Camshaft Oil Spray Bar Redesign and Rebuild

[grannyknot]

5 hours ago, Captain Obvious said:

When you run your oil pump with the drill, do you see a bunch of oil oozing out from around the cam journals? 

I did what Zed Head suggested, flipped the head up side down, filled a large syringe with lamp oil and filled the head oil system, most of it poured straight out tower 3 & 4 .

I've put the word out locally to see if any one has a spare set they can sell me.  I had a couple of heads that would have been good candidates but they went for pennies on the dollar last fall when I started purging the storage areas.

[Zed Head]

That's a first.  Should be an interesting project.  The cam towers have a lot of mystery attached.  Nissan says that if they're bad the whole head needs replacing.  You probably have read that.  Then, of course, there's the "tap the towers while spinning the cam" adjustment method if they're removed.  Haven't seen towers from a different head tried.  Seems like it should be possible, if the cam spins freely what could go wrong.

Too bad they don't have "tower saver" journal inserts.  Maybe you could make some.

 

[grannyknot]

1 hour ago, Zed Head said:

That's a first.  Should be an interesting project.  The cam towers have a lot of mystery attached.  Nissan says that if they're bad the whole head needs replacing.  You probably have read that.  Then, of course, there's the "tap the towers while spinning the cam" adjustment method if they're removed.  Haven't seen towers from a different head tried.  Seems like it should be possible, if the cam spins freely what could go wrong.

Too bad they don't have "tower saver" journal inserts.  Maybe you could make some.

 

I wish I had access to that kind of equipment or I would certainly give it a try.  Nissan also says to inline hone the cam towers if they are removed and I've never seen anyone do that, I've always had good luck with spinning the cam, taping the towers and tightening the bolts method. People install new cams on old tower bearings all the time, the heads can't be that different from one another, or at least I'm hoping they are not.

[grannyknot]

Picked up a set of used cam tower bearings today, came from an E31 head, all within spec, bolted them in and the cam slid in perfectly, first time with no binding! Very pleased.

Also, p/u the spray bar from the donor head, it's in much better shape than the other one, there is definitely more oil coming out of the spray bar although certainly no jets of oil, but then the oil is cold and the cam and rockers aren't moving as I spin up the oil pump and they help to splash the oil around.