1974 Oil Pressure Sender Location.......
05-03-2013, 08:06 PM
#1
Burning Brakes
Thread Starter
1974 Oil Pressure Sender Location.......
Just put the newly rebuilt engine back in the car, but I'm a bit puzzled by the oil pressure I'm getting. The matching numbers engine has been completely rebuilt, top and bottom. The oil pressure location for a 74 is above the oil filter, but this was plugged when I got the car, and the sender was under the distributor. However, the guage only shows the car making 20lbs max. Would the sender need to be moved to the original location to read correctly, or is it possible I have a dud sender? The sender is only a year old.
05-03-2013, 10:09 PM
#2
The oil pressure sender on a '74 smallblock is screwed into the port just above the oil filter boss.
Right after a rebuild, you might expect to see 30 to 40 psi at idle, and 55 to 60 psi at speed, after the engine is fully warm. The conventional wisdom is that a small block Chevy needs 10 psi per 1000 RPM to remain reliable. Screw a mechanical gauge in the port, to check the readings against the dash gauge.
I wonder if your engine rebuilder set up the bearing clearances too loose. A SBC is happiest with tight clearances- maybe 0.0027" on the mains.
Right after a rebuild, you might expect to see 30 to 40 psi at idle, and 55 to 60 psi at speed, after the engine is fully warm. The conventional wisdom is that a small block Chevy needs 10 psi per 1000 RPM to remain reliable. Screw a mechanical gauge in the port, to check the readings against the dash gauge.
I wonder if your engine rebuilder set up the bearing clearances too loose. A SBC is happiest with tight clearances- maybe 0.0027" on the mains.
05-03-2013, 10:44 PM
#3
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There is a sender for cars with a gauge and a sender for cars with a light bulb, but before you change things out test the gauge.
With the key "ON":
Remove the wire from the sender - gauge should read high.
Ground the wire:
Gauge should read low.
If that works now change the sender.
0 pressure= 0 ohms
40 lbs = 45 ohms
80 lbs = 90 ohms
With the key "ON":
Remove the wire from the sender - gauge should read high.
Ground the wire:
Gauge should read low.
If that works now change the sender.
0 pressure= 0 ohms
40 lbs = 45 ohms
80 lbs = 90 ohms
05-06-2013, 01:32 AM
#4
Burning Brakes
Thread Starter
Update time! Pulled the gauge cluster on Saturday to sort it out. I should have mentioned that both the sender and gauge were new. And my gauge cluster was from either a 72 or 73, and had a mechanical oip pressure gauge I replaced with the NOS one. And as a result, I had to modify the gauge cluster housing for the new gauge to fit. Turns out, it wasn't getting a very good ground. I now get around 60 on the road, and a bit less at idle. While I was back there, I fixed my clock that had the small gear off the end of the adjuster.
Still have to get the temp gauge working right. The highest it reads is just over the lowest mark. According to Willcox, it's displaying symptoms of a missing fibre washer under the 3 o'clock terminal, but it's there. Oh well, that can wait till next weekend!
Thanks very much for your help guys!
Still have to get the temp gauge working right. The highest it reads is just over the lowest mark. According to Willcox, it's displaying symptoms of a missing fibre washer under the 3 o'clock terminal, but it's there. Oh well, that can wait till next weekend!
Thanks very much for your help guys!