Less heavy battery and starter?

[Moderator]

I've been thinking about reducing rear axle and suspension weight. MGB's dual battery boxes, though very admirably tucked low and rearward, seemed to block my progress toward a lighter suspension. How could I get between them to install brackets, etc.?  Besides, everything about the battery installation seemed way overweight compared to what I've seen in racing paddocks. So here are some snapshots to show what I've recently done about it.

I've installed a Braille B2015 absorbed glass mat battery in lieu of my old Duralast size 26R-DL lead-acid battery. Since AGM batteries are sealed, they can be mounted inside the cabin, cool and clean. My new brackets are simple steel fabrications. The original battery boxes have been entirely removed.



Here you can see the protective cover I fashioned from some scrap stainless steel. Footroom is very minimally compromised. I might put a rubber pad on the cover, so it can function as a dead pedal.



"Because racecar"?



Short, simple cable routing leads to an amperage-sipping gear reduction starter, sourced from Ted Schumacher.



Here's a close-up of a Volvo Truck firewall passthrough. I think every single truck they've built in 30 years has used one of these, so they should be easy to find in truck scrapyards. As you can see, it comes with weather sealing o-ring and a robust boot. Bonus: it's a convenient power tap and jumpstart stud.
 


Results?

<table border="3">
<tr> <td></td> <td>what &nbsp; &nbsp; &nbsp; </td> <td>before &nbsp; &nbsp; &nbsp; </td> <td>after  &nbsp; &nbsp; &nbsp;</td> <td>difference  &nbsp; &nbsp; &nbsp;</td> </tr>
<tr> <td>1 </td> <td>Battery </td> <td>29.0#</td> <td>14.0#</td> <td>15.0#</td></tr>
<tr> <td>2 </td> <td>Starter </td> <td>21.8#</td> <td>8.0#</td> <td>13.8#</td></tr>
<tr> <td>3</td> <td>Cables </td> <td>2.2#</td> <td>0.8#</td> <td>1.4#</td</tr>
<tr> <td>4</td> <td>Bracketry and cover*  &nbsp; &nbsp; &nbsp;</td> <td>6.6#</td> <td>1.0#</td> <td>5.6#</td</tr>
<tr> <td>Sums </td> <td></td> <td>59.6#</td> <td>23.8#</td> <td>35.8#</td</tr>
</table>

* for the comparison, I only considered the weight of removing one MGB battery box, but actually I cut out both of them.

[BlownMGB-V8]

Buick 300 can use the SAE SBC mini-starter, about $75 everywhere.

Jim

[Moderator]

I meant to mention how impressed I was by <a href="https://www.batterycablesusa.com/">Battery Cables USA</a>.  Great service, products, and value. (They're a particularly good place to buy dual wall heat shrink!) And they delivered super-quick too.

[BlownMGB-V8]

I made a heavy duty cable crimper out of a chunk of steel and about 6 inches of 1/2" square stock. Drill a 1/2" hole through the steel and made a couple cuts to turn it into a slot or groove then grind a rounded chisel point on the square stock.

Lay the lug with the cable inserted into the groove, position the square stock above it as a driver and hammer the driver down to form the crimp. The driver can be turned 90 degrees to make additional cross crimps. Using a heavy hammer this can form some very good crimps. Then apply your heat shrink to seal it.

Jim

[MGBV8]

The original battery boxes have been entirely removed.

Of course, you have a GT, Curtis.  On the roadster, those battery boxes are thought to add a some strength to the unibody.

[Moderator]

I'll concede that MG engineers apparently thought there was some value in retaining modest bracing when they removed the driver-side battery box from all MGBs from 1975 onward.

However, I'm extremely skeptical that the bracing meaningfully affected torsional rigidity or crashworthiness because it's it's so very thin and also so far away from chassis pickup points, etc.  Perhaps they may have been more concerned about mitigating noise and vibration. Existing embossments in that area were very minimal.

I'm definitely not the first person to ditch the boxes and trim down to very minimal bracing. This pic shows both MG's driver-side bracing and also the modest bracing Rob left when he cut out his passenger-side battery box:

[BlownMGB-V8]

In addition to panel stiffness I do think it lends a bit more stiffness to the shock absorber attachment points. Note the proximity of the shock absorber humps.

Jim

[MGBV8]

The floor to the battery shelf is essentially a 90 degree turn.  What I see are four diagonal (sorta) reinforcing ribs.