dgrinnan Posted June 4, 2022 Report Posted June 4, 2022 I think the original oil pressure gauge for my 1947 WC is okay but the line from the gauge to the engine is missing. At first I thought it was a flare fitting at the back of the oil guage but when I tried t install a new line I realized the threads only went about half way and it actuall was not a flare connection. Does anyone know what type of connection is at the back of the oil gauge? I was able to adapt a new tempurature gauge from a 47 Chevy truck into the dodge instrument cluster. I was hoping to salvage the oil gauge but now I don't know. No one has an after market replacement and rebuilt ones are hundreds of dollars. Quote
Young Ed Posted June 4, 2022 Report Posted June 4, 2022 There was just a topic on this on the car side maybe 2 wks ago. The proper fitting is a gas pilot line fitting. It starts as 1 piece and cracks in 2 after installation. Quote
Tooljunkie Posted June 5, 2022 Report Posted June 5, 2022 If i recall, this is the type of fitting used. On engine side is inverted flare like brake lines use. For flex hose replacement you may want to consider a grease gun hose. Pressure isnt an issue as most are good for 10,000 psi. Easy to adapt as they are 1/8 npt. Quote
bkahler Posted June 5, 2022 Report Posted June 5, 2022 After much searching I ended up buying the Oil Pressure Gauge Sleeve/Nut from McMaster Carr. Quote
JBNeal Posted June 5, 2022 Report Posted June 5, 2022 I have been trying to get some follow-up on this with several manufacturers since this issue came up again a few weeks ago. I compared the McMaster ferrule to an original that I had pulled several months ago and verified that the thread pitches were dissimilar. So far, I have part numbers from 4 different sources that are confirmed as 3/8-24, not the 3/8-27 that should fit in the oil pressure gauge. I have one source that is still trying to get their factory in Mexico to supply the thread pitch information, but after 4 weeks, I'm not holding my breath on this. So as to not burden Ed with being the sole source for this fitting, I am leaning towards following David A.'s approach that should work as I have found just as many 3/8-27 die sources as 3/8-24 breakaway ferrule sources. Once I get some kind of confirmation from the 5th ferrule part number on my list, I plan on following up on this with a comparison either way. 1 Quote
dgrinnan Posted June 5, 2022 Author Report Posted June 5, 2022 (edited) I tried an oil pressure line kit from AutoZone. The compression adapter had the same diameter but had the wrong thread. They looked the same but it would not thread into the gauge. I have a flare fitting that is the correct size and thread. I am taking it to a plumbing supply supplier Monday to see if they have something that matches it. If I find a solution I will post for the group. Edited June 5, 2022 by dgrinnan Quote
Young Ed Posted June 5, 2022 Report Posted June 5, 2022 1 hour ago, dgrinnan said: I tried an oil pressure line kit from AutoZone. The compression adapter had the same diameter but had the wrong thread. They looked the same but it would not thread into the gauge. I have a flare fitting that is the correct size and thread. I am taking it to a plumbing supply supplier Monday to see if they have something that matches it. If I find a solution I will post for the group. If that fails PM me. We'll get you setup Quote
bkahler Posted June 6, 2022 Report Posted June 6, 2022 23 hours ago, JBNeal said: I have been trying to get some follow-up on this with several manufacturers since this issue came up again a few weeks ago. I compared the McMaster ferrule to an original that I had pulled several months ago and verified that the thread pitches were dissimilar. So far, I have part numbers from 4 different sources that are confirmed as 3/8-24, not the 3/8-27 that should fit in the oil pressure gauge. I have one source that is still trying to get their factory in Mexico to supply the thread pitch information, but after 4 weeks, I'm not holding my breath on this. So as to not burden Ed with being the sole source for this fitting, I am leaning towards following David A.'s approach that should work as I have found just as many 3/8-27 die sources as 3/8-24 breakaway ferrule sources. Once I get some kind of confirmation from the 5th ferrule part number on my list, I plan on following up on this with a comparison either way. Oh well, to late for me. I've already got the fitting installed. The nut did seem to snug up nicely so with luck I won't have a leak. However to be on the safe side I don't think I' will install the floor mat until I know for sure Quote
dgrinnan Posted June 8, 2022 Author Report Posted June 8, 2022 (edited) I have given up finding the correct fitting. I ordered the McMaster ferrule and will also try David A.'s approach. The McMaster ferrule screwed in about 3/4 of the way before it started to bind because of the difference in thread count. The die I ordered is due to be delivered today. I will know more after it arrives. UPDATE: I just received the 27 thread die and cut the threads on the McMaster fitting. Easy to do and the fitting now threads into the oil gauge with ease. This is a simple fix. Edited June 8, 2022 by dgrinnan 1 Quote
lostviking Posted June 15, 2022 Report Posted June 15, 2022 It appears that the 3/8-27 is used on gas burner valves. Here is a link that leads me to believe that: https://www.webstaurantstore.com/all-points-26-2937-3-8-27-x-3-8-cct-female-coupling/AP262937.html Quote
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