Got it to pass smog, the work begins now... 1986 Nissan 720 project

[datzenmike]

Dual plugs shorten the burn time so less advance is needed. On a 720 Z24 it's still 5 degrees +- 2 degrees for altitude, humidity and varying gasoline. This may be for a different country where it may have a single spark plug per cylinder, then 15 would be sort of close.

 

The early D21 Hardbody had the Z24i which is fuel injected, has a CAS (crank angle sensor) and the ignition advance is calculated by the EFI computer and constantly adjusted. Maybe it's set that far advance and the computer adjusts it down? But for sure 15 is 10 degrees too much on a 720's Z24.

[A guy named Rick]

21 hours ago, datzenmike said:

That's the point of oil changes in a timely manner. The oil is detergent and holds all the 'dirt' in suspension for the filter to... filter out. Heavy things like metal flakes from the block (basically fine fine grit) will settle to the bottom. They may rinse out with the oil but are safe where they are. There's not much that will float on/in oil that can be caught by the pick up screen. The screen is very porous. Over use of RTV comes to mind. Flakes of wood from a home made chain wedge. But these will flush out with the oil change. Engine oil is extremely clean. How many thousands of times does the entire contents of the oil pan pass through the oil filter. It's uncountable. The black is microscopic carbon which it much too fine to filter out. Even black oil can still be fine to use. Not always but usually. I've seen countless pick up screens and they are always the cleanest thing in the pan. When down a quart and near the next filter and oil change drop a quart of ATF in for a week then change when HOT. ATF is even more detergent and will flush the engine insides. You should be using a diesel oil for the increased ZDDP levels. It's much more detergent than gasoline oils and will make your engine cleaner as you drive.

 

38 minutes ago, datzenmike said:

Dual plugs shorten the burn time so less advance is needed. On a 720 Z24 it's still 5 degrees +- 2 degrees for altitude, humidity and varying gasoline. This may be for a different country where it may have a single spark plug per cylinder, then 15 would be sort of close.

 

The early D21 Hardbody had the Z24i which is fuel injected, has a CAS (crank angle sensor) and the ignition advance is calculated by the EFI computer and constantly adjusted. Maybe it's set that far advance and the computer adjusts it down? But for sure 15 is 10 degrees too much on a 720's Z24.

 

Yeah everywhere here i see 5 +-2. Of course Cali is 3 degrees 🙄

 

I'm doing the oil pump Tuesday. Taking it to a mechanic I know, and going to watch, and also have him check out other stuff too.You say use KA oil pump, any particular year? It's identical right? 

[datzenmike]

Not internally identical. The trochoid rotor is 13% longer.

 

 

Identical on the outside, impossible to tell the difference. If off, look into the larger inlet hole.

 

Regular oil pump. Rotor is down inside, you can just see the top of it...

 

 

High volume oil pump. Top and side of rotor is exposed...

 

 

The 280zx turbo automatic had something similar. But for sure the KA-E did and this is what I use.

 

KA24E in the '89-'90 S13 240sx NOT the later KA24DE  It had an internal crank driven oil pump.

 

KA24E in the '90-'97 D21 Hardbody. NOT the later KA24DE  It had an internal crank driven oil pump.

 

 

Years ago it was talked up that the Maxima LD28 had one, propane powered L4s in lift trucks and maybe the Z24i but I don't believe so. Part numbers do not match or supersede.

[A guy named Rick]

3 hours ago, datzenmike said:

Not internally identical. The trochoid rotor is 13% longer.

 

 

Identical on the outside, impossible to tell the difference. If off, look into the larger inlet hole.

 

Regular oil pump. Rotor is down inside, you can just see the top of it...

 

 

High volume oil pump. Top and side of rotor is exposed...

 

 

The 280zx turbo automatic had something similar. But for sure the KA-E did and this is what I use.

 

KA24E in the '89-'90 S13 240sx NOT the later KA24DE  It had an internal crank driven oil pump.

 

KA24E in the '90-'97 D21 Hardbody. NOT the later KA24DE  It had an internal crank driven oil pump.

 

 

Years ago it was talked up that the Maxima LD28 had one, propane powered L4s in lift trucks and maybe the Z24i but I don't believe so. Part numbers do not match or supersede.

 

Interesting, I just searched autozone and apparently the 4WD 720 uses the same oil pump as a 1990 2WD hardbody. Did you know that? Melling M-90 for 2WD and Melling M-152 for KA and 4WD Z24 

[datzenmike]

No and yes. They will interchange but the 720 used the same oil pump as on all the L and Z series engines. The D21 Hardbody uses a high volume pump. Naturally Melling would say the same because easier to carry one pump for two applications. I wouldn't want a Z24 oil pump on a KA but I have no problem having a KA pump on a Z series engine and I have had one on all my L20Bs. Why in the wide wide world of sports would a Z24 4x4 need a high volume pump but the 2wd doesn't?

