[larry]

I have a 77 280Z w/fuel injection, 3 into 2 header, Crane ignition, Center Force 2 clutch and 5 speed. The car runs great and is very strong.
I'm looking for information about building the N47 for power in the 3000 to 6000 rpm range.
For Example, how much can I mill for compression without screwing up the valve geometry? What about valve clearance? Is there a concern?
Can a stock cam be ground fo street performance improvements considering my set up?
If you have experience in N47 head rebuilding I would like to hear from you.
I picked up a spare N47 head to work on during the winter and have already started cleaning up the intake ports.

 

[Unknown User]

> I have a 77 280Z w/fuel injection, 3 into 2
> header, Crane ignition, Center Force 2
> clutch and 5 speed. The car runs great and
> is very strong.
> I'm looking for information about building
> the N47 for power in the 3000 to 6000 rpm
> range.
> For Example, how much can I mill for
> compression without screwing up the valve
> geometry? What about valve clearance? Is
> there a concern?
> Can a stock cam be ground fo street
> performance improvements considering my set
> up?
> If you have experience in N47 head
> rebuilding I would like to hear from you.
> I picked up a spare N47 head to work on
> during the winter and have already started
> cleaning up the intake ports.

Instead of milling the N47 head for compression why not just change to flat top pistons? Also I have a similar set up as you do...I would recommend the K&N air intake and a Webber WMTB to make your headers worth the $$ you spent on them. I would do these mods prior to the head work. BUt that is just MO. Hay I am going to get a new clutch for X-Mas from santa...how difficult was the installiation of yours?
Good luck-Travis 77z

 

[jeff]

> I have a 77 280Z w/fuel injection, 3 into 2
> header, Crane ignition, Center Force 2
> clutch and 5 speed. The car runs great and
> is very strong.
> I'm looking for information about building
> the N47 for power in the 3000 to 6000 rpm
> range.
> For Example, how much can I mill for
> compression without screwing up the valve
> geometry? What about valve clearance? Is
> there a concern?
> Can a stock cam be ground fo street
> performance improvements considering my set
> up?
> If you have experience in N47 head
> rebuilding I would like to hear from you.
> I picked up a spare N47 head to work on
> during the winter and have already started
> cleaning up the intake ports.
I'm with Travis. Instead of milling the head to increase compression get the '82-83 280ZX stock NA flat top pistons. These will get give you more than enough compression for the pump gas. This will leave you room to do some fancy head porting and combustion chamber shaping.

 

[240Dave]

> I have a 77 280Z w/fuel injection, 3 into 2
> header, Crane ignition, Center Force 2
> clutch and 5 speed. The car runs great and
> is very strong.
> I'm looking for information about building
> the N47 for power in the 3000 to 6000 rpm
> range.
YOU NEED A CAM FOR THIS, NOT A NEW CYLINDER HEAD.
HOW ABOUT A NEW BIG BORE THROTTLE BODY AND FILTER IF YOU HAVEN'T ALREADY GOT ONE.

> For Example, how much can I mill for
> compression without screwing up the valve
> geometry?
PROBABLY .050 IS THE MAX I WOULD MILL OFF A Z CYLINDER HEAD. IT SHOULD RAISE YOUR CR BY 1 FULL POINT OR SO. VALVE GEOMETRY IS NOT AFFECTED UNLESS YOU ALSO MILL THE TOP OF THE CYLINDER HEAD. WHEN PEOPLE REFER TO VALVE GEOMETRY, THEY ARE REFERRING TO THE ANGLE OF INCIDENCE OF THE CAM LOBE TO THE ROCKER ARM. IN OTHER WORDS, YOU WANT YOUR CAM LOBES TO RIDE ON THE CENTER OF THE ROCKER ARM. THIS IS NOT AFFECTED BY MILLING THE BOTTOM OF THE HEAD. CHAIN TENSION IS AFFECTED, BUT IF YOU HAVE A NEW TENSIONER, AND GUIDES, YOU CAN ADJUST THEM TO COMPENSATE FOR THIS, AS WELL AS ADJUST YOUR CAM GEAR TO GET THINGS BACK INTO SPEC.

What about valve clearance? Is
> there a concern?
YES, THERE CAN BE. BUT UNLESS YOU GET A RADICAL CAM LIKE .480 300 DURATION OR ABOVE, YOU WON'T HAVE ANY PROBLEMS. THIS CAN BE REMEDIED WITH RELIEF CUTTING INTO THE PISTONS. THESE CAMS ARE VERY LOPEY AND HARD TO DRIVE AROUND TOWN. I WOULD RECOMMEND A .450 LIFT 270-290 DURATION CAM. SHOULD KEEP SOME LOW END AND ENOUGH HP TO PULL TO 6500 RPM. STOCK CAMS SUCK AS THEY START GASPING AT 5000 RPM.

> Can a stock cam be ground fo street
> performance improvements considering my set
> up?
ANY CAM CAN BE REGROUND, HOWEVER, IT IS USUALLY CHEAPER JUST TO BUY ANOTHER ONE. MOST SHOPS WILL TAKE YOURS AS A CORE, AND GIVE YOU A REGRIND IN EXCHANGE.

> If you have experience in N47 head
> rebuilding I would like to hear from you.
HAVEN'T BUILT AN N47, BUT BUILT AN E88. NOW YOU'VE HEARD FROM ME.

> I picked up a spare N47 head to work on
> during the winter and have already started
> cleaning up the intake ports.
GOOD WINTER PROCECT. MAKE SURE NOT TO SMOOTH OUT THE PORTS TOO MUCH. YOU DON'T WANT IT LOOKING LIKE A MIRROR.