Gauge Sending units needed

[BigDog2026]

Installing a small block Chevy engine in a 1971 FJ40. What senders can I source to feed the stock oil and coolant temperature gauges? The Toyota dealer says they’re discontinued, and the auto parts store says they’d need the resistance range to match up.

 

[procomsignathid]

CityRacer (and Im sure others) have the bits you're looking for:

• Temp sender: OEM Coolant Temperature Sender for '72 and Earlier Land Cruiser FJ40 FJ45 - https://www.cityracerllc.com/products/oem-coolant-temperature-sender-for-72-and-earlier-land-cruiser-fj40-fj45?_pos=4&_sid=47ab2355b&_ss=r
• Oil pressure: Oil Pressure Sender for '58 to '82 Land Cruiser FJ40 FJ60 BJ40 BJ42 BJ60 - https://www.cityracerllc.com/products/oil-pressure-sender-for-58-to-82-land-cruiser-fj40-fj60-bj40-bj42-bj60?_pos=1&_sid=47ab2355b&_ss=r

Both of these would of course need adapters to fit your Chevy engine. My approach would be to use Toyota senders in the chevy engine with adapters (if it is possible). Alternatively, you will need to use the Chevy senders that work with that engine and put some electronics inline to match the correct resistance values that the gauges use. I know the factory service manual will specify resistances for the water temp, I havent checked the oil pressure gauge though.

 

[charliemeyer007]

Or you could look up the range in the manuals. Land Cruiser Factory Service Manuals (FSMs) - https://www.cruisercult.com/factory-service-manuals

When I put in aux tank from a datsun b210, I managed balance the sender unit with the addition of some 2% low value resistors so my 72's OEM fuel gauge would read from E to 1/2 which was full in the 12.5 gallon aux tank. Front OEM tank is 18.5 gallon.

My oil pressure gauge never read correctly even with 2 new senders. I installed a lighted direct read oil pressure gauge in a bracket I mounted on the steering column. I ran some 3/8 fuel hose from the back of the gauge to the engine side of the fire wall over the oil line - that way if the line broke I wouldn't get a face full of hot oil. I carry a pipe plug for the engine block to fix the leak for a broke line.

 

[pb4ugo]

I use the stk 40 gauge cluster for oil and temp with a toyota temp sender. My oil pressure senders maybe aftermarket, idk. To me the oil pressure gauge seems to read low. I've tried 2 different senders with the same result. It could be that the sbc runs lower oil pressure than the stk 6 cylder. I double checked it's reading with a mechanical gauge and my sbc has the proper pressures. 40psi cold and about 10 psi hot at idle. I used the later model senders for a 1975 FJ40. Toyota sells the temp sender adapter to screw into the sbc head. I dont have the part # handy. I used the search function to find the #. The stk oil senders threads are very close to the Chevy threads. My sbc has a short brass extension and 45* fitting, then the sender screws into the fitting. I used 40 color correct wiring.

 

[pb4ugo]

The temp sender adapter is 90404-16160

 

[B y r o n]

From Advance Adapters site: "WATER TEMPERATURE BUSHING: When installing a Chevy engine, 716023 will allow you to retain your stock sending unit. With this bushing you can reinstall the original Land Cruiser temperature probe back into the intake manifold or head of most Chevy blocks. This special bushing has a metric female thread for use with the original probe. The outside diameter of this bushing is 1/2” with a pipe thread. Ford engines, Chevy LT1, LT4, LS1, Vortec engines have a smaller diameter hole in the block for the sending unit. These blocks will require the bushing 716023-LS sensor adapters. We also offer in-line adapters that fit on the radiator hose and allows you to retain your vehicle stock temperature sending unit and stock gauge. These units are offered in either 1-3/8” or 1-1/2” hose diameter. 716673A - 1-3/8” with 1/2” sensor hole. 716674 - 1-1/2” with 1/2” sensor hole."

"OIL PRESSURE GAUGE: The original oil pressure gauge can be retained and the sending unit reinstalled back onto the new engine. On Chevy V8 conversions, you will need to use a 1/8" NPT x 1-1/2" pipe nipple and a 45 degree elbow for installation behind the V8 distributor. Use a thread sealant tape to compensate for the metric thread installation into the 1/8" pipe size."

 

[pb4ugo]

Here ya go. I found a post from Downey from another thread.

Expanding a bit on Dicks message above:
1. You can adapt your stock temp sending unit to the GM engine using Toyota #90404-16160 (if still available), or McMaster Carr #9151K96.
2. You can use any 1/8" NPT fittings to adapt your stock oil pressure sender to the GM engine. 1/8" NPT will not screw into the Toyota metric engine, but your metric sender will screw into 1/8" NPT, just use some thread sealant on Toyota sender.