'74 Argosy 20' Motorhome restoration/rebuild

[bkahler]

Originally Posted by Danec020

Doh! I was reading Elisa's thread about her propane tank and then switched to this one after and my brain didn't switch over. Sorry about that, I remember you've been hunting the right sending unit down and contemplating on what to do with the tank for a little while now. Ignore my scattered brain.

-Dane

My guess is you have other things on your mind at the moment

I ordered a new sending unit last night from Mill Supply. Once it comes in I plan on comparing the opening size of the new one with the tanks being sold on ebay. If they match I'll buy a tank from ebay instead of Mill Supply. Price difference is about $100. Be nice to save the money if I can

Brad

[martin300662]

Originally Posted by bkahler

My guess is you have other things on your mind at the moment

I ordered a new sending unit last night from Mill Supply. Once it comes in I plan on comparing the opening size of the new one with the tanks being sold on ebay. If they match I'll buy a tank from ebay instead of Mill Supply. Price difference is about $100. Be nice to save the money if I can

Brad

I think I maybe following the same route Brad. My tank has been at the specialist for nearly 4 weeks now, so I am expecting a call any day to say 'sorry, we couldn't revive it'.

[jm2]

the second owner of our coach replaced the factory tank with a single tank with a nominal capacity of 43 gallons. and, it doesn't hang below the body!

I've pumped as many as 42 gallons to fill it, so, it's about "as advertised".

i can try to take the dimensions and a picture on the weekend if that would be useful?

best,

[bkahler]

Originally Posted by martin300662

I think I maybe following the same route Brad. My tank has been at the specialist for nearly 4 weeks now, so I am expecting a call any day to say 'sorry, we couldn't revive it'.

That would be a bummer. The extra capacity of your tank would sure eliminate the hassle I'm going through trying to get my auxiliary rear tank resurrected.

[bkahler]

I've been refining my instrument cluster layout and I think I'm getting close to the point where I can place the order. The overall length is about 26" and the height is about 8"


For reference the original instrument cluster looks like this.


The current design layout has room for the following devices.

Round ball air vents (2 - upper corners)

Tachometer
Speedometer

Oil Pressure
Engine coolant temp
Engine oil temp
Transmission oil temp
Fuel level
LPG level
Voltage - chassis & coach (switch selectable)
Amperage - coach batteries
Air suspension
Engine vacuum

Headlight main beam indicator (blue)
Turn signal indicators (2 green)
Oil pressure warning (red)
Steps not retracted (red)

Onan generator Start/Stop switch (rectangular opening)

I still need to decide where to locate switches for fuel tank selection, DC voltage selection (chassis/coach) and LPG monitor switch (momentary toggle).

I'm thinking the previous three switches can be mounted on the aluminum dash that runs full length side to side below the instrument cluster.

Brad

[bkahler]

Originally Posted by jm2

the second owner of our coach replaced the factory tank with a single tank with a nominal capacity of 43 gallons. and, it doesn't hang below the body!

I've pumped as many as 42 gallons to fill it, so, it's about "as advertised".

i can try to take the dimensions and a picture on the weekend if that would be useful?

best,

Joseph, by all means post a picture and dimensions!

From my research I do know there were certain models of the P30 chassis after 1976 that had larger tanks but I haven't been able to find out much else about them.

Brad

[Isuzusweet]

How about an auxiliary switch for a set of fogs or driving lights? Don't forget the trunk light.....I thought someone was having me on when I read that on my dashboard, but no, there's a lamp in the spare tire????

Cheers
Tony

[bkahler]

Originally Posted by Isuzusweet

How about an auxiliary switch for a set of fogs or driving lights? Don't forget the trunk light.....I thought someone was having me on when I read that on my dashboard, but no, there's a lamp in the spare tire????

Cheers
Tony

Tony, thanks for the reminder! I do have a pair of Per Lux fog lights that came with the motorhome that I will be using.

