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Discussion Starter #1
Im installing a mechanical oil pressure gauge and I was wondering if I could still use the sending unit extension near the oil filter. Installing the small hose and fitting would be easier with the extension but Im not sure if I would get a good reading. Is it necessary to mount the hose/fitting directly into the block next to the oil filter? Thanks for the help.
 

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Liquids cannot be compressed. You could use a ten-foot extension and still get an accurate reading. Now, the water temperature is another story…
 

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Discussion Starter #3
OK, I was not sure if the oil would flow up the extension and ito the tube. Is the oil pressure port under direct pressure from the pump similar to the rockers?
 

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The oil may not completely fill up the tube because the tube will still have air in it (like air in your brake lines). The gauge will still read correctly in this situation, but it will have a damping effect on the readout (the needle won't move as quickly).

If that bothers you, you can "bleed" the line by cranking the engine briefly with the end of the line by the gage open ended to fill it with oil (be careful, it will spray out the end). That will get you faster response on your gage.
 

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Discussion Starter #6
ZRAY, thanks for the image but I am not using a sending unit on my gauges. I thought the accuracy would be better with a mechanical gauge. I could be wrong.

Handy Man, thanks for the tip.
 

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ZRAY, thanks for the image but I am not using a sending unit on my gauges. I thought the accuracy would be better with a mechanical gauge. I could be wrong.

Handy Man, thanks for the tip.

As My photo shows, I am using both the stock sending unit for the stock Ford warning light and also using an aftermarket mechanical gauge. Using both the sending unit and the aftermarket gauge does not affect the accuracy of either one.

In my experience, the air in the line has no measurable effect on the mechanical gauges accuracy or speed of measuring the oil pressure psi.

Z
 

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I just would add, that even if had the stock gauge instead of a warning light, I'd still want to also have a mechanical aftermarket gauge in place I just don't trust the Ford gauges as far as accuracy goes, but I do like their look.

Z
 

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ZRAY, thanks for the image but I am not using a sending unit on my gauges. I thought the accuracy would be better with a mechanical gauge. I could be wrong.

Handy Man, thanks for the tip.
Accuracy depends on the quality of the gauge, but a self-powered mechanical gauge has the potential to be excellent. Aircraft use them. Corvettes used them from 1953 well into the 70's.
 

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Many years ago friend of mine had the oil line pop loose on a mechanical gauge which sprayed hot oil on his legs (and polyester pants). To this day when he wears shorts you can see the big splotchy birthmark-like purple scars all over his legs. Never minding his particular hows and whys that pretty much put me off running a mechanical oil gauge. Ever.
 

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Many years ago friend of mine had the oil line pop loose on a mechanical gauge which sprayed hot oil on his legs (and polyester pants). To this day when he wears shorts you can see the big splotchy birthmark-like purple scars all over his legs. Never minding his particular hows and whys that pretty much put me off running a mechanical oil gauge. Ever.
You can always use a braided steel line to connect the gauge. Those are pretty much
Melt and burst proof within the pressure parameters generated by an engine oil pump.

However where fuel is concerned, as in a mechanical fuel pressure gauge, then using an isolator is common practice to eliminate the possibility of gas inside the passenger compartment.


Z
 

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Absolutely use your extension. It makes life so much easier, and my mechanical gauge works perfectly fine with it.
 

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Zray and I run similar setups. I too, left my electrical gauge in place and added the extension to facilitate adding a copper line concealed within that corrugated covering to my gauge. It's been in play for 8-10 years.
To my eye, it's just looks better.
 

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If you want to retain the factory gauge or light, you can drill and tap the oil pressure sender log for the mechanical gauge, and use both. On the engine in the photo, I used an electric oil pressure gauge, a low pressure light sender and a low oil pressure cutoff switch. It cuts the fuel pump off if it senses low or no oil pressure. Good to have if you are using an electric fuel pump.
 

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Ken, where do you get that sending unit?
Hi,
If you're meaning the electrical, it's my original OEM unit (available from many vendors). If you mean that silvery grayish contraption, I made it from my junk drawer. It's a brass piece that I plated. Obviously, the extension is available from Mustang vendors, as well.
Hope this helps...
 

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If you want to retain the factory gauge or light, you can drill and tap the oil pressure sender log for the mechanical gauge, and use both. On the engine in the photo, I used an electric oil pressure gauge, a low pressure light sender and a low oil pressure cutoff switch. It cuts the fuel pump off if it senses low or no oil pressure. Good to have if you are using an electric fuel pump.

Nice setup mate. I beat up adding the engine cut-off feature. Especially, since I lost an engine to loss of O/P years ago. Go figure......
 

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Nice setup mate. I beat up adding the engine cut-off feature. Especially, since I lost an engine to loss of O/P years ago. Go figure......
The 3 pin switch was originally found on the Chevy Vega, probably the only thing of value on that car. Or you can get it at Summitracing.com for around $30. P/N Holley 12-810
 

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Thanks for the link & P/N.
 
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