Low oil pressure switch and outdrive oil reservoir.

[jimh1626]

Have my 5.7 engine pulled and need to change the crank shaft and bearings. It dumped the oil and ruined the bearings. Has anyone installed a low oil pressure switch? I want it to shut down when oil is to low. Also has anyone installed a reservoir for the outdrive oil?

Thanks,

Jim

 

[Bondo]

Re: Low oil pressure switch and outdrive oil reservoir.

Have my 5.7 engine pulled and need to change the crank shaft and bearings. It dumped the oil and ruined the bearings. Has anyone installed a low oil pressure switch? I want it to shut down when oil is to low. Also has anyone installed a reservoir for the outdrive oil?

Thanks,

Jim

Ayuh,... The oil pressure switch is easy enough, though I wouldn't do it...
Just plumb it like Merc does for electric fuel pumps, only run yer ignition through it...

The drive oil bottle depends on what drive ya got...

 

[jimh1626]

Re: Low oil pressure switch and outdrive oil reservoir.

Ayuh,... The oil pressure switch is easy enough, though I wouldn't do it...
Just plumb it like Merc does for electric fuel pumps, only run yer ignition through it...

The drive oil bottle depends on what drive ya got...

Thanks Bond-O, But why wouldn't you do it?
The outdrive is an Alpha One.

Jim

 

[04fxdwgi]

Re: Low oil pressure switch and outdrive oil reservoir.

Ayuh,... The oil pressure switch is easy enough, though I wouldn't do it...
Just plumb it like Merc does for electric fuel pumps, only run yer ignition through it...

The drive oil bottle depends on what drive ya got...

If I'm reading this question about the oil sender right, he can just install a 1/8" NPT "T" in the hole where the oil pressure switch goes and add the second sender into the extra 1/8" hole and wire it accordingly. Have done that a millon times on performance engines to add a mechanical guage where the stock sender is required for the FI engine. I would install the audible alarm, vs a shut down. If the sender or wiring has a fault, it would kill the engine, leaving him stranded when there is no reason for it.

If there is no drive oil bottle there now and since the drive is of the Mercruiser Alpha / pre-Alpha variety, Mercruiser had an add on unit where a nice S/S line screwed into the vent port of the upper drive section, went thru the transom (dressed with a nice cover) and to a tank on the inside. Put one on an old pre-Alpha I had and worked real nice.

 

[Bondo]

Re: Low oil pressure switch and outdrive oil reservoir.

I would install the audible alarm, vs a shut down. If the sender or wiring has a fault, it would kill the engine, leaving him stranded when there is no reason for it.

Ayuh,... Exactly,... 'n when startin' it, it'll have to crank long enough for oil pressure to turn the ignition on, before it'll start...

 

[HT32BSX115]

Re: Low oil pressure switch and outdrive oil reservoir.

I would install the audible alarm, vs a shut down. If the sender or wiring has a fault, it would kill the engine, leaving him stranded when there is no reason for it.

Most oil pressure switched are normally-OPEN.....(they "ground" with low oil pressure).........so you would probably have to use a relay to provide IGN power when the switch is open (oil pressure normal)........



You could easily wire the ignition though the starter circuit so that you would have ignition while cranking............ Then the engine would start normally and oil pressure would be likely be adequate to keep it running after releasing the key.

The better way though, is to put a loud buzzer like the Radio Shack 108db model that will activate when your oil pressure switch closes (most of them close at less than 10 psi by the way....) .......believe me you'll hear this one!

What should be obvious though, is that if your oil pressure alarm activates at HIGH speed...........you either have an electrical (short) fault in the alarm circuit or you REALLY have less than 10psi oil pressure!! If it's the former, no problem......fix the wiring.......If it's the latter, you might already have engine damage!

Regards,


Rick

 

[jimh1626]

Re: Low oil pressure switch and outdrive oil reservoir.

Thanks everybody. I will go the alarm route, that does make sense. It might have engine damage at 10 psi, but better than nothing I guess. It dumped all the oil and ruined the bearings and crank before I knew it. It better be good to go for years to come when I get it back together.

Thanks,

Jim

 

[04fxdwgi]

Re: Low oil pressure switch and outdrive oil reservoir.

Most oil pressure switched are normally-OPEN.....(they "ground" with low oil pressure).........so you would probably have to use a relay to provide IGN power when the switch is open (oil pressure normal)........



You could easily wire the ignition though the starter circuit so that you would have ignition while cranking............ Then the engine would start normally and oil pressure would be likely be adequate to keep it running after releasing the key.

The better way though, is to put a loud buzzer like the Radio Shack 108db model that will activate when your oil pressure switch closes (most of them close at less than 10 psi by the way....) .......believe me you'll hear this one!

What should be obvious though, is that if your oil pressure alarm activates at HIGH speed...........you either have an electrical (short) fault in the alarm circuit or you REALLY have less than 10psi oil pressure!! If it's the former, no problem......fix the wiring.......If it's the latter, you might already have engine damage!

Regards,


Rick

Most oil pressure switched are normally-OPEN.....(they "ground" with low oil pressure).........
Don't want to nitpick, but that is Normally closed..... Ground on low oil pressure is closing....

 

[achris]

Re: Low oil pressure switch and outdrive oil reservoir.

Another good reason to go the alarm route is think about this.... You're flying along at WOT (I guess 30+ knots) and you have either a genuine oil pressure problem or a wiring fault. The ignition shuts down. Guess where all your passengers and loose equipement in the boat are going to end up? Not a pretty sight! (Check out the orginal S.L.O.W. system that OMC introduced on there little engines, and why they had to revise it to a slow S.L.O.W.).

Cheers,

Chris............

 

[Rocky_Road]

Re: Low oil pressure switch and outdrive oil reservoir.

The alarm kit you need is right here at iboats:

http://www.iboats.com/Cole-Hersee-M...074654188--**********.181657062--view_id.3876

It also has the engine temp switch, but you can just use the oil switch if you want.

Happy boating!

 

[jimh1626]

Re: Low oil pressure switch and outdrive oil reservoir.

Another good reason to go the alarm route is think about this.... You're flying along at WOT (I guess 30+ knots) and you have either a genuine oil pressure problem or a wiring fault. The ignition shuts down. Guess where all your passengers and loose equipement in the boat are going to end up? Not a pretty sight! (Check out the orginal S.L.O.W. system that OMC introduced on there little engines, and why they had to revise it to a slow S.L.O.W.).

Cheers,

Chris............

Now that's funny. I have had it up to 53 MPH by myself and a half tank gas, but that is assuming the speed odometer is correct.

Thanks,

Jim

 

[jimh1626]

Re: Low oil pressure switch and outdrive oil reservoir.

The alarm kit you need is right here at iboats:

http://www.iboats.com/Cole-Hersee-M...074654188--**********.181657062--view_id.3876

It also has the engine temp switch, but you can just use the oil switch if you want.

Happy boating!

Looks good I think I will go that route.

Thanks,

Jim

 

[HT32BSX115]

Re: Low oil pressure switch and outdrive oil reservoir.

Most oil pressure switched are normally-OPEN.....(they "ground" with low oil pressure).........
Don't want to nitpick, but that is Normally closed..... Ground on low oil pressure is closing....

Yeah....that is nitpicking..... Normally-CLOSED with no oil pressure......IS Normally OPEN WITH oil pressure........I guess it depends on your definition of "normal" .........

With an engine running, it's NORMAL to have oil pressure.....yada yada.............

but that is assuming the speed odometer is correct.

Pitot speedometers are notoriously inaccurate. So you can't usually make that assumption!