Wrongly manufactured rocker shafts?

-
oliver

oliver

Well-Known Member
Joined
Jan 12, 2011
Messages
567
Reaction score
252
Location
Vallejo, CA
Got a pair of rocker shafts, one pair is obviously not right. The set on the left came out of a 68 340 and the set on the right out of a 66 273. You can see the feed holes on the left pair are drilled correct and in the middle of the wear area. The set on the left has the holes drilled completely out of the wear area.... any input? or am i just whacked?

MtkaaWV.jpg

wVstE4S.jpg

qVGg1bf.jpg

SOA5Nxu.jpg
 
I believe that's the difference between adjustable rockers and stamped rockers, but I'm probably wrong on that.
 
jos51700 said:
I believe that's the difference between adjustable rockers and stamped rockers, but I'm probably wrong on that.
Click to expand...
I thought that too, but then obviously the wear area is not centered where the oil hole is. Either way they would put the contact in the same area of the rocker shafts.
 
The set on the left had stamped rockers used on them (according to the wear patterns I see) and the set on the right had iron rockers used on them.
 
Max1196 said:
The set on the left had stamped rockers used on them (according to the wear patterns I see) and the set on the right had iron rockers used on them.
Click to expand...
Yes, i know that. what im asking is if the oiling holes on the set on the right is not drilled in the correct location.
 
There is a certain orientation for the 273 shafts ( not sure bout 340) with notches cut into the end of them that may help to decipher.
 
Both shafts are right, it depends on what type of rocker arm you are going to use. The oil holes should direct the oil where it's needed, and on a stamped steel rocker you don't need oil squirting off to the side, like for an adjustable rocker arm that may have a hole there to direct oil to the pushrod tips and valve stems. The pushrods and valve tips get splash oiled from what collects and dribbles off the open sides of the rocker. Not so on a mech rocker as there's nothing there to catch and direct the oil. A mech rocker arm shaft used with a stamped steel rocker would have that side hole uncovered and spraying oil on the sides of the valve cover. A hydraulic rocker shaft used with a mech rocker arm might burn out the lash adjuster screw, pushrod cups and valve tips due to lack of oil.
 
airgrabber said:
Both shafts are right, it depends on what type of rocker arm you are going to use. The oil holes should direct the oil where it's needed, and on a stamped steel rocker you don't need oil squirting off to the side, like for an adjustable rocker arm that may have a hole there to direct oil to the pushrod tips and valve stems. The pushrods and valve tips get splash oiled from what collects and dribbles off the open sides of the rocker. Not so on a mech rocker as there's nothing there to catch and direct the oil. A mech rocker arm shaft used with a stamped steel rocker would have that side hole uncovered and spraying oil on the sides of the valve cover. A hydraulic rocker shaft used with a mech rocker arm might burn out the lash adjuster screw, pushrod cups and valve tips due to lack of oil.
Click to expand...


This is correct.


There is an issue if you use 273 rockers and shafts with hydraulic lifters. With a solid, there is lash in the system and allows oil to get to the bottom of the rocker. With a hydraulic lifter, there is never any clearance between the rocker and the shaft, and you get galling. For that, you need a banana groove. It doesn't hurt with solids, but it's a must with hydraulics.
 
Ive had both sets on adjustable and stamped rockers, they worked fine to me, but you would think extra holes would equal lower oil pressure.

Jake
 
xLURKxDOGx said:
Ive had both sets on adjustable and stamped rockers, they worked fine to me, but you would think extra holes would equal lower oil pressure.

Jake
Click to expand...


No pressure loss because the rockers only get oil for a short amount of time. If it was continuous flow to the rockers, then yes, you'd see a pressure drop.
 
yellow rose said:
No pressure loss because the rockers only get oil for a short amount of time. If it was continuous flow to the rockers, then yes, you'd see a pressure drop.
Click to expand...
Cool, thanks for the heads up.

Jake
 
well, looks like ill be spending time with the drill press and file soon.
 
oliver said:
well, looks like ill be spending time with the drill press and file soon.
Click to expand...


I don't remember for sure, but I think those shafts are pretty hard. I know all the aftermarket shafts are hard.

My W-2-5 stuff is harder than the hinges of hell and they have to be drilled to oil correctly.



So they are drillable, just hard. Probably.
 
xLURKxDOGx said:
Ive had both sets on adjustable and stamped rockers, they worked fine to me, but you would think extra holes would equal lower oil pressure.
Jake
Click to expand...
Actually, in the stock system, if you work out the restrictions in the oiling to the stock rocker system, the smallest restriction is where the rocker shaft sets on the rocker stand that has the oil passage to the rocker shafts. The clearance between the 5/16" diameter hold-down bolt and the hole in the underside of shaft there is the smallest flow area, and is smaller than the total flow areas of the rocker oil holes. The pressure inside the shafts is very low.

oliver said:
well, looks like ill be spending time with the drill press and file soon.
Click to expand...
Just don't carry the grooves past the edges of the rockers when they are in their proper position. Otherwise, it will leave open gaps at the ends for the oil to escape. An air cut-off wheel would sure be easier than a file but takes some more care.
 
You must log in or register to reply here.
-

Back
Top