oil pressure

4

46 ford

Member
we can't seem to get the oil pressuer gauge in the dash to show a reading. We bled the line from the filter to the oil pressure gauge sending unit in the block. THat line is clear. When we crank the motor oil bubbles up in the oil filter when we hav the top off. does this mean that we have sufficient oil pressure to attempt starting the motor?
 
46 ford said:
we can't seem to get the oil pressuer gauge in the dash to show a reading. We bled the line from the filter to the oil pressure gauge sending unit in the block. THat line is clear. When we crank the motor oil bubbles up in the oil filter when we hav the top off. does this mean that we have sufficient oil pressure to attempt starting the motor?
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If it were mine, i would remove the gauge sending unit from the block, and install a manual oil pressure gauge on the engine block pressure port, this way you will know for sure you have oil pressure.....Ed
 
I trusted an old sending unit about 400 miles the first time I built a flathead in a Merc.
I was driving down the highway, enjoying the ride, when the oil pressure gauge went to the bottom. Almost had a heart attack, and couldn't stop fast enough. I was lucky and just had the old sending unit die on me. Never have done without a "new school" oil pressure gauge and dual temp gauges on my motors since then. Just my 2 cents!
 
Another little ditty. Use a copper line on the oil pressure gauge. The little plastic ones that come with most gauges now, will melt really fast around a flat motor!
 
Install a mechanical unit to verify pressure on start up and then go back to your setup after pressure is confirmed.

Ronnie
 
53ash said:
Another little ditty. Use a copper line on the oil pressure gauge. The little plastic ones that come with most gauges now, will melt really fast around a flat motor!
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I would agree with the others on the mechanical gauge for start up. If you choose to keep it I would also go to copper as 53ash suggests. One more thing I would suggest is wind a couple of circles / or coils in the copper line between the firewall and sending unit and again at the back of the gauge to absorb vibration and prevent the tubing from cracking.
 
46 ford said:
we can't seem to get the oil pressURE gauge in the dash to show a reading. We bled the line from the filter to the oil pressure gauge sending unit in the block. That line is clear. When we crank the motor oil bubbles up in the oil filter when we havE the top off. does this mean that we have sufficient oil pressure to attempt starting the motor?
Click to expand...
Something very often overlooked is the (proper) pressure line of the oil filter. It is supposed to be restricted at the fitting in the block. As I recall it is about .060". You WILL lose pressure if this line is not restricted.
 
You won't lose much oil pressure without the inlet restriction to the filter because the outlet stand pipe in the filter is also restricted. I would put on a mechanical gauge as others recommended, remove the plugs, put a little oil in the cylinders and spin the engine with 12 volts. This will give you pretty close to the oil pressure you will have driving the car. G.M.
 
Re: oil pressure George M

[ This will give you pretty close to the oil pressure you will have driving the car. G.M.[/QUOTE]

George, By doing this where would you get the reading "for pretty close to the oil pressure you will have driving the car".
John
 
thanks for all the responses regarding mechinal gauges. What is the difference between a mechanical gauge and the actual factory dash gauge that is used in this truck?
 
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