Bob Drake sender

[TJ]

I'm old enough to remember the repo junk we used to get from Argentina. The parts we get today are far superior to anything we used to get from there. I'm a very happy guy to get the quality of parts that are available to us. Are they perfect, not always, but they are one heck of a lot better than 35-40 years ago.
To those that complain, I highly recommend that you go out and start a business reproducing parts for these cars. See how much $ it takes to get started and how much government BS you have to put up with just to get a business license. Then deal with the legal system regarding employees, taxes, environmental laws, copy right laws etc. This is just the beginning before you actually start making and selling the parts. if you think you can do it better go for it and let us know how it worked out. It's a free market world and there is nothing keeping you from becoming the competition.

 

[41ford1]

I used a fuel sensor from another source. It does not look like Drakes. It only fits the stock tank flange and it is a resistive unit. If you are questioning if a unit works with your stock gauge hook it up electrically and try it before installing it on the tank. Compare the swing to the one taken out. They need to match. The arm may need bending to make the travel match. The unit I got the resistance values are 10ohms Full and 83ohms Empty. This unit works with my stock gauge. We're dealing with 60 to 80 year old equipment so some checks and tweaks are warrented when adding new components.

 

[Flat Ernie]

I've posted on this many times. I won't rehash all of it, you can do a search if you like. These sending units can be made to work pretty well. Is it drop in and go? Nope. Should it be? Probably. Will it work? Most likely.

YMMV

 

[47COE]

I've used that same part number from Bob Drake in 3 different Fords.

When the tank is full, the gauge reads way over full. It reads over full or around full for a very long time. Then it drops like a stone towards empty. It is usable once you learn that when the gauge gets below half you had better head for the nearest gas station.

I've done some experimenting with the sender resistance curve and the gauge readings for various resistances. I think it will be possible to improve it but don't have the final answer yet.

Tom

 

[rotorwrench]

The first time I ever took a good look at the King Seeley fuel quantity sender I was amazed at how simple but ingenious the unit was. I have worked around resistive type units for years and they are actually more complex but not near as sturdy. The Resistive units have a brush that wipes the wire wound resistor on a flat piece of micarta. The act of wiping the resistor guarantees that the unit will eventually wear out just by friction alone plus the whole thing is bathed in fuel when the tank is topped off. The KS unit has a diaphragm that separates the float movement from the internal movement against the heater strip and preserves it with no fuel contact. The movement is very small since the float only pushes slightly against the diaphragm in a cam shaft action. In turn the diaphram just barely pushes against the heater's bi-metalic strip. You can tell that the tiny little contact points will eventually get worn out but there is no frictional wear to speak of. The unit has a small wire wound resistor in it to trim the unit for calibration. If you pop the cap off the top you can clean the little points and even adjust calibration if you are persistant enough to go so far as that.

No one in the resto part business has yet gotten brave enough to try to make a replacement for these marvalous little units. I've seen several repo part vendors carry indicator units (gauges) for the 60s muscle cars but no one has vetured into much for replacement gauges for the old Fords. I've never purchased one of these repro units to find out if they actually work or not but it would be interesting to know what the quality is. The Fords had different color and shape indicator faces that would have to be silk screened to match the originals. The basic works of the gauges are the same or similar enough the they could be used for most applications with just a change of the face plates. At least one made to work with the resistive unit would be welcomed if it works. Most die hard restorers will have original components rebuilt or find NOS parts rather than settle for the repro parts. The OEM stuff lasts a long time if properly cared for.

 

[Flat Ernie]

The first time I ever took a good look at the King Seeley fuel quantity sender I was amazed at how simple but ingenious the unit was.

Agreed. It is unique.

I have worked around resistive type units for years and they are actually more complex but not near as sturdy.

I respectfully disagree. When taken as a system, you have many more components that must work in concert. The KS sending unit (for every gauge except the 40 BATT gauge) works in a similar way - the oil pressure presses a diaphragm that bends the bi-metallic strip - the water temp heats the bi-metallic strip. All of them go into a gauge that has its own bi-metallic strip and heating coil and operates the gauge needle through a gear train. This is actually far more complex than a sliding resistive sending unit and an 'ammeter' - because all your resistive gauges are really just ammeters calibrated to read whatever unit you're measuring based on the sending unit. Even voltmeters are ammeters. They're just not ammeters like total-system ammeters everyone is irrationally afraid of.

The Resistive units have a brush that wipes the wire wound resistor on a flat piece of micarta. The act of wiping the resistor guarantees that the unit will eventually wear out just by friction alone

Your statement is accurate. However, I would venture to guess that the life expectancy of a resistive unit is pretty good. Is the KS better? Hard to say for sure. The real question would be if the KS system is superior, why didn't all the mfgrs go to it and why isn't it still being used? My guess is cost, primarily.

plus the whole thing is bathed in fuel when the tank is topped off.The KS unit has a diaphragm that separates the float movement from the internal movement against the heater strip and preserves it with no fuel contact.

