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09-03-2021, 09:15 PM | #1 |
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50 psi oil pressure gauge
Can oil pressure above 50 psi (actual) damage a 1937 original 50 psi oil pressure gauge and sender system? Or does the sender contact points cycle open and close on reaching 50 psi?
I have been running on a direct reading pressure oil gauge since fitting the reconditioned engine. Yesterday I fitted a serviceable original oil pressure gauge to the instrument cluster and a new Bob Drake 50psi sender. I am cautious about running this original, secondary, oil pressure indication system without knowing the original gauge and sender high pressure safe guards. My engine is a reconditioned 1937 221”. I am using a direct reading oil pressure gauge and Penrite 20W60 engine oil. On initial start up the oil pressure can go as high as 100psi and quickly returns to 40- 60 psi depending on high idle rpm. Our local outside air temp ranges from say 15-36c. On the road, with the engine 90c and running at the at 55 mph the oil pressure is 25 psi dropping to 8 psi at hot idle when stationary at stop lights. |
09-04-2021, 02:29 AM | #2 |
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Re: 50 psi oil pressure gauge
I know nothing about a Bob Drake sender unit, however using original KS sender and gauge you'll have no problems with the high oil pressure doing damage the gauge will just be pegged at first whilst it's getting above the 50 lbs .
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09-04-2021, 02:32 AM | #3 |
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Re: 50 psi oil pressure gauge
Cold oil will give you a higher pressure pump read on the gauge. All that matters is how it reads when it is hot. No one ever has an issue with cold oil or a cool radiator on startup. Sounds normal. Try a 10-30w. 20-60w is a bit much on a new engine. But on a new engine high oil pressure is a good thing thing as you hope bearings are tight and you dont need the higher velocity oil.
My 36 has a SW gauge up to 80. I bury it on startup. Some how it comes down when driving. Run hot at 25-45 at rpm, lowest has been at idle 15 (water/block temp 160-180). Normal flathead oil pressure hot are 8-10 at best sitting at idle ( I'm sure I'll get flack). Anything above 0. Flatheads are a low pressure oil system, well unless you are going to bonneville.,, Sounds fine to me other then running a heavy oil. Last edited by Tinker; 09-04-2021 at 03:13 AM. |
09-04-2021, 06:27 AM | #4 |
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Re: 50 psi oil pressure gauge
As a suggestion try a lower weight engine oil (30 or 40) to get the start oil pressure around 60#peak. At that point I would think the oil pressure sender should be good. The originals have a metal diaphragm that can crack over time and exposure to high pressure would shorten the life. Drakes???
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09-04-2021, 09:07 AM | #5 |
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Re: 50 psi oil pressure gauge
"On initial start up the oil pressure can go as high as 100psi"
Don't our engines have a pressure relief/return in the oil gallery? At what pressure do they trip? |
09-04-2021, 10:27 AM | #6 |
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Re: 50 psi oil pressure gauge
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If you're really getting 100psi cold at 15*C or about 60*F, it's not acting like a 20W60. It's acting more like a 60W60 single weight. If that's the case, you're pumping molasses cold. The pressure relief orifice might not be big enough to relieve the pressure. |
09-04-2021, 12:32 PM | #7 |
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Re: 50 psi oil pressure gauge
The specs in the ford book call for 30 psi at 2600 rpm and the relief valve opening at 30lbs.
If the relief valve is blocked or too strong of a spring in effort to raise hot oil pressure the cold pressure will be too high Do you know what oil pump was used? later pumps have additional pressure relief valve and were used with the 80 lb gauge era |
09-04-2021, 05:23 PM | #8 |
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Re: 50 psi oil pressure gauge
Re: 50 psi Oil pressure gauge
My question was: will an original 37 oil pressure gauge and sender system be damaged by actual oil pressure in excess of 50 psi on start up and a 5 minute warm up idle? |
09-04-2021, 08:47 PM | #9 |
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Re: 50 psi oil pressure gauge
I'd prolly worry more about engine damage from pumping something acting almost like gear oil when cold. My reconditioned early 38 21-studder was treated with 5w20 synblend for nearly 10 years. Then switched to Walmart 0W20 full synthetic over two years ago. About 20psi fast idle hot or cold --- northern NJ type cold below 32*F. 30psi tops hot revved up. With a bourdon gauge. Never trusted my original. Jack E/NJ
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09-04-2021, 09:21 PM | #10 |
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Re: 50 psi oil pressure gauge
Re: 50 psi Oil pressure gauge
My question was: will an original 37 oil pressure gauge and sender system be damaged by actual oil pressure in excess of 50 psi on start up and a 5 minute warm up idle? And, my answer was; you'll have no problems with the high oil pressure doing damage the gauge will just be pegged at first whilst it's getting above the 50 lbs
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09-05-2021, 08:17 AM | #11 | |
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Re: 50 psi oil pressure gauge
Quote:
No.
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09-05-2021, 07:29 PM | #12 |
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Re: 50 psi oil pressure gauge
Re: 50psi oil pressure gauge.
Many thanks to all who answered my question and those of you that also gave helpful information. Kind regards, Roger. |
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