Z24 eating oil - what to do?

[Jitenshakun]

I have an '83 (1st gen) 4x4 720 that had a Z24 swapped in by a previous owner. The engine is eating oil and rather than just fixing it I'm thinking get some more power while I'm at it. 

 

With the struggles to drop in a Ka24de (oil pan) do i

 

-build a Z24? 

-get a Ka24d? 

-3rd option? 

 

It's going to cost time and money no matter what, but I'd like to find an option that just let's me get up a highway grade hill without my foot on the floor. A bonus would getting up a fire road at 30km/hr rather than my foot to the floor, in 1st gear, at 10km/hr.

[captain720]

How much metal fab experiance and tools do you have available? The ka swap is doable but requires time, skills, money, and experiance or a combination of the above that makes up for what's missing.

 

Sounds like your Z24 may not be doing very good! If you have low range you should be able to use all the gears no matter the hill steepness on your fire roads. Do you have a Weber? Could be worth just getting a healthy Z24 in there.

 

As far as "building" a Z24 there isn't a lot to be done, some minor head work, a cam is available and a good carb is about the limit without going crazy 

[Madkaw]

My 83 has the z24 . With factory wheel size it’s quite zippy - even with the 3.90 gear set. Maybe you also have the same gear set which can be soggy with larger tires . 
I plan in a turbo eventually once I get my EFI dialed in . 
The lack of power comes in to play on the highway which I hope the turbo with supplement my power and avoid a bunch of downshifting on hills 

[Jitenshakun]

I have the 32/36 Weber and slightly bigger tires. 235/75-15. My gearing is the 4.32. It can crawl up anything, but on longer roads I'd prefer to travel at regular speeds. 

 

I have a NOS Mikuni branded cam I was going to pop in after I can get a pacesetter header (back ordered everywhere). 

 

I don't have any metal fab experience or tools so I think the KA is out. 

[datzenmike]

9 hours ago, Jitenshakun said:

I have an '83 (1st gen) 4x4 720 that had a Z24 swapped in by a previous owner. The engine is eating oil and rather than just fixing it I'm thinking get some more power while I'm at it. 

 

With the struggles to drop in a Ka24de (oil pan) do i

 

-build a Z24? 

-get a Ka24d? 

-3rd option? 

 

It's going to cost time and money no matter what, but I'd like to find an option that just let's me get up a highway grade hill without my foot on the floor. A bonus would getting up a fire road at 30km/hr rather than my foot to the floor, in 1st gear, at 10km/hr.

 

Oil consumption? Well this isn't a new vehicle and your idea of 'eating oil' may not be that bad. Is there a blue cloud following you? or maybe just leaks that add up?

 

Do a compression test on a warm engine and record the readings then with a couple of tablespoons of engine oil poured in the spark plug hole. This is a dry and wet test. If the readings jump up significantly specially on a low cylinder, then the rings are not sealing and the engine is tired.

 

Readings of over 150 would be good and all cylinders within 10% of each other also good

 

Excessive oil consumption can also be the valve guide seals and they are easy to change and cheap. Does the engine start with a large puff of blue smoke?

 

 

KA engine.

You'll want a good KA, can you find one? Otherwise it will need rebuilding and if rebuilding you may as well rebuild the Z24. A drop in good running KA24E or DE from a Hardbody would be best. It will bolt to your transmission which is a plus. It is EFI requiring re-wiring it's electronics into the 720 and replacing the stock fuel pump with a higher pressure one. The Hardbody intake looks like it takes a 4bbl when the throttle body is removed. You can make an aluminum plate adapter to fit the Z24 carburetor or a Weber and swap the crank angle sensor (CAS) on the KA for an L20B distributor. You could use the Z24 distributor and  use only 4 of the 8 plug wires. This would convert the KA to carburetor and be rid of the EFI.

 

7 minutes ago, Jitenshakun said:

I have the 32/36 Weber and slightly bigger tires. 235/75-15. My gearing is the 4.32. It can crawl up anything, but on longer roads I'd prefer to travel at regular speeds. 

 

I have a NOS Mikuni branded cam I was going to pop in after I can get a pacesetter header (back ordered everywhere). 

 

I don't have any metal fab experience or tools so I think the KA is out. 

 

Find your build date on the driver's door and locate the engine tag on the passenger side inner fender below the hood hinge. The tag will show what axle gearing you have. The '83 4x4 didn't come with 4.375 gears but the '80-'82 did. The tag will also show what engine was installed at the factory. '83 was the start of the Z24 engine and like you said it was swapped. If an '81-'82 it would have had the Z22.

 

Nissan wouldn't have installed 4.375 if the truck wouldn't go at highway speeds. The 520 has 4.88 and it would easily do the speed limit. 4.375s are nothing to worry about..

 

A Z24 and 4.375 gears should be able to climb a brick wall.

 

Do not waste any money on a header.... the stock exhaust is just fine for the RPMs and the power that the Z24 is capable of. Spend the money on something that will actually make a difference.

 

I wouldn't worry about a cam just yet. The Z series heads do not respond to performance add-ons very well. The port placement and design does not 'breath' very well. It was designed to make monster torque at below 4k (easily highway speeds) and very little pollution.

 

Probably make sure the Z24 is tuned up first. Valve lash set, timing at 5 degrees BTDC, NGK spark plugs. Check that both intake and exhaust side plugs are firing.

[Jitenshakun]

Good tips Mike. 

 

It's a 7/82 build and the engine tag says it had a Z22, but it now has a Z24 (block stamped). The Japanese made 83 does have the 4.37, but the mid model year change to US build on the 83 did pick up the taller gear on the 83. 

