curious about my z22

[Berta720]

So I recently got my 720 that has a z22 in it and I am just curious about a few things. Just reading around on here I have seen people say that they only rev to 6 grand which is fine but when I first got my truck I figured it would rev like crazy. I have also read that there are not many good ways to hop up the z22.

I have a few questions though like since its red line is around 6, does the engine not like being revved out for long periods of time or is the little guy totally ok with sitting at like 5 while cruising down the highway because I know some engines don't like going very high at all even if they can?

And are there any must do mods to the engine that I should do to increase reliability or like give it just that bit more of pep? I have done or will do all normal maintenance to it. Have not put plugs in yet.

[Stoffregen Motorsports]

There's not a lot you can do to a Z22 to make easy horsepower. You can install a Weber DGV or DGAS carb to liven it up a bit, but we're talking only a few HP. Installing a cam is the next logical step. Of course, a good exhaust system will help too.

 

These engines have a pretty long stroke, which means they like to live at lower RPMs, but that's no fun, is it?

[Berta720]

30 minutes ago, Stoffregen Motorsports said:

There's not a lot you can do to a Z22 to make easy horsepower. You can install a Weber DGV or DGAS carb to liven it up a bit, but we're talking only a few HP. Installing a cam is the next logical step. Of course, a good exhaust system will help too.

 

These engines have a pretty long stroke, which means they like to live at lower RPMs, but that's no fun, is it?

So if i want it to last I should not be revving the piss out of it then. good to know although the rpm its at on highway i don't have much control over.

and for future reference where would you find those carbs, are they found easily new or is it like an ebay find kinda deal ?

[Stoffregen Motorsports]

I should clarify that highway driving isn't going to kill the motor, it just doesn't make much horsepower in the upper RPMs. So until you get to highway speeds, short shifting is key.

 

Don't buy off ebay. Too many cheap knockoffs there. Buy from a reputable source like http://www.redlineweber.com/carb-kits/auto/nissan-truck/

 

or https://www.piercemanifolds.com/category_s/99.htm

 

Pierce Manifolds is Weber's main sales agent in the USA, and they have kits, and the prices aren't too bad, so play it safe, and buy from them.

 

Maybe I'm old (47), but I don't get the ebay thing. I'd rather go direct to the source.

[datzenmike]

An engine's power is made only in the head or primarily in the head. It's a pump that moves air in and out. The better it does this, the more power it can make. Straight air flow in and out and large large valves. Unfortunately the Z series head design limits air flow because of a sharp bend right at the valves. A 'larger' cam helps but performance wise it is already starting  with a big disadvantage compared to say the smaller L20B even though the cam timing,  lift and valve size are the same. To be fair the NAPS engine was designed solely to produce lower emissions and low speed torque and at this it does VERY well. Things that make it a great engine are increased displacement, 2 plugs per cylinder, cross flow design and as close to being a hemi combustion chamber as you can get. There's no need for good breathing above 4K on an emissions engine going 3K out on the highway. 

 

A better carb and a lower restriction muffler will help the air in and exhaust out but don't expect too much. A 'larger' cam is even better but you will probably loose some of your bottom end torque. It's a trade off.

 

Red Line for the Z22 is about 6,600 RPMs. This is the limit where you can safely rev all day. Above this steel begins to stretch. You're never going to be making any serious power there. So when the acceleration drops off go to the next gear. 

 

Find a Z24 and build it. It has stump pulling 130 ft lbs torque at 2,800.  

 

 

I have an L20B in my car but had a spare Z24 that ran very well in my 620. Just for fun last fall I fixed up a better breathing L20B head for it and put it on the Z24. The L20B makes about 95 HP so increasing the displacement 20% should increase the HP 20%. So somewhere around 115 hp?  

[Stoffregen Motorsports]

This topic keeps me up at night. I can't count how many times I've had people come to me to try and get more oomph out of an underpowered motor. One guy insisted on buying a 4cyl Chevy S10, instead of the V6, and then wanted to re-gear it and give it a bunch of other upgrades to get more power. I did not take the job, and I told him he should have gotten the one with the 4.3L V6.

 

Sometimes the best answer for more power is an engine swap. Swaps don't scare me, but they can be brutally expensive if you're paying for labor.

[Berta720]

1 hour ago, Stoffregen Motorsports said:

This topic keeps me up at night. I can't count how many times I've had people come to me to try and get more oomph out of an underpowered motor. One guy insisted on buying a 4cyl Chevy S10, instead of the V6, and then wanted to re-gear it and give it a bunch of other upgrades to get more power. I did not take the job, and I told him he should have gotten the one with the 4.3L V6.

 

Sometimes the best answer for more power is an engine swap. Swaps don't scare me, but they can be brutally expensive if you're paying for labor.

No I totally understand that, I didnt start this thread to build up a z22. I just started it for some more info about the engine. I did not get an old 4cyl nissan truck to do burnouts and drift everywhere I go. I was just more wondering if there were like essential mods just to help the engine out a bit.

[Berta720]

I do have some other questions though.

like will a z24 bolt into the same spot relatively easy?

How much torque would it take to strip a spark plug threads out?

Does removing all the egr and vacuum line bullshit help anything or will it actually run worse after that?

Which side are the primary spark plugs and which are the secondary?

I was just changing plugs last night and was wondering about this stuff.

[Stoffregen Motorsports]

A Z24 is essentially a bolt in upgrade.

