Gauges on E27

[hcpookie]

My 1975 E27 oil gauge is dead. I'm having trouble identifying it as there is no identifying mark on the body. The gauge reads vertical 0 - 40 - 80 and has an anodized aluminum frame. The back side is a pale green plastic and the tinned studs on the back are about 3/4" long. The only markings on the back are "S" (Sender or Signal) and "I" (Ignition or power).

I think it is OEM because it matches the rest of the gauges, which all reside in the wood panel with "ERICSON" etched on the front.

While there are tons of replacement gauges, I'd like to identify it so I can research the best replacement.

Before you ask the obvious, yes, I've verified the gauge is TU. The existing sender reads 10 ohms with engine off, and 40 ohms when engine is running.

TIA,
- Jerry

 

[HGSail]

Jerry

Ihad the same guages on my '29. I replaced them with a set that I found at West Marine (I can't remember the namebrand) and they have been working for seven years now. As long as they fit the hole opening everything should be ok.

Pat
E29
#224
Holy Guacamole

 

[Tom Metzger]

Jerry - I had thought that all oil pressure gauges work about the same. Here is the info from the Teleflex site. Note that your ohmmeter readings do not correspond.


1. To test the gauge, voltage from “I” to “G” terminal must be 10 - 16 VDC. With no wire on “S” terminal,
gauge pointer should rest below the 0 psi mark. Next, connect the “S” terminal to the “G” terminal (leave
“I” and “G” terminals connected). The gauge pointer should rest above the maximum pressure mark.
2. The resistance of the sender can be measured to determine the sender's correct operation. Remove
wire to gauge. Connect an ohmmeter to terminal of sender and to engine block. Approximate values are:
Zero pressure = 240 ohms, 1/2 gauge reading = 103 ohms, full gauge pressure = 33 ohms. You will get half
these values on a dual gauge sender.
3. If sender is shorted (0 ohms), gauge will read above full gauge pressure reading.
4. If the sender has an infinite resistance (open), gauge will read below 0 psi.
5. If gauge reads lower than expected, was sealer used on the sender threads (see picture)?
6. The accuracy of the system (gauge & sender) can be +/- 5 psi at 40 or 50 psi.
7. Pipe extenders to plumb both a sender and pressure switch (for horn or warning light) from one port is
not recommended. While pressure readings will be accurate, the amount of weight extended on the
fitting of a vibrating engine could cause fatigue breakage.
8. Teleflex does not offer senders for metric threaded ports.
9. Dual station installations:
When replacing one gauge in a two station installation, the second gauge may need to be replaced as
well. Mixing two gauge manufacturers to one sender may cause an error in both gauges.
If one gauge fails, the second gauge will read much higher than expected.
If the sender fails "open", both gauges will read below the 0 mark.
If the sender fails "short", both gauges will read above the full pressure mark.
10.Twin engines - it may be helpful in troubleshooting to switch either the senders or the gauges from engine
to engine.

 

[Joe Benedict]

Check out Moyer Marine for parts and information about Atomic 4's http://www.moyermarine.com . This is the best source I have found for both parts and knowledge.

 

[hcpookie]

Tom, thanks for that info. I have only "S" and "I" terminals - nothing else is marked. So I'm really not sure if it is a Telelflex?

I have always considered that sender suspect, as all of the Atomic 4 pics I've seen have never had a sender quite like this one. No matter, the gauge still reads "dead" with zero deflection even after directly jumpering to ignition power.

That the sender is either bad or mis-matched should be moot when I find the gauge, because I've been reading that oil gauges and senders are usually a package deal because they get calibrated. It appears that there are industry-standard ranges. If true then this sender is defective or the wrong calibration no matter that the gauge is dead.

WM has new ones for the $35 range so I'm going to try a new gauge first, then the sender next.

Thanks all!
- Jerry

 

[Emerald]

Hi Jerry,


As you may remember, or perhaps not based on your posts, you do not have a sending unit for an oil pressure guage on your Atomic 4. It is a sending unit for an oil pressure switch. It will only confirm that you do or do not have oil pressure. When I purchased it, it was supposed to be a sending unit for a guage, and it was not, and I herniated the 3 discs in my neck before I had a chance to replace it with the proper sending unit. You may also recall that I explained I had been using a mechanical oil pressure gauge on Avanti for testing etc., and had just started to look around for a sending unit for the electronic gauge in the control panel, and then found myself selling her.


So, what you need is not a new guage in your panel, but the correct sending unit on the engine side. Of note, the current sending unit will make your existing gauge read 0 when the engine is off, or full pressure when it is on. It is acting like a glorified idiot light, which is better than nothing, but not as nice as a real gauge. Of note, you mention the guage doesn't respond at all. That was not the case when I had it. Recheck and I think you'll find the guage does work.


OK, to summarize. You have a sending unit for a switch, not a sending unit for a gauge. You need to purchase the proper sending unit and your existing guage should work fine.


Remember, you can always contact me back channel if you want to talk about this on the phone.


-David
Independence 31
Emerald

 

[hcpookie]

David, thanks for that info. I honestly don't remember that info but there you go. I'll recheck the gauge, perhaps we didn't get a clean contact from the probe. Question is, what kind of sender does this need? If I knew the maker of these gauges I would think that would help, perhaps not. I've been out sick so I've kinda lost track of this project. When I get to it, I'm going to visit the local shops to see if they have any insight into this.

 

[Emerald]

Hi Jerry,


I think a fairly certain way to get this guage going would be to call John Fetherman at http://www.feathermanenterprises.com/ I found him to be a very good source of information on these engines, and very competitive on parts. I believe if you order a "standard" sending unit from him, you will find the guage makes sense. As Tom pointed out in an earlier post, the ranges of resistance are pretty standard. Even if you were to wire it "as is", it would serve as an idiot light in that if you have pressure it will show full, and if you don't, it will read nothing. Do note that the fuel pump on the A4 has an oil pressure interlock, so if you really don't have oil pressure, the fuel pump won't run, and your engine won't run either.


Hope this all helps, and hope you're feeling better soon.


-David
Independence 31
Emerald