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oldcarmark
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I just finished tearing apart my 292 to rebuild it this winter.One of my problems was slow oil to the right side rocker shaft.John Mummert mentioned that he has found that problem more often in the right side,Anyway,now I can see the problem.I can get a wire down from the top of the block into the centre cam bearing on the left no problem.The right side I cant do it from the top down or bottom up.It looks like more wear on the right side of the bearing or the bearing has turned slightly blocking most of the hole.If you are having a similar problem more with the right side than left this may be whats happened to yours.John Mummert mentioned that he thought it may be more wear on the right side of the bearing due to direction of engine rotation(as I recall).Now to get on with rebuilding it!
 
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PF Arcand
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Mark: According to Doc Fromader writing in the Nov. 2001 Classic Truck series on the Y Block, he says that it often has to do with the way the cam bearings were installed or which style of bearings were used. There were three types of bearings used in Y Blocks apparently. Also cross drilled cams were more likely to develop oiling problems. According to him, if the cam is cross drilled, a slotted oil feed bearing is needed with the slot favoring the right bank. Maybe some of the engine gurus on site will comment further..
Paul
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oldcarmark
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Interesting theory Paul.The one in mine is the newer style for the grooved oil passage(both cam and bearing are grooved) and this motor is original-never overhauled.
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Ted
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Putting a groove in the block in the center cam bearing hole that interconnects all three oil holes is the easy fix. The center cam bearing then simply press fits over this and at this point does not make a difference if the camshaft is the grooved or of the cross drilled variety. This will likely require restrictors to be installed at the rocker arms on each bank as this oiling modification frees up the oil flow to the top.
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Verne Schumann has talked about supplying a cam bearing set where the center cam bearing is grooved around its outer circumference which does essentially the same thing. An externally grooved cam bearing would likely need to be pulled into place rather than driven in though as tapping a grooved bearing into place could potentially cause some crush at the groove and in turn make the clearance at the cam journal too tight.
  Lorena, Texas (South of Waco)
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oldcarmark
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Hello Ted! Am I OK by just installing new correct grooved bearing as part of my stock rebuild or is this cutting a groove in the block a good idea anyway and how deep should this groove be?By restrictors are you meanining plug the return fitting at the end of the shaft or actually putting a restrictor in the feed hole in the rocker support stand?
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Ted
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oldcarmark (11/8/2009)
Hello Ted! I am OK by just installing new correct grooved bearing as part of my stock rebuild or is this cutting a groove in the block a good idea anyway and how deep should this groove be? By restrictors are you meanining plug the return fitting at the end of the shaft or actually putting a restrictor in the feed hole in the rocker support stand?I’m grooving the center cam bearing hole in the block for all Y builds. If the softer cam bearing set is used (usually cost less $), then the grooved camshaft can ultimately cause restricted or no flow to the top end due to the groove in the cam journal being pinched off by the softer bearing material being mashed into it. The addition of the groove in the block behind the cam bearing gets around this. I make the grooves ~.040”-0.055” deep with them being about 1/16” wide.. As far as restricting the oil to the top end, I’m doing it at the pedestal just before the oil enters the rocker shaft. I do still run the overflow tubes but these are partially pinched to allow some oil flow through them to get oil specifically to the timing gear. Leaving them partially open also insures that the rocker shafts are purged of air and full of oil which reduces the tendency for sludging in the shafts by keeping the oil moving at a faster rate. The distributor gear appears to get enough lubricant regardless if the rocker arm overflow tubes are eliminated or not. When eliminating the overflow tubes, there are those who have drilled a small oil hole in the front of the block under the cam thrust plate to provide additional oil to the timing set. That looks to be a viable option also. . Here’s a past thread giving more detail on timing gear oiling mods.
Pressurized timing chain oiling . And here’s a variety ofpast threads on oil modifications in general. Center cam bearing Pressurized rocker shafts Pressurized rocker shaft more Rocker arm overflow tubes Cons Rocker arm overflow tubes Pros Rocker arm overflow tube More Pros Timing chain oil trough Adding lifter valley holes for camshaft oiling Drilling additional holes for oiling and/or venting Valley holes for aiding crankcase evacutation
Lorena, Texas (South of Waco)
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Jeffs54Merc
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What about the Y-Block oiling system that fed oil through the valve cover studs. I have two of these kits just in case I ever need to install them. I found them on ebay for under $20.00.
Jeff Leydig
Stallions Auto Interiors
Stearns, Ky. USA
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PF Arcand
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Mummert hasn't commented here, but in his YBM comments has stated that many replacement Cams also have need of a deeper oil feed groove. His current stock have the groove machined deeper. However, I don't have the specs at hand, so it needs to be checked into...
Paul
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oldcarmark
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My understanding is that they work if there is no other way to fix the problem BUT they can reduce the amount of oil going to other areas like the mains.
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Rono
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Check to make sure that the rocker shaft isn't upside down. This can easily happen during a rebuild (I did it myself once) The center hole in the rocker shaft has to align with the one in the center rocker stand. Rono.
 Ron Lane, Meridian, ID
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