Oil Temp gauge


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ajs350
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Oil Temp gauge

Post by ajs350 »

I have a VDO oil temperature gauge that does not work. How can I tell whether it is the gauge at fault or the sender which is part of the oil drain plug? Thanks Ross.

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Re: Oil Temp gauge

Post by EMS »

Tough one. The way these usually work is, the resistance in the sender unit changes according to the temp, which will make the analog gauge needle move. You would need a source for a small current (how much I don't know) with a variable resistance that you can change from infinitive to lower in order to see if the gauge will move.
Maybe a car parts store can test it for you.

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Re: Oil Temp gauge

Post by SanDogDewey »

Input should be around 0-180 ohms.
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Don
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Re: Oil Temp gauge

Post by Don »

Remove the wire from the sender and connect it to ground through a 100 ohm resistor (get one at Radio Shack) and turn on the switch - It should read somewhere near mid-scale. If it does, buy a new sender. If it still reads whatever it's reading now, it's the guage . . . . or the circuitry associated with it

Don

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Re: Oil Temp gauge

Post by ajs350 »

I grounded the connector as suggested above and the gauge needle moved so it's definitely the sender.
Currently the sender is located inside the oil drain plug and sticks down under the sump 2 inches or more. I'd like to relocate it if I can. I saw in some posts senders located in one of the oil gallery plugs. Does anyone know if I can buy a new gallery plug pre tapped to accept the new sender?

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Re: Oil Temp gauge

Post by Don »

Mine was probably one of the ones you saw - I have the sender in one of the gallery plugs on the right side . . . . the sender wire runs up and joins the ignition wires where they exit the timing cover . . . . almost invisible

I don't think you can buy a gallery plug tapped for a sender, but it's pretty easy to do it yourself. Make sure you drill your hole in the exact center of the plug . . . . use a series of drill bits to enlarge the hole for the tap and take your time tapping the plug

Don't use any teflon tape or sealant on the threads. When finished, I filled in the inside of the completed plug with Marine-Tex epoxy to permanently seal everything - The sender can no longer be removed from the plug . . . . but it's never going to leak either ;)

PM me if you need a picture . . . . I never have any luck trying to post them here

Don

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Re: Oil Temp gauge

Post by George R. Garrison #0857 »

Don,, it's highjack time. Happy New Year and did ever buy the airplane? And, you open a very interesting pandora's BOX.

I cannot post any phot'o's on here either. It should not be that difficult. I've given up. WHY WHY WHY can't this issue get dealt with so that a few uncomputer skilled people can easily post there pic's.

Nils said, send your pic's to me George and I'll post them. Nils, I appreciate that. But, I want to do it. I'm a big boy and can take instructions, but this issue lights up my STUPID streak or what am I missing?

HELP, OH SUPREME COMMANDER!

PS: I copied and follow the instructions and my pic's still do not go thru.

Later, George In Delaware
I'm into motorcycles, wooden boats, airplanes, wood working and car restoration.

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Re: Oil Temp gauge

Post by ajs350 »

George, I had the same problem becuase my picture size was too big. You need to get the picture size down to 1024X768. This may not be the most elegant way to resize but here's how I do it.
Pull up your picture in Windows Picture Gallery. Click on E-mail at the top of the screen. This brings up an "Attach Files" box where you can specify the file size. Pick 1024X768 and click the "Attach" button.
This pulls up an e-mail with the picture resized and attached. Send it to yourself.
When you receive the e-mail copy the file back to your picture library and upload from that location.
I'm sure there's a better way but this works.
Ross

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Re: Oil Temp gauge

Post by Don »

George - PM sent

Don

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Re: Oil Temp gauge

Post by George R. Garrison #0857 »

Thanks Don for the PM

Now back to the subject at hand.

Hey, speaking of oil temperature, has anyone put a cylinder head temp gage on a CBX? And if so, whats the hottest cylinder.

With a CHT gage, you really don't need an oil temp gage. Both both is even better.

Now if we could rig a mixture control or maybe fuel injection would make more sense.

Later, George in Delaware
I'm into motorcycles, wooden boats, airplanes, wood working and car restoration.

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Re: Oil Temp gauge

Post by EMS »

George R. Garrison #0857 wrote: With a CHT gage, you really don't need an oil temp gage. Later, George in Delaware

I am curious. Why wouldn't you? How does the CHT relate to the point where your oil temperature causes the oil to break down and lose it's lubrication capabilities or the viscosity is insufficient to support your crank bearings? I have an idea about healthy oil temperatures, but I have no idea how hot the cyclinder head can get before the oil temp gets out of hand. :? :?
What's even more important in daily operation is the low side of the oil temp. I have not had a vehicle that I operated on public roads, where the high side of oil temperature was a concern. However, I always wanted to keep an eye on my oil temp to make sure it had reached a proper level to put a load on the engine.

