Here is a thread I started a couple years ago. It has some good info.
Reworking the 273 Adjustable Rockers
273 Rockers on a 1971 340
- Thread starter CFD244
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Here is a thread I started a couple years ago. It has some good info.
Reworking the 273 Adjustable Rockers
Yeah but I don't get the feelin the OP is doin "all that".
My engine is a '71 340 with 10.5:1 (stock) with 2.03 J heads. Have a Comp Cam XE262, HP exhaust manifolds (69), and a Holley/Edelbrock six-pack. Automatic 727 with 3.23 8 3/4 sure grip. Got a great deal on the rockers and wanted to use them. Pretty much a stock engine with a couple of add-ons.
nm9stheham
Well-Known Member
The ball oiling mods are for extended high RPM use, like racing. The stock oil restriction system gets even more restrictive at high RPM's so mods have to be done. For more mundane use they are ok as is.
The banana grooves are easy to add; a cutoff disc on a Dremel or a triangular file will do it. Just keep the groove ends within the wear area of the rocker body to try to avoid creating extra leak points. BTW, the pressure inside the rocker shafts is very low, like a few psi, so this is not super critical.
The banana grooves are easy to add; a cutoff disc on a Dremel or a triangular file will do it. Just keep the groove ends within the wear area of the rocker body to try to avoid creating extra leak points. BTW, the pressure inside the rocker shafts is very low, like a few psi, so this is not super critical.
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Disagree with this thinking.
Even with the cam timed oiling hole matchup 30 psi is 30 psi and 50 psi is still 50 psi. If you think it's not critical try running your motor with the oil passage part way plugged.
nm9stheham
Well-Known Member
But at 30-50 psi at the gauge, there will be nothing like 30-50 psi in the shafts.... Maybe 5 psi...10 psi.... Really a lot lower. That's the way it was designed to be with the 'oiling interruptor' setup in the cam path. The whole rocker oiling setup is a bunch of leaks made to just get dribbles of
oil where needed LOL .... which is why it starts to fall apart with high RPM use.
What I wanted the OP to know is, if he put in banana grooves and got one a bit wide, then don't freak out. He says he is not pushing this engine hard.
oil where needed LOL .... which is why it starts to fall apart with high RPM use.
What I wanted the OP to know is, if he put in banana grooves and got one a bit wide, then don't freak out. He says he is not pushing this engine hard.
yellow rose
Overnight Sensation
This is exactly correct. The shafts and rockers are the last parts to get oil. While the dribble system (and the oil cloud that is floating around in the valve covers) will oil mostly stock stuff, it doesn't take much with an agressive lobe to start killing parts.
That's the reason why I use HV pumps and keep the idle oil pressure above 40 hot. It's not a Chevy. They don't oil the same, contrary to all the whiz bangs in gym shorts.
Low idle oil volume (and the pressure loss due to low volume) is hard on shafts and rockers.
Wyrmrider
Well-Known Member
sure the chevies and stock mopar have the shafts sitting in a bathtub of oil, not so with Iron or aluminum on steel rockers
I can remember customers who put restrictors in their blocks or even "better" in their rocker stands
and started burning up their balls, scoring their shafts, and overheating their springs, dry guides- they ruined a lot of good parts
and of course it was all my fault and they wanted me to fix it for free
see my lifetime warranty above
and I agree with YR HV pump is for low speed not high speed where the stock pump puts out more oil than you can use and HV costs HP
and restriction is on the suction side at high rpm
I can remember customers who put restrictors in their blocks or even "better" in their rocker stands
and started burning up their balls, scoring their shafts, and overheating their springs, dry guides- they ruined a lot of good parts
and of course it was all my fault and they wanted me to fix it for free
see my lifetime warranty above
and I agree with YR HV pump is for low speed not high speed where the stock pump puts out more oil than you can use and HV costs HP
and restriction is on the suction side at high rpm
According to yr if you lineup the hole in the rocker arm and the shaft, oil will squirt out. That is a high on the shaft hole for oil to squirt out of not a low dripple out hole.
I don't recommend the op over slotting the shaft to the point of leaking out the side at the bottom.
That is unless he doesn't mind dry startups after the oil leaks out of the shaft after it sits over night or over the weekend.
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yellow rose
Overnight Sensation
It will if the volume is there. I have some OE shafts in the shop and some brand new W2 shafts out there I need to take some pictures of and post in that other thread. I keep forgetting about it.
Technically, and this was from the MP people I talked with in Seattle at the Nationals in 1990ish, if the rocker has the oil feed hole where Chrysler says it should be (it should break through the rocker just under the adjuster pad) then the 9/32 adjuster setting is correct for any rocker.
If you adjust the adjuster to that number, you'll see the relationship between the adjuster, cup on the pushrod and the oil hole in the rocker. When it's correct, the oil should squirt out of the feed hole and hit the reduced diameter of the adjuster and run down into the cup.
This only happens if the hole in the shaft lines up with the hole in the shaft, and the volume is there to do it.
I've had to repair OE Hemi shafts that had the oil feed holes in the wrong location. 3 different shops missed it. Couldn't keep the adjusters in it until it was fixed.
The W2/5 shafts are all wrong. If they come from Chrysler, the oil holes are off on every shaft. Chrysler knew this, and didn't bother to release a bulletin to fix it.
The shafts for the 273 adjustable rockers are different than the shafts for the stamped steel rockers. Do NOT interchange them.
273 shaft: The 8 oiling holes point to the intake manifold.
318/340 shaft: The 8 oiling holes point downward and the square notch points down and to the left. On both heads.
273 shaft: The 8 oiling holes point to the intake manifold.
318/340 shaft: The 8 oiling holes point downward and the square notch points down and to the left. On both heads.
Then slap um on there with the correct pushrods and go.
2 pages of confusion lol
Exactly. Nuthin new.
nm9stheham
Well-Known Member
Welcome to the internet LOL
yellow rose
Overnight Sensation
LOL.
You just need to learn to enjoy the ride. Look at the scenery as you read through these threads. Soak it all in.
That's the kind of jacked up grade school crap my old lady tries to blow up my skirt any time we go somewhere, or something is irritating me.
Then I ask her how'd shed enjoy an ambulance ride!!
Then is a two or three nights in the motor home.
Damn, I ENJOY THAT RIDE!!!!
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