Oil pressure will only read up to 20psi. I have applied up to 60psi air pressure on sending unit and still only get 20psi indicated. Both old and new gauge react the same way. I replaced the mylar circuit panel with no change. The resistance on the sending unit wire when disconnected on both ends is o ohms. The only thing I can come up with is the sending units I have are not compatable with the gauge resistance wise. Any one ever run into anything like this before. Thanks Ed
-
-
Re: 78 oil pressure
ED------
If you have a GM #15591103 oil pressure sender, that sended should be compatible with your gauge. Otherwise, I don't know.In Appreciation of John Hinckley -
Re: 78 oil pressure
Thanks Joe, Both the senders I have are aftermarket senders I believe. I will see if I can still get the gm unitComment
-
Re: 78 oil pressure
Ed-----
An aftermarket sender should be ok, if it's the right one. There is sometimes "confusion" on the part of auto parts stores countermen on these things. The correct one for your application looks like a "cannister". There is another style which looks much "narrower" and "thinner". This one is for an application with warning light and NOT a gauge. Of course, this type was never used on Corvettes because Corvettes always had gauges.In Appreciation of John HinckleyComment
-
Re: 78 oil pressure
Yes they are both cannister type, Much larger than the other type. I
guess I will try the pn you suggested its only $36 from gm parts direct. I have this oil pressure gauge and sender set up on a homemade test bench now and it still will only go to 20psi with 60psi applied. The gauge will peg out if ground is removed so its not a sticky gauge. Hope sender is the fix. Thanks EdComment
-
Re: 78 oil pressure
There are two "cannisters" one for 60 psi gages and one for 80 psi gages. I have Borg-Warner part numbers for both. Let me know if you want them. These parts look exactly like OE, and with the part numbers you can look them up on the B-W site. They might have a picture and you can probably go to other sites, like NAPA, and cross reference the B-W number. AKAIK any brand including GM is made by the same manufacturer - probably Dana Controls at the time, and Dana Controls was acquired by Standard Motor Products last year.
I installed one of these in my Cosworth Vega when I replaced the clock with an oil pressure gage circa 1981. Both the gage and sender were from a '73 Pontiac Grand Am and there were other applications. Some years ago the OE GM sender developed a leak, so I replaced it with the B-W unit and they were visually identical.
DukeComment
-
Re: 78 oil pressure
Yes duke please post p/n I have the 80psi gauge but would like both numbers. Thanks EdComment
-
Re: 78 oil pressure
Borg-Warner brand oil pressure gage sending units part numbers:
(for 80 psi gage) S769
(for 60 psi gage) S767
There is also a S768 for 80 psi gages, but it shows a hex a the electricl lead end in addition to one at the threaded end.
These numbers are from a fairly old catalog, so verify them on the B-W site, and then use the cross reference function on the NAPA and Delco sites, but as I said before, regardless of the name on the packaging, the part inside is probably the exact same item made by the same manufacturer.
IIRC the first B-W replacement caused some gage dithering problems, and I was able to exchange it for a new one, which has now been on the car for at least seven years. The intense second order vertical shaking force of an inline four (13g, 233 Hz, on the CV engine at 7000 revs) puts a HUGE vibration load on the sender. Since cruciform crank V-8s are free of all shaking forces and rocking couples below fourth order, the V-8 vibration environment is benign compared to an inline four.
Make sure the electrical connections are clean, and DON'T use teflon tape or sealer on the threads since this is the ground path. The threads are called "1/8"-27 Dryseal" (I think this is the same as 1/8 NPT, but not sure) and they should seal without sealer.
DukeComment
-
Re: 78 oil pressure
Duke-----
During the 1974-82 period (the electric oil pressure gauge period for C3 Corvettes) all Corvettes used an 80 pound gauge. The oil pressure sender currently known as GM #15591103 is the only sender applicable to all Corvettes.In Appreciation of John HinckleyComment
-
Re: 78 oil pressure
The GM part numbers listed in my '94 vintage B-W buyers guide for the S767 80 psi sending unit "cannister" are 370801, 547034, 2039841, 6464137, and 14039612.
This part has gone through a lot of evolution.
DukeComment
-
Re: 78 oil pressure
Duke------
Yes, there was quite a "line of succession". The first electric oil pressure sender used on a Corvette for the 1974 model year was GM #6462137. That was superceded for PRODUCTION and SERVICE by GM #370801 and GM #547034 which was last used for the 1981 model year. 1982 used a different sender.
GM #2039841 was originally used for another application and was merged into GM #547034 and later "line of succession". It was never catalogued for a Corvette application, though (although it might work).
GM #14039612 was a SERVICE-only sender as far as C3 Corvettes go; it was never used in a C3 PRODUCTION application. It superceded the GM #547034 in October, 1983.
That was not the "end-of-the-line", though, as far as C3 Corvette oil pressure senders. GM #14040816 superceded GM #14039612 in April, 1990 and GM #15591103 superceded GM #14040816 in October, 1992. The GM #15591103 continues to be available in SERVICE for all 1974-81 Corvette applications.In Appreciation of John HinckleyComment
Comment