is in my engine to the best I can.

 

[Jadaharabi]

Or does the oil puddle in the hole and run down the threads into the pushrod cup?

The oil is under pressure. If you take out the adjuster an look inside, the bottom thread stops just above the bottom of the oil hole. Then the hole is opened up so the oil goes all the way around the screw. Guess what is on the opposite side of the screw from the oil passage. A HOLE.

 

[Jadaharabi]

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!

I drilled the hole for the valve tip oiling to .125 personally.
The grove is on the bottom and 90 degrees from that are oil holes facing the pushrod. I have no hole in the shaft on the valve side. Correction the banana grove is on the spring side of the hold down bolt at the bottom.
If you take out the adjustment screw and look in the bottom of the hole you will see why the oil can blow out the side hole.

 

[Jadaharabi]

I am just learning something I did not know. I just went thru alot to put a solid lifter cam back in my SB. Using these rockers. I just want to understand what is in my engine to the best I can.

If yours is a street motor I would tap the hole on the pushrod side and put #8 set screws in them to lock the Adjuster and at the same time plug the hole. I would leave the oiling hole in the top of the arm alone.

I have evolved in my plugging the pushrod hole to going to use the set screw to lock the adjusters that are not equipped with a jam nut.

 

[Jadaharabi]

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.

Here is the picture from page 32

 

[Jadaharabi]

Trying again to upload

 

[Rapid Robert]

Jad, OK, plug top hole. drill .125 hole aimed right at valve tip. close outer side hole on adjuster side. grooves/hole in middle of groove goes down with that hole slightly offset toward valve side. Good so far! Last question (I promise!). Are you saying there are additional holes in the shaft 90 deg to those grooves/holes that are already on the bottom? I dont think I seen em and you did say to drill NO holes in the shaft. (just wanting to confirm). If so I'm good once I do your rocker mods & leave the shaft as is. Holler when you can. RR

 

[yellow rose]

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.

You are not getting what I am saying.

You can modify and drill all you want. To get the oil correctly on the pushrod and ball, the oil hole in the rocker arm MUST line up with the oil hole in the shaft. It IS that simple. I have never seen an original 273 rocker shaft. I have only had DC or MP ones, and at one time I had some Isky shafts. Not one of them had the oil holes in the correct location.

Again, the ONLY way to get the correct oiling to the pushrod cup/rocker ball, the oil feed hole in the shaft MUST line up with the oil feed hole in the rocker.

This means that whoever is assembling the engine must, MUST mock the head up and physically LOOK to VERIFY the holes are lined up. This is with the rockers on the shaft, the valves in place at the correct installed height, and the adjuster removed and look at it. If you can't see the oil hole in the shaft you need to figure out why.

I have written EXTENSIVELY on this, tried to get it published on other than internet forums, and actually sent in drawings to Chrysler with measurements to see if they would correct and publish the information.

They told me it is the final assembler who is responsible for correct oil timing. Chrysler will NOT admit that for DECADES they have been selling incorrectly machined parts through it's racing programs. Neither will they publish ANYTHING in reference to it.

In my opinion, you can't build a performance engine with out checking this. I know there are thousands and thousands of cars out there with rocker systems that have not been corrected. But eventually, luck runs out.

I am very dogmatic about this because of the costs I incurred sorting out what should have been engineer by Chrysler. It should be a routine check on ALL Chrysler engines, just like P/V clearance or bearing clearances. And corrected when found.

 

[toolmanmike]

Agree to disagree. There is so much oil splashing around under the valve cover that everything gets oil. Now if you gave a 8,000+ rpm race engine you might want to make some modifications. Mopar never has had a problem with rocker arm/shaft/pushrod failures with stock engines (100,000+ miles) so oil hole orientation is not an issue unless you want it to be.

 

[nm9stheham]

Thanks for the thread and notes and all the discussion. Now I know why some of the 273 rockers I possess have the oil hole plugged behind the adjuster, and why a couple of shafts have extra holes.

 

[Jadaharabi]

Jad, OK, plug top hole. drill .125 hole aimed right at valve tip. close outer side hole on adjuster side. grooves/hole in middle of groove goes down with that hole slightly offset toward valve side. Good so far! Last question (I promise!). Are you saying there are additional holes in the shaft 90 deg to those grooves/holes that are already on the bottom? I dont think I seen em and you did say to drill NO holes in the shaft. (just wanting to confirm). If so I'm good once I do your rocker mods & leave the shaft as is. Holler when you can. RR

My picture with the drill inserted shows, I aim at the rocker arm tip in the center of the pad. With the grove at the bottom, my shafts have a hole at the pushrod side 90 degrees from the bottom. I did not drill this second set of holes an they appeared to be factory or professionally drilled. If someone has done them by hand they are excellent with a hand drill or press The shafts came that way with the rockers used.