[A guy named Rick]

8 minutes ago, datzenmike said:

No and yes. They will interchange but the 720 used the same oil pump as on all the L and Z series engines. The D21 Hardbody uses a high volume pump. Naturally Melling would say the same because easier to carry one pump for two applications. I wouldn't want a Z24 oil pump on a KA but I have no problem having a KA pump on a Z series engine and I have had one on all my L20Bs. Why in the wide wide world of sports would a Z24 4x4 need a high volume pump but the 2wd doesn't?

 

I have no clue. Go on autozone and check it out though. I'm assuming something to do with the possibility of more dirt getting into the oil from off-roading and filtering it quicker? Fuckifiknow 😆 

 

Just found this: https://www.zcar.com/threads/melling-oil-pump-flow-numbers.73767/

 

The high volume one is only .25 gpm more, but more flow is still more flow.

Edited August 15, 2021 by A guy named Rick

[datzenmike]

Engines are sealed up pretty good. Nothing gets in but air and fuel.

 

Can't comment on an after market pump only the stock Nissan ones in the KA engines. Like I said my 17 psi hot oil pressure at idle went to 29 with no other changes.

[datzenmike]

The larger internal rotor for the KA24E in the Hardbody is 15020-S8005*

The internal rotor for the 280zx turbo automatic with oil cooler** is 15020-S8000. (the last two digits signifies a minor production change. 05 could be a different supplier)

 

* This is definitely the high output rotors that I measured and are 13% longer.

** I believe ALL 280zx  Turbo automatics came with the oil cooler, couldn't get it without and why they needed more oil flow to overcome the oil cooler hoses and radiator resistance at low speeds. Manuals did not come with oil coolers..

 

 

The 280z and 280zx non turbo use the same rotor as all L and Z series 4 cylinder engines. 15020-21001

 

The 280zx turbo manual transmission does us a different part number 15020-V0300. Also used in the D21 with the Z24i engine. Now why would the Z24i need extra oil flow???? This is unconfirmed but again I say only the 280zx turbo automatic has the high output. Who you going to believe? Nissan or some after market parts maker named Melling??? I say they are wrong.

 

Get the oil pump from the KA24E in the D21 Hardbody and you can't go wrong.

[A guy named Rick]

7 hours ago, datzenmike said:

The larger internal rotor for the KA24E in the Hardbody is 15020-S8005*

The internal rotor for the 280zx turbo automatic with oil cooler** is 15020-S8000. (the last two digits signifies a minor production change. 05 could be a different supplier)

 

* This is definitely the high output rotors that I measured and are 13% longer.

** I believe ALL 280zx  Turbo automatics came with the oil cooler, couldn't get it without and why they needed more oil flow to overcome the oil cooler hoses and radiator resistance at low speeds. Manuals did not come with oil coolers..

 

 

The 280z and 280zx non turbo use the same rotor as all L and Z series 4 cylinder engines. 15020-21001

 

The 280zx turbo manual transmission does us a different part number 15020-V0300. Also used in the D21 with the Z24i engine. Now why would the Z24i need extra oil flow???? This is unconfirmed but again I say only the 280zx turbo automatic has the high output. Who you going to believe? Nissan or some after market parts maker named Melling??? I say they are wrong.

 

Get the oil pump from the KA24E in the D21 Hardbody and you can't go wrong.

 

Got it. But, should ii not go aftermarket then? Would you say stick with OEM (if I can get it)

 

Edit: just looked up part # and it's just the rotor. Are you saying just rebuild the pump?

Edited August 16, 2021 by A guy named Rick

[Charlie69]

The oil pumps on these motors last for a long time.  I have one on a Z24 with over 450,000 miles on it and I will clean it up and check for wear and continue using it when I rebuild the engine.

 

If you have low oil pressure I would be checking main, rod, and cam bearings as the culprit.  Worn main bearings will drop oil pressure.

 

Look at the inards of the oil pump there is minimal parts that wear in them.

Edited August 28, 2021 by Charlie69

[datzenmike]

The rotor is the difference so I used it. The case is also different but not all applications had the part number for the case.

 

I only deal with Nissan parts, I have no interest or trust in melling, their quality or what their application chart says... it could be wrong. I put used Nissan KA oil pumps in my L series engines. It's an oil pump, if wear, it will be minimal because... OIL pump. Pressure at hot idle on a very tired L20B went from 17 to 29 PSI no other changes. they are cheap and plentiful in wrecking yards and Nissan quality. 

 

As Charlie said low(er) oil pressure is from increased oil flow bleeding out from between worn rod and main bearings. As the mileage goes up the pressure goes down, it's inevitable. The high volume pump replaces the oil faster than it can bleed away and the pressure.... goes up. Simple as that. 

 

8 hours ago, A guy named Rick said:

 

Got it. But, should ii not go aftermarket then? Would you say stick with OEM (if I can get it)

 

Edit: just looked up part # and it's just the rotor. Are you saying just rebuild the pump?

 

If you go aftermarket make damn sure you get one from A Hardbody KA24E and inspect per the pictures I posted to be sure it has the larger rotor before you put it on. The oil pump is the heart. Stick with Nissan not some Chinese donated organ.

[Crashtd420]

https://www.amazon.com/dp/B00T3MGEHO/ref=cm_sw_r_cp_apap_yIJKpibXvBcR2

 

This is a new Hitachi brand....

