How to open up rocker arm oil passages.

-
Duggie

Duggie

Well-Known Member
Joined
Apr 10, 2020
Messages
663
Reaction score
583
Location
Tacoma WA
Hello all.

As part of my reassembling of the cylinder head after shaving off .075", I soaked the rocker arms in the 'new-improved' EPA compliant carb cleaner and blew them all out with compressed air. I also gave them all the once over with a toothbrush.

Upon adjusting the valves with the engine running, I noticed oil is leaking out at the rocker shaft between the rocker arms and spacers, but some rocker arms have oil flowing through the V groove valley in the top of the rocker and some don't.

What is a reliable way to open these rocker arm oil passages up?
Rocker.jpg
 
On SBM the rocker shafts are directional. Not sure about slants... Are you sure you got the shaft in in the correct orientation?
 
Duggie said:
Hello all.

As part of my reassembling of the cylinder head after shaving off .075", I soaked the rocker arms in the 'new-improved' EPA compliant carb cleaner and blew them all out with compressed air. I also gave them all the once over with a toothbrush.

Upon adjusting the valves with the engine running, I noticed oil is leaking out at the rocker shaft between the rocker arms and spacers, but some rocker arms have oil flowing through the V groove valley in the top of the rocker and some don't.

What is a reliable way to open these rocker arm oil passages up?
View attachment 1715908273
Click to expand...
Use rtv top and bottom if it bothers you.
How much is leaking?
 
Last edited:
Dana67Dart said:
On SBM the rocker shafts are directional. Not sure about slants... Are you sure you got the shaft in in the correct orientation?
Click to expand...
Yep, I'm certain. Lots of oil coming out between the rocker arms and spacers, and some rockers have oil flowing along the top groove. There is also a flat spot on the end of the shaft to help with orientation.
 
Duggie said:
Hello all.

As part of my reassembling of the cylinder head after shaving off .075", I soaked the rocker arms in the 'new-improved' EPA compliant carb cleaner and blew them all out with compressed air. I also gave them all the once over with a toothbrush.

Upon adjusting the valves with the engine running, I noticed oil is leaking out at the rocker shaft between the rocker arms and spacers, but some rocker arms have oil flowing through the V groove valley in the top of the rocker and some don't.

What is a reliable way to open these rocker arm oil passages up?
View attachment 1715908273
Click to expand...
Did you take a thin wire and run it through each rocker arm passage? It either that or using a can of carb cleaner and the straw spout to run pressurized carb cleaner through each passage to be sure they are open. Each rocker has two passages.
Also did you remove the cup plugs from the ends of the rocker shaft and brush out the inside? That also is important.
Loctite in the replacement cup plugs.
And as mentioned previously, on mechanical rocker arm motors you can put the shaft in the wrong way. The small hole on the hydraulic slant six shafts helps to prevent that on the hydraulic motors.
But yes, all of the rockers should be oiling, if not either some passages are blocked or the shaft is installed wrong.
 
my68barracuda said:
Did you take a thin wire and run it through each rocker arm passage? It either that or using a can of carb cleaner and the straw spout to run pressurized carb cleaner through each passage to be sure they are open. Each rocker has two passages.
Also did you remove the cup plugs from the ends of the rocker shaft and brush out the inside? That also is important.
Loctite in the replacement cup plugs.
And as mentioned previously, on mechanical rocker arm motors you can put the shaft in the wrong way. The small hole on the hydraulic slant six shafts helps to prevent that on the hydraulic motors.
But yes, all of the rockers should be oiling, if not either some passages are blocked or the shaft is installed wrong.
Click to expand...
* The wire I used would not go past the hole opening. Too large maybe? What direction is the passage supposed to go when trying to force the wire past the hole? Can the wire be sent through the opposite direction?
* I tried a pressurized can of carb cleaner. It blew back and I wasn't able to see where it should have been coming out if clear.
* Can the right diameter wire be fed all the way through both passages? Do both passages originate from one origin hole?
* I did not! Do I buy new cap plugs or reinstall the old ones?
* Shaft placement triple checked on install.

