oil pressure

[Anonymous]

My Haynes manual tells me that you should have 1.42 psi of oil pressure at 3000 rpm; oil temperature 60 degrees Celsius.

[brs127s]

I have a couple of questions about guages.

I am going to try and add a 0 to 15 pound oil guage. My questions are: 1. Will a fuel guage work, or will I need one which specifies it is for oil? 2. Would it be better to use a liquid filled guage, or is a regular guage okay? Keep in mind I may be leaving the guage on the bike.

VDO makes a oil/fuel pressure guage with a 0 to 15 psi range, but it is not liquid filled. All of the other guages I have found have been described as fuel pressure guages.

[brs127s]

Okay folks,
I stopped by the local Racing supply shop and picked up a liquid filled pressure guage with a 0 to 15 pound range. I want to put it on the bike when the oil gallery plug is on the right side of the engine, just below the back side of cylinder #4. There are two routes I could go to mount the gauge. Route one, by a metric to 1/8NPT adapter and replace the plug with the adapter. Route two, drill a hole through the plug and tap it to 1/8 NPT.

I would like to go with route 1, if I can find an adapter to fit the crankcase. Does anyone know what size the oil gallery plug is? If not, I will remove mine tonight. I thought if I could find out the size, I would call around today to find the adapter and try to put the gauge on the bike tonight.

[brs127s]

Just in case anyone is following this thread, I tried to order the adapter to go from metric to NPT in order to add an oil pressure guage to my bike. I got the adapter, and immediately knew it was the wrong thread pitch. I took it home just to see if it would fit. Sure enough, it was the wrong pitch. I have now ordered a second gallery plug and crush washer. When I get it, I will drill a channel though the center of it, and have it threaded to 1/8 inch NPT.

[Hap Call]

Just in case anyone is following this thread...

I am following it very closely!

Hap

[brs127s]

Well, if everything goes as planned tonight, I will install a pressure guage tonight. I plugged the hose going to the cooler and the hose coming back from the cooler, and started the bike up last Saturday. At first I thought the oil light was going to stay off, but as it warmed up it would come on at 1000rpm. I am guessing that the original switch has such a low pressure resistance, that it will be nearly impossible to find an aftermarket replacement; or the five minutes in which I ran the bike with the cooler damaged the oil pump(I seriously doubt this thought).

I got the new injector(oil gallery) plug yesterday, and my buddy drilled the channel through it, and started the tap. I am hoping to put it on the bike tonight, and finishing the tap job, so that the elbow will be facing up, thus making the gauge face up.

[brs127s]

Okay folks, I now have the oil pressure guage on my bike. When I first started it up, I had a pressure reading around 11 to 12 pounds. I think this was becuase the oil was cold and thick. As the bike warmed up, the pressure dropped. Now as I understand it, the pressure should be above 1.4 and below 3.6 at 60 degrees Celsius(140 degrees Fahrenheit). How do you know when you are at 60/140?. I had the bike running for quite a while, and the longer it ran, the less pressure the guage would show. I believe this to be normal. I know the oil is flowing(don't ask how I know, jsut trust me). These engines truly have low pressure, high volume oiling systems. Before my engine was hot(over the 140 mark I assume), I had readings that were within the specs.

My pressure light still comes on at idle. I may have to live with that. After contemplating about the switch, I realized just the slightest flow of oil would prevent the original switch from touching the crankcase. Therefore it would be virtually impossible to have an aftermarket setup which would be like the original setup. If someone has a pressure switch housing adapter, is still using a pressure switch, and the light stays off, please let me know.

I haven't unplugged the hoses to and from the oil cooler yet, so I don't know how much of a pressure drop there may be.

[jknappsax]

oil pressure light

That's great! Did you mount it on that modified oil galley plug? As to the oil pressure light blinking on at idle, mine only does it when the oil level gets a little low (that's when on a long trip I check the oil level right away, and usually it's a few ounces low; I always fill to the top of the sight glass when on the centerstand, and have for years). I am running a Lockhart oil cooler with the adapter plate to divert to and from the cooler. What year is your bike? When I installed a Lockhart on a previous (1977) GS 750 I owned, Lockhart sent a mod to be done to the pressure switch, a mylar washer that went under the metal disk on the switch plunger, which kept the switch from shorting to the case and blinking the light on. It was maybe SLIGHTLY larger in diameter than the metal disk, so I guess the disk couldn't deflect sideways and short. Maybe you need this mod?

