0-30 ohms gauge, 0-90 ohms sender, how do I make this work?

[Reyals Bemus]

Installing an '87 Blazer tbi tank which uses a 0-90 ohms sender, but would like to keep the factory gauge which operates on 0-30 ohms. Is there any way I can make these two work together? Is it possible to re-wind either the sender or gauge to match the other in ohms range?

[Rich 5150 69]

What year truck we talking about, `64 to `66 used the same style gauge except the `66 model year changed to 90 ohm gauge....!

[hotrodder]

I have done this switch a couple of times. I remove the sending unit that is attached to the pick-up tube on both units, spot weld the ohms that matches the factory guage to the blazer tube and you are ready to go. If you don't want to spot weld it J.B. Weld will work.

[Reyals Bemus]

My truck is a '64. I had heard GM made the switch to 0-90 ohms going into '66 like you suggest, but after doing some searching I also read guys saying that their '66s still had the 0-30 ohms gauge.

If there actually is a repro or good original '66 gauge that is 0-90 ohms, that would be awesome!

[Reyals Bemus]

That's a good idea hotrodder. So JB Weld will not dissolve in fuel?

[Snailed]

My '66 is 0-30ohm. Pretty sure they all are.

You could set the 0-90 sending unit up with a longer arm so it only uses the first half of it's range.

Or, you could leave the arm the same and put a stop on it so it only goes to 30. You wouldn't know how much fuel you had above a half a tank, but it would still be useful.

[Rich 5150 69]

I`m sure you can also purchase a 0-30 ohm universal sender from VDO, or classic to fit the burb tank.

[gulfcoast66]

Originally Posted by Rich 5150 69

What year truck we talking about, `64 to `66 used the same style gauge except the `66 model year changed to 90 ohm gauge....!

Not to thread jack but is the 66 90 ohm? Because I have a 72 suburban tank and I think its a 90 ohm I may be able to just wire it up... ????

[pdxhall]

I found this outfit online. I haven't tried them yet but I need to change a mustang fuel sender to a 66 chev gauge. I don't know how spendy they are but it's an option.

http://tristarrradiator.com/Custom%2...ed%20Page.html

[Captainfab]

This is what I would do.....

Originally Posted by hotrodder

I have done this switch a couple of times. I remove the sending unit that is attached to the pick-up tube on both units, spot weld the ohms that matches the factory guage to the blazer tube and you are ready to go. If you don't want to spot weld it J.B. Weld will work.

['63GENIII]

I did it with a '91 Blazer tank sender by taking the sender out, unwinding the resistor wire, measure and cut 2/3 of the wire off and carefully rewind as evenly as possible. I don't have it in the truck but did test it on the bench with a good '63 cluster and the range - accuracy seems to work well.

[Reyals Bemus]

Okay so I won't electrically damage the sender by tack welding it to the tube?

I also found out Classic Instruments makes a 0-30 ohms universal sending unit (part #SN36) that will fit in tanks anywhere from 6"-24" deep. (https://www.classicinstruments.com/p...oductCode=SN36) This blazer tank conveniently does have a circular pad toward the corner of the tank where I could install this unit. Wonder if its any good? This may be a more reliable solution?

Here's a view of the top of the Blazer tank. Notice the round spot in the corner.

[Captainfab]

Just be careful where you are grounding to.

Originally Posted by Reyals Bemus

Okay so I won't electrically damage the sender by tack welding it to the tube?

[jtrichard]

capfab you broke 13000 posts

[Snailed]

Originally Posted by Reyals Bemus

I also found out Classic Instruments makes a 0-30 ohms universal sending unit (part #SN36) that will fit in tanks anywhere from 6"-24" deep. (https://www.classicinstruments.com/p...oductCode=SN36) This blazer tank conveniently does have a circular pad toward the corner of the tank where I could install this unit. Wonder if its any good? This may be a more reliable solution?

The SN36 is what I put in the tank I built for my '66 and it works perfectly. The Classic sending units seem to be better quality than Autometer or VDO and much better than the reproduction sending units that come with cheap imported fuel tanks. I would say the classic one is on par with OEM quality.

