MGB fuel tank in HB

This is an area for discussion about modifications to Vivas.

MGB fuel tank in HB

Postby caribougone » Sun Mar 21, 2021 7:24 am

After sitting for decades, the top half of my fuel tank was rusted like swiss cheese. I'm not likely to find another nearby (west coast of Canada) and I doubt used tanks can be shipped so I must look at alternatives. I do have a used MGB tank. (from one of those times I needed a part for my BGT and ended up taking the whole wreck) Has anyone put one of these in their Viva before?

Held roughly in position, it looks quite doable. It would bolt up under the floor with almost 6 inches on the exhaust side between the tank and the frame member. The gauge and fuel outlet are on this side so I think I'd bend the exhaust pipe away a little until it's roughly under the member to give myself more peace of mind. It's somewhat larger than the original tank (12 gallons vs 8) but not so big as to interfere with the flexible brake line. The fuel goes in on the wrong side though so I'd have to cut a hole in the floor for it and move the filler neck over to the right of the licence plate. (or have a long filler pipe run across inside the trunk from left to right)
User avatar
caribougone
SL Viva
SL Viva
 
Posts: 34
Joined: Tue Nov 03, 2020 4:04 am
Location: British Columbia, Canada

Re: MGB fuel tank in HB

Postby brading » Sun Mar 21, 2021 3:45 pm

Do not know about putting an MG tank in a Viva but am pretty sure you will have trouble with the MG fuel sender unit and your fuel guage.
Do not know the range of the HB, the HA is 0 ohms empty and 30 ohms Full, the HC is 17 ohms empty and 260 ohms full. Did find out a 73 MG Midget it is 240 ohms empty and 30 ohms full. So you more than likely will have to modify to get the original sender to fit the MG tank.
There is a Module you can get from the USA that reverses the ohms and allows you to set the ohms, which allows you to use senders and gauges from different maker.
First thing I would do is to check the original and the MG senders ohms rating with a meter.
If I can be of any more help let me know.
brading
De Luxe Viva
De Luxe Viva
 
Posts: 18
Joined: Fri Mar 05, 2021 11:09 am
Location: Kings Lynn UK

Re: MGB fuel tank in HB

Postby rizzo » Sun Mar 21, 2021 5:56 pm

There is an option to get it repaired, well over here there is https://radiator-repair.co.uk/classic-a ... fuel-tank/ if this sort of process is available on your side of the pond it might just be an easier solution.
HB 1159 1968 10K White
HB 4000 1968 Green
User avatar
rizzo
Brabham Viva
Brabham Viva
 
Posts: 909
Joined: Sun Nov 09, 2008 10:43 pm
Location: North Yorks

Re: MGB fuel tank in HB

Postby droopsnoot » Sun Mar 21, 2021 6:46 pm

I've thought about using an MGB tank in an OHC HC, but never done anything about it. The fuel outlet would need some work because it's just where the OHC exhaust tailpipe goes, but my thinking was that a new tank could be easily and safely modified, and not incredibly expensive compared to having a custom tank made.
droopsnoot
Old Nail
Old Nail
 
Posts: 2121
Joined: Mon Oct 31, 2005 2:08 pm
Location: Cheshire

Re: MGB fuel tank in HB

Postby caribougone » Sun Mar 21, 2021 8:34 pm

The old tank was really beyond repair. Some holes in the top were large enough for me to reach inside it. The top two inches of the sides were also ridden with smaller holes. The bottom half (where the 1982 gasoline was) wasn't too bad except for a quarter inch of sludge on the bottom, plugging the outlet pipe.

