Z24 Oil pump losing prime

[DwayneOxford]

Why??

Pressures up OK after finally picking up.

Only thing I'm seeing in FSM is regulator valve.

Is it the check valve? Or is there one elsewhere?

[datzenmike]

What makes you think this Dwayne? Takes too long for the oil pressure light to go out when started? That may be the sender.

 

Do you have a factory gauge? They are 'weighted' I think is the term so they don't read instantly. It kind of averages out the little ups and downs. This is done because it would upset and freak out the owner if they saw what the oil pressure really does. Same with the fuel gauge it would bounce all over.

 

I'm guessing 8-10 seconds after start up to full pressure reading. Try turning the engine off. (start counting) Once stopped turn ignition on and see how long to drop to zero. Probably takes this long to go up too.

[Stoffregen Motorsports]

Always verify the gauge before any other action is taken.

 

Buy a cheap mechanical gauge. Remove the sender and hook up the new gauge. Start the engine. See if it's better/worse.

[DwayneOxford]

Have mech. gauge. Have another truck, picks up way faster.

What holds prime?

[datzenmike]

The oil pump is a positive displacement style. Hard for oil to get past it and back into the pan. Some oil filters have an 'anti drain back' feature. A really dirty oil filter would take a little longer for pressure to get past it and to the sender.

 

If due for an oil change do it. Engines at the factory are started for the first time on just assembly lube and they're fine.

[Stoffregen Motorsports]

20 hours ago, DwayneOxford said:

Have mech. gauge. Have another truck, picks up way faster.

What holds prime?

But that gauge is in the other truck, right?

 

Electrical gauges rely on wire continuity to read accurately. If the wire connection is loose or dirty, or the wire itself is oxidized, the reading can be off. If the grounds are not great, it can mess with the readings too.

[DwayneOxford]

Mechanical on both.

 

[datzenmike]

Big question... Is the hot idle (assuming both idle at same RPM) oil pressure lower on the engine with the slower build????

 

Any chance the one that builds pressure faster might have a KA oil pump?

 

Both running same oil and viscosity?

Same oil filter?

Same miles? wear?

 

 

To check it is, or isn't the pump, swap them.

 

If the 'problem' persists then the engine with slower build of pressure may just have more bearing clearance wear.

If the 'problem' switches engines then the oil pump has excessive wear.

 

[DwayneOxford]

Got PN for KA pump? Think I'll replace it.

The one that does better is higher mileage.

[datzenmike]

They were on the KA24E in the S13 240zx but NOT the KA24DE.

They were on both KA24e and DE engines in the D21 Hardbody.

 

08-'89 through '97 Hardbody KA24E oil pumps are 15010-40F00

 

I have used them on all my Datsuns. Highly recommend them.

[DwayneOxford]

Thanx Mike!!

[banzai510(hainz)]

0023 Hitachi

https://www.ebay.com/itm/265799946283?epid=202912852&hash=item3de2e9502b:g:x44AAOSwG5Jiszm4&amdata=enc%3AAQAIAAAA8JlIwMk%2Fkm1E3Ps1%2FbGZXnIaKjAcNEJmIJ2prMUFtU9%2FEyUQLwyfR3pY4IF60Q3QDON3slUDIHCT1gIo27%2BN4WFQOfyHP%2BOCgKkXpFzQBU7JdfhvEwd9D5ExksqVsLwBlfFL8prQIWpx1o%2BSQheR6pAU2Bmf3duMcPbqnO93qYa2nreXaNV9wEK29VMi931EIP4rU5bKmJPk1F5rD9CQVQVoKu3zSJdVjXNq98piGufZ4ujcdvIxRhuG%2Fj%2BMMCtnihns%2B%2Frrm1n8tjN1Mfm%2BvkOAyYIS251wHPr8QiluS7UCo1r9hkTHejOWIACvZfIJgw%3D%3D|tkp%3ABk9SR7aZxMPEYg

[DwayneOxford]

21 hours ago, datzenmike said:

They were on the KA24E in the S13 240zx but NOT the KA24DE.

They were on both KA24e and DE engines in the D21 Hardbody.

 

08-'89 through '97 Hardbody KA24E oil pumps are 15010-40F00

 

I have used them on all my Datsuns. Highly recommend them.

This OK?

https://www.amazon.com/MOCA-Assembly-1998-2004-2002-2004-1995-1997/dp/B078RNR8LQ/ref=sr_1_3?crid=37QUI4GH2HU6X&keywords=Nissan+15010-40F00+oil+pump&qid=1692825028&s=automotive&sprefix=nissan+15010-40f00+oil+pump%2Cautomotive%2C324&sr=1-3

[datzenmike]

Doesn't say what it fits but if for KA engine it's ok. Otherwise all oil pumps look the same from the outside so make sure you get what you pay for.