:thankyou:
 
Duggie said:
Hello all.

As part of my reassembling of the cylinder head after shaving off .075", I soaked the rocker arms in the 'new-improved' EPA compliant carb cleaner and blew them all out with compressed air. I also gave them all the once over with a toothbrush.

Upon adjusting the valves with the engine running, I noticed oil is leaking out at the rocker shaft between the rocker arms and spacers, but some rocker arms have oil flowing through the V groove valley in the top of the rocker and some don't.

What is a reliable way to open these rocker arm oil passages up?
View attachment 1715908273
Click to expand...
When I built my /6, I took a piece of .049 stainless wire about three inches long and hit one end (about an 1/8") with a hammer on my little anvil. That made the wire flat. I chucked the wire up in my hand drill, clamped the rocker down and used the drill and wire like "rotor-rooter."
Norm
 
circlepilot said:
When I built my /6, I took a piece of .049 stainless wire about three inches long and hit one end (about an 1/8") with a hammer on my little anvil. That made the wire flat. I chucked the wire up in my hand drill, clamped the rocker down and used the drill and wire like "rotor-rooter."
Norm
Click to expand...
That was bein a smart fart right there.
 
circlepilot said:
When I built my /6, I took a piece of .049 stainless wire about three inches long and hit one end (about an 1/8") with a hammer on my little anvil. That made the wire flat. I chucked the wire up in my hand drill, clamped the rocker down and used the drill and wire like "rotor-rooter."
Norm
Click to expand...
Now you're talking! What do people use .049 stainless wire for? Where would a rookie find some?
 
Tig rod, I don't know about size. Around here, though, nobody sells "a few" rods anymore. Find a welding shop "I guess"
 
Duggie said:
* The wire I used would not go past the hole opening. Too large maybe? What direction is the passage supposed to go when trying to force the wire past the hole? Can the wire be sent through the opposite direction?
* I tried a pressurized can of carb cleaner. It blew back and I wasn't able to see where it should have been coming out if clear.
* Can the right diameter wire be fed all the way through both passages? Do both passages originate from one origin hole?
* I did not! Do I buy new cap plugs or reinstall the old ones?
* Shaft placement triple checked on install.

:thankyou:
Click to expand...
Yes the wire can be sent either way.
I am thinking there is a passage to each end, the adjuster end and the valve tip end.
You would need to buy new cup plugs, they are 3/8 cup plugs iirc, typically one would pound a screw driver through the existing to pop them out.
To install new, ring with red Loctite and use a socket that matches the flange - OD of the cup plug and use a hammer to knock them in.
If the passage was open, carb cleaner would easily spray from each inside (shaft) to each exit. Wear safety glasses, Don’t spray in your eyes.
Ask for piano wire. Google that or stainless steel wire. Try Lowes or Home Depot. Or get an old battery cable or other large gauge cable, strip the insulation off and free one of the copper wire strands.
 
Last edited:
Duggie said:
Now you're talking! What do people use .049 stainless wire for? Where would a rookie find some?
Click to expand...
I have an abundance of it, due to me being an aircraft mechanic and repair shop owner. It's referred to as "safety wire." I use it for a lot of things on my motorcycles and cars. BTW that was a typo on my behalf. It's .041 not .049, you could use .051 also.
Safety Wire - Stainless Steel - 1 Lb Spool | Aircraft Spruce
 
circlepilot said:
I have an abundance of it, due to me being an aircraft mechanic and repair shop owner. It's referred to as "safety wire." I use it for a lot of things on my motorcycles and cars. BTW that was a typo on my behalf. It's .041 not .049, you could use .051 also.
Safety Wire - Stainless Steel - 1 Lb Spool | Aircraft Spruce
Click to expand...
Whoop! I have a spool of that from Spencer Aircraft, left over from building a wood and fabric experimental aircraft from a set of blueprints. AKA; How to spend the most money possible building an airplane. Mine is .032" though. Maybe good enough to open it up enough to spray carb cleaner through?
 
