NOS 60 lb. aren't even so easy to get anymore and never thought I'd see an NOS 80 lb. but there was one on eBay not too long ago. Not in my watch list anymore, but I doubt it sold - IIRC it was listed for $425 ish. One of the somewhat well known parts places on there had it -I'd recognize the name if I saw it and if I run across them I'll let you know.
Thank you Sir. There are a few 80 pounders on eBay. All are incorrect finish (easy fix) but not the right part number.
Not sure this is the same but it is 80 LB . Just in case . https://www.ebay.com/itm/1967-72-GT...=item23aff949e4:g:XEUAAOSw9g1b-eB-:rk:16:pf:0
Korrie, If you are going to use this on your 70 car then I have a question. Generally we always drill out the oil passages on the 69-70 blocks, like they were on the 71-72 motors. If you did that then I don't think the 80 PSI sender will give you an accurate reading. The 71-72 cars used the 60 PSI sending unit, with the larger bore oil passages. Just saying. Duane
Duane, how does that really matter though? Since the stock gauge has no numbers, the readings are kind of arbitrary. One could always hook up a good mechanical gauge, if even temporarily, to calibrate the stock gauge to observed readings of both gauges. Or is this one more thing to be anal about. I'm not sure drilling out the passage would effect pressure reading of the sender. Just thinking that the sender converts pressure to a resistance and that modifies the gauge needle position. Pressure is pressure.
I agree with Larry. Larger passages increase volume, not pressure. More pressure would require a high pressure pump and we do not want to go that route. BTW, my passages were enlarged.
Larry all I am saying is this, If you have two different diameter holes/pipes and you put the same amount of liquid/volume thru them, then the one with the larger diameter will have a lower pressure, due to the larger cross sectional area of the pipe. That's just simple hydraulics. The 80 PSI senders were sized for a specific diameter passage, The 60 PSI senders were sized for the larger diameter passage. I think that is why they went with the 60 PSI sender for the 71-72 cars, so it would continue to read the same at the gauge. My thoughts were if you use the 60 PSI sender on a 69-70 motor with the expanded oil passages then the gauge on the dash would read like it was supposed to. You guys can certainly do whatever you want. If you want to spend the money for an 80 PSI sender then have at it. Duane
I understand your reasoning Duane. I just think if you pump a certain volume of oil into any size pipe, it will fill that pipe, and once it is full, pumping any additional volume will create pressure. At that point, the size of the pipe is irrelevant as the pressure maxes out regardless. Also, the volume of oil running through the oil pump is not fixed, it increases with oil pump RPM, assuming the pump has correct clearances. Of course the oiling system is not a closed pipe, it has leaks (bearing clearances). The larger those clearances, the more volume you need to maintain higher pressures hence the need for the bigger pump when bigger racing clearances were used. I never thought of a sender as being calibrated for a specific sized passageway, I thought of it as just a conversion from pressure to a resistance, to drive a gauge. I'm thinking if your engine develops 70 psi, it will max out the gauge unlike the 80 psi sender where it would read somewhat lower. I could be wrong of course. Maybe we need an engineer to weigh in. I think we had a thread that discussed pressure and volume. I'll see if I can find it.
All the sender does is measure what it sees in terms of psi it doesn't care how big big or small the supply is, it just knows I'm seeing X amount of psi and I am going to send X amount of signal to the gauge
Ha! Okay. I guess I have a correct oil pressure sending unit, then. Wonder if anyone refurbishes them.....
