Just finished the rebuild of my 56 312. The block was checked very closely for plugged oil passage and all were cleaned out. Since I had just replaced the cam and timing gear just 500 miles before I decided to rebuild I kept the same cam but had new cam bearings installed and the holes were lined up! This was done by a good shop. Before the rebuild I had good oil flow coming from both rocker arm tubes on both sides of the engine. Now the left side does not have any oil dripping from the shaft nor coming from the tube. The right side is okay. Any thoughts????
Left rocker arm oiling problem
- Thread starter cjc56
- Start date
Hot Rod Reverend
Well-known member
Did you check oil flow with the car running or just by spinning your shaft on your oil pump? You probably know that there were two types of cams, one with cross-drilled holes at the center journal (feeding both sides of the block/heads) and then one with a center groove. If you have the cross-drilled cam, you will not get any oil to the left side if you are only spinning the pump shaft because the cam is not rotating. Rotate the camshaft while spinning your oil pump and see what happens.
if you know you have a center grooved cam, then take blucar's advice.
Let us know how it turns out!
if you know you have a center grooved cam, then take blucar's advice.
Let us know how it turns out!
Tinker
Well-known member
Just more stuff...
http://www.ford-y-block.com/assemblyerrors.htm
Rocker shafts. It is amazingly simple to install the rocker arm shafts upside down on a Y-Block. The shaft stands are identical and will bolt down either way. You must be absolutely certain that the oil hole in the shaft aligns with the hole in the stand and is at the bottom when the stands are bolted down. If done improperly no oil will get to the rockers. The best way to check for proper assembly is to look for the holes for the overflow tubes at the right hand end of each shaft. If the hole is visible with the rocker arms installed on the head it is correct.
http://www.ford-y-block.com/assemblyerrors.htm
Rocker shafts. It is amazingly simple to install the rocker arm shafts upside down on a Y-Block. The shaft stands are identical and will bolt down either way. You must be absolutely certain that the oil hole in the shaft aligns with the hole in the stand and is at the bottom when the stands are bolted down. If done improperly no oil will get to the rockers. The best way to check for proper assembly is to look for the holes for the overflow tubes at the right hand end of each shaft. If the hole is visible with the rocker arms installed on the head it is correct.
The rocker arms are installed correctly and the cam shaft has a center groove. I just removed the rocker arms/shaft and put a vac pump in the oiling hole on top of the head. It held a vacuum!!!! I guess that means there is a clog. Looks like I will need to remove the head. Does anyone have any suggestions before I start removing the head???
Ole Don
Well-known member
Remove the left rocker shaft and spin the engine to see if oil comes up through the head. If it does, run a 1/4 drill in the second rocker stand from the right, and make sure it goes in through the first side of the rocker shaft. I'll bet the left rocker shaft is upside down, or swapped end for end. If no oil comes up, check to see that the head gasket is not upside down. When putting on the heads, the colors do not match side to side when they are correct.
dmsfrr
Well-known member
http://ford-y-block.com/assemblyerrors.htm
Head gaskets. The 2 head gaskets used on a Y-Block are identical. It might seem that the same face of the gasket would go against the block and the opposite face would go against the head on each side. This is not the case. What is critical is that the open coolant holes are at the back of the head and the blocked portion of the gasket is at the front. Look for the word FRONT on the gasket and place it at the front even if it looks wrong. This places 1 of the gaskets face up and one face down. Notice that there is a square corner at one end of the gasket, this must be at the front of the engine. This can be checked without removing the heads. If you are having overheating problems check for these square corners at the top front corner of the head near the intake gasket.
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one rocker arm bolt is hollow with a cross drilled hole to let the oil into the rocker shaft, if it isn't put in the hole that lets oil that comes thru the head no oil to rockers, also you say the hole in the head for oil to go to rockers holds vacuum I think the oil passage between the block and head is plugged, its shallow when new and when the head is milled it can seal it up, when I have my heads milled I make sure the machine shop deepens that one inch passage in the head
CrownVic55
Senior Member
If no oil with rocker shaft off the head and it holds a vacuum I would suspect the center cam bearing is not properly line up. Happened to me when I rebuilt my 292. Machine shop put in wrong bearing and would not let oil through. He checked it with air and said it was ok but I had to buy new cam bearings and install my self. When compared, the bearings were wrong-parts man said they were probably Chevy bearings. Only way to be sure is pull the cam and verify oil hole line up.
Y-Blocks do not have any hollow rocker arm bolts.
dmsfrr
Well-known member
Not originally, but there were many after-market kits installed on y-blocks that brought in an oil supply thru an external tube to a hollow valve cover bolt and down to the rocker shafts. This helped correct rocker oiling problems without having to open up the engine.
dmsfrr
Well-known member
Here are four pictures of the top and bottom of a y-block head and both sides of the block, with the oil passages noted with red. The offset oil passage groove in the bottom of the head is approx 1/4 inch wide and 1/8th inch deep.
I don't have an extra head gasket here so looked at a few online images. The ones I saw have a hole for the oil passage in either position. (last pic)
I don't have an extra head gasket here so looked at a few online images. The ones I saw have a hole for the oil passage in either position. (last pic)
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