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MG MGB GT V8 Factory Originals Technical - Moving the battery

I have removed my heater and Im thinking of putting the battery in its place. Has anyone done this?
If so what battery holder did you use or did you make one and will the battery fit. On the same subject what battery do you use for your V8. Denny
dbw morris

If you can go without a heater, you might want to think of aircon before you move the battery

RW - cold/damp/jealous

I only drive the car March thru October. In the warmer months I drive without a top rain or shine. I live in Ohio. Denny
dbw morris

OK - I can understand why you want easy access to your battery.

Assuming your setup leaves space, it would be easy enough to put a battery tray there and re-run the cables and hopefully leave things so that the heater could be refitted later.

There is a small weight issue to balance against the improved accessibility. Over here the 'infrequent users' have a trickle charger permanently wired in and those that have had an MGB for lengthy periods will probably have a second earth strap in the engine bay.

Pity about the Winter months - must go and wash all the salt off mine

Good wishes


If you've removed your heater, then IMHO the most logical thing to do is duct air from the cowl to the carburetor
(a.k.a. cowl-induction). The air is pressurized at speed and it's significantly cooler than air at grille-level relative to the sun-heated road. This works well and is easy to do.

Putting a big chunk of lead and acid way up in the air is a vintage Triumph idea... (Is that too harsh?) The MGB battery location is both low and far back, both of which help handling considerably. Bonus: with a single 12V you can choose to put the weight off-center to partially balance driver weight.

Is it too late to mount your engine a few inches further back?

You might also want to consider that if you ever have an accident bad enough to push the engine rearward, the firewall will probably tear open. The last thing you need at that point is a cloud or flood of battery acid.

Are you using a 215? It's such an easy-to-start engine you shouldn't need a very big battery at all. You'll have no trouble finding strong 12V batteries to fit the standard location. I recommend a kill-switch to eliminate parasitic loads so the battery stays strong from October to March. With a modern battery you won't need a charger if you have a kill switch.

Curtis I really like the Idea of doing the cowl induction. Would you have the duct work run right up to the air filter or try to make a new filter duct combination, which would be harder than the former.
Great idea I think I saw this somewhere on the internet on an MGBV8. Denny
dbw morris

Plenum Induction? Wasn't the firewall there for a reason? The plenum is open to the car's interior. Does the proposal for induction via the plenum include closing all openings to the interior?

IIMO it's not a good idea. Two reasons, first moving 30+ pounds up about 2 feet doesn't do anything good for the center of gravity and the handling, and second, ask any midget owner about the corrosion in this area after a couple of years. I replaced the battery tray in my Midget when I rebuilt the car 4 years ago and although I try to keep the area clean it's still starting to show signs of rot already.
Bill Young

See if this old photo helps...

You wouldn't have to do it the same way I did... but my approach was to use a rectangular air filter (sandwiched up tight to the "firewall") and a fabricated "cobra-head" on top of the carb.

Dom asked: "Does the proposal for induction via the plenum include closing all openings to the interior?" Answer: yes.


Curtis how does it work do you block off the inside and then add the duct work. Where did you get the air cleaner. It looks pretty cool but does it really work any better than the 14" K&N filter. Curtis the photo is the one I have seen. Denny
dbw morris

Blocking vents to the car interior only takes minutes.

I suppose you could use all sorts of filters. I used a Fram oiled-gauze Ford Probe filter. That was 1991 - I'd probably use something different today. I went to Advance Auto and looked at everything they had. This filter has a nifty steel box around its perimeter - I wouldn't be surprised if it was made by K&N. It appears to be washable. I bought spares, but the original filter still looks fine.

Here's a snapshot from the first trial fit-up:

These snapshots don't show well that the aluminum duct has a 1/2" box-tube frame that clamps tight against the filter to four studs mounted on the firewall.

How does this filter compare to a 14" K&N? I haven't measured pressure drop across the filter or anything, but I couldn't sense any "improvement" by temporarily removing the filter from the system. I believe it's big enough. I don't have any way to measure the performance advantage of cooler, pre-pressurized air either, but I'm sure it must be significant.

Sorry... here's the correct link:

Well, in terms of the thread topic.....ahem....I have also chosen to mount the battery in the bay. As I was hacking and hewing to get the swap engine back and down, chunks of firewall a-flyin, it was not a stretch to just take off the "tray" under the cannisters/washer bottle above passengers legs to allow the full 8 inch height for a side terminal Group 75, with 650 cold amps. This was started 1/2 inch to the fender side of the hinge to avoid and hood lift foul, and continued under the fender top 10 inches, with the removal of the brace portion from the firewall forward. I rewelded a brace back behind the left side of the battery placement, and smoothed off and rolled the cut area. Good heads up on the corrosion, although today's batteries are sealed, I've been amazed to notice what happens next to a bottle of muriatic on the shop shelf: everything within 3 feet radius glazes over with a fine rust! Guess I'll powder coat the tray pieces, then screw em in and use the "plastic" coat rattle cans to touchup. Anyway, a #10 running 1.5 foot, sure beats the resistence in the MGB cable which is almost 7 feet long if I remember. FWIW, I originally mounted the swap engine ( a 3.8 90* V6) in one day without hammer or saw, but to get her back 3 more inches, behind the cross member and down 2 more inches took another full day and lots of weight reduction firewall removal. Now, what happened to the thread topic?
vem myers

Vem it seems the majority thought it was a bad idea. I have removed my heater so I feel the batery would go in that spot. What is your diamention of your battery and what brand. Denny
dbw morris

D- The Bat is 7.5 inches high, side mount. It is 10 inches wide and 6.5 deep: Kirkland. Personally, I am pleased with the relocation, and feel the 28 # weight, although elevated on the pass side engine bay is thoroughly offset by the low slung, way back siting of the engine, with the benefit of almost no voltage lost to resistence, and fan speed up the wazoo!
vem myers

I have been contemplating this relocation as well. My goal was to free up the are of the battery box in order to tuck smallish mufflers up in that vacated area. It looks like this is possible. Has anyone done this successfully?
Michael Willis

On the mgb race car we need mufflers at certain urban tracks. I use a small 12" glasspack that goes right through the LH battery box so I get some kind of ground clearance with a lower ride height. Spent lots of time getting the exhaust tube sucked up against the floor

Kept the battery in the RH box, as it's not a V8 with twice pipes
greg fast

It should not be too hard to find a battery sufficiently low profile enough to fit on the unaltered passenger foot well. Then it's a very quick and easy job though you might want to put a plastic dish under it. Of course if you did want a big battery, you could just buy a cheap baking dish and rivit drop into a hole. Vem was cutting anyway, but for the rest of us buying a "flat" battery (ha ha) would be easier.

This thread was discussed between 08/03/2005 and 24/03/2005

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