Engine Question for sbc 350 swap folks

[Masscj7]

I know several here have done this swap, did anyone retain their stock Jeep OEM oil pressure gauge? If so, what electrical sender did you use for the gauge?

I spoke to Faria Beebe today who made the gauges back then. While they had some info about the gauge, they were not able to tell me the ohm range of the OEM gauge which dictates the sender.


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[ohio4x4wrangler]

Use the sending unit that matches the gauge. Ron

 

[RiverandSand]

Best bet is buy a sending unit for a 6 or 8 cyl amc motor of that year. Same for the temp gauge. The SBC isn't any different that those of the AMCs in regards to threads both are SAE. I found using Standard motor sending units work the best.

 

[TSB8C]

When I did my SBC, I used the same sender from the AMC 6 cylinder with an adaptor to screw it in. I later got the Dakota Digital guages and used the senders they came with.

 

[DaveMueller]

I think I have this in a spreadsheet at home, I'll try to remember to check. As others have said though, usually the sender and gauge are a matched set.

 

[Masscj7]

I found that the stock gauge is croughly 240ohms - 33 ohms and the Stewart Warner sender I got for their gauge is basically that. So I’m going to try that first, then may try can AMC V8 sender, and if none work, I’ll throw in the new Stewart Werner gauge. Thanks for the replies folks.


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[Masscj7]

Rehashing this one, so I put in a sender from Stewart Warner to my stock CJ gauge. (I know I have oil pressure, I had a mechanical gauge hooked up for initial startup)

With the SW sender, upon ignition turn on, gauge sweeps to middle of range, but upon start up, gauge drops off range.

I ordered a sender for a 258 and the store sent me a two prong, what seems to be just an open close switch. Is this correct?

Seen some pics on the web, looks like stock used to have a T fitting that had both the two prong switch and also a single post/prong which I’m guessing is the actual sender.

I’d like to try a stock Jeep sender on the gauge next before swapping the gauge. Searching Rockauto, all are a 2 prong switch.


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[Petescj]

Rehashing this one, so I put in a sender from Stewart Warner to my stock CJ gauge. (I know I have oil pressure, I had a mechanical gauge hooked up for initial startup)

With the SW sender, upon ignition turn on, gauge sweeps to middle of range, but upon start up, gauge drops off range.

I ordered a sender for a 258 and the store sent me a two prong, what seems to be just an open close switch. Is this correct?

Seen some pics on the web, looks like stock used to have a T fitting that had both the two prong switch and also a single post/prong which I’m guessing is the actual sender.

I’d like to try a stock Jeep sender on the gauge next before swapping the gauge. Searching Rockauto, all are a 2 prong switch.


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Might want to put this in a different post since your asking about a 258 part and not really SBC related. Just trying to get you a quicker response. Im no help with a 304 and not a good enough memory anymore.

 

[TSB8C]

So your stock Jeep CJ oil pressure gauge has three connections. You have the "S" terminal, the "I" terminal, and a ground lug. One side is a red wire with ignition power from the fuse box. On the other side is a purple wire coming from the oil pressure sensor on the engine. The ground lug is grounded via the mounting bracket. The sensor is a variable resistor with a single prong connector that this purple wire connects to and then of course the sensor is grounded where it screws into the fitting on the engine. Be careful of using teflon tape on the threads as that can interfere with the grounding. I don't recall what year models, but some had a "splitter" type brass fitting that screwed into the engine. Then the oil pressure sensor screwed into one port on this "splitter". The other port had a two prong sensor that was just a switch. This connected to the electric choke circuit on a Motorcraft carb. When oil pressure hit a set threshold, it closed the switch. I also seen some guys drill and tap a third port on this "splitter" to connect a mechanical gauge.

You can check the oil pressure sensor with an ohm meter by confirming 240 ohms at 0 psi, 103 ohms at 40 psi, and 33.5 ohms at 80 psi. You can confirm the oil pressure switch (2-prong if you have this) for your choke circuit by measuring infinite ohms (the switch is open) at 0 psi and zero ohms (the switch is closed) at any pressure above 15 psi.

When I did my SBC swap and still had the stock gauges, I just used the same Crown sensor from the 258 with no problems. The threads are the same, so it screwed right in on the SBC. So same sensor, same gauge, same readings. And from Novak: "You can also keep your fuel gauge and AMP / volt gauge as factory. Your oil pressure gauge and water temp gauges can use the original Jeep sensors, as adapted into the ports on the engine assembly."

When I installed the Dakota Digital cluster, that came with its own sensors. So then I had to swap.

Here's some pics for reference showing (1) Crown oil pressure sensor, (2) the "splitter" setup on a 258 (with a 3rd hole drilled and tapped into the side of the splitter), (3) the "splitter" setup on a 304, (4) the mod to add a mechanical gauge, and (5) the oil pressure port on the SBC where the original stock sensor screws in (in the block just behind the intake next to the distributor). Depending on your distributor (HEI, etc) you may need an adaptor to extend the sensor upward and/or at an angle for clearance.