That would be another switch that I would likely mount on the long aluminum dash section.

Have you tested your spare tire light? I can see that being handy when you're trying to change a flat in the middle of the night. BTDT!

[bkahler]

This is going to be a long winded post...

I received the sending unit from Mill Supply today and of course it was packaged very poorly and damaged in shipment



What appears to be some kind of a back flow preventer is broken off. You can blow air down through the white part but blowing the other way there is a check valve of some sort that prevents air flow. However the way it appears to have been mounted I don't see how any fuel could ever really be returned through it. The original sending unit does not have this device on it so I'm not convinced that it's needed.

Part of the dilemma that I've been having on what to do about a replacement tank and sender is no one sells the exact tank and sender for my year and model of P-30 which means I (and Martin!) have been doing tons of research to try and find something that will fit. I'm pretty sure I've narrowed the search for a suitable tank down to a Spectra GM29 tank. The caveat to this tank is while it's listed for 73-79 the description states it will not work with a 74-76 sending unit, you have to use the 77-79 sending unit. Unfortunately for the P-30 application Spectra does NOT list a sending unit as being available for any of the P-30 applications

If that's the case then where did Mill Supply come up with a sending unit for the 77-79 P-30 fuel tanks

I think I've solved that little problem. Mill supply uses their own part number for the sender which is 81-990 which is to be used with their tank number 81-914. The pictures for the 81-914 fuel tank looks identical to the pictures I've seen for the Spectra GM29 tank. But there was no way to verify that because of the different part numbers.

The sending unit that was supplied by Mill Supply had a manufacturers part number FG12Q stamped on it. A little googling came up with the fact that this is a Spectra number. What's even more interesting is this same sender that Mill Supply sells for $112 sells everywhere else for about $70 or less

The odd thing is this sender is not listed for a P-30. It's listed for pretty much every Chevy and GM pickup that was ever made in the 70s and 80s but not a P-30.

Comparing measurements between my old sender for the 11.25" deep tank and the FG12Q sender there is about 1" difference in pick up depth. The FG12Q is shorter and has float settings of 3" from top of tank being full and 9-3/4" from top of tank being empty. My original sender float moves almost to the bottom of the pick up tube and almost touches the top of the tank when full.

So what Mill Supply is doing is selling a sending unit designed for pickups with shallower tanks as suitable for a P-30 with a deeper tank. Using the FG12Q sender in the GM29 tank means due to the location of the pick up tube there will be almost 4 gallons of fuel in the tank that is unusable. I know you don't want to suck right at the bottom of the tank but 4 gallons to me is a lot considering the fuel tank only holds 30 gallons total!

I don't mind that the sending unit will read full for a long time before the reading starts dropping but I am a little concerned that it will say empty when there is 5-1/4 gallons in the tank (4 unusable!). Maybe that's ok too. I guess my biggest beef is the 4 gallons that are unusable.

Looking at the pickup tube it appears the top two bends could be straightened out slightly which would drop the pick up point down somewhat. That would lower the float slightly as well which is probably no big deal.


Assuming I decide to keep this sender (after talking with Mill Supply about the damage) I would likely remove the remains of that back flow preventer entirely. If the original tank didn't have something like that then I see no reason to keep it.

The good news is I can order the GM29 tank from ebay (cheapest I've found) instead of having to spend an extra $100 and buy Mill Supply's tank.

Decisions decisions

PS, I told you it would be long winded!

[Gregsch]

No need to apologize. I think I spend two hours in front of the pc for every hour I spend wrenching on the MoHo. I have come to the conclusion that's just the way it is when working on a 35 year old, hand built Moho, that is made entirely of off the shelf parts from other vehicles.

[bkahler]

Originally Posted by Gregsch

No need to apologize. I think I spend two hours in front of the pc for every hour I spend wrenching on the MoHo. I have come to the conclusion that's just the way it is when working on a 35 year old, hand built Moho, that is made entirely of off the shelf parts from other vehicles.