So I guess I will tear apart my motor an get you some pictures of them this week if I can. While I'm at it I will check the hole alignment in relation to the pushrod oil passage.

Did you take out the adjuster screw an look in where the oil passage an the machining hole are in relation ship to the bottom thread?

Something else to consider is the fact that under load as the rocker is moving the oil will work it's way around the shaft to the oiling holes.

 

[Jadaharabi]

Agree to disagree. There is so much oil splashing around under the valve cover that everything gets oil. Now if you gave a 8,000+ rpm race engine you might want to make some modifications. Mopar never has had a problem with rocker arm/shaft/pushrod failures with stock engines (100,000+ miles) so oil hole orientation is not an issue unless you want it to be.

At High rpm the oil coming off the top of the rocker arm, inside the valve cover is being beaten into a spray mist. That is another reason to plug the hole on the top.

I am not talking about a stock engine but about a 6000+ rpm one.

 

[Rapid Robert]

No need to tear down bro. you have done more than enough already. I will (1) cap the top hole (2) pull adjuster & check inside hole (clocking to bottom threads) (3) if good then cap outside hole (on that side) (4) other side, drill 1/8 hole to oil pushrod cup (drill bit pic) (4) check if there is a second set of OE holes in my shaft(s) 90 deg to the OE bananna grooves/hole. I have a bunch of shafts so I will see what I see today. RR

 

[Jadaharabi]

Thanks for the thread and notes and all the discussion. Now I know why some of the 273 rockers I possess have the oil hole plugged behind the adjuster, and why a couple of shafts have extra holes.

Your welcome. Glad we could help.

 

[Jadaharabi]

You are not getting what I am saying.

You can modify and drill all you want. To get the oil correctly on the pushrod and ball, the oil hole in the rocker arm MUST line up with the oil hole in the shaft. It IS that simple. I have never seen an original 273 rocker shaft. I have only had DC or MP ones, and at one time I had some Isky shafts. Not one of them had the oil holes in the correct location.

Again, the ONLY way to get the correct oiling to the pushrod cup/rocker ball, the oil feed hole in the shaft MUST line up with the oil feed hole in the rocker.

This means that whoever is assembling the engine must, MUST mock the head up and physically LOOK to VERIFY the holes are lined up. This is with the rockers on the shaft, the valves in place at the correct installed height, and the adjuster removed and look at it. If you can't see the oil hole in the shaft you need to figure out why

You got my curiosity up. I'm going to check mine.

 

[Jadaharabi]

No need to tear down bro. you have done more than enough already. I will (1) cap the top hole (2) pull adjuster & check inside hole (clocking to bottom threads) (3) if good then cap outside hole (on that side) (4) other side, drill 1/8 hole to oil pushrod cup (drill bit pic) (4) check if there is a second set of OE holes in my shaft(s) 90 deg to the OE banana grooves/hole. I have a bunch of shafts so I will see what I see today. RR

(1) good if not a street engine
(2) I just wanted you to see the design relating to the factory drilling out the area beneath the oil passage and hole. The adjuster no longer is touching the rocker body at that point.
The oil will shoot out from there.
(3) don't worry about this being good just plug the hole or use a set screw as a lock for the adjuster that also plugs the hole.
(4) yes

 

[yellow rose]

Agree to disagree. There is so much oil splashing around under the valve cover that everything gets oil. Now if you gave a 8,000+ rpm race engine you might want to make some modifications. Mopar never has had a problem with rocker arm/shaft/pushrod failures with stock engines (100,000+ miles) so oil hole orientation is not an issue unless you want it to be.

We can agree to disagree but that won't make me incorrect. The oil hole orientation is for HYDRAULIC valve gear. As I said, I have never looked at a set of OEM 273 rocker shafts, buy I doubt that Chrysler made the 273 with the oil hole in the correct place, simply because of low production numbers and cost.

What happens is that Most engines have an honest 70, maybe 80 pounds of seat pressure and a cam lobe that is very, very slow and stable, to keep thing s quiet. Then we come along, use 90 to 100 PERCENT MORE spring pressure, with much higher spring rate BTW, and use lobes that are much more aggressive. Then add to that the guys who use a 1.6 rocker which loads the PR cup and adjuster even more. The next thing you know, you are bluing adjusters and cups.

If you are using a roller cam, the loads are SIGNIFICANTLY higher yet.

In the end, the issue SHOULD be corrected. I'm not a big fan of splash oiling. Neither is Chrysler. They don't want to tell you they have screwed us for decades.


Just for clarity, ALL W2 and W5 shafts are drilled with T/A offset oiling holes!!!!! If you actually check them, they are even wrong for T/A offsets, because the holes are radially incorrect. The oil hole never lines up.

