Oil pressure switch

Jeandr · Mar 11, 2009

Has anyone ever put a simple oil pressure sensing switch coupled with an idiot light on a Norton? I'm thinking of doing that, finding a switch with low enough trigger point (10 psi or so) and only run a warning light if the oil pressure falls to zero.

There are also oil pressure sending units, these give out a signal amplitude that varies with oil pressure, I could make a bar graph display or even just a red / yellow / green light cluster.

I'm just trying to find something small and unobtrusive and keep cables and oil lines to a minimum, that is why I am trying NOT to put a gauge.

OTOH, I never had an oil gauge or warning light on any of my Nortons and none ever broke because of oil pressure loss, is it necessary to use any form of monitoring?

Jean

norbsa48503 · Mar 11, 2009

I am told that the BSA one is a light at 6.5 lbs and the Triumph one is just a bit higher. There are some thread differences so watch out for this as you build it up. I would use the BSA one to keep the light from going on all the time at hot idle. I like the look of the gauge if it's done right. I also like to know that I am making 40-50lbs at highway speeds and don't worry too much about hot idle lbs.

BrianK · Mar 11, 2009

I'm with Greg. An oil pressure GAUGE is a very nice thing to have on any bike. Will give advance notice of any number of impending ills...

BrianK · Mar 11, 2009

Jeandr said:
OTOH, I never had an oil gauge or warning light on any of my Nortons and none ever broke because of oil pressure loss, is it necessary to use any form of monitoring?

This is really a function of (i) how likely is it that you will experience a low pressure situation and (ii) how likely is it that a monitoring system will alert you in time enough to do something about it?

Probably the chance of "(i)" is fairly small - but then again, the consequences if that remote risk materializes can be fairly devastating. The likelihood of "(ii)" is probably not 100% but still fairly high.

My house has never burned down, but I carry fire insurance...

RennieK · Mar 11, 2009

Jeandr said:
OTOH, I never had an oil gauge or warning light on any of my Nortons and none ever broke because of oil pressure loss, is it necessary to use any form of monitoring?

Jean

On a road trip I stopped to check my oil in a small town. (perhaps I sensed a raspy sound in the engine). Oil level was real low and I tightened the lower rear oil tank filter/nut which was oily. I made it another 30 miles when the raspy sound came back but this time my pistons and cylinders were scored. It turned out my oil drain plug had come loose and was retained from coming right out by the side cover but this was enough to drain too much oil. (fortunately I was only about 80 miles from home and not stuck doing repairs in some other town.) After that I fitted an oil pressure gage AND wired my oil plug. On long trips where you are riding non stop between gas tank fills it doesn't take much of an oil leak to cause big problems.

Your idea sounds good, anything to allow you to see oil pressure activity is good IMHO.

JimC · Mar 11, 2009

I run an oil pressure gauge on my 72 Combat. If I used a 10 psi oil pressure switch I would get a steady alarm at idle once the oil is hot. Pressure drops down to 2-3 psi with hot oil and less than 1000 rpm. That's with a fresh bottom end (0.0015 clearance) and a new oil pump. At startup I have 50+ psi at idle. At higher rpm I have approximately 10 psi for every 1000 rpm. There are many conditions where a Norton will lose oil pressure. One indication is a seized engine. Another is an oil pressure gauge showing zero. Over the years I've had both. I'll take the gauge, thank you.

Cookie · Mar 11, 2009

I used to run an oil pressure guage from my dad's Chris Craft. It worked pretty well but these days I think a warning system would be a good idea.
That might also save those guys who forget to turn on an oil tap.

Jeandr · Mar 11, 2009

JimC said:
I run an oil pressure gauge on my 72 Combat. If I used a 10 psi oil pressure switch I would get a steady alarm at idle once the oil is hot. Pressure drops down to 2-3 psi with hot oil and less than 1000 rpm. That's with a fresh bottom end (0.0015 clearance) and a new oil pump. At startup I have 50+ psi at idle. At higher rpm I have approximately 10 psi for every 1000 rpm. There are many conditions where a Norton will lose oil pressure. One indication is a seized engine. Another is an oil pressure gauge showing zero. Over the years I've had both. I'll take the gauge, thank you.

