'86 720

[P.Rubber]

I just bought a '86 720 with the z24 engine, everyone I know who says they know Nissans tell me I need to scrap the head on it and put a L20B head with a Weber downdraft carburetor new headers, and keep my z24 block, I've read multiple threads on this topic on multiple forums. Can anyone tell me if this is the best route to go, or another way that is going to be worth it?

 

Thanks.

[poor-mans-720]

Its called an LZ build. Cause its half a L, and half a Z motor... I am currently doing one for my Z22 820 4x4. I need more hp and torque. Running big tires so need it. Search out LZ build. There are tons more info. And no right or wrong way to go. I am using a closed L20 head. There are like 3 or 4 different ones to go with. But I got a screaming deal on trading for mine. All L20 gear. Still dont know if I wanna do SU's or a Weber though.

 

[P.Rubber]

[DREWSDIME]

Whats wrong with the Z24 in there now? They are good motors, depends on what your planning on doing?

[P.Rubber]

[P.Rubber]

[P.Rubber]

[P.Rubber]

Everyone tells me that the head on the z24 is garbage for anything performance, I know a guy who had a 620 that went 102 in 2nd, and now all I can think about is how much I want to do to this truck. I only paid $500 for it, and for the shape it's in, I dont want to sell it, I love the truck. Just want to do more to the truck, engine-wise, body-wise..etc. And that's just it, I don't know exactly what I want to do too it, I just want ideas.

[datzenmike]

It's a lot of bother and a lot of parts to buy plus some custom modifications. Your compression will be at least 9.4 so some pinging or more expensive gas. You will need an L20B head and the two manifolds. Because of the difference in the way both motors are tilted (there is about 22 degrees) the L series head and manifolds will be tilted down on the driver's side. The L20B air filter won't clear the 720 master cylinder. Timing chain cover must be built up or welded by 3/4" to mate with the L head. The timing chain has to be lengthened. You will need an L20B distributor. L20B exhaust does noy fit the 720 down pipe. Throttle cable moved to the left side of motor or changed.

 

Get a new replacement 32/36 Weber and call it good.

[datzenmike]

Everyone tells me that the head on the z24 is garbage for anything performance, I know a guy who had a 620 that went 102 in 2nd,

 

RUBBISH. 102 feet maybe!

 

The head on the Z24 isn't easy to modify for performance but it still runs good. It's 20% larger than the L20B and has about 30% more torque. Your truck and motor looks fine don't fuck it up... drive and enjoy it.

[P.Rubber]

I mainly want to clean that engine bay up, its way too cluttered for my liking.

[P.Rubber]

http://www.webercarbsdirect.com/PhotoGallery.asp?ProductCode=WK646

[datzenmike]

I mainly want to clean that engine bay up, its way too cluttered for my liking.

 

Doesn't matter no one can see it.

 

Your truck and motor looks fine don't fuck it up... drive and enjoy it.

 

All that stuff has a reason for being there so don't start ripping it off. None of the Z24 emission controls are working at full throttle so it won't run any better and can only run worse.

[P.Rubber]

I don have to go through emissions here cause of the age of the vehicle...so I want to do something to it.

 

[P.Rubber]

I'll look into the Carb.

[datzenmike]

I don have to go through emissions here cause of the age of the vehicle...so I want to do something to it.

 

I don't get this. It's fine right now, leave it alone. Next week you'll be back needing help because it isn't running right, won't start, getting shitty mileage, back firing..... You get discouraged and end up selling it.

[P.Rubber]

Part of the reason I was even looking into any upgrades is because it diesels, it won't idle while cold did a full tune up adjusting the timing did everything i myself know how to do.

[P.Rubber]

Part of the reason I was even looking into any upgrades is because it diesels, it won't idle while cold did a full tune up adjusting the timing did everything i myself know how to do.

[P.Rubber]

Anyone have any ideas?

[datzenmike]

When warm is the choke plate still closed, or not fully open?

 

On the front of the carb there is a small round sight glass. The fuel level should be near the middle....is it?

 

What did you set the time at?

[P.Rubber]

I'll look tomorrow at work. My time is still.off a degree or two.

 

[P.Rubber]

I've been told my choke could need adjusting but I'm not sure if its an electric choke or manual.

[datzenmike]

So what did you set the timing at?

 

They only came with electric.

[P.Rubber]

My time is at like 5 degrees and the sight glass is.half full.

[c10jim]

Clean truck!