Okay i am confused

[robftw]

So my head is a 1977 N47.

I was planning to take this camshaft and get it re-ground and put it on my P90... But here is the problem... its got a spray bar, i thought all 77+ were internally oiled? And the final cam tower is damaged slightly near where the cam sits, i may be able to grind it smooth.

What can i do to remedy this, use the N47 cam towers + spray bar + N47 cam ? Or can i use the P90 towers + no spray bar + n47 cam? I don't know what to check for the cam shaft differences externally vs internally oiled.

[240260280z]

My 77 has spray bar.

I have read that some have swapped cam towers between heads due to this reason but I have also read that this is not recommended because the towers are bored In situ on the associated head.

Why not just get the p90 cam reground?

[robftw]

My 77 has spray bar.

I have read that some have swapped cam towers between heads due to this reason but I have also read that this is not recommended because the towers are bored In situ on the associated head.

Why not just get the p90 cam reground?

it came off a zx with 150k miles, the N47 cam only has 62k

The valve train on the P90 was rebuilt, the cam however was not replaced.

[preith]

The N47 to the best of my knowledge was internally oiled - every one I've seen has been this way. It's my guess it was swapped out. I ran a P90 on a naturally aspirated engine WITHOUT a spray bar on my street 280, it was trouble free. As long as the cam is internally drilled I don't see a problem without the spray bar. If you're doing any kind of sustained high rpm, such as time trials, etc, you may want to run both with a high volume oil pump, and the oil plug at the top of the block bore out a little larger - per Honzowetz's book.

[Travel'n Man]

Call Dave Rebello at Rebello Racing - super knowledgeable and can help guide you - if you do need a reground - he can knock that out for you as well

[robftw]

The N47 to the best of my knowledge was internally oiled - every one I've seen has been this way. It's my guess it was swapped out. I ran a P90 on a naturally aspirated engine WITHOUT a spray bar on my street 280, it was trouble free. As long as the cam is internally drilled I don't see a problem without the spray bar. If you're doing any kind of sustained high rpm, such as time trials, etc, you may want to run both with a high volume oil pump, and the oil plug at the top of the block bore out a little larger - per Honzowetz's book.

According to the original owner it was never swapped, which is why im confused. Stupid question, but without having to take my valve cover off and taking a look at the P90cam is there an easy way to check if the N47 cam is internally drilled?

[Jeff G 78]

The N47 to the best of my knowledge was internally oiled - every one I've seen has been this way. It's my guess it was swapped out. I ran a P90 on a naturally aspirated engine WITHOUT a spray bar on my street 280, it was trouble free. As long as the cam is internally drilled I don't see a problem without the spray bar. If you're doing any kind of sustained high rpm, such as time trials, etc, you may want to run both with a high volume oil pump, and the oil plug at the top of the block bore out a little larger - per Honzowetz's book.

Not ALL of them Phillip. I happen to have a bone stock N47 with a spray bar. I bought the head about 10 years ago from a guy in San Diego who claimed the head was owned by a Nissan race team and was a take-off head that had zero miles on it when removed in 1976. The complete head was clearly brand new when I got it. The cam and rockers had no wear patterns and everything else looked like it had zero miles and wasn't cleaned or reworked. The seller said that it was from an early production '77 engine.

[Zed Head]

The drilled cams have small, but easily visible, holes on the base circle of each cam lobe to let the oil out. If your cam doesn't have the holes, then it's a spray-bar cam.

[preith]

Not ALL of them Phillip. I happen to have a bone stock N47 with a spray bar.

Thanks Jeff. Yeah, I shouldn't be surprised being the owner of a carb'd N42 head (without FI notches).

One tidbit on the spray bar - don't forget the little oil block-off plates if you use the towers originally used with it.

[robftw]

Well its not internal, I guess im going to throw the whole head up on ebay and try to get another P90 cam shaft minus the rockers because those are getting reground

[LeonV]

Why? Just swap cam towers and be done with it, procedures are on the web if you search. Basically, slowly tighten the towers down, making sure the cam spins free. Some slight tapping with a rubber mallet may help...

[robftw]

Why? Just swap cam towers and be done with it, procedures are on the web if you search. Basically, slowly tighten the towers down, making sure the cam spins free. Some slight tapping with a rubber mallet may help...

I've read conflicting things about this, so im a bit weary of doing it