Sorta reminds me of the old Johnny Cash song "One piece at a time"

https://www.youtube.com/watch?v=sIuo0KIqD_E

[martin300662]

Brad, in my random internet searches whilst looking for info on tanks and senders, I did read that all 'modern' replacement senders had to be plumbed either for emissions (if original equipment) or fitted with a anti-tip (one-way) valve (and it was then up to the the installer to either do the right thing and vent via an emissions canister or simple connect a pipe higher than the filler to stop siphoning), could it be that?

Regardless it seems Mill Supply are trying to pull the wool over folks eyes!

[Keyair]

Its been a while since I stopped by here Brad.
Did you forget a gauge hole for the Trim and rudder gauges?
Seriously tho, I am working on my dash gauge panel and have decided to have all the driver oriented switches within reach of the driver and the coach switched more centralized. That way, you don't have to be IN the drivers seat to put the compartment lights on for example..

[bkahler]

Originally Posted by martin300662

Brad, in my random internet searches whilst looking for info on tanks and senders, I did read that all 'modern' replacement senders had to be plumbed either for emissions (if original equipment) or fitted with a anti-tip (one-way) valve (and it was then up to the the installer to either do the right thing and vent via an emissions canister or simple connect a pipe higher than the filler to stop siphoning), could it be that?

I think you've nailed it. Your suggestion jogged my memory about the anti rollover valve used in the Spitfire race fuel cell. Looking at the broken valve closer, when it's right side up air passes through and when tipped upside down air flow is blocked.

This got me to thinking, since this sender is for 70s and 80s Chevy pickup trucks I decided to see what kind of fuel pump they use.


Turns out the pickup truck fuel pumps don't utilize a return line from the pump to the the fuel tank like the P-30 fuel pump does. That means the smaller pipe on the FG12Q sending unit is not a return like I thought but a vent or anti-siphon valve as you suggested.

So if I use this sender I will definitely have to remove the remains of the anti siphon valve from the smaller pipe on the sender so I can use that pipe as the return from the pump.

Nothing is ever easy is it

Regardless it seems Mill Supply are trying to pull the wool over folks eyes!

I don't blame a company for trying to make a profit. But if everyone else is selling something for $70 and they are selling it for a $112, well that's a pretty good chunk of profit there.

Regardless since this sending unit is probably the best option out there I might as well see about using it with the mods that I've suggested.

Brad

[bkahler]

Originally Posted by Keyair

Its been a while since I stopped by here Brad.
Did you forget a gauge hole for the Trim and rudder gauges?

You don't know how much I wanted to figure out a way to incorporate those two gauges but in the end I just couldn't justify the space in the instrument cluster

Seriously tho, I am working on my dash gauge panel and have decided to have all the driver oriented switches within reach of the driver and the coach switched more centralized. That way, you don't have to be IN the drivers seat to put the compartment lights on for example..

Your 345 is a lot bigger than my little 20. I've been thinking about switch and gauge location and any sort of gauge(s) I use for the coach tell tales would take up space somewhere. The original monitor panel is rather large and takes up fair amount of space.


By putting the battery monitoring instruments in the instrument cluster frees up space elsewhere in the coach.

Also as Martin has done in his 20 the drivers and passenger seats are actually in use when the coach is parked so access to the gauges and switches shouldn't be much different than if they were located elsewhere.

At one time I even considered adding this water level gauge to my instrument cluster but in the end decided it wouldn't be worth the effort needed to design and build a module to convert the 5 discrete signals from the holding tanks to analog signals.


So in the end I opted to centralize as much as I could.

[martin300662]

Brad, you finding out Mill Supply FG12Q senders made me go and look again at the sender I bought to try and swap the level mechanism. It is a GM part original (GM#25093914 made by ACDelco) for a S10/Sonoma 20 gallon tank, but does have 0-90ohm range. It is setup for two options of pickup; an open pipe or a shorter pipe able to have a electric fuel pump (there are two separate tubes), but the longer tube has a support bracket to hold the fuel pump if using the shorter outlet....both are 11 3/4".



