23-05-2018, 06:01 AM
Hello Dave
You've done a very nice neat job there, lots of time spent shaping and fettling that aluminum, having just finished an entire single seater body in ali, I know just how long the details take.
I'd suggest that one of your problems is the location of your SU pump, basically it's being cooked by the exhaust so that any fuel flowing through it is pre-heated so to speak.
I'd suggest you did 3 things, firstly make up another heat shield for the pump, you can shape it up between the pump and the exhaust. Secondly find a little bit of modern car door pinch rubber and stick it onto the flange of the lower valance just next to your armoured wiring. This will hold the back of the bonnet flap open just a bit and effectively create a 'louvre' to draw air out and thus create airflow over the pump and carb to cool them down. Easily removed for shows etc and the bonnet side has enough flex to handle the small deviation. Thirdly, an optional step is to create a small aluminum air scoop under the car in the gap between the chassis and the side valance which cups cold air from the front, scoops and redirects it upwards to cool the pump and it can exit out the edge of the bonnet. Painted Matt black it would be almost invisible down there.
I had a similar issue with my '61 Alfa Ti a few years ago, issues with the mechanical pump led me to fitting an SU pump alongside the coil (power source). It ran very well until it stopped every so often.... A rag wrapped around it and soaking it at every stop was the answer until I could rebuild the mechanical pump whereby it hasn't missed a beat. The SU was a pusher type pump and relied on the fuel and airflow to keep it cool. When it got hot it got grumpy and boiled the fuel within it, despite it being on the opposite side to the exhaust.
As an aside I have some very neat stick on type heat shielding material that I use for my heat shields, very sticky stuff, aluminum layer on th visible side with a composite weave in between. Works extremely well and in your case would be invisible under or behind your heat shields. I'll get a picture of the box for you.
Aye
Greig
Sunny South Africa
You've done a very nice neat job there, lots of time spent shaping and fettling that aluminum, having just finished an entire single seater body in ali, I know just how long the details take.
I'd suggest that one of your problems is the location of your SU pump, basically it's being cooked by the exhaust so that any fuel flowing through it is pre-heated so to speak.
I'd suggest you did 3 things, firstly make up another heat shield for the pump, you can shape it up between the pump and the exhaust. Secondly find a little bit of modern car door pinch rubber and stick it onto the flange of the lower valance just next to your armoured wiring. This will hold the back of the bonnet flap open just a bit and effectively create a 'louvre' to draw air out and thus create airflow over the pump and carb to cool them down. Easily removed for shows etc and the bonnet side has enough flex to handle the small deviation. Thirdly, an optional step is to create a small aluminum air scoop under the car in the gap between the chassis and the side valance which cups cold air from the front, scoops and redirects it upwards to cool the pump and it can exit out the edge of the bonnet. Painted Matt black it would be almost invisible down there.
I had a similar issue with my '61 Alfa Ti a few years ago, issues with the mechanical pump led me to fitting an SU pump alongside the coil (power source). It ran very well until it stopped every so often.... A rag wrapped around it and soaking it at every stop was the answer until I could rebuild the mechanical pump whereby it hasn't missed a beat. The SU was a pusher type pump and relied on the fuel and airflow to keep it cool. When it got hot it got grumpy and boiled the fuel within it, despite it being on the opposite side to the exhaust.
As an aside I have some very neat stick on type heat shielding material that I use for my heat shields, very sticky stuff, aluminum layer on th visible side with a composite weave in between. Works extremely well and in your case would be invisible under or behind your heat shields. I'll get a picture of the box for you.
Aye
Greig
Sunny South Africa