Engine Rebuild Plan

[Zed Head]

28 minutes ago, Zed Head said:

 If it's an N47 head there's no real benefit to swapping to an N42 head.

You're going to swap a similar head on to an existing short-block, and install a high-performance cam shaft.  So far.  You could just install the cam shaft and save the head swap money.

[wil84911]

You're going to swap a similar head on to an existing short-block, and install a high-performance cam shaft.  So far.  You could just install the cam shaft and save the head swap money.

 

That was the plan though rebuild that short-block but more research says an N42 performs better.

 

 

12/70 260Z motor Mallory dist triple Weber 40s ext oilcooler headers twice pipes Tokico Iluminas Eibach springs frt/rr sways

[Zed Head]

That's bad research.  They are identical except for the exhaust port liners.

[dutchzcarguy]

5 hours ago, Zed Head said:

That's bad research.  They are identical except for the exhaust port liners.

That depends.. In europe for example we have no exhaust port liners…  therefore these heads can be better.  personaly i think there is not much if any diff. in the N42 and N47.   I've got a N42 on my 280zx and it has a compr. of 10.1 to 1 standard.  it runs very well.

[madkaw]

I’d venture to say all the early dished pistons BLOCKS are the same . Performance wise I would find a later flat top piston block. 

Cylinder head. N42 and N47 are the same except for the exhaust ports . The 42 lends itself to more porting advantages , but for just swapping parts it’s a wash 

[siteunseen]

N47 was the first oiling cam as far as I know, N42 had spray bars.  My 9/'76 N47 had both. 

[Zed Head]

7 hours ago, dutchzcarguy said:

no exhaust port liners…  therefore these heads can be better.

That seems to be the assumption that is made, based on appearance.  But there is no data to back it up.  The big rectangular exit hole of the N42 head looks better compared to the N47 hole.  Bigger is assumed better.  But...no proof.  And Nissan's specs are exactly the same.

Just adding some info for wil849's search.  Lots of ways to spend money with no significant benefit.  And possibly make power costing mistakes, like putting round headers on square exhaust ports.  

Edited July 26, 2018 by Zed Head

[wil84911]

That seems to be the assumption that is made, based on appearance.  But there is no data to back it up.  The big rectangular exit hole of the N42 head looks better compared to the N47 hole.  Bigger is assumed better.  But...no proof.  And Nissan's specs are exactly the same.
Just adding some info for wil849's search.  Lots of ways to spend money with no significant benefit.  And possibly make power costing mistakes, like putting round headers on square exhaust ports.  

Thank you Zed. Thanks for everyone’s feedback. It really helps. We try avoiding the expense but want the best possible combo and I still make lots of mistakes.



12/70 260Z motor Mallory dist triple Weber 40s ext oilcooler headers twice pipes Tokico Iluminas Eibach springs frt/rr sways

[Zed Head]

Good luck.  You can spend a lot of money just on the rebuild.  Check that head for warpage.  It might need machining, which will add cost.  A big shave will need camtower shims.  All kinds of nickel and dime stuff.

Your new camshaft will need a set of rocker arms and lash pads.  I'd put a list together and see where you can save.

[wil84911]

Good luck.  You can spend a lot of money just on the rebuild.  Check that head for warpage.  It might need machining, which will add cost.  A big shave will need camtower shims.  All kinds of nickel and dime stuff.

Your new camshaft will need a set of rocker arms and lash pads.  I'd put a list together and see where you can save.

 

Thank you.

 

 

 

12/70 260Z motor Mallory dist triple Weber 40s ext oilcooler headers twice pipes Tokico Iluminas Eibach springs frt/rr sways

[dutchzcarguy]

16 hours ago, siteunseen said:

N47 was the first oiling cam as far as I know, N42 had spray bars.  My 9/'76 N47 had both

Nope... N42 in my euro 280zx from early 1979..   ('79 was it's first year in the Netherlands! )  was already a self oiling cam..

 

 

[Zed Head]

9/76 is before 1979.