MGB question for the braintrust

[Nickshu]

Dad is looking at a 1965 one owner MGB. Owner is too elderly to keep it so son, who is not mechanically inclined, is selling it. Car has not been driven in quite a few years but owner's son had a friend help him and they did get it to start and drive a short distance a couple weeks ago but the battery is dead and starter is questionable.

My understanding is this car has a 6 volt positive earth electrical system with dual 6 volt batteries. I can winch it on and off my trailer, but will need to get it running enough to get it off my trailer and onto my lift to do an underbody inspection before he decides to buy.

Soooo, can I just use a regular 12v car battery to get it started? Neither of us have any experience with 6v or positive earth systems.

The car is located 90 minutes drive each way away from us in a storage so don't want to drive down to have a look ahead of time.

Thanks in advance.

[LWJ]

Yes.

Commonly converted to 12v batteries. Occasionally reversed polarity. Check before putting the battery in. If the dufass goofed with it, who knows what they did. My car came with a 6v regulator!

Super simple cars. I had a 65 with old style pull handles. It was really gratifying. Parts are easy to come by. Not expensive. Simple to work on. I rebuilt my first engine, trans and rear end on that car.

Picture? Deferred maintenance needs to be addressed. Can have rust on the floorboards. Try not to deviate from most stock parts as they actually work well.

Have fun! Great cars.

[Nickshu]

Originally Posted by LWJ

Yes.

Commonly converted to 12v batteries. Occasionally reversed polarity. Check before putting the battery in. If the dufass goofed with it, who knows what they did. My car came with a 6v regulator!

Super simple cars. I had a 65 with old style pull handles. It was really gratifying. Parts are easy to come by. Not expensive. Simple to work on. I rebuilt my first engine, trans and rear end on that car.

Picture? Deferred maintenance needs to be addressed. Can have rust on the floorboards. Try not to deviate from most stock parts as they actually work well.

Have fun! Great cars.

Here's a couple photos of the car provided by the seller. Dad restored a '72 TR6 a few years ago so no stranger to the British cars.

Sent from my Galaxy S20+ using Tapatalk

[911boost]

Hard top, nice!

[harvardma]

Up to 67 they were positive ground. Two 6 volt batteries in series to get 12 volts. Many cars have been converted to negative ground as well as a single 12 volt battery. You need to just see how it is actually wired.

[LWJ]

Lovely. Looks to be a similar transition car as mine. I believe those are old style pull handles. Not quite certain due to picture resolution.

A beaut!

Safety Fast!

[smadsen]

MG's, Healey's, Triumph's, most British cars of that era (post early 1950's) were 12 volt cars, although most were positive ground. Batteries were big and heavy. Manufacturers tried to mount two 6 volt batteries, usually behind the front seat, near the rear axle, to use the batteries to better balance the car. My experience with big Healey's was the later cars went to one 12 volt in the trunk, like any modern car, but still positive ground. If you re-wire with one 12 volt, even if just to drive it around the neighborhood, DO NOT REVERSE THE POLARITY. You can do serious damage to several components, generator, some wiring, starter, dash components, etc.

[Aerkuld]

The older MGB's are, I thought, positive earth, 12v electrics. They are 6v batteries, but they sit in separate compartments on either side of the transmission tunnel, under the back 'seat'. The two 6v batteries are connected in series to give 12v, NOT parallel to give 6v.
A12v battery should be fine to jump it, but you'll want to go to one of the terminals on each of the two batteries. It should be easy to tell which battery terminal connects to ground, which connects to the electrical system on the other battery, and which is the connection between the two batteries.
As others have said, make sure it hasn't been converted to negative earth. It was quite commonly done and, from what I recall, not too difficult.

[Rinty]

I converted a '73 B to a single twelve volt, and the starter would turn the engine over much more quickly than with the stock set up.

IIRC, you could get compact single twelve volt batteries that would fit in one of the 6 volt cavities behind the seats.

[Nickshu]

Thanks guys that helps a lot! We will trace to ground at the batteries to see if it's been converted to negative and if it has 2 batteries will put the jumpers across both in the correct orientation.

