Plugging Oil Sending Unit Port

Hi all, a few questions here on oil and temp sending units. I have a '67 CJ5 with an F-Head I4 :hurrican:. The original owner had riddled the dash with aftermarket gauges. I have torn everything out as I want to return the dash to stock.

At this point I am trying to fire the rebuilt engine for the first time in 10 years and the hole in my engine block from the old oil gauge/sending unit is causing problems (the unit is still in the block with the hose open at the gauge end). At this point my only goal is to fire the engine. The new oil and temp sending units have to wait until I rewire the speedo cluster.

Therefore, what is the best way to plug the port for the old sending unit after I remove it (see pic here: http://chiantera.blogspot.com/ ). Also, since this is an aftermarket sending unit does the stock F-Head unit install in the same port?

Re: the temp sending unit (see pic here: http://chiantera.blogspot.com/), this too was hooked up to an aftermarket gauge that is gone. I cut the wire to toss the gauge and an unidentified fluid seeped out. Do I have to worry about plugging this port too or can I just leave the unit as it is for now since my understanding is it is simply a probe in the thermostat housing that sends temp to the gauge via the wire. So the unit is essentially closed and I don’t have to worry about coolant shooting out. Please confirm that. Just as with the oil sending unit, does the stock F-Head unit install in the same port?

Thanks in advance for your help.

Mike

 

If you have the new temp sending units, I'd remove the existing non-operative senders you have now and run it. You can leave the water temp sender alone as it wont leak, the fluid that escaped when you cut the tube is what makes the gauge work. Put a plug in the oil sender elbow if you don't want to put the sending unit in. I'd put in the senders, won't hurt 'em to be un-wired for a bit.

 

Thanks, SIDSCJ. Part of the problem is that I don't yet have the new sending units, so I'm looking for a temporary solution. However, I will order them now based on your advice.

I guess this leaves me with one last question. If I do screw in the new oil sending unit and not wire it immediately, won't there still be a hole for oil to escape, or am I missing something? What is confusing to me is that I don't understand how the stock oil sending unit operates. Is it a closed unit that somehow works on resistance or is it like the one that I have where the oil actually moves to the gauge.

I really appreciate your help with this becuase I can't find any good info anywhere else. I'm dying to get this thing fired!

 

for a temporary solution, I'd just kink off the oil sender line and clamp it with a pair of vice grips.

The fluid that escaped from your temp sender was Ether. You can start it the motor without worrying about it.

 

If you're using the oil warning lamp in the cluster and NOT a mechanical gauge, it will be a closed unit (essentially a switch). You can remove the tubing piece off the elbow of the oil port on the block and put a plug in there also. Make sure and get the right thread size.

 

I believe the threads in both locations are normal pipe thread. The appropriate size pipe plug from the hardware store and a little teflon tape would work great to plug the holes in the block. Although, if this is the first time firing up a new rebuild I would want to know the oil pressure.

 

On your gauges... You may want to do some research to see what type of gauges you want. The temp gauge comes in both electrical and mechanical. The oil pressure gauge also comes in either electrical or mechanical. Note that on the mechanical oil gauge you can get it with either metal or plastic feed line. Plastic line in the heat area to me is no good. If the line breaks, it wont take long to pump out all your oil. Also since you don't know what this engine is about yet, I would sure like to have an oil gauge on it before first start up.

 

Thanks, guys, for all of the input. DrDanteIII, that's a great temp solution. Why didn't I think of that (thanks on the ether too). SIDSCJ, you set me straight on the oil sending unit....I forgot it is a light and not a gauge. tomtom/Walt, great point about wanting to know oil pressure for the fire. I'm kicking myself for not keeping the oil gauge that was in there at least until I fired the engine.

Walt, I’m reverting back to the stock speedo cluster, so the oil gauge will be electrical. Considering this, would you be comfortable with a working oil light for the first fire? Or should I go out and get a mechanical gauge with the intention of discarding it after I fire the engine?

 

The idiot light is ok for what you are doing as it will tell you yes oil or no oil.