Temp needle adjustment

[greg g]

Checked with search, but can't find the procedure or the don't tough that part you fool.  Scored a working temp gauge but its a bit on the optimistic side.  At 160 it reads 170 plus, at 170 its at 180 and at 180 it is showing 200+, at 190 its pegged. I thought I saw a post about a week ago,but before l break out the needle nose pliers, and screw it up, thought l had better check the collective wisdom.  With this and the fuel gauge sender, the dashboard will be completely operative with exception of the safety sentinel!

[Plymouthy Adams]

the repair manual states that gauges within 30 degrees of accuracy are subject to adjustment and that you procedure is to bend the link between the gauge mechanism and the bourdon tube.  I have adjusted other gauges in the past in this manner...takes a light tough, no gorilla gripping is allowed here.

[rallyace]

Or you can go the easy way and get an Equus temp gauge at AutoZone for $20.

[greg g]

2 hours ago, rallyace said:

Or you can go the easy way and get an Equus temp gauge at AutoZone for $20.

I have one of those already, l was going to try the Fitch method to repair the one in the car, but this one came up as a result of talking about the repair process at a cruise in.

[greg g]

2 hours ago, Plymouthy Adams said:

the repair manual states that gauges within 30 degrees of accuracy are subject to adjustment and that you procedure is to bend the link between the gauge mechanism and the bourdon tube.  I have adjusted other gauges in the past in this manner...takes a light tough, no gorilla gripping is allowed here.

No gorilla grip left, will it survive a left handed all thumbs assault?

[Plymouthy Adams]

only you can answer that question........I think with a little forethought and an approach that is not rushed and with respect to the engineers who have long passed...you will emerge successful

[busycoupe]

How did you find out that the gauge is reading low?  Did you measure engine temp? Where and how did you read the temp?

[Plymouthy Adams]

1 minute ago, busycoupe said:

How did you find out that the gauge is reading low?  Did you measure engine temp? Where and how did you read the temp?

this very testing procedure is also outline in the repair manual.....it entails pulling the sender out of the head and immerse in hot water sufficient to register on the gauge and compare to that of a known valid reading thermometer...

[busycoupe]

Thanks, I forgot that his gauge was out of the car.  I wonder if an infrared temp gun could be used on the engine.  Perhaps by measuring the head temp near where the gauge bulb is inserted.

 

[Plymouthy Adams]

the use of an infrared thermometer is again, an approximation as the skin effect of the head on the exterior will display different than the actual internal circulating water within the block as will the reflected reading itself.  By following the instruction of the repair manual, you are effecting the most accurate calibration possible with the existing parts which will be still quite reliable....even with that...you should check the reading at various temp setting for the best overall display as you could distort the link to display dead on at one temp but be a few degrees off at another reading...that is the trade off on self calibration

[PT81Jan]

13 hours ago, greg g said:

Checked with search, but can't find the procedure .....

Maybe that is what you are looking for ...?

http://p15-d24.com/topic/43975-temperature-behaviour-reading-cranbrook-218-engine/?page=2&tab=comments#comment-497295

Good success ! Jan

[Jerry Roberts]

I usually use tweezers to adjust the tiny arm .   

[Plymouthy Adams]

with a pair of tweezers you can lift an elephant and place him in a match box........just reverse the binoculars....it really does work in theory....looks good on paper....lol

Edited July 12, 2018 by Plymouthy Adams

[greg g]

On 7/11/2018 at 12:28 PM, busycoupe said:

Thanks, I forgot that his gauge was out of the car.  I wonder if an infrared temp gun could be used on the engine.  Perhaps by measuring the head temp near where the gauge bulb is inserted.

 

What Tim said.  The replacement gauge, tube and sensor were in hand, so the sauce pan method was used with a cooking thermometer.  I was looking at my manual last night.  It has language regarding adjustment but no illustration.  My manual covers p 15 to p 23.  It did however mention that exposing the sensor to temps above 250 will cause sensor failure, evidenced by a non working gauge who's pointer will not return to low temp rest position.which is what my present gauge presents.  So l guess my original engine got well and truly overheated.  Probably why it had a rebuilders tag riveted on.

[martybose]

The hard part of adjusting the temp gauge is the fact that you can't just adjust it for the high temp, you have to adjust it so it is accurate at all temps.  When I did mine the first attempt was dead on at 200, but 20 degrees off at the low end.  It took several hours, alternating between 200 and 100 degree water, before I was able to get it accurate at both temps.  Patience is your friend here.

 

Marty

[DJ194950]

2 hours ago, martybose said:

The hard part of adjusting the temp gauge is the fact that you can't just adjust it for the high temp, you have to adjust it so it is accurate at all temps.  When I did mine the first attempt was dead on at 200, but 20 degrees off at the low end.  It took several hours, alternating between 200 and 100 degree water, before I was able to get it accurate at both temps.  Patience is your friend here.

 

Marty

 

Marty that is true patience and determination!!  ?

 

DJ

[DrDoctor]

   The temp gauge on our car was broken, so I took a SW gauge, took the face plate off of it, and replaced it with the one from the original gauge. I bent the needle on the shaft of the SW gauge to set at zero when cold, and compared it to another reliable gauge in a pot of water on the stove. They were within 10^o of one another, and since it isn’t the Space Shuttle, I consider that close enough “for gov’t work” . . .  Thx.

[Jerry Roberts]

On 7/12/2018 at 10:17 AM, greg g said:

evidenced by a non working gauge who's pointer will not return to low temp rest position.which is what my present gauge presents.  

Greg , now that you mentioned this , it changes things .  The first thing that you should try is to move the needle back to the low temp position .   You do this by supporting the flat bar with the slot in it  with your finger and push-bend the needle back into position . This will also move the needle back from it's too high position .  I once found a needle that was loose on the shaft . The needle in the attached photo pulls right off with pliers , your needle may be attached differently . 

Edited July 14, 2018 by Jerry Roberts

[greg g]

Tweaked it today.  Didn't realize the whole flattened tube moved, interesting that the ether can exert enough pressure to coil/uncoil the flattened section of tubing.  Did the sauce pan test again the pointer is vertical just over 160 degrees, my engine runs pretty much all the time at 170.  So normal will present a vertical needle so a quick glance will assure its in the groove.  Pretty much within  five or six degrees from 150 to 190.  Now to get the gumption to do the upside down under the dash thing to get it swapped.