Noob with a 720

[tomcat]

Hey everyone, im new here, as well as to Nissans. I just picked up an 83 720 KC. with only 90k original miles on it!

 

now for the questions!

 

 

engine:

I would like to get some more power out of it How much power can be made on the z24 with carb, cam and headers? Also i was considering a KA24e swap, from what i hear its a direct bolt in swap? how true is that?

 

Also, im having an issue, where if i accelerate hard, and shift at about 3k or so she backfires like you wouldnt believe, and i can smell gas, it seems like its dumping raw fuel right into the exhaust, then BAM! what could cause this? could my timing be off? im not too sure what to do with all these spark plugs?! lol ( it has new cap/ rotor/ wires and plugs btw) also i clecked the carb to see if the choke was stuck, but its not.

 

Drivetrain:

What are some good tranny swaps/ rear end swaps? My tranny seems like the syncros are failing on 2nd gear. also if im going to have more power i would like some better gear ratios.

 

Suspension: anyone do a 5 lug conversion?

 

 

 

 

thanks in advance!!!

[datzenmike]

Hey everyone, im new here, as well as to Nissans. I just picked up an 83 720 KC. with only 90k original miles on it!

 

now for the questions!

 

 

engine:

I would like to get some more power out of it How much power can be made on the z24 with carb, cam and headers? Also i was considering a KA24e swap, from what i hear its a direct bolt in swap? how true is that?

 

Also, im having an issue, where if i accelerate hard, and shift at about 3k or so she backfires like you wouldnt believe, and i can smell gas, it seems like its dumping raw fuel right into the exhaust, then BAM! what could cause this? could my timing be off? im not too sure what to do with all these spark plugs?! lol ( it has new cap/ rotor/ wires and plugs btw) also i clecked the carb to see if the choke was stuck, but its not.

 

Drivetrain:

What are some good tranny swaps/ rear end swaps? My tranny seems like the syncros are failing on 2nd gear. also if im going to have more power i would like some better gear ratios.

 

Suspension: anyone do a 5 lug conversion?

thanks in advance!!!

 

The Z head has performance limitations. It does not breath all that well, the valves almost touch so larger ones are out, same with cam lift and duration. There is an upper limit before they hit each other or the piston tops. One way to rid yourself of all these problems at once is to swap an older L series head onto it. Better cam, valves and breathing, more after market performance parts. You will need to lengthen the timing chain and use an L20B timing cover that has been made 2cm taller. Basically a broken L20B for all the parts.

 

Headers are over rated. The Z24 is never going to rev high enough nor make enough power to make a header necessary. Fastest way to get more go is to swap in a lower ratio rear end. 4.11 or 4.375 will perk it up.

 

The KA motor will bolt to the Z24 transmission, yes. Motor mounts, i don't know about. The best oil pan and pick up it from a Hardbody truck with the rear sump that clears the front steering. Early KA24Es from the 240sx have the better intake and the EFI wiring is on it's own harness unlike the Hardbody which is mixed in with the main wire harness to the motor.

 

Backfire? Out the intake or the exhaust?

[tomcat]

backfire out the exhaust.

[tomcat]

Just built a full 2.25 stainless exhaust from the manifold back. Truck runs a LOT better, backfireing seems to have stopped. ? maybe it was due to a lack of backpresure in my original leaky pipe?

 

 

While i was under there, i notice the rubber doughnut that supports the U joint in the center of the driveshaft is GONE, and my driveshaft is wobbling around in there, i have heard talk of a one piece driveshaft? where do i get one? or do i have to make it? any benifits besides not having the u joint in the center? any issues/ problems?

 

Also i decided to start removing some of the EGR and emissions crap, anyone know what can and can not be removed? anyone have a drigram showing the vacuume hoses and Emissions system?im sure its in the manual, i just dont have one.......... yet. thanks.

[Sealik]

Just built a full 2.25 stainless exhaust from the manifold back. Truck runs a LOT better, backfireing seems to have stopped. ? maybe it was due to a lack of backpresure in my original leaky pipe?

 

 

While i was under there, i notice the rubber doughnut that supports the U joint in the center of the driveshaft is GONE, and my driveshaft is wobbling around in there, i have heard talk of a one piece driveshaft? where do i get one? or do i have to make it? any benifits besides not having the u joint in the center? any issues/ problems?

 

Also i decided to start removing some of the EGR and emissions crap, anyone know what can and can not be removed? anyone have a drigram showing the vacuume hoses and Emissions system?im sure its in the manual, i just dont have one.......... yet. thanks.

 

 

Here's a link for the vacuum diagrams

 

http://720world.ning.com/forum/topics/vacuum-diagrams-1