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By alanfreeman - 9 Years Ago
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On the passenger side bank of cylinders of my 256 Y-Block on cylinder #1, the rocker arm which is second from the front is getting no oil and the push rod is not rotating. There is plenty of oil on all seven of the other rocker arms and the push rods are rotating on these. There is also oil coming out of the overflow pipe. Where is a good place to start in figuring out why this one rocker arm/push rod is getting no oil? Thanks, Alan S. Freeman
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By charliemccraney - 9 Years Ago
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Been so long since I had stock rocker arms, but I remember that I could loosen the adjuster screws all the way and slide the rocker arm out of the way. Don't know how accurate that memory is. If that's possible, slide the rocker aside to inspect the shaft oil hole and condition of the shaft. You will need a mirror. If that turns up nothing, you will need to disassemble, clean, and inspect the shaft and rocker arm.
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By Doug T - 9 Years Ago
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Charlie is right, you can loosen and remove the adjuster then slide the rocker away from the shaft stand. There will be a hole in the bottom of the shaft that is probably plugged since the other rockers are getting oil. There is a copper colored overflow tube at one end of the rocker shaft on each side of the engine. Oil should be flowing out of these tubes and down adjacent to the end push rod. Be careful that the push rod does not come up and out of the lifter in the engine valley they can be a bit of a nucence to retrieve from the hole.
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By alanfreeman - 9 Years Ago
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If the hole in the shaft is open, is there an oil passage in the rocker arm itself that could be plugged? Does the oil passage in the rocker extend to both sides (i.e the push rod side and the valve side)? Can I clean out the rocker without removing the whole rocker assembly and taking it apart? Alan
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By charliemccraney - 9 Years Ago
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There is a groove in the rocker arm. A hole intersects that groove for the pushrod oiling. If the hole in the shaft is clear, then the shaft or rocker arm is probably worn, preventing adequate oil flow to the rest of the rocker. If that one is worn, then they all likely are. That's just the one that gave up first.
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By 2721955meteor - 9 Years Ago
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if ther is no oil coming out the bleed tube ,you must have litle or no oil coming up the pasage in the head ,I would pull the rocker asembly and remove pushrods. pull coil wire and rotate the engine, and see how much oil is coming, if you get oil flow problem is rocker shaft full of sludge.if no oilcoming up the hole you have deep isues,tho some on this site have good ways to clear pasage with out tear down. at leastyou will need a new rocker shaft and consider eliminating the bleed tube when suply iscorected. if after you ar up and runing push rod does not turn you have cam isues. you need som luck,wish you well
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By miker - 9 Years Ago
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I don't want to sound negative, but before you pull the rockers check the valve clearance on the one in question, and a couple others. If there's a bunch of clearance on that one valve its not a good sign.
Last summer I developed a little tick in one valve. When I went to set them, #1 exhaust had .25 clearance. Lifter head had fractured, found two of the pieces in the pan.
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By alanfreeman - 9 Years Ago
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As I said in my original post, there is plenty of oil coming out of the overflow tube. I checked the hole in the shaft visually and with a piece of steel wire and it is clear. The hole in the rocker is also clear. While watching the engine run with the valve cover off I happened to notice a slightly wobbling push rod next to the non-oiling one. I have another running 256 engine on a stand which had good oiling to the rockers when last run. I will put the entire rocker assembly from that engine on the one that has the problem.. Is there any reason that doing this would not be a good idea? Alan
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By Ted - 9 Years Ago
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alanfreeman (4/17/2015)
As I said in my original post, there is plenty of oil coming out of the overflow tube. I checked the hole in the shaft visually and with a piece of steel wire and it is clear. The hole in the rocker is also clear. While watching the engine run with the valve cover off I happened to notice a slightly wobbling push rod next to the non-oiling one. I have another running 256 engine on a stand which had good oiling to the rockers when last run. I will put the entire rocker assembly from that engine on the one that has the problem.. Is there any reason that doing this would not be a good idea? Alan
Swapping out the rocker arm assembly with another unit that's a proven 'oiler' does sound like a good idea. Also change the pushrod out on that particular valve as running without oil may have galled the cup end thus creating additional friction at the adjuster which is keeping the pushrod from turning.
On the rocker assembly that’s not oiling on that single rocker, I’ll suggest slotting the oil holes in the shaft which may potentially fix that particular problem. Also check the clearance to the shaft on that particular rocker as too much clearance can also minimize oil to the rocker hole. Be sure to look at the ball adjuster on the #1 intake rocker and insure it’s smooth and not galled due to running without oil as that can still be a problem later down the road.
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By alanfreeman - 9 Years Ago
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Problem solved. Plenty of oil now to all rockers and no more funny noises. Thanks all. Alan
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By MoonShadow - 9 Years Ago
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What did it turn out to be? Chuck
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By alanfreeman - 9 Years Ago
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The non-oiling rocker was worn out. The funny noise was caused by the adjoining push rod which was slightly bent and not turning with the engine running. Both problems were fixed when I swapped out the complete rocker assembly from my spare engine with two new push rods, In fact, this worked out so well that I plan on also swapping out the rocker assembly on the other bank of cylinders. Alan
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