To my knowledge, there has never been a gas tank explosion caused by a resistive type sending unit. I don't claim to know about every gas tank explosion, but if there were a risk, I promise you that in today's litigious society, we wouldn't have these in all our cars. The KS system, on the other hand, would be far more dangerous if it were exposed to gasoline vapors as the resistive unit is because by making/breaking the contact, you're virtually guaranteeing a spark.

No one in the resto part business has yet gotten brave enough to try to make a replacement for these marvalous little units. ... The Fords had different color and shape indicator faces that would have to be silk screened to match the originals. The basic works of the gauges are the same or similar enough the they could be used for most applications with just a change of the face plates. At least one made to work with the resistive unit would be welcomed if it works. Most die hard restorers will have original components rebuilt or find NOS parts rather than settle for the repro parts. The OEM stuff lasts a long time if properly cared for.

Agreed. I think it comes down to market and pricing more than anything. I think you're right - the same gauge mechanism could probably be used for most/all with a face change, and certainly the sending units are largely the same as well. Same is true for the other gauges (oil press & temp).

Stock gauges can be made to work with the repro gas sending units. I've done it several times and helped a couple others do theirs. I would like to see a better matched sending unit - I think the one they're all using is something that was originally intended for a different application that is 'close enough' to preclude any expenditure on R&D and tooling for something new in an effort to keep the price point down...but that's just a guess on my part.

 

[L78CHEVELLE]

I have purchased three gas tank sending units from Bob Drake for some of the 1940 Fords I own. One runs out of gas at half tank. I took it out three times and adjusted it with no improvement. I just stop and fill up the tank at three quarters full. Second one leaks around the sending unit when I fill the tank up into the filler neck. Took it out twice with no improvement. Put the original non working unit back in the tank and no leaks, but gauge doesn't work. Bob's leaking sending unit runs out of gas at half tank. Third one works well with no problems. I would take the working one out and switch it to the other cars with problems, but I'm afraid if I try to put it back the way it is then the working one will start having problems. That is 33% satisfaction. Can a company continue to sell a product with a 33% satisfaction rate? Only if they tell the new customers they have not had any complaints. Before I go, I have tried the sending back for a refund stuff which works, but the expense for return shipping and the time lost is not worth it. I chose to have a some what working gauge that will allow me to drive the cars NOW. I still do buy parts from Bob, and the majority of his hard parts like rubber seals and so on work well enough.

 

[Henryat1140]

In Re: new fuel sender. I'm 99% sure this is the same one sold by Carpenter.

I bought one and made a bench test setup with a full charged 6V battery and a NOS out-of-the-box fuel gauge. Manipulating the arm manually, the gauge could not be made to read below 1/4 or above 3/4.

I made this test several times, and put a digital ohmmeter on the unit. I don't remember the exact ohm readings, but the lower (upper reading on tank) was about 19 ohms, and the upper (low fuel) was about 89 ohms.

I called Carpenter and after getting transferred a few times, got to talk to their electronics person. He said with those ohm readings the gauge should read accurately. He had no explanation of why the thing didn't work.

I should have sent it back, but it had a new solid poly float on it, and the problem w/ our tank was a leaky float, so we used the float from the new unit.

So before you get your hopes up about the "new, improved version 2" sender you might want to make a bench test and see if you get any better results.

I don't know why they couldn't put a trimmer pot on the ends so you could make a precise adjustment. <sigh>

 

[Lawson Cox]

am not a big Drake fan, for many reasons. However, that said, I am using one of his sending units, with originall gauges in my 35 PU with his reproduction tank with no complaints after tweeking it several times by bending the float arm.



I have the same set up and ran out of gas last year with over a 1/4 tank indicated. It has never worked right but better than nothing...

BTW- I have `36 gauges.

So do I.

 

[Flat Ernie]

I have purchased three gas tank sending units from Bob Drake for some of the 1940 Fords I own. One runs out of gas at half tank. I took it out three times and adjusted it with no improvement.

Sounds like your float arm isn't moving through the full range of motion. Shorten it, or bend it up, or both.

Second one leaks around the sending unit when I fill the tank up into the filler neck. Took it out twice with no improvement. Put the original non working unit back in the tank and no leaks, but gauge doesn't work. Bob's leaking sending unit runs out of gas at half tank.

Send it back if it leaks.

Third one works well with no problems.

This should satisfy you that the design of the mechanism is sound. I think your experience speaks to quality control.

Before I go, I have tried the sending back for a refund stuff which works, but the expense for return shipping and the time lost is not worth it. I chose to have a some what working gauge that will allow me to drive the cars NOW.

Sounds like you've got more than one car. Why not send the bad one back for replacement one at a time. I realize this is extra return shipping, but...

In Re: new fuel sender. I'm 99% sure this is the same one sold by Carpenter.

Could be - couldn't tell you.

I bought one and made a bench test setup with a full charged 6V battery and a NOS out-of-the-box fuel gauge. Manipulating the arm manually, the gauge could not be made to read below 1/4 or above 3/4.

