Camshaft Oil Spray Bar Redesign and Rebuild

[Captain Obvious]

Robert,

Your bar sounds just like how mine was. I don't think anyone bumped mine. I'm thinking that it was just thermal expansion and contraction. It's too consistent across owners. Take your bar off when you get a chance and see what the sealing surfaces look like.

Haha!! Maybe I've got another one of these things in me? Are your tubes in good shape? Mostly straight and spray holes not messed up?

I thought one of the aftermarket vendors offered one? Either MSA or Black Dragon? Do they not offer it anymore?

[EhlersRS]

Richard,

Okay, now that you mentioned the thermal expansion and contraction of the spray bar, that would make more sense rather someone "bumping" into the bar. From what I know about the car, it was last drove 20+ years ago and possibly the engine was started within the last decade. I just checked Black Dragon and didn't see one listed and MSA states the product is not currently available (http://www.thezstore.com/page/TZS/PROD/SMEC07C/17-8071). While searching more on this topic, I ran across other posts of guys looking for a replacement. The tubes look straight, but I'll try to pull the bar off tomorrow and get the status of the condition. Have a good night!

Robert S.

[Phred]

As a machinist and engine builder, I applaud your effort.

Phred

[5thhorsemann]

Captain, have you had a chance to blueprint the blocks? If so would you consider selling a set of prints?

[240260280z]

I always wondered why the oil bar was not on the other side of the cam so that less oil would be slung off the top as the lobe rotated?

It seems to do the job OK but oiling at a point just before the cam and rocker start pressing would seem to be a better location to me. Maybe the stock location is supposed to be more of a rocker and cam oiler than a cam oiler?

[5thhorsemann]

I always wondered why the oil bar was not on the other side of the cam so that less oil would be slung off the top as the lobe rotated?

It seems to do the job OK but oiling at a point just before the cam and rocker start pressing would seem to be a better location to me. Maybe the stock location is supposed to be more of a rocker and cam oiler than a cam oiler?

Perhaps for cooling the cam?

[Mikes Z car]

Shortly after I changed out the rings on my 1st 240Z the cam started making a horrible screeching sound. With the valve cover off I saw the cam lobe closest to the firewall had no oil on it and looked dry. Couldn't see the problem so I re bent the spray bar a little (might have taken it off and stuck pins in the orrifces) and never had further trouble with it. Never could tell what caused it to stop oiling on that one lobe.

[Captain Obvious]

I always wondered why the oil bar was not on the other side of the cam so that less oil would be slung off the top as the lobe rotated?

I don't really know either, but my only guess would be that there was simply more room on that side because of all the rocker mechanicals were already there. I never took any measurements, but I bet the cam isn't centered between the two inside walls of the valve cover.

About being a rocker oiler... The holes in the original spray bar does not point straight out. They actually point down a tiny bit. Not angled down far enough to hit the rocker, but definitely not parallel to the mounting bolts. No idea why.

Captain, have you had a chance to blueprint the blocks? If so would you consider selling a set of prints?

Blueprint? Heh... Let me refresh my memory tomorrow and see how smudged the back of my napkin is. Actually, the last time I made one of these, it became clear that I might be making more, so I did actually jot down some dimensions instead of just doing it all on the fly. Again.

[Captain Obvious]

Never could tell what caused it to stop oiling on that one lobe.

It was probably a crusty goober stuck in the hole. I've seen some really crusty spray bars by now! I think that when the oil starts to leak out of the bar from places you DON'T want it to, the decreased flow in the areas you DO want flow causes the oil to bake and gel.

That's something I forgot to mention before... Since the tubes thread into the distribution blocks on the redesign, you can take them out to clean them if necessary. I've threadlocked them in place, but I used the non-permanent grade.

As a machinist and engine builder, I applaud your effort.

Thanks Phred! I appreciate it!

[Bonzi Lon]

I always wondered why the oil bar was not on the other side of the cam so that less oil would be slung off the top as the lobe rotated?

It seems to do the job OK but oiling at a point just before the cam and rocker start pressing would seem to be a better location to me. Maybe the stock location is supposed to be more of a rocker and cam oiler than a cam oiler?

I will put out there, Physics.

The viscosity of the oil will make it stick to the cam. With a properly adjusted valve train, the oil will be 8 to 10 thousands thick on the base circle ready to lubricate the rocker as it rotates. The spray bar in its stock position allows time to fill the base circle. The hole on the internally oiled cam is on the back side of the wipe so it also has time to fill the base circle.

At least that is how I see it.

Bonzi Lon

[240260280z]

I think the oil hole on the drilled cam just leads the rising side of the lobe so it seems more logical as this is the high pressure rolling side (especially if the cam lobe is asymmetrical) , however it seems that the drilled cam will also fling oil all over the inside of the valve cover too (wasteful).

Maybe moving the oil bar to the other side of the cam will null the effects of low-Zinc oil on it? (i.e. quantity vs. quality).

[newbzee]

As a new Z owner, I've finally had time to start tinkering with my 73' junker and sure enough ran into the dreaded bad cam oiler bar. The rear tube was just hanging on and ready to fall out at any time. I was able to solder it back in with good results but as mention above, the distribution block is bent so it doesn't seal and I'm assume oil isn't getting to where it needs to be. Since this is a fixer, what are my options? Is there a bar from another year that is available? What could I expect a machine shop to charge to make one from scratch? The block looks cast so I'm assuming trying to bend it back into shape is right out, especially without a back-up plan. Any ideas?