project 1951 Pontiac Chieftain

[Guest Hooli]

He plays by sense of smell

[Momentary Lapse Of Reason]

"Ain't got no distractions"

[PhilA]

This morning I decided to start on the fuel gauge.

 

 

Only one side of this is burned up.

 

 

However, argh! Smaller gauge wire. Thankfully it's the same as the wire I bought, 36AWG. Executive decision made to re-wind the fuel gauge for 6V, especially as the other bobbin doesn't undo and is still in good shape. Plus, it'll limit the current through the sender unit, which is made from fragile wire. The label on it gives big warning about hooking it up wrong else it'll be burned out.

 

 

Unwound it, counted 1055 turns. Cleaned the metal up.

 

 

Wind wind wind.

 

 

Much better!

 

 

Cleaned the paint out of the frame as it was kinda burned and flaky also.

 

 

New coat of Heirloom White, which looks a funny color because the light in that side of the garage quit working.

 

 

Fitted the coil back in and soldered it to the terminal lug.

 

 

Tested on 6V through the regulator with random resistance lamp hooked up to it. Works well!

 

Phil

[purplebargeken]

Frankly rather impressively amazing.

[Skizzer]

Had a bit of a go at the horn push.

 

That didn't fix it.

 

 

He plays by sense of smell

"Ain't got no distractions"

Can’t hear no buzzers or bells.

[loserone]

This thread is a constant source of awe

[PhilA]

Calibration! Spent a bit of time pfaffing with the coil positions to get things right.

 

30 ohms (full).

 

15 ohms (halfway mark)

 

0 ohms (empty)

 

And powered down on the stop.

 

 

Getting somewhere now! Next up, pull the wiring out and test the fuel sender. There should be a reading as the tank has a certain amount of fuel in it.

 

Phil

[N Dentressangle]

Beautiful work. Nice to see gauges which can be restored, given some ingenuity, skill and research.

[hairnet]

He plays by sense of smell

when the missus shouts dinner he runs for the kitchen

[PhilA]

 

Bon

 

 

Phil

[somewhatfoolish]

Calibration! Spent a bit of time pfaffing with the coil positions to get things right.

 

30 ohms (full).

Not exactly ideal for upping the voltage to 12v, that; half an amp is a lot for frilly little bits of wire, and presumably the current goes up with the fuel going down? Or is it a voltage divider?

[PhilA]

It's a voltage divider. So, I'm keeping that one standard to original (130mA) so it's calibrated for 6.0 volts, rather than the original 6.3 on the vehicle's regulator.

 

Should be a bit more accurate now.

 

Phil

[PhilA]

Well, as it turns out, it's now verging on impossible to get the original engine temperature sender unit.

That, and the original ones have a habit of being wildly unpredictable and unreliable.

 

On the scale:

130 ohms is cold

60 ohms is normal

5 ohms is OMGHGF

 

So, I went to AutoZone. I found a sender unit with the correct size and thread pitch. It's for a 1972 Chevy C10 pickup truck.

 

1500 ohms is cold

700 is normal

250 is OMGHGF

 

What I'm going to do is rewind the coils to match the (more modern and easily available) sender unit.

 

Phil

[PhilA]

Well, I spent until 11pm in the garage last night screwing about with the temperature gauge.

I unwound the "pull" coil by eye, got it to read for about 600 Ohms, unwound it a bit more and completely upset the balance. So I rewound it again and will need to work on that a bit more. What took the time was resetting the needle/core/return weight position as I caught it with my finger and upset it all so the needle wouldn't return and was also pointing at the wrong points for minimum and maximum scale.

 

I think I have a handle on that now. It's probably going to be quite a fine adjustment, looking at it.

 

Phil

[PhilA]

I'm trying. I don't know if I'll be able to make the gauge sensitive enough for this sender.

 

Thankfully there are others available that don't have quite as wide a range of resistance from hot to cold that physically fit.

 

Failing that I put it back as it was and gut one of these senders and put a thermistor in that with as similar a curve to the 50's original that I can get.

 

Phil

[PhilA]

I have a "nearly right" sender unit coming in on Tuesday.

 

However, on a side note I did find a picture of an original (bASe spec) interior, complete with the grab handle rope.

You can see the top part of the horn ring being broken is common... That and the hood latch pull.

 

 

That's what I need to duplicate. Apparently it was a chain inside a plastic tube with the cover sewn up over it.

 

Also this is the original green for the engine.

 

 

I think it will clash with the blue. Thoughts?

 

 

Phil

[tooSavvy]

Use 'Austin Green'.....

 

*I recall a colour like that on Deltic ??

[Noel Tidybeard]

chain in plastic sleeve- bike lock if long enuff?

[PhilA]

Maybe. It might just stay black. You can see the fuses though- one gray, the other painted some gaudy yellow. I put out feelers for a spare.

 

Phil

[PhilA]

chain in plastic sleeve- bike lock if long enuff?

Good call that man. Hadn't thought of that. A wire rope version may be better suited, because thinner.

[cort1977]

Pretty sure you can buy chain and sleeve by the foot at home despot or the blue one.

[PhilA]

I'll have a shufty next time I'm there- I didn't look at the mounting anchors yet to see how it's meant to be fixed in place.

 

Phil

[Asimo]

That engine-green looks much like the colour British military vehicle engines were painted.

[PhilA]

That and Onan generators.

[LightBulbFun]

That and Onan generators.

 

and invacars    (tho it looks a little green for that)

[N Dentressangle]

Looks like the Land Rover engine colour called 'Duck Egg Blue' as well, AKA Light Admiralty Grey:

 

https://www.ebay.co.uk/itm/500ml-Land-Rover-Light-Admiralty-Grey-Duck-Egg-Blue-Engine-Paint-High-Temp-/252067571663

[mat_the_cat]

I'm trying. I don't know if I'll be able to make the gauge sensitive enough for this sender.

 

If your nearly right unit isn't good enough, you could give in and buy something like this (assuming you have similar your side of the pond).

 

https://www.spiyda.com/fuel-gauge-wizard-mk3.html

 

I have one for the fuel gauge on the Stellar, which works well after I gave up trying to match it by adding series and parallel resistors!

[PhilA]

That's a handy device. I would probably be able to use something like that- I had tested before and managed to get the gauge to read 0-600 ohms but much past that and it wouldn't pull over smoothly and had a large amount of hysteresis, meaning the linearity was gone. It would lift up a little then snap over in the last 50 ohms or so.

Luckily it's not a very dynamic needle (unlike an oil pressure gauge or volt meter, say) so getting it balanced is the key.

 

It's a case of experimenting- I have a bit of wire left spare yet to try.

 

Phil

[DeeJay]

Just watching fast and loud.

A 54 Chevy belair has the same type of rope behind the front seats. 

 

 

 

[PhilA]

Almost- the fittings for the non bench seat are slightly different, that was brought in for the 1953 model year.

 

Phil