 

 

KA high volume oil pump. Compare the height of the rotor to the one below.

 

 

[datzenmike]

4 minutes ago, DwayneOxford said:

This OK?

https://www.amazon.com/MOCA-Assembly-1998-2004-2002-2004-1995-1997/dp/B078RNR8LQ/ref=sr_1_3?crid=37QUI4GH2HU6X&keywords=Nissan+15010-40F00+oil+pump&qid=1692825028&s=automotive&sprefix=nissan+15010-40f00+oil+pump%2Cautomotive%2C324&sr=1-3

 

 

Should be says...

 

Replace Oil Pump Assembly NO#: 15010-V0300, M152, M111, 15010-S8000, 15010-40F00, 01165009G, 15010V0300, V0800 etc.

 

15010-40F00 is the one.

[banzai510(hainz)]

for 29 $ its made in China/Taiwan????

 

The Hitachi 0023 is a best bet. But I dont know where its made at.i got one and never said. Maybe those are outsourced also. But lisence by Hitachi.

 

Otherwise the Nissan ones will say Made in Japn for sure on the box

10 minutes ago, DwayneOxford said:

This OK?

 

[datzenmike]

Look at it this way your oil pump is really like your heart. Do you really want one that was stolen from a homeless crack head in Mexico because it's cheaper? Reputable ones are just over $100 so..... 

 

 

If you want cheap and good go to a wrecking yard and pull one off a D21 Hardbody. Tell the  guy $25 with no bill of sale and you'll never see me again. If he want's more tell him that if your engine seizes up you'll sue him for a new one.  All mine were off Hardbodies, nothing wrong with them because they are really well lubricated.

[DwayneOxford]

1 hour ago, datzenmike said:

Doesn't say what it fits but if for KA engine it's ok. Otherwise all oil pumps look the same from the outside so make sure you get what you pay for.

 

 

KA high volume oil pump. Compare the height of the rotor to the one below.

 

 

Thanx! I remember you posting that back when. I take it except for seeing the rotor height thru the hole there's no visible physical difference seeable from from outside? I'm gonna call them before I order.

[datzenmike]

Or check it when you get it.

 

The rotor is 13% longer so it pushes that much more oil than the early one. Hot oil pressure on my old L20B was 17 PSI at idle. With no other change than to the wrecking yard pump it read 29 PSI and it goes up faster. Maximum pressure is the same at 55-60 PSI because that is set by the relief spring.

[DwayneOxford]

On 8/23/2023 at 4:08 PM, banzai510(hainz) said:

0023 Hitachi

https://www.ebay.com/itm/265799946283?epid=202912852&hash=item3de2e9502b:g:x44AAOSwG5Jiszm4&amdata=enc%3AAQAIAAAA8JlIwMk%2Fkm1E3Ps1%2FbGZXnIaKjAcNEJmIJ2prMUFtU9%2FEyUQLwyfR3pY4IF60Q3QDON3slUDIHCT1gIo27%2BN4WFQOfyHP%2BOCgKkXpFzQBU7JdfhvEwd9D5ExksqVsLwBlfFL8prQIWpx1o%2BSQheR6pAU2Bmf3duMcPbqnO93qYa2nreXaNV9wEK29VMi931EIP4rU5bKmJPk1F5rD9CQVQVoKu3zSJdVjXNq98piGufZ4ujcdvIxRhuG%2Fj%2BMMCtnihns%2B%2Frrm1n8tjN1Mfm%2BvkOAyYIS251wHPr8QiluS7UCo1r9hkTHejOWIACvZfIJgw%3D%3D|tkp%3ABk9SR7aZxMPEYg

On "special" https://www.amazon.com/Hitachi-OUP0023-Oil-Pump/dp/B00T3MGEHO/ref=sr_1_9?crid=36HQ94KCXU2JY&keywords=15010-40F00+oil+pump&qid=1693859106&sprefix=15010-40f00+oil+pump%2Caps%2C326&sr=8-9&ufe=app_do%3Aamzn1.fos.d977788f-1483-4f76-90a3-786e4cdc8f10#customerReviews

[banzai510(hainz)]

I wish I would have bought mine sooner.

I just put the KA/280zx turbo pump on my 510 this weekend. Had it on my 521 maybe 2 years. At idle the pump barely read 15/20ilbs. Now 30/40 plus at idle

[datzenmike]

My very worn L20B was 17 stock pump and 30ish hot idle with a used KA pump.

[DwayneOxford]

Got it today.

[DwayneOxford]

Well, I "went for it" without reading up and suffering the consequences. Woulda been a dang sight easier if they'da made the drive shaft where it'd remove from top, not fall out the bottom.

[datzenmike]