L28 options for a street car

[Gareth]

Hello,

 

a few weeks ago I got a smoking deal on a N42/N42 longblock on German eBay (it cost me roughly 45 euro ~ 63 bucks), and I fetched it without hesitation. Now the block is in my garage, waiting to be completely rebuilt. I am not in a rush, because the factory L24 is going to stay in my Z for a while. I thought of a few options:

 

- rebuild it, overbore slightly (0,5mm), throw in some aftermarket pistons and a decent street cam, bump the compression, rework the head, use at least 45mm carbs (Weber DCOE?), get a lightweight flywheel and pulleys

- as above plus an LD28 crank (I should be able to source a complete LD28 for pretty cheap), 240Z 9mm rods, 2mm or 3mm overbore with appropriate pistons

- as above plus a complete LD28 block and even longer rods for a decent rod/stroke ratio

- leave it for better times and make it a gazillion-HP L-series monster (yeah right...)

 

I would like to stay NA, and I don't want to make it too much of a race engine. At first I thought that option no. 1 was the most reasonable one, but considering the fact that I may have a source of a complete LD28, the 240Z rods are in my L24, and either way I'm eventually going to buy an aftermarket piston set, wouldn't it be wiser to go the stroker way? I was also considering the LD28 block idea, but I'm afraid of the differences in lubrication and the need to drill the head for 12mm bolts. I'd also have to resleeve the block, because of LD28's smallish bore.

 

Another question is, what kind of headwork will I need in both cases? My N42 should be the same N42 as in the US, but it came out of a 280ZX - I suppose they were factory equipment on Euro S130s (I've seen at least three different Euro ZXs with N42s). I read some FAQs and BRAAPs posts, such as this one:

 

The N-42 head is a great maximum effort race head if class rules allow extensive carving and welding to the head. In this case, weld the chambers, open the exhaust ports as described above, perform some serious valve unshrouding and “waa laa”, you now have a wonderful maximum effort race head that would SUCK on a street engine.[/b'] (Side note; If you intend on having your valves unshrouded and have not done this type of work before, you are best served leaving this to a qualified experienced engine builder, preferably one that has been successful in extracting noticeable to impressive documented performance gains. If you are not sure what you are doing, do not attempt to unshroud the valves yourself. In experience can hinder the flow worse than what the heads were stock.) Of course there is more to building/machining/porting a maximum effort cylinder heading than just welding a chamber and/or unshrouding valves. There are items such as setting spring heights, clearancing the retainers, stem seals, and guides for the mega lift cam, deciding on just how far to go with oversize valves even to the extreme of offsetting the valve guides to allow even BIGGER valves if the cylinder bore permits, etc.

 

If the N42 is the best maximum effort race head, then should I slightly redo it, or leave it on a shelf and search for something else (my factory E88, Maxima N47, 280ZX P79 or P90)? If I should leave the N42 as-is, then what mods should I do to it?

 

Thanks in advance. This forum is great!

 

Tony