Trojan Boat Forum

Looking to install a oil pressure switch for electric fuel pump shut off. Any locations other than existing sending unit on left side of block ? Did not want to tee off that if I did not have to. Motors are 1989 454 Crusaders, already have new pressure switches just trying to look for a clean installation.

You should be able to add a tee and put the low pressure switch and the regular sending unit in the tee. I would prefer a nice thick walled brass tee. Great idea when using an electric fuel pump in a boat. Convinced my brother to do so several years ago. May want some easy way to momentarily bypass it also, just so you can get fuel to the carb in the spring and fill the bowls. Good safety piece!

Have you checked for an existing switch for a no pressure alarm? Check the back of the block. Sometimes pressure is picked up off the end of one of the main oil galleries. There should be a plug on each side/bank. This is another location you can use or tee off of. By the way, you need a switch that closes when there is pressure, not the other way around as a normal no pressure alarm switch does. Those are closed with no pressure. So you need a NO (normally open) switch which closes and supplies power to the pump only in the presence of pressure as opposed to a switch used for an alarm which is NC (normally closed) which closes in the absence of pressure. Clear as mud?

Yes close on pressure - If I remember they close on 6-8 psi or so. Correct me if I am wrong.

For this application, the lower the better IMO. If something happens with oil pressure and I'm ten miles out, I'd still like to be able to limp home on 5 psi if I have to and I know that would be doable at that preasure. I'd rather have the option to take the chance and try to make it to safe harbour rather than have the switch take that option away. Of course if the pressure continues to drop and she seizes then the choice is over but I may be a lot closer to safety by then, and that's what really matters to me. A block can be replaced! By the way, the switch isn't just a good idea, it's mandatory.