NEW oil gauge vs original

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
Post Reply
User avatar
orione6a
G-Sergeant First Class
G-Sergeant First Class
Posts: 88
Joined: Sun Nov 01, 2015 8:05 am
Location: Pensacola, FL

NEW oil gauge vs original

Post by orione6a » Wed Nov 15, 2017 5:36 pm

Hey Folks,
I am finally at the stage where my MB is about road worthy. When I bought my MB, the only 2 instruments that were original were the speedo and the oil pressure gauge. I bought a set of new gauges to replace all of my instruments. Everything seems to work pretty well, except for the oil pressure. It shows 20 psi on start, and then drops to 0. I put a new rubber feed line to the metal gauge feed line (which is original to the Jeep) I thought maybe there was an obstruction or just old dirt in the metal line, so I removed the gauge and cleaned out the line. I replaced the new gauge, and basically the same readings were duplicated. So, I put my original MB gauge in, and the idle pressure was just below 20. So then I took that gauge out, and compared the gauge openings. The original seems to be about 3/16, and the new might be a shade over 1/16. Is this my problem? Should I go ahead and drill the opening to match the old gauge? Any and all ideas are greatly appreciated

Kris


dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: NEW oil gauge vs original

Post by dinof » Wed Nov 15, 2017 6:19 pm

I don't know if you should drill the gauge out or not, but I bet it was a great relief to see your old gauge registering that your oil pressure was Ok.

Drilling out the gauge might work, but I would be afraid (and my bad luck as well) that some shavings might remain in there and get back to the motor.
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike

ndnile
G-Second Lieutenant
G-Second Lieutenant
Posts: 551
Joined: Wed Sep 17, 2014 8:09 pm
Location:

Re: NEW oil gauge vs original

Post by ndnile » Wed Nov 15, 2017 6:48 pm

Obstructions aside, the diameter of the hole should not be an issue. The only time oil moves through the hole is when there is a change in oil pressure. The fact that it initially registered 20# at starts indicates that oil can flow through it.
Doug
Sacramento Area
1943 Willys MB
1943 GPW-125334 (Sold)
1962 M170
1959 Willys Wagon

fiveftsix
G-Second Lieutenant
G-Second Lieutenant
Posts: 575
Joined: Thu Dec 27, 2012 5:37 pm
Location: Kissimmee FL

Re: NEW oil gauge vs original

Post by fiveftsix » Wed Nov 15, 2017 6:54 pm

Don`t drill any oil guage hole bigger
The hole size is taken into account when the gauge was designed
Geoff Bull

User avatar
orione6a
G-Sergeant First Class
G-Sergeant First Class
Posts: 88
Joined: Sun Nov 01, 2015 8:05 am
Location: Pensacola, FL

Re: NEW oil gauge vs original

Post by orione6a » Wed Nov 15, 2017 7:09 pm

I agree that oil is flowing to the gauge. I just don't think that there is enough flow through the smaller hole to provide and accurate pressure indication. My original shows about 40 on start, and settles to about 20. The new gauge shows 20 on start, and settles down to 0. It does react to throttle changes, but settles to 0 when idling. Am I missing something? Am I really the only one this has happened to? I figure someone has changed gauges and maybe had the same results. I certainly wont run the new gauge as it's not accurate anyway.

fiveftsix
G-Second Lieutenant
G-Second Lieutenant
Posts: 575
Joined: Thu Dec 27, 2012 5:37 pm
Location: Kissimmee FL

Re: NEW oil gauge vs original

Post by fiveftsix » Wed Nov 15, 2017 7:21 pm

The internals of an oil pressure guage are designed and set with a set sized restriction.
Different makes may differ.but the internals are matched to the restriction so don`t try change it.
You say you have a new oil guage first off Where was it made ?
I`d rather trust the original any day to any repro one especially if it came out of China or even India for that matter!!!!!the pressure readings your getting is fairly normal a little low on start up but 20 is good at idle,.
It can run at only 5 psi when hot

Geoff Bull

Jerry Hudgens
G-Colonel
G-Colonel
Posts: 1829
Joined: Sat Nov 08, 2003 6:47 pm
Location: Crestview, Florida

Re: NEW oil gauge vs original

Post by Jerry Hudgens » Thu Nov 16, 2017 2:24 pm

There is a simple way to test your gauge for accuracy. Hook your compressed air source through a regulator that has a T fitting to a good, air pressure gauge. Hook your oil pressure gauge to the same T fitting as your air pressure gauge. Apply your compressed air source to your hook up and adjust the regulator to say 10. 20. 30. and 40 psi as indicated on your air pressure gauge. Compare the air pressure gauge reading to your oil pressure gauge. Their readings should be close assuming both gauges are functioning correctly.

Pressure is pressure no matter if its oil or water or air. Its expressed (in this case) as force per square inch (pounds per square inch).

Jerry Hudgens

dinof
G-Major General
G-Major General
Posts: 2860
Joined: Fri Jan 08, 2010 4:32 pm
Location: Arcadia & Johannesburg Ca.

Re: NEW oil gauge vs original

Post by dinof » Thu Nov 16, 2017 4:23 pm

While we are on the subject, my gauge takes about 15 seconds to register the 20lbs, when I restart the jeep when it has ran. Is that normal? No reving, just starting it up and letting it idle......

I figured that if it was the motor, I would always have low pressure when idling. Gauge getting old?
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43
1928 Model A Roadster Pickup
1930 Model A Tudor
1968 Taco Minibike


Post Reply

Return to “MB GPW Technical Knowledge Base”

Who is online

Users browsing this forum: Bobby Nowland, Google Adsense [Bot], Wolfman and 59 guests