[Zeke]

Get it no questions asked. That is unless it's been driven in salt. Looks like that is a possibility. So, go over the body from the outside and inside where you can access. If it passes the test I wouldn't worry about needing a lift before buying it. You can see the essentials lying on a blanket with a flashlight. Just be SURE to look at the body, in the boot, in the engine bay, bottoms of doors, quarter panel seams, all of it. There is a lot more to see from above than below.

[beatnavy]

From the looks of it that's a solid car, and the hardtop is a bonus. MGB was my first restoration project (mini restoration), but yeah, they are pretty simple overall, and while there are rust issues, I don't recall NEARLY as many on mine as on an early Porsche.

Door skins near the handle are one area really prone to rusting (and then splitting).

[wdfifteen]

Looks like fun! The wire wheels don't appear to be rusty, that's a big plus, and indicates that the rest might not be rusty either.

[Nickshu]

Originally Posted by Zeke

Get it no questions asked. That is unless it's been driven in salt. Looks like that is a possibility. So, go over the body from the outside and inside where you can access. If it passes the test I wouldn't worry about needing a lift before buying it. You can see the essentials lying on a blanket with a flashlight. Just be SURE to look at the body, in the boot, in the engine bay, bottoms of doors, quarter panel seams, all of it. There is a lot more to see from above than below.

Originally Posted by beatnavy

From the looks of it that's a solid car, and the hardtop is a bonus. MGB was my first restoration project (mini restoration), but yeah, they are pretty simple overall, and while there are rust issues, I don't recall NEARLY as many on mine as on an early Porsche.

Door skins near the handle are one area really prone to rusting (and then splitting).

Originally Posted by wdfifteen

Looks like fun! The wire wheels don't appear to be rusty, that's a big plus, and indicates that the rest might not be rusty either.

Thanks guys. The story is it's been a one owner always garaged car since new and has lived in South Dakota and Colorado for all of it's life. They report some rust on the floor pans and that is all. Being a British car however Dad wanted to inspect it before deciding to buy it. Seller's son is a friend of a friend and he is allowing us to pickup the car, haul it up to my house so I can put it on my lift, and do our own PPI.

[Rot 911]

Having owned several MGBs in my life I can tell you that one of the most common places rust materializes on MGBs is down in the rocker panels—also known as the sills. Low on the car and always in the elements, these sections of the body are quick to fill with dirt and moisture, a lethal combination for steel. Rusty sills are not only ugly, but since they’re often also structural problems, they can quickly lead to sagging doors and a flexing body.

As bad as all this sounds, the repairs are pretty straightforward. parts are readily available and fairly inexpensive.

[harvardma]

There is a vertical panel behind the front wheels with a rubber seal to the fender. Stuff gets past that seal and packs into the area, holds moisture, and rots out this area. Take a close look there.

[aigel]

Need to make sure you see what's been done to the car. 80% chance it has been converted to a 12V battery and neg. ground!

Ah - fond memories. I had a 67 BRG.

I bought this 12V neg. ground converted car for a song. Owner thought it had a cooling system / engine problem because after warming up it would stop running. It had sat for a couple years and he moved and couldn't deal with it anymore.

Turns out the car had an ignition coil hooked up wrong - assuming it was still pos. ground. So after a few minutes the coil would overheat and the car would stop running.

I had a mechanic buddy at the time. He spotted that after a couple rounds of re-creating the symptoms.

So, in summary, the other guys are correct with their assessment, my input is to be checking carefully what's been done and making sure everything matches the conversion or lack thereof.

G

[Bill Douglas]

No technical contribution to the thread, but it sure LOOKS GOOD.

[wdfifteen]

Originally Posted by aigel

I bought this 12V neg. ground converted car for a song. Owner thought it had a cooling system / engine problem because after warming up it would stop running. It had sat for a couple years and he moved and couldn't deal with it anymore.

Turns out the car had an ignition coil hooked up wrong - assuming it was still pos. ground. So after a few minutes the coil would overheat and the car would stop running.

Boy does that sound familiar! When I bought my '47 Dodge (6 volt, positive ground) the owner told me it needed a valve job. It ran like crap.
Same story as yours. The battery was in backwards and the coil had not been switched. I switched the battery terminals, polarized the generator, gave it a good tune-up and a new coil connected properly, and it ran great for years.

[Rinty]

Another common rust spot is the shelf just above each upper front suspension component. Road gravel and salt can accumulate there and cook the metal. Easy spot to clean and rust proof once you have the car.