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engine build advice.


Guest dvanecek

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Guest dvanecek

Ok I have a 81 L28 NA motor with a p79 head. I also just bought a 240z carb setup off ebay for $140 shipped inluding linkage, carbs intake, air cleaner. I think hta was a pretty good deal, was it? The motor has nothing. I will need distributor, clutch, flywheel, etc. The motor will be going into a model A. I plan on running a 4.11 ish strainght axel rear and a ZX 5 speed. I will be pulling the head to have it decked since it needs a new head gasket.

 

so here's the questions. Lightened flywheel? port, polish head while I have it off? cam recommendations? can have it decked more to raise compression?

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Guest dvanecek
How much money do you have to spend??????

 

I'm not wanting to drain my account, and I don't want to get really exotic. I figure If I have to buy and replace thing I might as well do it right. I don't mind spend a little money to upgrade things. I was thinking a nice strong cam. maybe try my hand and porting and polishing the head myself if I can find templates. You're in Marrietta? I live in Roswell. crazy.

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Guest dvanecek
Have you tried Delta Cams? They are based out of Tacoma, WA I think. Thats where I got mine, and Im really happy with it. I'll try to get you the number. Less expensive than most cams.

 

How is your motor currently setup? did you replace the followers, etc as recommended?

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If you're going to build a N/A L28 with SU's and you don't want it to be a dog the I would suggest the following build up...

 

F54 block which you have, over bore 20 thousands of an inch

New FLAT TOP pistons and rings.

 

p-79 head with a mild cam 460 lift 270 duration new nissian rocker arms and performance springs to prevent valve float. Use the flepro 1mm head gasket.

 

Flywheel from a 2+2 for the 240mm contact surface and a 780lb pressure plate.

 

Headers and at least 2.5 inch exaust (or 3 inch).

 

turbo oil pump

 

distributor from a 79-80 zx distributor with E12-80 ignition module plus the coil from the any ZX

 

since you're using the great SU's you need to get some new needles known as "SM" needles.

 

New timing chain set

 

new main and rod bearings

 

altinator should be from a turbo ZX (70 amp) or from a maxima ( I think its 120amp).

 

With that setup you should be able to get about 170 to 190 RWHP with the 1mm head gasket and the 20thou over bore should get you to 8.8:1 CR compaired to the stock 8.52:1 not much of a difference but unless you are planing to shave that head or use a N42 head it will be hard to get that CR up to a bad a$$ 10:1 or higher. if you want crazy HP (250 and higher) then turbo that sucker... and thats a whole differnt list of stuff to build.

 

Good luck

 

P.S. I have an L28 NA with almost that exact build up (n42 head instead)

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I'm not wanting to drain my account, and I don't want to get really exotic.

 

Well, since we don't know how much you got in your account, we still don't know how much you're willing to spend.

 

Here, this isn't very exotic: a good tune up. Proly make more horsepower than a cam. this is going in a Model A, like Ford?

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Guest dvanecek
Well' date=' since we don't know how much you got in your account, we still don't know how much you're willing to spend.

 

Here, this isn't very exotic: a good tune up. Proly make more horsepower than a cam. this is going in a Model A, like Ford?[/quote']

 

Yep stripped down model A. As far money goes. It really doesn't matter in the sense that this will be a bit of a side project, so If i have waite a while to do something right then I will. It will get done when I can afford to do it. I would rather not touch the bottom end. If it's good and solid I don't plan on tearing it down so over bore it out unless I need to rebuild it. I just want to make the best decision while I'm doing what I need to do to get it together. All I have is a long block and the carb setup, Like I said I need a new cam no doubt the one in it is shot, so what are the recommendations, I need a flywheel is the lightened one worth the money? I need an ignition setup, so what's recommended. etc.

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I was actually gonna order their rebuild kits. they look pretty straight forward and I have rebuilds carbs in the past. Are they any gotchas? any tips besides sm needles

 

I've never used them because I have triple Webers, but I hear nothing but good stuff about them.

 

A rebuild kit is fine. I only suggest the rebuild service because of all the neat stuff they do...

 

  • SU carbs are completely stripped to bare aluminum, cleaned, inspected, blasted to remove all stains, acid stripped, and machine polished.
     
  • Domes and pistons are "dashpot drop-tested and matched". The drop test ensures that the pistons go up at the same rate, equalizing the flow of air/gasoline to your engine.
     
  • All steel linkage and hardware is acid stripped and cyanide zinc replated with the factory colored yellow/orange/purple zinc plating and baked for 5 hours. Includes replated throttle return springs and center linkage for free when available.
     
  • After the bodies are machined, the carbs get polished. All ZTherapy carbs are machine polished with a unique high pressure (22 G's of force) machine polish technique. This is not a wheel polish. These carbs shine better than when they came out of the molds. By polishing in this way, we close the pores of the metal. They shed dirt better, and look great!
     
  • Throttle Shafts are sized to receive double sealed stainless steel roller bearings. Carb bodies are precision machined for shaft alignment and installation of both bearings. This alignment process in conjunction with the bearings virtually eliminates shaft binding, vacuum leaks and idle problems for years to come.
     
  • New Nissan or Genuine SU or ZTherapy hardware is installed. You get new choke nozzles, clamps, new needles, gaskets, Needle & Seats, gas tubes, ect... This ensures that your carbs will perform for another lifetime!
     
  • Your carbs are reassembled to factory specs with great care. All carbs are fitted with custom ZTherapy nozzles to cure the sticky choke problems inherent in SU/Hitachi carbs. The result is a carb set that looks and performs as new.
     
  • Shipped with a free "Just SU's" video to aid in installation, tuning and balancing .
     
  • Warranty: ZTherapy Inc extends a three year limited warranty on this service.

 

Another option is to send them to Rebello Racing. They don't do the throttle bushing-bearing replacement, but they do the "Big Bore 240Z SU 50mm" modification.

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Guest dvanecek
I've never used them because I have triple Webers' date=' but I hear nothing but good stuff about them.

 

A rebuild kit is fine. I only suggest the rebuild service because of all the neat stuff they do...

 

 

 

Another option is to send them to Rebello Racing. They don't do the throttle bushing-bearing replacement, but they do the "Big Bore 240Z SU 50mm" modification.

 

There stuff looks good, But I'd rather try my self first and spend the other $500 on other things. Has anyone here done the head shim deal? I need to have my head machined anyways and the higher compression and a reground cam should be a nice easy setup.

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