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Re: Oil Temp gauge

Post by George R. Garrison #0857 »

Cylinder head temperature will tell you quickly how hot the entire engine is. Range 200 to 400 degree's depending on the engine. Most 2 strokes will seize at about 400. If the CHT is keep in range, the oil will always be in a safe range unless high or low oil pressure is indicated. CHT will indicate a hot cylinder quicker than oil temp. You may have good oil temp on a CBX but high CHT instantly at full power or in an airplane in climb when there is insufficent airflow.

The oil pressure will be high if the oil temp/cht is low and pressure will be low if the temp is excessively high. Simple thick and thin theory.

Now, crank in EGT / Exhaust Gas Temp gage/probe in exhaust and now you can adjust the mixture to stay in a safe combustion temp range.

(I'm not sure how it would benefit a CBX and I may have opened my mouth connected fingers before putting my brain in gear). But, with an aircooled aircraft engine. If you have CHT on the hottest cylinder, you no longer need oil temp. If the cylinders hot, you will have sufficent oil temp. If you have a CHT probe on each cylinder and a selector to the gage, now you can monitor the temp of any of the cylinders individually.
But, the selector should always be returned to the hottest cylinder position.

The EGT is king for combustion temperature monitoring, you simply lean to a point where the EGT temp peaks and richen the mixture 50 deg's while in cruise and your at the most economical rate of fuel consumption and at a safe combustion temp that does not destroy the goodies in the combustion chamber.

We can even monitor the temp of the intake air on the CBX so we don''t get carb ice inside one of our six carbs.

So, maybe someone has used a CBX engine on an airplane and already done all this?

Yes, low oil temp also will leave moisture inside the crankcase, but with CHT in range, the oil will be hot enough to evaprate the moisture.

Later, George in Delaware
I'm into motorcycles, wooden boats, airplanes, wood working and car restoration.

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Re: Oil Temp gauge

Post by Don »

Conversely, on a CBX, the oil temp will tell you pretty quickly when the cylinder head is getting too warm . . . . since so much of the oil is up on top of the cylinder head trying to cool it ;)

I replaced the near useless voltmeter on my bike with an oil temp gauge - You would be surprised what you can learn from the gauge. On my bike, other than sitting near motionless in city traffic, the oil gets hottest running down the freeway at 75 or 80. Once you get the oil hot, it really takes a long time to cool it off . . . . even with the aftermarket 10 row cooler I have on the bike. The oil runs coolest at a steady speed of about 35 mph

Don

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Re: Oil Temp gauge

Post by ajs350 »

Don wrote:Mine was probably one of the ones you saw - I have the sender in one of the gallery plugs on the right side . . . . the sender wire runs up and joins the ignition wires where they exit the timing cover . . . . almost invisible

I don't think you can buy a gallery plug tapped for a sender, but it's pretty easy to do it yourself. Make sure you drill your hole in the exact center of the plug . . . . use a series of drill bits to enlarge the hole for the tap and take your time tapping the plug

Don't use any teflon tape or sealant on the threads. When finished, I filled in the inside of the completed plug with Marine-Tex epoxy to permanently seal everything - The sender can no longer be removed from the plug . . . . but it's never going to leak either ;)

PM me if you need a picture . . . . I never have any luck trying to post them here

Don
Here's what I did to relocate my temp sender from the drain plug to the oil gallery plug. Thanks go to Don for answering my questions and teaching me along the way.

Here you can see the original location as part of the oil drain plug. It looked terrible and seemed to be asking for trouble hanging down like that.

4396

Scribe lines across the Hex of your oil gallery plug. Center punch and drill out to 11/32 one drill size at a time. Then tap with an 1/8th inch pipe tap. What I did not know until Don explained it to me was that pipe taps make a bigger hole the more you tap them. Therefore make frequent checks on how far your sender will thread in until you get it all the way and then STOP tapping!

4397

Once I had the sender in I filled the cap with JB Weld.

4398

This is what it looks like installed.

4399

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Re: Oil Temp gauge

Post by NobleHops »

ajs350 wrote:
Don wrote:Mine was probably one of the ones you saw - I have the sender in one of the gallery plugs on the right side . . . . the sender wire runs up and joins the ignition wires where they exit the timing cover . . . . almost invisible

I don't think you can buy a gallery plug tapped for a sender, but it's pretty easy to do it yourself. Make sure you drill your hole in the exact center of the plug . . . . use a series of drill bits to enlarge the hole for the tap and take your time tapping the plug

Don't use any teflon tape or sealant on the threads. When finished, I filled in the inside of the completed plug with Marine-Tex epoxy to permanently seal everything - The sender can no longer be removed from the plug . . . . but it's never going to leak either ;)

PM me if you need a picture . . . . I never have any luck trying to post them here

Don
Here's what I did to relocate my temp sender from the drain plug to the oil gallery plug...
Outstanding write-up and photos Ross, thanks for posting that.

N.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

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