Duggie said:
Whoop! I have a spool of that from Spencer Aircraft, left over from building a wood and fabric experimental aircraft from a set of blueprints. AKA; How to spend the most money possible building an airplane. Mine is .032" though. Maybe good enough to open it up enough to spray carb cleaner through?
Click to expand...
.032 will work, but you will have to make your drill wire shorter, as it will want to bend easier. Use a good air gun with a rubber tip and at least 90 psi to blow out the oil ports.
Norm
BTW, what kind of homebuilt was it. Did you finish it? Fly it?
 
circlepilot said:
.032 will work, but you will have to make your drill wire shorter, as it will want to bend easier. Use a good air gun with a rubber tip and at least 90 psi to blow out the oil ports.
Norm
BTW, what kind of homebuilt was it. Did you finish it? Fly it?
Click to expand...
This is good - I have a plan! I'll report back when I get er done. My welding buddy is on the way over to spend some more time building the exhaust from the Clifford headers he welded up to fit, so it will be a few days before I get back to the rockers.

My airplane was a TEAM EROS. A 50 hp, dual carb, dual ignition Mini-Max. I used to build custom hardwood furniture for a living so I figured I could source aircraft grade spruce and build it for nothing. Buying everything that wasn't wood - one part at a time was a lot more expensive than just buying the kit from TEAM. I have a CFI in SEL but didn't have a tailwheel endorsement at the time. Tried three times to get my endorsement in a '41 Taylorcraft that as 300 miles away and came up snake eyes each time. Mechanical issue, WX, CFI had the flue.. I wasn't going to be the test pilot without an endorsement and some emergency procedure currency after spending all my time and money building and not flying... Got to crow hop it on the gravel strip I was hangered at. Barb wire fence on one side and a drainage ditch on the other. At the '08 market crash I had to sell it for pennies on the dollar. If I didn't need what I owned to sleep on, cook with, or drive to three part time jobs, I sold it to survive. I was a little bitter about the whole thing until I met an old acquaintance that had to sell his antique Harley collection to survive. At the end of his sad sack story he had this grin on his face and he said if he didn't have the stuff to sell, he never would have make it. Completely changed my outlook on the '08 market crash!
Eros.jpg
 
Duggie said:
This is good - I have a plan! I'll report back when I get er done. My welding buddy is on the way over to spend some more time building the exhaust from the Clifford headers he welded up to fit, so it will be a few days before I get back to the rockers.

My airplane was a TEAM EROS. A 50 hp, dual carb, dual ignition Mini-Max. I used to build custom hardwood furniture for a living so I figured I could source aircraft grade spruce and build it for nothing. Buying everything that wasn't wood - one part at a time was a lot more expensive than just buying the kit from TEAM. I have a CFI in SEL but didn't have a tailwheel endorsement at the time. Tried three times to get my endorsement in a '41 Taylorcraft that as 300 miles away and came up snake eyes each time. Mechanical issue, WX, CFI had the flue.. I wasn't going to be the test pilot without an endorsement and some emergency procedure currency after spending all my time and money building and not flying... Got to crow hop it on the gravel strip I was hangered at. Barb wire fence on one side and a drainage ditch on the other. At the '08 market crash I had to sell it for pennies on the dollar. If I didn't need what I owned to sleep on, cook with, or drive to three part time jobs, I sold it to survive. I was a little bitter about the whole thing until I met an old acquaintance that had to sell his antique Harley collection to survive. At the end of his sad sack story he had this grin on his face and he said if he didn't have the stuff to sell, he never would have make it. Completely changed my outlook on the '08 market crash!
View attachment 1715908590
Click to expand...
Well done! Most people start one and never finish. We had a Variez that was donated to the Aviation School (South Arkansas University) where I taught for 12 years. It had 4 different owners before we got it. I retired in 2014 and it still looks about the same. My tail wheel endorsement is "grandfathered" as I flew tail wheel before the endorsement requirement, Same as my complex. However, having not flown a conventional gear plane in a while, some stick time with our instructor would be recommended. As for complex...I do my BFR in the 172RG we have. My neighbor builds ad sells a biplane ultralite. Our ex-mayor has a RV-4.
Norm
 