[LostMy65]

I clicked on the link but didn't see a price.
Maybe because I'm on my smartphone.
Does someone know the price?

[Reyals Bemus]

Snailed, thats great to hear. I think I'll try fitting the SN36 sender to my tank.

LostMy65, the sender is $44 from Summit (http://www.summitracing.com/parts/cin-sn36/)

[Blue666]

Are you putting that tank under a long bed or a short bed? I have the same tank & would love to see your install. Thanks.

[luvbowties]

Originally Posted by Reyals Bemus

Snailed, thats great to hear. I think I'll try fitting the SN36 sender to my tank.

LostMy65, the sender is $44 from Summit (http://www.summitracing.com/parts/cin-sn36/)

Hey, Reyals Bemus, I have THOROUGHLY researched this topic and know for fact that our Chevy pickup senders thru 1966 all had 0-30-ohm-resistor senders. (Chevy cars changed earlier.)
Sam

[Reyals Bemus]

I just want to thank you all for the helpful responses and advice.

One question I have for you, Snailed. How does the SN36 sender mount to the tank? Based on the pic on their site, one would assume its by drilling five perimeter holes for those screws to thread into. But is the tank metal thick enough for those screws to grab securely? Or is there a piece to the sender I'm not seeing in the pic>

[Snailed]

It does come with a flange and gasket to mount it with screws. You can also use just the stud the arm hangs from if your material is heavy enough (I do that sometimes) but probably not on a thin steel tank.

You will probably want to make a ring out of steel or aluminum that has threaded holes to properly clamp the gasket and reinforce the tank. If you can't reach the new hole from the original sending unit opening you can make your backer ring in a C shape and wind it down into the tank. You will likely need to either use adhesive or welds to hold it in place until you install the sending unit.

I'm sure people have gotten away with just using sheetmetal screws but I have never tried it that way.

[hotrodder]

It seems you have decided not to do the sender switch, but to answer your question, as long as you " tack weld" the sender to the tube you would be fine JBWeld will not dissolve. I guess it's weather you are willing to go the extra expense or use what you have, I don't think I would drill hoes in the tank, the metal shavings have to go somewhere, probably down.

[Reyals Bemus]

I tell you what I'm going to do- buy the SN36 sender, see what it looks like, and possibly just take that unit and tack it in place of the Blazer unit instead of mounting the whole thing separately in the tank. I'd just like to be working with a new sender one way or another instead of messing around trying to re-use the 50 year old factory one.

So yea I think I've got it narrowed down to either:

1. Taking the sender itself off the SN36 and affix it to the Blazer fuel module.
2. Just installing the SN36 separately in the tank.

We'll see what's what when it gets here.

Blue666, I am installing this tank in place of the original tank in my '64 SWB panel truck. It looks like this tank will fit really well once I pop out one of the extra rear crossmembers. I will be sure to take pics along the way and report back.

[luvbowties]

Originally Posted by Reyals Bemus

Okay so I won't electrically damage the sender by tack welding it to the tube?

I also found out Classic Instruments makes a 0-30 ohms universal sending unit (part #SN36) that will fit in tanks anywhere from 6"-24" deep. (https://www.classicinstruments.com/p...oductCode=SN36) This blazer tank conveniently does have a circular pad toward the corner of the tank where I could install this unit. Wonder if its any good? This may be a more reliable solution?

Here's a view of the top of the Blazer tank. Notice the round spot in the corner.

Just a caution on installing any float-sender--be SURE to allow for baffles in any tank that might interfere with float-swing.
Sam

[Snailed]

[QUOTE=Reyals Bemus;6313754

1. Taking the sender itself off the SN36 and affix it to the Blazer fuel module.
2. Just installing the SN36 separately in the tank.

[/QUOTE]

It may be possible to just drill a hole (about 7/16" I think) in the mounting plate of the blazer unit and install the Classic unit with it's bracket too. Not sure if that's what you meant but it could be the simplest way. It was for me.

The middle stud on my fuel tank plate is the SN36 sending unit mount and signal terminal. I just drilled a hole and put it in.