As I said, I have published this stuff IN DETAIL on several sites. I have even sent drawings to Chrysler, with details and how far off the clocking is. They will admit, if you call them on it, that it is wrong. They just won't do it publicly. And that is disgusting.

 

[Jadaharabi]

You are not getting what I am saying.

You can modify and drill all you want. To get the oil correctly on the pushrod and ball, the oil hole in the rocker arm MUST line up with the oil hole in the shaft. It IS that simple. I have never seen an original 273 rocker shaft. I have only had DC or MP ones, and at one time I had some Isky shafts. Not one of them had the oil holes in the correct location.

Again, the ONLY way to get the correct oiling to the pushrod cup/rocker ball, the oil feed hole in the shaft MUST line up with the oil feed hole in the rocker.

This means that whoever is assembling the engine must, MUST mock the head up and physically LOOK to VERIFY the holes are lined up. This is with the rockers on the shaft, the valves in place at the correct installed height, and the adjuster removed and look at it. If you can't see the oil hole in the shaft you need to figure out why.


In my opinion, you can't build a performance engine with out checking this. I know there are thousands and thousands of cars out there with rocker systems that have not been corrected. But eventually, luck runs out..

OK I took pictures about 10 of them. Then went to upload them an got nothing but error messages. I will try again later for the pics.

However the holes on my shafts lined up with the holes on the pushrod side of the 4 that I checked using unmodified rockers. They are stock 273 rocker arms and shafts.

Now I said the holes lineup. When the pushrods are in place an the engine is turning over the hole is never uncovered. The hole in the shaft is straight below the hole in the rocker at zero valve lift and even farther away at max lift.

These rockers were used on the D Dart with a 273 using a .500 lift cam from the factory. I'm using them on a .462/473 lift "stock" cam in a 360.

Glad you got my interest up on this because the guy that assembled my motor put the shafts in upside down. The grove was on top and the other holes were on the valve side. Now I'm going to remove the intake to see if he put the valley baffle hold down straps on correctly.

 

[Rapid Robert]

I did not read thru the last couple of replies (but I am going to tomorrow) as I am spent & fixin to hit the hay in about 5 minutes but I did check my shafts today & yeah there is another hole(s) besides the one(s) on the bottom with the groove & it is offset 63 degrees from that hole(s) (to the valve side iirc). EDIT I could cap the (offset) holes in the shaft with JBweld & redrill them inline with the 1/8" drilled hole in the rocker on the valve side (the drill bit photo). clocked for when the spring is closed/relaxed. Should I go ahead? this is a 6K+ circle track 360. thank you for your time. PS should the redrilled in the shaft hole (if you recommend I redrill) be 1/8 also?

 

[nm9stheham]

RR, if the holes are on the valve side, you may have the shafts reversed side-to-side.....???

Regardless, IMHO, a hole in the .090"-.100" range is adequate, and a .12" should work OK too. Keep in mind that with the stock oiling system that there are 3 places where the oil flow TO the rocker shafts is limited:
1. The 'oiling interrupter' holes in the cam: .049 sq inch flow area and about a 5-6% duty cycle per calculations and some estimating
2. The head bolt to oil passage clearance inside the head, approx .050-.060" sq inch flow area with standard head bolts; this will get restricted down further if the ARP head studs are used, since the studs are considerably thicker than the bolts.
3. The clearance between the rocker shaft hold down bolt and the hole in the rocker shaft through which it passes; about .034 sq inch with the stock 273 shafts and 5/16" hold down bolts.

So the rockers will rise in level to some level due to this pulsating oil flow and the level will fall due to the outflow from the shaft. With some RPM's I think the shaft will fill fairly well, BUT for the pushrod oiling holes to be effective, the shaft has to fill higher since it is 'uphill'. So some checks on the restrictions above are in order too.... which I think is one of Yellow Rose's points in all of this.

 

[Jadaharabi]

I did not read thru the last couple of replies (but I am going to tomorrow) as I am spent & fixin to hit the hay in about 5 minutes but I did check my shafts today & yeah there is another hole(s) besides the one(s) on the bottom with the groove & it is offset 63 degrees from that hole(s) (to the valve side iirc). EDIT I could cap the (offset) holes in the shaft with JBweld & redrill them inline with the 1/8" drilled hole in the rocker on the valve side (the drill bit photo). clocked for when the spring is closed/relaxed. Should I go ahead? this is a 6K+ circle track 360. thank you for your time. PS should the redrilled in the shaft hole (if you recommend I redrill) be 1/8 also?

Is the notch on the end of the rocker shaft on the drivers side of the motor at the front and down? Then is your notch on the passenger side at the rear and down?

Do Not use JB weld inside your motor. IF you wanted to plug the holes in the shaft do like Yellow Rose said and pound a piece of lead shot into the hole. (I use lead shot in my carbs to restrict passages sometimes.)
Don't drill anything just yet. We are going to talk about oil volume in my next post.