Temperature and oil pressure warning system installation

[Mahoneymik]

I'm trying to install a Temperature and oil pressure warning system but at the Oil Pressure Sending Unit, there's what looks like an Oil Pressure safety switch. Here's a bad photo...
Can anyone tell me how to attach the warning system with the safety switch installed? I've looked around the forum, but I can't find a schematic or anything.
Thanks!

[hanleyclifford]

There are actually 3 NPT oil holes along the block. One is where you have the OP switch. The second is behind the carb and usually not used. The third is directly over the oil pressure adjuster, a very useful second OP point also being 1/8" NPT. It is not a good idea to use a T fitting so as to use just one point. The extra weight and engine vibration can cause the nipple to break off in the block.

[ndutton]

The pictured switch does look like an oil pressure safety switch due to the number of terminals but it raises a few questions:
Q1: Since nothing is connected to it, why is it there?
Q2: Do you have an electric fuel pump?
Q3: Do you have an oil pressure gauge?*
Q4: If Q3 = yes, where is the gauge sender that usually occupies the port in the picture?

Heed Hanley's warning about overloading a single oil pressure port with an array of senders/switches hanging off a lengthy pipe. The solution of spreading the senders over two oil pressure ports works up to the point you have more senders than accessible ports at which time you're forced into a Tee arrangement. Another solution is to fashion an oil pressure sender manifold out of 1/8" pipe fittings (Tees, nipples and elbows) and mount it to a nearby bulkhead connected with a flexible hose. That's how I have my three oil pressure senders (gauge, OPSS for fuel pump and alarm switch). It relieves all stress off the port in the block, makes the sender array much more accessible and makes for neater wiring with all three in one place. Be sure to provide a ground wire from the block to the remote manifold.

*Not everyone has an oil pressure gauge. The Newport 27's and 30's built in the 70's had only a temp and oil pressure alarm system similar to what you're installing in lieu of gauges.

Here's a picture of my remote sender array

[joe_db]

I would put a better close ended lug on that ground wire and connect it over near the starter.

[hanleyclifford]

Notice the alligators hanging handy to Neil's oil pressure array, no doubt for the quick diagnostic bypass.

[hanleyclifford]

I would put a better close ended lug on that ground wire and connect it over near the starter.

Agreed. That stud is a structural engine component requiring specific torque. Also, the spark/heat potential over the carb would make me nervous. I like grounding on the flywheel cover.

[hanleyclifford]

Another example of an oil array:

[Al Schober]

I'll put in another plug for the 'oil array'. Whatever you've got using oil pressure (mechanical gauge, electrical gauge sender, safety switch, alarm), get them off the engine. Build a manifold using 1/8" NPT tees and nipples, connected to the engine block using a grease gun extension hose (less than $10 at Home Depot). Some of these things also need a ground, so you'll also have to run a ground wire to the 'array'.

[Mahoneymik]

The pictured switch does look like an oil pressure safety switch due to the number of terminals but it raises a few questions:
Q1: Since nothing is connected to it, why is it there?
Q2: Do you have an electric fuel pump?
Q3: Do you have an oil pressure gauge?*
Q4: If Q3 = yes, where is the gauge sender that usually occupies the port in the picture?

Heed Hanley's warning about overloading a single oil pressure port with an array of senders/switches hanging off a lengthy pipe. The solution of spreading the senders over two oil pressure ports works up to the point you have more senders than accessible ports at which time you're forced into a Tee arrangement. Another solution is to fashion an oil pressure sender manifold out of 1/8" pipe fittings (Tees, nipples and elbows) and mount it to a nearby bulkhead connected with a flexible hose. That's how I have my three oil pressure senders (gauge, OPSS for fuel pump and alarm switch). It relieves all stress off the port in the block, makes the sender array much more accessible and makes for neater wiring with all three in one place. Be sure to provide a ground wire from the block to the remote manifold.

*Not everyone has an oil pressure gauge. The Newport 27's and 30's built in the 70's had only a temp and oil pressure alarm system similar to what you're installing in lieu of gauges.

Here's a picture of my remote sender array

In answer to your questions:
Q1: Good question! This is how I bought the boat two years ago and I've been working on getting it into shape. It looks to me like something is missing. Is it the "gauge sender" that you're talking about?
Q2: I do have an electric fuel pump. It's just out of the pic to the right.
Q3: None of my gauges are presently working. I have no idea where (or what) the sender is. Is it the "bell" looking piece that usually sits where the safety switch is? Is it unsafe to take the boat out in this condition? As you can tell, I'm still pretty new to all of this.

[Mahoneymik]

Agreed. That stud is a structural engine component requiring specific torque. Also, the spark/heat potential over the carb would make me nervous. I like grounding on the flywheel cover.

Thank you! I'll take care of that this weekend. I'll need a longer gnd wire. Is that something I can buy at an auto parts store? And will I now need a torque wrench? Does anyone know off hand what the proper torque there should be?
And might someplace like Sears have a crimping tool kit that I should buy for these kinds of repairs? I'll need something for them as I think I'm going to have to re-wire a lot of the gauges.

[Mahoneymik]

I would put a better close ended lug on that ground wire and connect it over near the starter.

Thank you! That will happen this weekend.