[Charlie69]

Great explanation Mike.

[A guy named Rick]

So today i put in new u-bolts. I had re-used the ones from when it had been lowered by previous owner. Those were long and tacky looking, and well I didn't know what I was doing then.

 

Here's a pic of the new ones. My question is, the one on the right isn't as straight as it should be. Is that going to be a problem? I believe it may be riding against the spring. The pic is looking through the rear shackle.

 

 

It has been lowered back down but not driven anywhere, however has already been torqued down (i went 60ft-lbs)

[A guy named Rick]

I also have a pic of the smog that was done before I had bought the truck in 2012. Side by side comparison from when I smogged it this year are night and day. I really cleaned it up.

 

 

 

I just realized they had lower rpm's for the speed. Wonder if that was a trick to make it pass 🤔 

Edited August 18, 2021 by A guy named Rick

[datzenmike]

It's fine but if you are like me, and like symmetry..... Loosen all four nuts. With a hammer, tap that saddle the U bolts are sitting on to the right till they are even. Tighten them back up.

[A guy named Rick]

31 minutes ago, datzenmike said:

It's fine but if you are like me, and like symmetry..... Loosen all four nuts. With a hammer, tap that saddle the U bolts are sitting on to the right till they are even. Tighten them back up.

 

As long as it's ok I'll leave it. Besides, been reading how u-bolts are TTY and won't have the same clamping force after loosening and retightening. At least they aren't as bad as the old ones. God they were so ugly since they were for 3 inch lowering blocks, and on top of that they were more crooked than just the one on the right. I didn't know what the fuck I was doing then.

[Charlie69]

As long as my trucks pass emissions I do not care how just that they passed.  Every year emissions testing will be different.

[A guy named Rick]

I think my smog tech ran a gear lower. Either way, the guy i bought the truck from didn't go through it with a fine tooth combo how I did. Not saying I was perfect, but still. 

[powderfinger]

5 hours ago, Charlie69 said:

As long as my trucks pass emissions I do not care how just that they passed.  Every year emissions testing will be different.

This is one of the things I like about living in NC. Vehicles 35 years and older do not require any type of inspection. 🙂

 

[Charlie69]

The 35 plus year old vehicles are the ones most likely needing a safety inspection!!!  LOL

[A guy named Rick]

15 hours ago, Charlie69 said:

The 35 plus year old vehicles are the ones most likely needing a safety inspection!!!  LOL

 

This was for sure true of my 240z when I was driving it. Had I continued, I can't say for sure I would still be alive. SOMETHING would have happened. 

 

 

Then, there's the new vehicles that fall apart in 1/10th of 35 years 🤔

[A guy named Rick]

Mike, you and others recommend Shell Rotella right? i used the 15-40 T4 triple protection, though the jug says it's a heavy duty oil. my truck did NOT like that oil. after it got warmed up it sounded like a diesel at idle after driving it 30 miles. Ran good, but at idle it didn't sound good. also when changing the oil, the valvoline 10W-30 I had in their was damn near black after like 1000 miles, and half a quart low at least. I'm hoping the filter i used wasn't too small. Don't cuss me out, but i used a Fram (never had problems before) and it does look rather short but i doubt that has any effect. I'm going to go home later and drive it, listen to what i hear, get a better decription. going to check valve lash too. honestly, what i heard sounded like it was coming from the *gulp* bottom end 😱

[datzenmike]

Apparently there is or is now a 10w30 T4 so this past year I switched. I drive only in warm weather and noticed no difference.

 

Filters are filters but some are made with cheap inferior quality parts. For the same price you can get better ones. They can't filter out black. That's just carbon. If the oil that was in there was a diesel oil they are more detergent that gas engine oils and will clean your engine more. The oil tends to discolor more quickly till it's cleaned out.

 

 

15w40 is roughly the same viscosity as 10w30 once hot. 10w30 is thinner than 15w40 when it's cold which is important when below freezing. If the oil is too thick it doesn't flow into the bearings as well as a lighter oil, but once warmed up they are pretty much the same. Cold cranking can be slower with the wrong thicker oil. 

 

[A guy named Rick]

50 minutes ago, datzenmike said:

Apparently there is or is now a 10w30 T4 so this past year I switched. I drive only in warm weather and noticed no difference.

 

Filters are filters but some are made with cheap inferior quality parts. For the same price you can get better ones. They can't filter out black. That's just carbon. If the oil that was in there was a diesel oil they are more detergent that gas engine oils and will clean your engine more. The oil tends to discolor more quickly till it's cleaned out.

 

 

15w40 is roughly the same viscosity as 10w30 once hot. 10w30 is thinner than 15w40 when it's cold which is important when below freezing. If the oil is too thick it doesn't flow into the bearings as well as a lighter oil, but once warmed up they are pretty much the same. Cold cranking can be slower with the wrong thicker oil. 

 

As far as the noise goes, I probably have bigger problems then 😱 FML cool, puts me closer to a KA swap then 😉 It's strange how it sounded totally different after putting in 15-40

Edited August 28, 2021 by A guy named Rick