Welcome to our Site for MG, Triumph and Austin-Healey Car Information.


MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Expansion tanks/placement and cold air feed

Afternoon all,

I was looking at putting some ducting in to feed my carb some delicious cool air. I found this stuff in a hardware shop earlier (whilst I was supposed to be looking for something else, but the mind wandered...) Whilst not exactly pretty (and we will see about it's durability) it seems to fit perfectly.

*Slight* problem is the expansion tank now won't fit.

Any bright ideas on where to mount it? Or ideas for a different and more compact expansion tank?

If not, I will have to rethink the cold air idea.


Malcolm Le Chevalier

Pic 2, seems designed to go in here!

Malcolm Le Chevalier

can you mount the tank on the LH splash shield where the 1275s have theirs?
David Smith


I don't know about the tank, but if you get the aluminum dryer vent it would look better than the plastic.

CR Huff

Yeah, I will look for some aluminium ducting at some point in the future, all being well.

This was the only stuff they had, but at 3 I thought I would give it a go, give me chance to see how things would work out.
Malcolm Le Chevalier

The other side is quite congested with wires, oil cooler pipes etc.

But I might have found an elegant solution. It just squeezes in the gap, hanging it off the top radiator mount hole and I just need to fab up a bracket to mount to the wheel arch.

Need to check it doesn't protrude too close to the wheel, but that's for tomorrow. Time for a beer.


Malcolm Le Chevalier

The big problem with the plastic ...

as the engine bay heats up so does it and with in a few moments it will both sag/loose its shape and blow hot air because the air gets preheated as it travels the length of the tube

Aluminum will repel heat as long as the aluminum tube is not touching anything hot that heat can be transfered thur the aluminum material

but yeah... looking good.. have incorperated a temp controled computer fan into the system yet


Yeah... bodged fitting the tank with cable ties. Didn't like having a bracket protruding into the wheel well. Needed the car going, so considering this a prototype arrangement. Also fabbed up a small bracket/heatshield arrangement to go under the carb inlets.

Not been that far in it, but it seemed to idle better after a good blast. Although that might have been me imagining benefits from my efforts.

Fan is a future project Prop! :-)

Pic is a bit rubbish.


Malcolm Le Chevalier

Hi Malcolm, in a previous life I designed and made machinery to make the white PVC wire reinforced ducting that you have it is barely capable of containing tumble dryer hot let alone an engine bay, although its soften point will be well over 100C.

The aluminium hose is slightly better but it is still not really suitable for an engine bay.

There are much better and more suitable hoses available for ducting.

By the way I guess the PVC hose is 4" (100mm) diameter - it used to cost me less than 0.27p per meter to make and I used to make well over 1 million meters a year.
Martyn Wilks

Wow! I paid 3 for the metre I have.

The white PVC wasn't going to be long term, just mucking about figuring out how things were going to fit together. Also, I figured that at speed the air flowing through it wouldn't have time to get significantly warmed by the engine bay heat even with the shoddy hose.

The "proper" ducting stuff is pricey, but probably worth it long term.

Malcolm Le Chevalier

We used to sell it for 0.90p a meter to the likes of B&Q etc
Martyn Wilks

This thread was discussed between 21/05/2016 and 23/05/2016

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now