 

De-cluttering an engine and bringing it back to its simplest form will help, but sometimes there are benefits to the various systems. I don't have any experience with the Z series trucks (in their stock form), so I can't give you specifics. I don't know if the Z motor likes the EGR or not, but it may be possible to simplify it.

 

About 15 years ago, I wanted to clean up the 1990 Toyota 22RE engine in my 1957 Land Rover. but keep the EFI. I was able to get rid of just about everything (which wasn't a whole lot of stuff), and by reverse engineering the EGR system, I was able to delte two solenoids and about two pounds of vacuum tubes and retain a functioning EGR, which actually helps the 22RE.

 

You may have to do some of that reverse engineering to effectively delete components.

 

 

[Berta720]

9 minutes ago, Stoffregen Motorsports said:

A Z24 is essentially a bolt in upgrade.

 

De-cluttering an engine and bringing it back to its simplest form will help, but sometimes there are benefits to the various systems. I don't have any experience with the Z series trucks (in their stock form), so I can't give you specifics. I don't know if the Z motor likes the EGR or not, but it may be possible to simplify it.

 

About 15 years ago, I wanted to clean up the 1990 Toyota 22RE engine in my 1957 Land Rover. but keep the EFI. I was able to get rid of just about everything (which wasn't a whole lot of stuff), and by reverse engineering the EGR system, I was able to delte two solenoids and about two pounds of vacuum tubes and retain a functioning EGR, which actually helps the 22RE.

 

You may have to do some of that reverse engineering to effectively delete components.

 

 

thats fine with me. Its a project truck and I like to tinker around a bit. I have to go repair some spark plug holes later tonight so

[datzenmike]

The plugs are intake and exhaust side. The exhaust are one step cooler heat range but both fire together at the same time. Intake are powered directly from the ignition switch and the exhaust through a fuse... I don't know why, they just are. You can swap intake side for exhaust side and there's is no change. Ive heard stories about the exhaust plug firing during the exhaust stroke but this is not so. Two spark plugs means two ignition sources for the combustion process and like burning a candle at both ends it shortens the burn time. This is turn allows less ignition advance to be used and there is less heat loss to the combustion chamber and cylinder walls which increases the amount to do work pushing the piston raising the engine's efficiency and there is less time for NOx compounds to form. In addition leaner fuel air mixtures and higher EGR mixtures can be used. 9,000 HP dragsters use dual plugs, there's a good reason to like them.

 

As for EGR it is simply an inert gas that takes up space in the combustion chamber displacing a small amount of fuel and air. This lowers the peak combustion temperatures and the small loss of power is simply made up for by pressing down on the gas peddle further. You can't miss what you don't know you're missing. In addition the throttle is farther open than if no EGR present, so the engine doesn't have to work as hard to suck in air past the throttle plate restriction and there is some gain there. This is all happening above idle and at part throttle and you won't feel any loss. EGR is NOT working under the following conditions...'

 

The engine is cold or not yet warmed up

It is at idle

It is at full throttle.

 

EGR only tempers the fuel mix at part throttle to lower combustion temperatures so no HP is lost when you really need it for acceleration... (at full throttle)

EGR needs a ported vacuum signal from the carburetor, so if a hose falls off it's simply deactivated. This is not a manifold vacuum leak so has no effect if leaking.

 

Two possible problems are...

 

1/ The metal tube that supplies inert (oxygen depleted) exhaust gas to thee intake can erode and leak in outside oxygen rich air. The engine will run lean from too much oxygen. This would effect part throttle running when the EGR is active.

 

2/ The EGR valve can collect exhaust deposits and not shut tightly. This is disastrous for idle when EGR should not be present. Easy enough to wire brush them off every 30K miles

 

 

 

 

 

[Stoffregen Motorsports]

So beneficial? Or just not worth deleting? Those are two distinctions.

 

The 22RE actually runs better with the EGR (and stock EFI), so deleting would not give any advantage. That is the only engine I have ever intentionally left the EGR active. So back to my statement, that I don't know if the Z22 actually likes it.

 

 

[Berta720]

Ya know what my truck idles like crap. Maybe I should check if my EGR is stuck open. Another question. What is the exhaust feed tube on the front side of the engine for. It just feeds exhaust all the time. What is the purpose of that one?

 

[datzenmike]

It won't run if the EGR is fully open, I mean just not fully closed. You can reach inside under the EGR cap and using you finger nail lift up on the vertical rod and let it drop. This will usually dislodge the deposit. Or carefully unbolt and use a wire brush. I find they are generally rusty and this results in something broken off.

 

The tube on the front does indeed connect to the exhaust but this is part of the air injection system (AIS) Every time there is an exhaust pulse traveling down the exhaust pipe there is a small vacuum wave right behind it. At the air filter housing is a one way reed valve that won't let any exhaust pulses in but it does allow the vacuum wave to draw some filtered air out and then close and wait for the next vacuum pulse. So that tube contains  a series of little puffs of oxygen rich air working it's way down and mixing with the exhaust so the catalytic converter can burn away any un-burnt gas. Requires nothing to run and has no effect on the engine only on the emissions in the exhaust. Genius!

[Berta720]

Ok that's good to know. So its not really needed if that cat is gone then. By open I meant just a lil bit. 

[datzenmike]

Does no good without the cat. You can remove the pipe and plug with a metric pipe plug.

 

Deposits causing it to not close fully is basically a vacuum leak.