circlepilot said:
Well done! Most people start one and never finish. We had a Variez that was donated to the Aviation School (South Arkansas University) where I taught for 12 years. It had 4 different owners before we got it. I retired in 2014 and it still looks about the same. My tail wheel endorsement is "grandfathered" as I flew tail wheel before the endorsement requirement, Same as my complex. However, having not flown a conventional gear plane in a while, some stick time with our instructor would be recommended. As for complex...I do my BFR in the 172RG we have. My neighbor builds ad sells a biplane ultralite. Our ex-mayor has a RV-4.
Norm
Click to expand...
Nice! I love the Cessna RGs. I ended up owning the '41 T Craft for a few years. Most fun I had flying is a toss up between flying fire watch over logging camps between Olympia WA, the Columbia River, and the Pacific Ocean at 300' AGL and ferrying Cessnas for a local Dealer. Great times!
 
The round band that goes through the rocker part of the rocker arm can turn inside the rocker arm over time. It has only a slight press fit and is easily turned if you put it in a vise. I've noticed that when they turn, the oil hole becomes misaligned and can prevent oil from passing through it. It's easy to spot by looking at the oil hole inside of the rocker and seeing if it lines up. Many people that have high spring pressures put a small weld bead on the sleeve/rocker junction to prevent it from turning or moving under increased spring pressures...
 
CNC-Dude said:
The round band that goes through the rocker part of the rocker arm can turn inside the rocker arm over time. It has only a slight press fit and is easily turned if you put it in a vise. I've noticed that when they turn, the oil hole becomes misaligned and can prevent oil from passing through it. It's easy to spot by looking at the oil hole inside of the rocker and seeing if it lines up. Many people that have high spring pressures put a small weld bead on the sleeve/rocker junction to prevent it from turning or moving under increased spring pressures...
Click to expand...
Thanks for the tip! I've yet to have time to take the rockers back off. Hopefully I can get back to it before the month is over. I'll post results when I do.
 
Progress update. I checked all the rocker bushings, and none have spun so the oil fed holes are where they need to be. Then I soaked the rocker for a couple hours in a very non-EPA compliant parts cleaner that has actually caused the only instance of "flash rust" I've ever seen in person.

I then used a piece of wire in the drill to open up the oil pathway from the center of the rocker to the trough on top of the rocker, working from the trough side. The wire broke through the crud like a metal drill bit going through a piece of wood.

It worked so well, I used the same wire on the oil pathway from the center of the rocker bushing to the end of the rocker that depresses the valve stem. Smaller opening and a longer, curved pathway. While trying this I was thinking about the wire breaking off in the pathway. Yep - broke that wire right off in the end of the second rocker! Because I'm slow in the head, I went to a smaller diameter and shorter wire and broke that wire off in the 6th or 7th rocker.

Yep. I need two replacement rockers!

The rest of the rockers were worked with a thin wire and a pair of pliers alternated with going back in the nasty parts cleaner. Tedious work and a couple puncture wounds in my fingers but those tiny oil passages are functional again for the first time in what must be decades.

Now to go post a "Wanted" advert. for two /6 rocker arms...:BangHead:
 
Boil the sludge a bit with a propane torch, then clear passages with wire. The shaft is likely crudded up too so best to scrub it out so no chunks come loose and plug the arms.
 
You must log in or register to reply here.
-

Back
Top