Camshaft oiling evolution

[Randalla]

Can anyone give me the production dates when the following changes were made for cam oiling on S30's? The first scenario was a spray rail only (1970-1972?). The second scenario is cars that came with both a spray rail and an internally oiled cam (1973-?). The final scenario is cars that came from the factory with only an internally oiled cam (?).

[LeonV]

External until '77, internal after that. There was no factory combination of both, at least not in the US.

http://datsunzgarage.com/heads/index.htm

[Randalla]

Are you absolutely sure about that? The reason I ask is I have been working on a friends 1973 240-Z, which has both a spray rail and an internally oiled cam. He is the original owner, has all the repairs and paperwork from new and there is no record, or recollection, of a cam shaft being replaced. I pulled the cam cover off for the first time in nearly 40 years he said. There was nothing to suggest any work or changes had been done previously. I don't recall having seen another 73 with both the rail and internally oiled cam.

[LeonV]

Are you absolutely sure about that? The reason I ask is I have been working on a friends 1973 240-Z, which has both a spray rail and an internally oiled cam. He is the original owner, has all the repairs and paperwork from new and there is no record, or recollection, of a cam shaft being replaced. I pulled the cam cover off for the first time in nearly 40 years he said. There was nothing to suggest any work or changes had been done previously. I don't recall having seen another 73 with both the rail and internally oiled cam.

It sure didn't come from the factory that way. The cam was changed at some point, does it have any markings on it?

First time pulling the valve cover off in 40 years? I guess if the guy never did a valve adjustment, that would explain the need for a replacement cam...

[Duffman]

Randy, wondering if what I read to you from the 73 FSM had nothing to do with internal oiling of cam. Maybe we misinterpreted the description as being both (?). Did you go back and look at the 73 FSM just to make sure?

[Randalla]

Duffman, here is literally what the 1973 Datsun 240-Z service manual says in the engine lubricating system chapter:

"The rocker mechanism is lubricated under two types of lubricating methods. The rocker arm and valve are lubricated intermittently by the oil fed through the oil gallery in the camshaft and the small channel at the base circle portion of each cam. Lubricant is supplied to this oil pipe (spray rail pictured) through No. 3 camshaft bearing, and the rocker arm and valve are lubricated intermittently by the oil through the small holes or the oil pipe."

This is confusing at best. I may be reading this completely wrong but it sounds to me like in 1973 there were two means of lubricating the top of the motor.

[Zed Head]

Have you actually seen the holes in the cam shaft at each lobe's base circle, or are you assuming from the service manual. A picture would be interesting.

[Randalla]

Unfortunately I have returned the car to its owner until he gets a new spray rail at which point I will again have the car to take a photo and post. However, I know what I saw when I removed the valve cover. It was definitely an internally oiled cam. The only explanation at this point seems to be a mid-late 70's cam swap, even though the owner claims that was never done.

[Randalla]

Mystery solved. After re-reviewing the repair history, the owner found a receipt from 1997 showing the camshaft was replaced with an internally oiled one. Wonder if there is any benefit to running both the oiling systems as currently installed on his car???

[5thhorsemann]

More oil is good I would think.

[Zed Head]

I've seen it discussed over at Hybridz. The main concern is whether or not there's enough flow through the orifice in the block to get equal oil supply to all of the holes. I guess you could get an imbalance, although it doesn't seem likely. Some say there's plenty, others drill out the restriction in the block to be sure. You might search around over there to get a better idea.

Why is the cam shaft being replaced? `

[Randalla]

The camshaft is not being replaced. We had the valve cover off to assess timing chain stretch and possibly move the cam gear one hole.