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oil pressure safety switch

Posted: Mar 12th, '10, 08:04
by scenarioL113
I was thinking about installing an oil pressure safety switch. I have come across a few but they seem to all cut-off at different PSI.

I figure 10 PSI would probably be ok. Can anyone recommend one in particular?

http://www.holley.com/12-810.asp 5PSI

http://www.longacreracing.com/catalog/i ... 8&catid=11 10PSI

http://static.atechmotorsports.com/glob ... -g1438.pdf 7PSI

Posted: Mar 12th, '10, 08:26
by Bruce
If you have detroits, 5 psi. Everyone else 10 should suffice.
Use it to trigger an alarm or something.

Don't do an auto shut down, because it can and will shut off at the time you need the engines the most. I ain't kidding.

While I have many stories about that, Pat I think has the most dramatic I've ever heard.

Posted: Mar 12th, '10, 09:16
by CaptPatrick
The short version is that an oil pressure stitch, wired to shut down the engine, dumped the stbd engine when entering a narrow inlet on a bad wind day. Broached, port side to, in 6' breakers between a stone jetty and a coral reef. Inlet is about 60' feet wide and the boat was 48'.

Managed, after about 30 very long seconds to re-fire the engine while keeping centered in the cut on one engine. Spun the bow into the incoming breakers and backed safely on through the inlet.

Not a scratch on the boat, but my skivies weren't as lucky.... The oil pressure shut down circuit got bypassed post haste that day.

Inlet was Puerto Aventuras, MX. Normal conditions are 12 second - Pucker Factor 12.

Posted: Mar 12th, '10, 09:25
by In Memory Walter K
Install a Murphy gauge-You can set it at any pressure you want the alarm to go off at with a simple allen wrench and it won't shut you down.

Posted: Mar 12th, '10, 17:17
by Rawleigh
I just bought a Murphy off of Ebay. A lot of stationary diesels use them. They are not watertite though, so you may need to mount it inside the cabin or in the engine box..

Posted: Mar 14th, '10, 18:51
by gplume
I have had good luck using a Stewart Warner 76580 switch. Since it is a 3 terminal NO/NC, you have options on how you want to wire it (ground or hot side). They offer other pressure ranges, but 10 PSI seemed right for my engines. Agree....you don't want any kind of auto shut down feature ...just an alarm. I wired 4...2 on the bridge, and 2 down below. If you wire it right, you can use the same switch to activate your alternator so it does not start drwaing unto the oil prssure builds up.