 

My last compression test was 155/165 ish but I'll do another one. 

 

"eating oil" is 2L per hour of highway driving. 

 

The spark plugs are bone dry (32/36 is too lean right now) and my exhaust is clean. No blue (or white) smoke on startup or when running. 

 

I'll get my Weber tune sorted a little better, check compression, and report back. 

 

[banzai510(hainz)]

2 liters per hour?  Is that right? 2 liters

 

You sure it not leaking soemwhere??????????  a oil line /sender leak

 

what your sparks plugs look like?

 

at that rate of 2 L per hour I pull the motor asap and clean it up or find another motor

[Jitenshakun]

I went on a cruise and brought some oil just in case. When I stopped to check half way the dipstick was dry and it took a lot of oil. 

 

I am sure it isn't leaking given how dry everything is. Also, because it was a cruise my friends were watching my exhaust for me and it was clean the whole time. 

 

My spark plugs are chalky white (way too lean). 

[datzenmike]

2 hours ago, Jitenshakun said:

Good tips Mike. 

 

It's a 7/82 build and the engine tag says it had a Z22, but it now has a Z24 (block stamped). The Japanese made 83 does have the 4.37, but the mid model year change to US build on the 83 did pick up the taller gear on the 83. 

 

My last compression test was 155/165 ish but I'll do another one. 

 

"eating oil" is 2L per hour of highway driving. 

 

The spark plugs are bone dry (32/36 is too lean right now) and my exhaust is clean. No blue (or white) smoke on startup or when running. 

 

I'll get my Weber tune sorted a little better, check compression, and report back. 

 

 

July '82 is definitely an '82 model year and all 4x4 were 4.375. The '83 model year started November '82.

 

The '83 had either 4.11 or 3.889 on the early ones.

 

At 60 miles per hour you went 60 miles and used 2 quarts????????????????????????????????????????????????????

 

Did you fill it up before leaving because no smoke, clean plugs and no leaks.... that isn't possible.

[Jitenshakun]

Compression test results

Dry

140/140/145/138

 

Wet

160/155/155/140

[Jitenshakun]

I have the 83 and 83 First Revision manuals. My 83 is clearly a 4.375. The Nissan badged 83 is the 3.889.

 

Datsun model years flip in July, not Nov. For this truck the big late 82 change was the move to US manufacture and Nissan badging. Lots changed. 

[datzenmike]

Good! For years I've had this wrong. Right, the 4.375 was used with the Z22 till the Z24 engine change around November or about 4? months into the '83 model year.. Lots of changes at that time. 

 

Compression is... ok and even. 2 liters in 60 miles... if it was blowing it out the exhaust your plugs would be dripping oil. The smoke would be like

 

 

 

[Jitenshakun]

[Jitenshakun]

Sorry for the crap photos, I'm figuring out the sizing to upload. Let me just say ordering parts for a Datsun 83 is a royal pain. 

 

Plugs are white and dusty. In fact, I need to get richer jets for my carb. 

 

I'm really stumped. I measured the oil myself based on Z24 capacities and topped up based on the he dipstick. 

 

Could my twin spark be amazing at burning oil? 

 

I'm going to watch my oil consumption a lot closer now, while I keep an eye out for another Z24

[Jitenshakun]

White, but tiny residue as well? Could be blowing oil but burning it off right away? 

[captain720]

The Z24 is not that good at burning oil and making it disappear. If it's using it you can see it out that back in a blue cloud and it would be dripping off the plugs like Mike said. 

[datzenmike]

'83  has always stumped me too. Engine change, dash gauge change some other things I can't remember, all around 11 '82. 

 

I had an old 283 that went 250 miles on a quart and the plugs were black, crusty wet with oil and that's twice the cylinders and half your amount.

 

This don't look right.

 

That powder deposit on the outer electrode is bad intake valve guide seals. The oil being sucked in is atomized and mixed with gas and air and will combust much cleaner than oil coming up past the oil control rings. That oil is in contact with the cooler cylinder walls and is like dripping oil on a hot frying pan. It smokes badly.

 

If the engine puffs a blue cloud only on start up this is another indication of bad seals.

 

 

 

You can change the valve seals easily and with few tools without taking the head off by removing both rocker arm shafts carefully, with the rocker arms on. Loosen all the bolts slightly in stages till fully loose. This will close all the valves and get the rockers out of the way. Push a couple of feet of yellow nylon rope in the spark plug hole (tie a large knot on the end to keep it from falling in) Turn crank shaft pulley bolt by hand with a wrench to compress the rope against the closed valves. Now you can compress the springs and remove the keepers with no fear of dropping a valve down inside. Pry the old seal up and off and tap the new ones down and on. Turn the crank backwards to release the rope, and on to the next cylinder. When done install the rocker shafts and tighten in stages, not each bolt all at once. This can be done even on the side of the road. I've never used compressed air. I find that kind of scary. You need a fitting, hose, compressor and a reliable electricity source and once started you can't really stop in the middle.

 

 

[Jitenshakun]

This would be a new adventure for me so I may call a friend to help. 

 

It's definitely powder around the edge of the plug, not an oily residue. 

[A guy named Rick]

3 hours ago, datzenmike said:

Good! For years I've had this wrong. Right, the 4.375 was used with the Z22 till the Z24 engine change around November or about 4? months into the '83 model year.. Lots of changes at that time. 

 

Compression is... ok and even. 2 liters in 60 miles... if it was blowing it out the exhaust your plugs would be dripping oil. The smoke would be like

 

 

 

 

Lmao good example Mike.