The Stovebolt Site Forums The Shop Area Engine Shop Oil pressure gauge problem

I had to pull my dash to fix a sticking needle on my ammeter. Got that fixed, but when I put the panel back in the dash I noticed my oil pressure gauge isn't correct anymore. With engine off it read towards the top of the gauge. Starting the engine makes it peg. Since I've been running a 30lb gauge for years with a full pressure 235, I expect it to peg, but I can't figure out why it no longer returns to 0 with the engine off.

Any suggestions? Going to pull the dash again this weekend and pull it out again (the OP gauge and the ammeter are in the same metal plate that screws into the back of the instrument cluster).

Thanks,

Hy David Bush, please remember to tell us what year and model of truck you are asking questions about. Is the oil pressure gauge in question an electric one or a mechanical one?

Sorry, 1946 1/2 ton with a '54 235 engine. OEM '46 oil pressure gauge.

Hy David Bush, it could be that the Bourbon tube inside the gauge has bent or ballooned and the needle that is connected to it can no longer go back to the zero setting. If the gauge was the original zero to thirty gauge for the 216 engine it was only a matter of time before before the over pressure of the gauge by a full precision bearinged engine damaged the gauge.

Perhaps, but I've been running that gauge with that engine since 1986 without issue. Guess I'll pull it apart again this weekend and see if I can determine a cause. I'd like to replace it with a 60lb gauge that would fit in the stock instrument cluster, but I haven't been able to find one. I could have sworn I saw them for sale years ago for just this type of 216 to 235 engine swap.

Would a GMC gauge work? Or are they totally different in 1946?

That's a fine question. I don't know. Guess I need to research that. Anybody used a 60lb. GMC oil pressure gauge in a '46 Chevy with a pressure 235?

Turns out they do make them, but they're pretty darned proud of them.

http://www.bowtiebits.com/store/sto...&Category_ID=1&Sub_Category_ID=4

Trying to get the old gauge to work again.

Is that "Bourbon tube" filled with Jack Daniel's, Jim Beam, or Old Crow?
Jerry

I think 3B was drinking and experienced a Freudian slip/slurp?

Is that a Bernoulli tube?

Bourdon tube

http://www.secondchancegarage.com/public/653.cfm

Thanks Tim.

Easy to get those Italian/Swiss names mixed up, unless you work in a lab.

sounds like there might have been a pressure leak some where and oil might have gotten into the gauge assembly

Oil pressure gauge is fixed. Thanks for all the replies. Turns out that last time I had it apart when I was putting the plate back in that holds the ammeter and the oil pressure gauge I hit the bottom of the brass piece that is the indicator needle and popped it loose. When I got the whole thing apart (after pulling the dash again), I saw there are two little pins that the needle piece pivots on and they had popped out of place. The piece they snapped into was slightly v-shaped, so it wasn't in that securely to start with. Took some small needle nose and bent the flanges in until they were parallel and then reinstalled the needle. Secure now. Checked needle clearance and bent it out slightly so it didn't contact the gauge face. Working fine.

https://imgur.com/8RNkEVb

Plate is sitting on the seat with the OP gauge removed. Sorry for the blurry, but that's what I got.

Pain pulling the dash, but I couldn't get the top two screws out any other way. While I was at it, with the wheel off, I lubricated the mast bushing, cleaned all the horn contacts and centered the steering wheel.