The Stovebolt Site Forums The Shop Area Engine Shop Oil Pressure Gauge

My 235 is pegging my 30 lb. stock oil pressure gauge, even at idle. Will this hurt the gauge long term if I don't swap it out?

Me too. I'll wait for someone to chime in.

Not much chance of serious damage, but it might affect the accuracy of the gauge a little if you run it long term. A 0-60 PSI GMC oil pressure gauge will fit the same dash cluster, but the color of the gauge backing might be different. Some of the resto-ripoff parts suppliers sell a new 60 PSI Chevy dash gauge, I believe.
Jerry

RBs36- The only vendor I could find listing a 1936-39 GMC 0-80lb oil pressure gauge is Jim Carter PN: RESP285 which is a combination Amp meter on top and oil pressure on the bottom unit. However it's currently listed as "Out of Stock". Don't know if they would be able to help you with just the oil pressure gauge, so you may need to talk to them directly.

If no luck with that route, you may have to resort to an add-on under dash gauge to monitor your oil pressure.



John - Here are two of our usual vendors that offer higher pressure reproduction 0-60 psi oil pressure gauges for 1940-46 Chevy trucks:

The Filling Station SA-496

Jim Carter SP234

Dan, seems all the stuff one might really need are always out of stock, or with Filling Station, a "waiting list" that never seems to get filled.

I replaced my '37 truck 30 psi gauge with a later 80 psi from a GMC. I used just he mechanism, not the face plate, and printed my own face plate to stick on the original gauge. It was a '39 - '46 GMC oil pressure gauge, there is a few of them on eBay now. The working side is the same design as the early gauges, just he face plate was changed. BowTie Bits used to sell converted gauges. There decal sets come with a 0-60 oil gauge decal.
Mine is not accurate, I could not get it to track right using compressed air and a regulator, I set 40 psi to be accurate, below or above its off. Its good enough for me and I know its got oil pressure. I used a color printer to make a face plate decal, my local decal shop gave me a small piece of white peel and stick I used to print on. I have a decal set with the 60 psi oil gauge decal I used to scan, then changed the numbers to fit the 80 psi gauge. The '39 Chevrolet cars used 0-60 so that's what I believe BowTie Bits was using to convert the gauges, there's a few of on eBay as well.
You can just change the working side and leave the 0-30 face plate, if its in the middle of the gauge, its around 40 psi. The Chevy car gauge, 0-60 would be a better choice and if I come across one for the right price, I'am going to change mine out again.

This same basic question came up in The Electrical Bay and had to do with the temperature gauge. The answer is if you have a bourdon curl (over the years the term has become a bourdon tube for reasons I don't quite understand) type gauge that is pegged at the maximum it can distort the thing so that it doesn't work any longer or isn't accurate any longer. The curl has to be sensitive enough to measure slight changes. With the temp gauge (which has a closed tube design) the needle will usually just stay at the top of the register if it gets pegged out. With the oil gauge as Jerry said over time it generally just won't be accurate any longer. If you have enough oil pressure, you can ruin it. 0 to 60 gauges are pretty common. If you need to change the color of the face plate, you could use the printable decal I made for the site a few years ago. I think it is stored as a sticky in the Interiors section. I did this for the 0 to 60 gauge. Have it printed by Kinko's or somewhere that has a color laser printer for the best luck. You could have it printed on waterslide decal paper or just on coated paper to which you would add a double sided sticky backing. Either way coat it with clear spray so it will last longer. Good luck!

I had an original early GMC gauge that would have been a bolt in swap, only it wouldn't read anywhere close to actual numbers. The inner workings were full of dried up oil I could not get out. I tried for weeks soaking it and never could get it to work. I drove my truck for 20 years with a 30 lb gauge with no issues, once i installed the high pressure gauge, the oil pressure didn't go much over 45 on a cold start and runs around 30 while driving, so it wasn't pegged, just at the top of the scale. 250 inline six with 5w-30 full synthetic oil.

The one in my 36 gmc was inaccurate and then stopped reading at all. I sent it out to be rebuilt, somewhere up in Washington I believe. It was less than $100 including shipping. I didn't have the face redone as I wanted it to look like the rest of the original gauges.
I'm running a 4.3 vortec engine and the pressures are probably higher than a 235.