Oiling Issue Resolved, but the damage is done

79SpiritAMX wrote: Hi,   I did a silly thing...I put an older head on my 79 AMC 258 engine with the shaft rockers...now I realize after looking through this post and the that the engine block itself is not set up to furnish oil to the rockers?    I have not started it up yet...what do I do??  Should I buy an external supply line?   This engine is all together and painted up and the shop doing the work will not tear the engine down again without gouging me for work performed.        For the external oil supply line....Who would make this for me...anyone out there that could sell me something that should work?     I don't have the funds right now to do a full rocker chevy big block rocker modification like the one on the MOJO page so I think I need to go with the oil supply line, and it needs to look professional.  If anyone is interested....I am willing to pay.  Thanks.  Chris

Your engine should oil the top though the pushrods...........................

There are no head oiling passages in stud rocker head blocks. Shaft rocker blocks have a passage drilled down from the deck to the third cam bearing journal. This passage matches up to a passage in the head that goes up through the #5 rocker shaft support.

When the oiling issue with shaft rockers was first discovered AMC made an external oiling kit. The kit consisted of a 1/8" copper line and a special rocker shaft support bolt. The bolt was drilled through the top of the head for a 1/8" OD copper line. The hole was drilled down just far enough that the bolt could be cross drilled for oil to exit inside the shaft and oil the rockers. The line was soldered into the top of the bolt (a good epoxy would work now). It extended through a grommet in the top of the valve cover, which had to be drilled for the grommet, of course. From there it went down to a fitting in the main oil gallery, I believe into a T in the oil sending unit. If I were making one I'd use a hard steel tubing up through the valve cover then a screw-on fitting for the copper line. Or a hard copper tubing up through the cover and a fitting with a soft line to the oil supply. The line must be removed to take the valve cover off.

Chris, I know you have a nice shiny new engine, but stud rocker heads are pretty easy to find and cheap. A 4.0L head might even be a nice upgrade at this point. You're not talking about a lot of money or long delay to just swap the head. Maybe someone here has a used head and could use a freshly rebuilt shaft head? You might lose some money in a swap or to change the head, but I think it would be better than the external line kludge. It will be "factory approved", but there's no way to make it look like it is anything more than a kludge to fix a mistake.

The later fix was to modify a head bolt that passed through the oil passage to allow more oil by. (http://www.mattsoldcars.com/RestoreAmerican/boltmod.shtml)

Here's a possibility, the pedestile rocker head lubes the  rockers by oil coming up the hollow pushrods, from the lifters, right? This oil comes out the pushrod hole at the top and thru the hole in the pushrod cup then flows across the rocker arm to it's center pivot.

Edited by tyrodtom - Nov/08/2009 at 4:38pm

No matter what you do it's going to look a bit shade-tree. The braided line might look better -- the size will make it look a bit more like another PCV hose or something. Would make it easier to use a piece of hard tubing coming up out of the bolt, then a threaded 90 on top. The 90 would have to be screwed off to pull the valve cover. The tubing can be welded to the top of the bolt, doesn't have to match the hole if the weld is good.

I don't think I'd trust hollow pushrods to provide ample oil to the shaft. While there should be pressure at the tip of the rocker, there's no way to know if enough will get through the rocker to the shaft. It MIGHT work, but....

You'd have to get a 72 or 74 block with shaft rocker head. 73 used bridged stud rockers, as did everything after late 74. When AMC came out with bridged rockers in 73 Buick filed a patent dispute.  AMC reverted back to the shaft rocker sometime in mid to late 73 through 74 while the dispute was worked out. Don't know if they worked it out or the courts did, but by 74 the bridged rockers were back in use.

Oh, I'll tell you something else about that big port head -- flow sucks! The ports are big, but have practically a 90° turn into the cylinder. This slows velocity way down and hampers flow. A stock 91-96 4.0L head outflows those old big port six cylinder heads even though the ports are noticeably smaller. I finally convinced Chris Morrison (the author of the Mojo Javlein pages with all the head info you referred to) of this, and the last time I talked to him he was planning on using a 4.0L head. I haven't talked to him in several years now, can't say whether he did or not. When we first discussed using a 4.0L head he told me he simply had too much time and money in his modified head to give it up -- he was going to run it a while first. Sort of like you now...

 Hi Everyone!         I really appreciate all the feedback I got off my little situation.    My decision in all this is to stick with the head that I bought and make it work.   I'm in too deep.