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Can anybody help me with this question? I have an L-28 motor in my 240Z with an oil cooler in the front of the car and as far as I can tell a stock pan. My problem is that the oil pressure is aonly about 10 - 15 lbs. at idle and when she's running at about 3-4000 rpm the pressure is about 40-45lbs. The guage itself seems very sluggish in response to revving ( it doesn't snap to life). I have replaced the the sending unit and have also installed a mechanical pump and have had the same results. The oil pump is new but is a non turbo type. Should I purchase the uprated pressure springs or go to a turbo type pump. IS all of this concern due to the oil cooler?
 

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A slow guage is normal in Z's (from what I gather)

> Can anybody help me with this question? I
> have an L-28 motor in my 240Z with an oil
> cooler in the front of the car and as far as
> I can tell a stock pan. My problem is that
> the oil pressure is aonly about 10 - 15 lbs.
> at idle and when she's running at about
> 3-4000 rpm the pressure is about 40-45lbs.
> The guage itself seems very sluggish in
> response to revving ( it doesn't snap to
> life). I have replaced the the sending unit
> and have also installed a mechanical pump
> and have had the same results. The oil pump
> is new but is a non turbo type. Should I
> purchase the uprated pressure springs or go
> to a turbo type pump. IS all of this concern
> due to the oil cooler?
 

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Replace the gauge and get a high volume pump...

> Can anybody help me with this question? I
> have an L-28 motor in my 240Z with an oil
> cooler in the front of the car and as far as
> I can tell a stock pan. My problem is that
> the oil pressure is aonly about 10 - 15 lbs.
> at idle and when she's running at about
> 3-4000 rpm the pressure is about 40-45lbs.
> The guage itself seems very sluggish in
> response to revving ( it doesn't snap to
> life). I have replaced the the sending unit
> and have also installed a mechanical pump
> and have had the same results. The oil pump
> is new but is a non turbo type. Should I
> purchase the uprated pressure springs or go
> to a turbo type pump. IS all of this concern
> due to the oil cooler?

You should upgrade the pump, and if you want accurate readings, replace the Z oil pressure gauge with an Autometer or something similar. The pump upgrade should have a higher flow capacity as well as higher pressure. Remember, pressure and flow are two different things. You can have low pressure, but high flow, and vice versa. Since you've added a oil cooler, you need to increase the pumping capacity and pressure. Nissan Motorsports sells a turbo pump that has 5mm larger gears. This increases flow over stock, and then you can install different springs to bring the pressure back up.

Dave
 

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Re: A slow guage is normal in Z's (from what I gat

Use 20W-50 oil or relax. You only NEED 10 psi per every 1000 RPM... you are fine.

My''71 worked just fine until I sold it 8 years later.
 

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Re: Replace the gauge and get a high volume pump..

> You should upgrade the pump, and if you want
> accurate readings, replace the Z oil
> pressure gauge with an Autometer or
> something similar. The pump upgrade should
> have a higher flow capacity as well as
> higher pressure. Remember, pressure and flow
> are two different things. You can have low
> pressure, but high flow, and vice versa.
> Since you've added a oil cooler, you need to
> increase the pumping capacity and pressure.
> Nissan Motorsports sells a turbo pump that
> has 5mm larger gears. This increases flow
> over stock, and then you can install
> different springs to bring the pressure back
> up.

> Dave
Also, since the many 240z's idle with low oil pressure showing on the guage, I have replaced the sending unit with one from a dastun roadster. These are still available from Nissan, and I should have the part number at home, if anyone wants it. It puts the guage up to where it idles above 0, and you could tell if oil pressure actually was a problem. Thanks, Joe
 

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Another sending unit alternative...

> Also, since the many 240z's idle with low
> oil pressure showing on the guage, I have
> replaced the sending unit with one from a
> dastun roadster. These are still available
> from Nissan, and I should have the part
> number at home, if anyone wants it. It puts
> the guage up to where it idles above 0, and
> you could tell if oil pressure actually was
> a problem. Thanks, Joe

I used a gauge sender from a L series engined Maxima. It was a 1 wire unit, just like the 240Z, and screwed right in. Pressure readings were solved, although the gauge was still slow. Cost $5 at local junkyard.
 

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> Can anybody help me with this question? I
> have an L-28 motor in my 240Z with an oil
> cooler in the front of the car and as far as
> I can tell a stock pan. My problem is that
> the oil pressure is aonly about 10 - 15 lbs.
> at idle and when she's running at about
> 3-4000 rpm the pressure is about 40-45lbs.
> The guage itself seems very sluggish in
> response to revving ( it doesn't snap to
> life). I have replaced the the sending unit
> and have also installed a mechanical pump
> and have had the same results. The oil pump
> is new but is a non turbo type. Should I
> purchase the uprated pressure springs or go
> to a turbo type pump. IS all of this concern
> due to the oil cooler?

Sounds like it is working fine. I have a 260Z - it lay in a field for some time. When I cranked it up I was somewhat dismayed to find zero oil pressure. Performed the guage check (grounded out the contact on the guage) and the guage slowly rose to maximum. So guage OK. Cleaned the contacts and tried again - some readings but they fluctuated with wiggling the wire. Finally spent $14 CDN on a mechanical pressure guage. Cranked the motor, oil pressure shot up immediately to ~45-55 PSI, then gradually feel to around 10-15PSI at a slightly high idle. Apparently this is normal. The stock guage is unfortunately a current sensing guage that reacts extremely slowly to oil pressure fluctuations. That said - it isn't a problem it just isn't anywhere near as cool as seeing the guage flick to life when the motor is started...

Incidently, I have purchased (I will be picking it up tomorrow) a replacement sender unit. From all of the email I have read it doesn't really sound like it matters a whole heck of a lot where you purchase this unit - Nissan or otherwise. All of them are susceptible to damage easily.

Hope that helps.
Steve
 
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