Will oil pressure damage gauge ???

I changed the oil pressure gauge on my old tractor to a 30 lb (top end) gauge. It had a 100 lb gauge on it when I bought it. So now, right after start up, it pins the gauge all the way to 30 pounds ...... then it drops back to about 15-18 pounds once it warms up (which I am fine with). Will pinning the needle at 30 pounds for a while after start up damage the gauge? I'm not looking for engine problem fixes here, just comments on the gauge issue. Thanks for replies ......

I would question the accuracy of a gauge after it has been pegged, some internal parts may be bent or the rack gear might have jumped a few teeth, better to have a higher pressure gauge.

It depends on how good the gauge is and how hard it hits when it pegs. It will loosen the hand and or twist it by hitting the stop. On precision gauges pegging is death but on an oil pressure gauge you are looking more for drastic changes so accuracy won't matter so much.

Can you find a 50 - 60 # gauge?

Yes, probably a good idea, except I have to remove the fuel tank to get at the back of the dash to make the switch ..... not a big job but one I'd rather not do. I'll live with the 30 lb for now, nothing can break down because of it anyways.

When 17 - 18 years old some friends of mine and I went through a phase when oil pressure was bragging rights for our cars.

When I rebuilt the 327 in my 64 Impala SS, I installed a high volume oil pump. In the day, the pumps came with both OEM and high pressure relief springs. I stretched the high pressure spring an inch or two and installed it. With 40W oil (Don't ask) the engine held 80+ PSI at just about any RPM above idle and pegged the SW gage.

A close friend had a 409/425 in a 57 BelAir. In order to out do me, he simply removed the relief spring in the high volume oil pump in his 409 and replaced it with a nail, cut to fit. Though he drove it around for several weeks without incident (Who knows what the oil pressure was), I well remember things starting to go bad when cold weather set in. (He too used 40W oil. Don't ask.)

One evening while cruising around, I heard a "pink" (It was hard to hear anything in his 409/427 57. The radio was useless.) and the SW oil pressure gage filled up with oil. I pointed this out to my driver friend and asked to get out. (I was in the front seat.) Rather than stopping the car, he down shifted and nailed it. As expected, the glass in the gage broke and oil sprayed out inside the car. He thought this was great fun.

Later, after replacing the gage, he installed a high capacity (longer) oil filter for a 409 truck engine. He had the proper truck filter canister but did not have the proper, longer canister bolt so he welded two automotive bolts together to make a canister bolt of the proper length. Apparently, his welding was not so good.

One winter morning when the temperature was near 0 (Still 40W oil. Don't ask.), he started the engine to allow it to warm up before leaving for school. He had removed the automatic choke from the rear AFB and installed a hand choke (Don't ask.) and a hand throttle for warm up, etc. (Again, don't ask.) After starting the engine, he adjusted the choke, set the throttle for somewhere around 1,200 RPM, turned on the heater and headed for the house for breakfast. Before reaching the house, he heard a muffled "explosion" and the engine speeded up noticably. His welded canister bolt had failed at the weld and the pressure had blown the filter canister off of the engine, impaling it into the ground beneath the car.

He shut things down before more serious damage.

To this day, he remains the honorary oil pressure champion.

Dean

And people on here always ranting about how stupid people are today.

Many years ago I was reviving a 400 small block in a 71 caprice. It had been sitting for about 10 years. This whole operation was destined for the dirt track. Anyway, on first start up it pegged a brand new auto meter 100 psi oil pressure gauge for several minutes. The pressure relief valve had apparently stuck and who knows what the actual pressure was. (see dean's post below) The oil filter was also permanently bulged. Anyway, after it loosened up the bourdon tube inside the gauge was sprung and I had to send it in for repair. It would show 20 or 30 pounds with the engine not running.

It's hard to say if that will ruin your gauge. If the actual pressure is like 40 when cold it may be ok. A quality gauge is probably tougher than a cheapy. If it always goes back to zero then I wouldn't worry about it too much.

It all depends on how much overpressure was applied to it. Chances are that if the needle returns to zero on its own, chances are the bourdon tube was not stretched and the gear did not jump any teeth. Most gauges will tolerate some overpressuring.