Engine: Oil restrictors to the heads

[Kenmike2]

On the more modern (mid-60's)V8 rocker shafts, what is the size of the oil hole that regulates flow to the rocker shafts?

Thanks

Ken Michael

[StudeRich]

Ken, the 1961 and up Rocker shafts have Small Oil holes for the rockers, and the '51 to '60 have Large.

I do not have one shaft of each laying around right now to measure, but in your Stude. Repair Shop you must have plenty.
Just match the rocker stands, rockers and shafts to the same year push rods and you will be fine.

[Flashback]

I have thought about the same thing. I was thinking (dangerous) about restricting the earlier engines, to avoid so much oil going to the overhead. Would this be an advantage? Kinda like using pipe cleaners in chevy engines. Could the head be tapped and plugged, then drill an orfice?

[gordr]

I have thought about this problem, too. Even the later rocker arms and shafts, when they become worn, dump a huge amount of oil. My thoughts on this are, what would happen if you greatly restricted the oil flow at the rocker arm stand that feeds oil to the head? Would the tiny trickle of oil simply take the path of least resistance, and run out the first few rockers nearby, or would it continue to fill the entire shaft? I had thought about about maybe taking a known worn rocker shaft, welding the individual oil holes closed, and redrilling them with a much smaller hole, maybe .050" Aim to reduce the peak oil flow to about 25% of factory?

Ideally, what a guy could do is both: take one head, and restrict the oil feed from the block; on the other side, restrict each individual rocker feed hole, and drive the car until the engine basically dies. Carefully compare wear on both heads, and see if rockers on the back end of the "feed restricted" head were unduly worn. If I had a daily driver Studebaker on the road right now, I would be doing this for sure. The collector cars simply don't do enough miles for this test to be practical.

[shifter4]

There's been some discussion of this in the past. I think it's been discussed on the
Racing Studebakers site , and was also in the Dick Datson info , and I remember that
improved drain back was also a part of the solution.
It's slightly amusing that a Stude contemporary engine , the Ford Y-Block , was known
to starve the rockers , and kits were sold to supply additional oil upstairs. You occcasionaly
would hear a squeaking Y Block , as one or more of the rockers went basically dry.

[Chicken Hawk]

I have tapped the oil supply hole in both the heads and block (not both on the same engine) and put a plug in with a .060" hole for drag racing and on street driven cars drilled a .090" hole. If I remember correctly, the hole in the later shafts is 3/32". To further restrict oil to the lifters I drive a 3/32 roll pin in the oil holes in the block.

Ted

[Flashback]

Thanks, Ted, That's the "I have done It" answer I was looking far. Do you use both the roll pin and the orfice on street cars?

[Chicken Hawk]

Yes, do both on street driven cars.

Ted

[DEEPNHOCK]

I built an experimantal 'reverse oiling' setup on my '61 Hawk.
Pulled the oil off the head plug, ran it through the filter(s) (I added a second oil filter), and then through a gate valve and on to the rocker shaft.
Fed the rocker shaft through the stud from the top on reversed stands (so the oil did not come up from the block).
That way ALL the oil that came up to the top was filtered and ALL the oil draining back down was filtered.
Had small brass gate valves, and gauges, so I could see what the oil pressure was at what gate valve position.
I could shut off all the oil to the rocker shafts with the flip of the gate valve (did that for drag racing).
Did it work? Yes, it did. (It looked like a still)
Also shimmed the pressure bypass valve spring to boost oil pressure.
Also zipped all the teeth off the fiber cam gear, and replaced it with an aluminum one.
Also sheared the oil pump drive pin on the distributor shaft.
Also blew up a brand new oil filter and added a lot of rust preventative to the underside of the hood and engine compartment.
Conclusion.....
Curiosity can be expensive.

[gordr]

Ted, roll pins in the holes in the block, or roll pins in the holes in the rocker arm shafts? You did say 3/32" roll pins. Sounds like an easy way to restrict the oil flow.

[Chicken Hawk]

Roll pins in the block (lifter feed holes). Yes, 3/32" roll pins. Restricts the oil but still enough to let sufficient oil through.

Ted

[gordr]

Aha! I get you now. So, the lifters down in the valley area get too much oil as well, or is that mainly a way of directing more of the oil flow to the main and rod bearings?

[JoeHall]

I built an experimantal 'reverse oiling' setup on my '61 Hawk.
Pulled the oil off the head plug, ran it through the filter(s) (I added a second oil filter), and then through a gate valve and on to the rocker shaft.
Fed the rocker shaft through the stud from the top on reversed stands (so the oil did not come up from the block).
That way ALL the oil that came up to the top was filtered and ALL the oil draining back down was filtered.
Had small brass gate valves, and gauges, so I could see what the oil pressure was at what gate valve position.
I could shut off all the oil to the rocker shafts with the flip of the gate valve (did that for drag racing).
Did it work? Yes, it did. (It looked like a still)
Also shimmed the pressure bypass valve spring to boost oil pressure.
Also zipped all the teeth off the fiber cam gear, and replaced it with an aluminum one.
Also sheared the oil pump drive pin on the distributor shaft.
Also blew up a brand new oil filter and added a lot of rust preventative to the underside of the hood and engine compartment.
Conclusion.....
Curiosity can be expensive.

Jeff, you were kind enough to advise me in another thread, Heat Riser Mod To Intake Manifold to avoid installing what you called, "valve gizmo things" that could cause problems down the road. What could possibly be done to the intake, or most anything else for that matter, that could result in more catastrophe than your above gizmo mod to the oiling system

[11SecAvanti]

In the past I have experimented with these mods. I no longer restrict oil to the heads but do use the later small size rocker shaft. But you must keep the small hole open. Have seen trash get lodged into those tiny holes and that can cause heat friction on the rockers from lack of oiling. Have also seen these restrictor holes plug up from silicon used on the pan gaskets, etc. Check your shaft for any "bluing color" and you have too little oil to the rockers. Also, if you restrict oil to the upper end you will destroy the springs pressure tension because they need lots of oil for cooling.