The Stovebolt Site Forums The Shop Area Engine Shop oil pressure reducer

I want to use the original gauge (0 - 30 lb) on my '39, but the engine is a high pressure '58. Anybody know if there is some sort of cheap pressure reducer that I can put in line? Or will the low pressure gauge handle the higher pressure??

i think it will just peg the gauge. when the pressure gets below 30 then it would be right. assuming the engines oil pressure is higher than 30. you could hook up a mechanical gauge just to check the pressure first then compare to the original gauge. would kind of be like a oil pressure light till it gets below 30 psi. which would be fine with me.

I'm a bit worried that the excessive pressure might bend one of the innards on a relatively spendy little gadget. I did think about putting a late model gauge maybe in the engine compartment so as to extrapolate just what the old gauge is trying to say. If I could find a cheap regulator valve, I would but that in line after the engine compartment gauge, and then have the best of both worlds.

Thanks for the quick reply.

the 58 isn't really a "high pressure", it's just not a splash oiler, a full pressure - the 58 engine won't peg the gauge for long, just when cold until it's up to temp, when it might run about 30 at speed and about 10 at idle [unless it's a fresh rebuild with a high volume/pressure pump] - it won't bother the gauge

Red,

I guess my ID was wrong on the innards of the engine. It's a fresh rebuild, but with a stock oil pump. It's modified for full flow, but no additional pressure. I was expecting it to run in the 30 lb range when warm. It was just the initial blast that worried me. I guess I don't have much to lose, so I'll leave it as it is, and give it a try. I'm still a bit out from running it much. I did have it running, but only briefly, and with a really cheapo gauge just to make sure there was any pressure at all.

I do appreciate the input.

Thanks,

Gary

In the 47 to 53 trucks, Chev used a 0 to 30 gauge and GMC used a 0 to 60. In 39, GMC used a full pressure motor so if the gauges looked similar, you might be able to use a GMC movement. That is the a common fix for the 47 to 53 year trucks.

Trucker

I will try to keep that in mind, if the 30lb gauge go belly-up. I think it's possible to change faces, at least on some of them.

Thanks,

Gary

There are thousands of 235's out there running a 30lb gauge.
You will not have a problem.

I've been running a hopped up 350 for years using the ORIGINAL guage..... HOWEVER, I had a local shop, D&M Restorations re-calibrage my guage so that what ever it reads the pressure is actually double. So, when it reads 15lb its really 30 and when it reads 30 its really 60. I wanted to keep it original but ai also wanted to know exactly what my pressure is.

Its ot going to hurt your guage to ped it out but if you want to know exactly what the pressure is you'll have to do something.

I think the 39 guages are the same as my 37. I found out to late but you can use the guages out of a 260Z and have instant 12 volts stuff. All you have to do is snap the bezel around the "Z" guages and you have it made. If you can do without originality I suggest that. Go to a junk yard for imports and get the complete set for cheap. Heck a guy even gave me a set. Different years hae different color combo....some black dial,red marks..others may have white dial with black or red marks.
Here is a pic of what I'm talking about.

http://i140.photobucket.com/albums/r19/LutherParris/52Panel/picsforphotobucket005.jpg

I think I will simply run the old gauge, install a new gauge under the hood, and see how the two compare. That way, I will know, with relative accuracy, where I am with the pressure.

Interesting on the 260Z gauges. I have the original amp, oil, and speedometer that work. I have a replacement original temp ordered, and will try to change the face plate on a reconditioned 12v fuel gauge that is also on the way. My fuel sender is still working, and it should be compatible with the incoming gauge.

I have all the cases apart, blasted, and painted. I think it will look quite good when done.

For the record, the only real changes on the truck are the '58 235, and a '55 front axle. All original sheet metal and hard parts. I've owned it since '61, and have driven it to and in Mexico, Canada, and from the Pacific to the Atlantic and back under it's own power. We have a history together.

I have about 2 years in a frame up, but all my amature work, so not show quality. It will be a driver, as it always has been.

Thanks, All,

Gary

Chipmunk,

I just pulled up the photobucket pic. Very interesting. Many would never know that the gauges are not the real thing. Certainly something to keep in mind.

Gary