I guess I could live with something like that, at low RPM, the light would come on giving me an indication the circuit is working and as revs built up, the light would go out indicating oil pressure is correct. Having a light is most likely better than nothing which is what 99% of Nortons now have and it is easier to run a little wire and hide a small LED than either fitting a gauge where it can be seen or fitting a gauge but making it impossible to see when riding (seen that many times on choppers).

Jean

splatt · Mar 11, 2009

I like the idea of a pressure indicator,the problem is even a failing bearing will still develope oil pressure,just abit slower and lower. If the light comes on at 6000rpm it's probably to late any way,a gauge does give you a better over all indication,but if you use alight you could always use the warning light assimilator as it never works,then you will be able to see if your bikes running or not.

Jeandr · Mar 11, 2009

LOL, even with my failing hearing, I can tell without a visual indication when my bike is running.

Jean

PS Gauges are nice IF you look at them and from what I am reading, the pressure varies greatly from idle to red line and from temperature variations. I am a bit paranoid about things breaking, but I am not willing to learn how to decode a gauge with all the variables, like is that small pressure drop due to the weather or due to an upcoming failing bearing?

RennieK · Mar 11, 2009

Jeandr said:
I am not willing to learn how to decode a gauge with all the variables, like is that small pressure drop due to the weather or due to an upcoming failing bearing?

Not to mention multi grade oil

RennieK · Mar 12, 2009

After my little incident of my oil drain plug vibrating loose I installed this one in my Dunstall fairing.

I always felt good seeing the needle move after that.

I just scraped off 25 years of grime to take this shot. Boy am I going to have a lot of work to do...

Jeandr · Mar 12, 2009

He he, you even have the red / yellow / green indicators to go along with the gauge. Now get going and clean it up, spring is just around the corner, closer still in BC.

Jean

splatt · Mar 12, 2009

what gives it away that your bike is running,a high pressure switch{10psi} will give you as much head scratching as a gauge,jims figures are about spot on,2-3psi at idle, 10psi per 1000rpm.were do you mount a pressure switch, is it off the rocker feed.

batrider · Mar 12, 2009

I like the idiot light idea too. It is not obtrusive and could work with the turn signal indicator that I don't have a use for now. I'm not sure I want to be reminded about the 2-3psi every time I'm idling though.

To me, and from past threads I guess at least one or two others on here, monitoring a gauge would be a distraction and just another thing to agonize over. And also it isn't stock-looking! (Strictly a matter of my own preference! As Ted Knight says in Caddyshack - "Looks good on you though!")

Russ

norbsa48503 · Mar 12, 2009

I think it fits in fine. JMO though.

And with drilled intake rocker shafts The hosing is done.

arc · Mar 14, 2009

Firstly i'd like to say thank you to all contributors for making my life a lot simpler with all the knowledge on the forum javascript:emoticon(':lol:')(i've been lurking for sometime whilst sorting my 74 850).Anyway ihave a oil pressure switch fitted to my bike(see pics)it's not the prettest but works well.My bike is non standard and has been rewired to a minimum,so when the ingnition is swicthed on the ignition light is wired to the pressure switch and goes out when running.if it comes on during running i'm in trouble!!!!I had this fitted when i was experimenting with anti wet sump valves and i can say that it lights up at tickover with one fitted so they restrict oilflow?IMHO therefore i do'nt use them(and i've tried a few)..........Hope this helps . http://s559.photobucket.com/albums/ss33 ... ndo002.jpg

Jeandr · Mar 14, 2009

Neat! Did you use a Triumph or BSA switch? Mine will most likely be hidden from view, but I like the thinking behind your installation. I have had my intake spindles modified to use a single oil feed to the rockers and I will take the oil pressure from the other side by a small pipe going to a manifold hidden under the gas tank.

Jean

arc · Mar 14, 2009

Hi Jean,Not sure of the origin of the switch it was done for me at the local shop although i fitted it (easy).Yours sounds good if you can tuck it away somewhere,i must admit mine is a bit ugly stuck out there but it works well and as i said an easy mod.Good luck with yours........................ Andy

splatt · Mar 14, 2009

Jean, why don't you try and fit the switch on the back of the bottom banjo bolt,or make up an adapter for that area, it wouldn't look out of place down there.

Oil pressure switch

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