It is pre-wired for the electric pump. It has the typical large diameter return but also a anti-tip outlet for venting.

I am now starting to think that maybe this sender could be used as a direct replacement either without or even with an added electric fuel pump (they are $230ish from Rock Auto/Amazon/etc so not a cheap part - I only bought it (for less than $50) to satisfy my curiosity.

What do you think?

[bkahler]

Well I stand corrected on a couple of points on the Spectra FG12Q sending unit.

After a close comparison the pick up tube inside the strainer on the old sending unit is actually a little farther off the bottom of the tank than the new unit.

The strainer on the old unit is larger giving the impression that it reaches deeper into the tank. Closer inspection revealed the tube inside only sticks into the strainer about an inch. The tube in the new strainer actually sticks in a little farther. So in reality the new sending unit will actually suck a little more fuel out of the tank before it starts sucking air.

Also the float when showing empty actually reads empty a little sooner on the old unit than the new unit. It was the old sending unit from the rear auxiliary tank that had a float that went from the top to the bottom of the tank, my bad The new sender reads full sooner and empty a little later.


The only other minor problem with the new sending unit is the tube that I will be using as a return from pump is 5/16" diameter and the fuel pump return fitting is 1/4". Not a real big problem, just a minor annoyance

Brad

[martin300662]

Hey Brad, did you ever order the aluminum fridge vent panels mentioned on one of the threads? I ordered two from RV Parts Nation; they were backordered but have just arrived.

They are made from aluminum, but unlike the photo on the website they are painted.



They look OK quality and I will see if they can be fitted during 'bodywork' to replace the plastic ones Airstream NE used.

But maybe worth noting they are Dometic parts, designed to be used with the RM 2214 R fridge.

[bkahler]

Martin, shouldn't you be sleeping?!

Originally Posted by martin300662

Brad, you finding out Mill Supply FG12Q senders made me go and look again at the sender I bought to try and swap the level mechanism. It is a GM part original (GM#25093914 made by ACDelco) for a S10/Sonoma 20 gallon tank, but does have 0-90ohm range. It is setup for two options of pickup; an open pipe or a shorter pipe able to have a electric fuel pump (there are two separate tubes), but the longer tube has a support bracket to hold the fuel pump if using the shorter outlet....both are 11 3/4".

11-3/4" is to long but from the looks of the assembly it could be shortened relatively easily. The depth of the original tank is 11-1/4" from the sending unit opening.

Also, some sort of strainer would be needed at the end of the pickup tube.

It is pre-wired for the electric pump. It has the typical large diameter return but also a anti-tip outlet for venting.

I am now starting to think that maybe this sender could be used as a direct replacement either without or even with an added electric fuel pump (they are $230ish from Rock Auto/Amazon/etc so not a cheap part - I only bought it (for less than $50) to satisfy my curiosity.

What do you think?

I think it has definite possibilities. When you get a chance could you measure the diameter of the top where it fits in the tank?

Brad

[bkahler]

Originally Posted by martin300662

Hey Brad, did you ever order the aluminum fridge vent panels mentioned on one of the threads? I ordered two from RV Parts Nation; they were backordered but have just arrived.

They are made from aluminum, but unlike the photo on the website they are painted.



They look OK quality and I will see if they can be fitted during 'bodywork' to replace the plastic ones Airstream NE used.

But maybe worth noting they are Dometic parts, designed to be used with the RM 2214 R fridge.

Actually yes I did, I just forgot to post a picture of it! It seems to be of the same quality as the one that was on the 310 which when translated means somewhat cheap and flimsy but usable

Definitely better than using plastic when possible. It will be interesting trying to get paint to stick to them.

I only needed one vent as I will likely be placing the fridge in the same location it was originally so my existing roof vent is still usable.

Brad