I made this test several times, and put a digital ohmmeter on the unit. I don't remember the exact ohm readings, but the lower (upper reading on tank) was about 19 ohms, and the upper (low fuel) was about 89 ohms.

I called Carpenter and after getting transferred a few times, got to talk to their electronics person. He said with those ohm readings the gauge should read accurately. He had no explanation of why the thing didn't work.

I should have sent it back, but it had a new solid poly float on it, and the problem w/ our tank was a leaky float, so we used the float from the new unit.

So before you get your hopes up about the "new, improved version 2" sender you might want to make a bench test and see if you get any better results.

I don't know why they couldn't put a trimmer pot on the ends so you could make a precise adjustment. <sigh>

Was your test with a Carpenter unit or a Drake unit? If Carpenter, then I'm not certain it's a valid comparison.

I pulled an old repro one out of my '40. It was working OK, but was old and when I took it out to clean the tank of old sealant, it fell apart. Quality. I have no clue whose unit it was, but it was not an original KS.

I purchased a Drake sending unit along with a new tank. I adjusted the arm so that when it was at the bottom limit of movement (empty), the float was about 1/2" off the bottom of the tank. I then accepted whatever reading I got when the tank was full. It was pretty close if I recall - 7/8 tank or so, but I do recall it not being quite full. I think if I had wanted to play with it a bit more, I could have altered the length and angle so that I got full range of motion on the sending unit and been relatively accurate.

I chose to have the empty side of my gauge be a little more accurate than the full side...

As mentioned, I've converted a couple of cars - in the interest of full disclosure, all of mine have been converted to 12V, as have the few folks I've assisted. All the gauges are reduced using a true electronic L7806 CVR so the gauges see a steady and constant 6V. Dropping resistors will vary your voltage as will the later model Ford OEM choppers used up through the '90s. They vary voltage for two reasons, but the primary reason is that your generator/alternator varies the output voltage. Also, an original 6V car will have varying voltage due to varying generator output. The variable resistance sending units will send different voltages to the gauge if the input voltage varies - the original KS senders dampened this effect tremendously due to their design and provided a more stable gauge reading. That's why I only use true electronic CVRs when doing a 12V conversion - it's more important with the repro gas sending units, but helps for more stable readings across the board on the gauges.

 

[rotorwrench]

The best of the resistive types I've worked on were Rochester types made for aircraft. They are designed to be assembled but not easily disassembled. However, they are easier than most I've come across. Most go bad due to wear on the fine wire of the resistor. Usually the brush is worn out too. Modern fuels don't help with longevity. The parts oxidize too much after a relatively short period. I've repaired a few but most go in the trash. My old 51 Mercury King Seeley fuel quantity system still works just fine. I've cleaned some pretty nasty stuff out of the tank on it before but the fuel sender is still like new under the cap.

On a conversion a person has to find a resistive type gauge with a normal D'arsenval meter movement then find a sender that works in the same Ohmic resistive value as the gauge was designed for. I've had to do this on aircraft where the original parts are no longer available. The tricky part is getting a sender with a float that can be adapted to the tank. Yogi's sells some that can be adapted for different depth tanks and in various Ohmic values for the classic & hot rod cars. There are probably others out there as well.

The King Seeley current based system if used with a resistive type sender, would require an Ohm range that is way off for the ones that are available out there. The range is too great for the average resistive type senders.

 

[Henryat1140]

>>Carpenter and Drake fuel senders the same?

I cannot say for a certainty, but the pictures look identical.

Correct me if I'm wrong, but if the gauge doesn't read full or empty at the extremes of travel, then no amount of bending or manipulation of the arm will correct that.

IMO this is just one of those projects that someone, Drake? Carpenter? has made a couple of attempts to produce a workable product, but the market isn't there to support a real development and testing process.

 

[19Fordy]

Ernie, I always enjoy and appreciate your well thought out explanations. Thanks.

 

[Flat Ernie]

The King Seeley current based system if used with a resistive type sender, would require an Ohm range that is way off for the ones that are available out there. The range is too great for the average resistive type senders.

Actually, the repro resistive sending units can be made to work reasonably well with the original KS gauges.

>>
Correct me if I'm wrong, but if the gauge doesn't read full or empty at the extremes of travel, then no amount of bending or manipulation of the arm will correct that.

As with many things, it depends. It's not quite as black and white because there are two adjustments. Bending is only one, length of the arm is the other. You need to adjust the length so the arc it scribes from empty to full is the same as the depth of the tank. Then you need to bend it so it rests on neither the bottom or the top. This requires a fair bit of trial and error.

IMO this is just one of those projects that someone, Drake? Carpenter? has made a couple of attempts to produce a workable product, but the market isn't there to support a real development and testing process.

I think the market is not there for a KS repro. I think the market is only there for a relatively inexpensive replacement that doesn't require R&D to sort out. Hence my comments about them just finding one that would work with a little fiddling.

Ernie, I always enjoy and appreciate your well thought out explanations. Thanks.

You're welcome. I always feel like I can't quite explain it well enough via written word though. There's also the inertia of internet rumor to overcome.