The fuel sender/gauge incompatibility is an issue, thanks for pointing that out. The original sender had dissolved too much to be of any use (just a plate with a blob, and the float found in the debris at the bottom of the tank) but earthing the sender wire via a selection of resistors I was able to confirm the gauge is the 0-30 Ω type. The MGB one has a range like the Midget. The sender mounts on the side so I could put it in upside down and rebend the float arm to make it read from low ohms (E) to high (F) but the range would still be way off. Those gauge converter modules are a neat solution.
User avatar
caribougone
SL Viva
SL Viva
 
Posts: 34
Joined: Tue Nov 03, 2020 4:04 am
Location: British Columbia, Canada

Re: MGB fuel tank in HB

Postby brading » Mon Mar 22, 2021 12:03 am

Up to the mid 60's GM used a 0 -30 ohms sender which you should be able to find over there.
brading
De Luxe Viva
De Luxe Viva
 
Posts: 18
Joined: Fri Mar 05, 2021 11:09 am
Location: Kings Lynn UK

Re: MGB fuel tank in HB

Postby brading » Mon Mar 22, 2021 12:07 am

Click on products, then click on Accessories for modules.

https://www.tanksinc.com/
brading
De Luxe Viva
De Luxe Viva
 
Posts: 18
Joined: Fri Mar 05, 2021 11:09 am
Location: Kings Lynn UK

Re: MGB fuel tank in HB

Postby caribougone » Mon Mar 22, 2021 5:43 am

I've been browsing pictures of pre-1965 GM fuel senders and it would take a little work to fit one. The seal is very important as it's on the side of the tank and it could get tricky as the old GM ones have 5 mounting holes on the plate and the MG tank isn't made for that. They're also not a great deal cheaper than a converter module, so I'm leaning towards the module. There are a few different ones to choose from. The main thing now is to fit a fuel tank so I can legally drive the car. A working gauge can come a little later.
User avatar
caribougone
SL Viva
SL Viva
 
Posts: 34
Joined: Tue Nov 03, 2020 4:04 am
Location: British Columbia, Canada

Re: MGB fuel tank in HB

Postby caribougone » Wed May 19, 2021 4:53 am

Well I went ahead and did it, so I thought I'd better share!

I cut off the old big fuel pipe from the MGB gas tank and filled in the hole, as well as the small hole near it. (1970's MGBs here had a return fuel line to send fuel vapours to the engine bay) I then cut a new hole as close to the corner as I could and welded in some exhaust pipe of the same diameter as the original HB filler pipe, trying to get the angle about right. I cut the filler pipe off the rusted out HB tank and have a short bit of rubber hose between it and the new tank's pipe. I also cut a circle of metal to fill the hole where the MGB sender was on the side using a new rubber seal. I would have just left the old sender in but I threw it out a year ago as it didn't work. Silly me, should never throw anything away...

Rather than buying a new MGB fuel sender and a converter, I found this Chinese one on eBay that will work directly with the original gauge. (0-30Ω) https://www.ebay.ca/itm/193843366021?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2648&autorefresh=true

It's a 6.5" vertical shaft with a ring that floats up and down along it so no long arm in the tank, which is nice because 1970's MGB tanks have a surprising amount of things to avoid inside. (picture of cut open tank is from MG Experience forum) With this knowledge of the innards, I drilled holes to mount it between the baffle and the huge round thing the vent line went to. It just touches the bottom of the tank, a perfect fit!


The tank fits nicely, bolted up between the frame members, needed spacers on the bolts holding it up as the flange isn't flush with the floor. I also cut a metal plate for the floor of the trunk over the tank.

The tank's has a screw on fitting for the fuel line. (on the side above the old sender) I reused the MGB line and bent it so it goes neatly around the tank to near where the existing fuel line to the engine bay is. In fact, I put an electric fuel pump there as my mechanical one doesn't work. The fuel sender is earthed along with the fuel pump using one of the bolts I mounted the pump with.

The only modifications to the body were the holes I drilled for the mounting bolts, so if I ever happen upon a good Viva/Epic fuel tank, I could easily remove the MGB tank and drop the original style one in.
User avatar
caribougone
SL Viva
SL Viva
 
Posts: 34
Joined: Tue Nov 03, 2020 4:04 am
Location: British Columbia, Canada

Re: MGB fuel tank in HB

Postby droopsnoot » Wed May 19, 2021 9:12 am

Interesting to see that it works, my current restoration doesn't have a fuel tank and as it needs the one that's difficult to find even here, the MGB tank might be something I need to look into more. Thanks for the detailed write-up.
droopsnoot
Old Nail
Old Nail
 
Posts: 2121
Joined: Mon Oct 31, 2005 2:08 pm
Location: Cheshire

Next

Return to Modifications

Who is online

Users browsing this forum: No registered users and 5 guests