DIY heatshield

[jagnut66]

Hi,
I have been having some fueling problems with Elsie May when she is hot and, as another member pointed out, there is allot of heat coming from the exhaust manifold. So I got a stainless steel offcut (£18 from my local metal suppliers) and made a couple, as Sally has the same exhaust system, so I'll fit one to her also. Good value as I still have half left over for something else.
All you need is a drill, some metal bits and a grinder with cutting discs and flap discs. You will need some sharp drills though, as stainless is tough to drill through. I also have metal files, both flat and for holes but you could get away without them.
To mark out the position of the HS2 carb I used a spare spacer and sourced a decent hole cutter from RS Components.
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You will need a good one, otherwise you won't get through it. You can get smaller sizes if you wish, I chose 40mm as it allows for the fitment of a HS4, should I wish to try one again in the future. However I believe 32mm will do for a HS2.
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And this is what I made:

Morris Minor heatshield 1.JPG (631.24 KiB) Viewed 1215 times

Morris Minor heatshield 2.JPG (462.34 KiB) Viewed 1215 times

Morris Minor heatshield 3.JPG (488.54 KiB) Viewed 1215 times

Morris Minor heatshield schematic.JPG (558 KiB) Viewed 1215 times

The overall length is 19cm and they are 16cm wide. The top is 14.5cm after the cut out, which allows for the throttle mechanism.
The bottom half is bent over to allow for the angle of the exhaust downpipes, as is the lower side section.
Please note I quote no angles, as this was done by eye. For bending the metal I do have a large vice (a good investment in itself) which I used, plus my ever useful hammer, though I fine tuned the angles by hand.
The size of the heatshield is dictated by the area covered by the HS2, though it should suit a HS4 as well, from looking at the ones I have.
Also regarding the angle of the bend away from the exhaust, I have a Maniflow system fitted, if you have a standard Minor exhaust system then the angle will be different anyway, though this heatshield would fit one.
I was spurred on to make this when a heat shield supplier couldn't supply me one and I thought, well why not get an offcut and make one yourself.
Basically this cost me £18 for the metal, £17.32 (plus postage) for a hole cutter (which I can use again on something else), plus time and effort. I used up two cutting discs, worn down by the stainless steel and finished off several 'used' drill bits, which needed replacing anyway.
If I can do it anyone can, so save yourselves some money and have a go.
Best wishes,
Mike.

[JOWETTJAVELIN]

It is a good plan - I don't know why the Minor came without a heat shield because the Morris Oxford Series MO had one. But the later Series II Oxford never had a heat shield either so perhaps it was BMC penny-pinching, and petrol was different back then so might not have boiled so easily. Heat shields for the Minor have been marketed from time to time.

[svenedin]

ESM sells the Grumpy HS2 carb heat shield.

[jagnut66]

ESM sells the Grumpy HS2 carb heat shield.

Yes but it looks like cheap painted metal (though please correct me if I'm wrong) not stainless steel, which is better for this purpose.
That said, I enjoy little challenges like this, if someone simply wants to buy a cheap off the shelf ready to fit item then that would do.
Best wishes,
Mike.

[svenedin]

ESM sells the Grumpy HS2 carb heat shield.

Yes but it looks like cheap painted metal (though please correct me if I'm wrong) not stainless steel, which is better for this purpose.
That said, I enjoy little challenges like this, if someone simply wants to buy a cheap off the shelf ready to fit item then that would do.
Best wishes,
Mike.

I agree the ESM heat shield does not look great but others may not have your fabricating skills, me included! Stainless steel is far better.

[jagnut66]

I agree the ESM heat shield does not look great but others may not have your fabricating skills, me included! Stainless steel is far better.

I think you and 'others' are probably more capable than you give yourselves credit for, take your time, plan things out, then give it a try.
I started with no skills and very little knowledge, what I can do now is self taught or learned through reading manuals etc. and giving it a go.
Sometimes I succeed, sometimes I fail............. then I try again.
Great for building confidence too.
Best wishes,
Mike.

[myoldjalopy]

Well done Mike. I assume/hope it makes an appreciable difference to your car, although I have never had any issues with vapourisation in any of my Minors. I wonder why some cars seem to suffer and others not?

[svenedin]

Well done Mike. I assume/hope it makes an appreciable difference to your car, although I have never had any issues with vapourisation in any of my Minors. I wonder why some cars seem to suffer and others not?

I've been rebuilding an SU fuel pump this evening. The outlet from the pump has a non-return valve in it to prevent syphoning of fuel backwards when the pump is mounted higher than the tank (as it is in the Minor). Mine was absolutely full of crud and the washer inside had turned to mush. I doubt it worked as a non-return valve in that state. I wonder whether this has any significance in relation to your question above?

[jagnut66]

I wonder whether this has any significance in relation to your question above?

I can't answer for 'myoldjalopy' but in my case I took the fuel line off the carb and put it in a jar, switched on and fuel was pumping through strongly, so I don't that's the issue with me.
That said I've got an new pump ordered, as it looks like it's been on there for some time, so it's the weak link left in my E10 proofing mission.
I also have an ethanol compatible rebuild kit, so once swapped I intend to rebuild it into a 'good spare'.
Best wishes,
Mike.

[svenedin]

Good idea. That is what I was doing tonight. Making a “good spare” with a rebuild kit.

I think your test shows the pump can pump well enough but it doesn’t really test the non-return valve. When sitting in traffic, with everything getting rather hot, the pump is only having to pump occasionally. If fuel vaporises in the line between pump and carb it could push fuel vapour backwards past a faulty non-return valve. Then when the pump tries to pump again it will struggle. Anyway it’s just an idea. It may be completely incorrect.

[jaekl]

Vapourisation occurs in the vertical rise of the fuel line to the pump first because the pulling of the pump lowers the pressure with temperature and pressure being the parameters where fuel boils. Any vapourization that may occur on the way to the carb is replaced by the pump and out through the bowl vent. The valve in the pump will not allow anything to flow in the opposite direction. Its function is to allow the pump to pull fuel from the tank as the diaphragm is pulled by the solenoid.

[svenedin]

Vapourisation occurs in the vertical rise of the fuel line to the pump first because the pulling of the pump lowers the pressure with temperature and pressure being the parameters where fuel boils. Any vapourization that may occur on the way to the carb is replaced by the pump and out through the bowl vent. The valve in the pump will not allow anything to flow in the opposite direction. Its function is to allow the pump to pull fuel from the tank as the diaphragm is pulled by the solenoid.

Yes. All I'm suggesting is, having stripped my pump down and found the valve full of crud, there may be cars out there where the non-return valve does not work.

[JOWETTJAVELIN]

Another point to bear in mind is the engine fan, which has the benefit of shifting air around the engine when sitting in traffic. Worth considering if you run without the engine driven fan and have experienced petrol vaporisation.