[brs127s]

jknappsax,


Yes, I ordered a new gallery check plug and crush washer, and had it drilled and tapped for 1/8 inch NPT. I added a 90 degree brass elbow, and screwed my gauge onto the elbow. I tapped the plug so that my elbow would be facing up, and tapped the female end of the elbow so the bottom of my gauge was to the back of the bike, and top of the gauge was to the front.

Where does your pressure switch screw into your adapter? Mine is on an elbow off the side of the adapter. When I called Hayden, they mentioned something about a mylar disk also, but they were not sure. If the kit I had originally came with the disk. I haven't heard anything from Hayden for quite a while. I may send them another email in the next day or so.

Also, do you have any kind of a thermostat or a check valve on your cooler setup. From what you mentioned about adding oil level to the top of the sight glass, I assume you don't, but I may be wrong. When adding oil to the top of the sight glass, doesn't that put you over the full mark?. Is this additional amount of oil just the capacity to fill the cooler?

thanks,
Brandon

[jknappsax]

oil pressure switch placement

The adapter that came with the Lockhart cooler replaced the original oil pressure switch plate on the crankcase, and had fittings that took barbed hose fittings to go to and from the cooler, and a threaded hole to screw the original pressure switch into. It doesn't seem to have any restricting valves of any kind. As far as the oil level, I just fill to the top of the sight glass, which is only a little above the fill line, which 4qts. of oil with a new filter at oil change takes it to. I do this because my bike uses a little oil when I run all day at 5500rpm, and I figure this gives me a little margin . I've done this for 10,000 miles, and never had a problem.

[brs127s]

Does anyone have any idea where I can find a low pressure oil pressure gauge. The one I added to my motorcycle did not like heat. As soon at the oil heated the gauge up, it would not register the pressure properly.

thanks

[brs127s]

Update:

I ordered a new VDO mini-pressure gauge from Summit Racing. It is not liquid filled, but I was told it would work for oil pressure by Summit and VDO. I got the gauge yesterday and added it to the bike. Started the bike and let it warm up. The needle will bounce a little, but it is not too bad. I took the bike for a spin to make sure it was warmed up. At 3000 rpm, it had between 3.6 and 3.8 psi. This is the upper end of the range specified in the shop manuals. At its lowest idle, it registered 1.2 psi. This was with the original switch housing cover and pressure switch. Tomorrow night, I will change the original cover with the adapter and recheck the pressure. When I have the results, I will post them.

[brs127s]

Oil pressure and the cooler installation...It's finally done

Well, I believe I am finally done with the cooler installation, after much trial and error. Everything seems to be working properly My oil pressure dropped two tenths of a pound. At 3000 rpm it was running 3.4 to 3.5 psi(before the adapter, it was 3.6-3.7 at 3000 rpm) and at idle, 1000 to 1100, it was running 1.1 to 1.2 psi(before it was 1.4 at 1000 to 1100 rpm). I do not think this is a significant drop. It still has a pound at its lowest idle (850 to 950 rpm).

I plan to add a thermostat to help the temperature reach its optimal operating range. I can definitely tell the operating temperature is down while the bike is in motion. I will try to get some pictures if anyone would like to see them.

Brandon

[saaz]

I am interested in all this...

By the way, in looking at transmission coolers for my car, I notice there are thermostats available for oil coolers..permacool among others seem to have them. Just the thing for air cooled bikes I reckon.....

[Hap Call]

Re: Oil pressure and the cooler installation...It's finally

...I will try to get some pictures if anyone would like to see them.

Brandon

Brandon, you are now the oil cooler and oil pressure go-to guy here in the forums! It would be great to see some pics...maybe you could condense your experience and write an article for the Garage Section of the GS Resources.

Hap