Sunday, 30 November 2014

Alloy SU carburettor mounts

With both my TR7's officially of the road it is time to start on some typical winter jobs. First job I will be tackling are the rubber carburettor mounts with which the SU's are mounted to the manifold on the DHC. British Leyland decided it would be a good idea to use rubber mounts, as they act as heat insulators and vibration dampers. When they are new they probably do their job quite well, but after well over 30 years even the best original mounts will be well past their prime. Not to mention the very poor quality of the aftermarket items. When I restored the DHC I thought it a good idea to extend the life of the original mounts as long as possible, by supporting them with some heavy duty cable ties. Clearly visible in this picture ...

To start the winter jobs, this weekend I dusted of the AutoCad file I created almost three years ago, to record the various dimensions of the original mounts.

The original plan was to find a local workshop to fabricate this from alloy. But the biggest problem here is that it sometimes takes ages before the items are ready. And that is when I was reminded of the fact that Schaeffer AG (the switch panel company) can work aluminium up to 10 millimetres thick. After a final dimension check against an original mount I redesigned the mount.

This way it can be fed into the design software as provided by Schaeffer AG. I went for a 6 mm base plate with four recessed holes to fit countersunk M8 Allen head bolts.

Against which a 10 mm spacer is fitted. This part has four threaded holes (with M8 threads), enabling the two parts to be screwed together and preventing the bolts from tuning when fitting the carburettors. Giving a total thickness which is exactly the same as the original mounts.

As there are probably cheaper options available I will first do some more checks before hitting the 'order" button. Also finding some countersunk M8 x 45 mm Allen head bolts with the correct (DIN) head dimensions has to be done before the order is placed, as the dimensions are crucial. Something to sort the coming week.


Patrick said...

Hello from France
I dont remember if i send to you before the link with the "alloy TKC 1338" I'have bought in 2008 and since perfect work on my TR7 drophead
Your work on the TR7 coupé : great and with your pics I know where the rust could born.

Beans said...

Hi Patrick,

I do know the mounts you have used. And the Dolomite Club in the UK and the TR7 IG in Germany also sell something similar.
But for me it's not just upgrading the cars, it is also the fun of designing and making (or in this case having them made) my own parts.