Water branch repair

- by Colin Danks

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When you have an original engine with all matching numbers (and possibly even original oil!) it seems a shame to scrap the block if all it needs is a re-bore, facing top and bottom and some way of attaching the side water branch to heavily corroded fixing points. That was the conundrum until it was suggested that a stainless repair plate is available from one of our northern Austin 7 suppliers - John Barlow.

The repair plate comes in laser cut form with 10 pilot holes drilled (2 for the water branch studs and 8 for fixing the plate).

My method of fixing was to use 8 x M4 x 6mm countersunk cap head set screws to fix the plate to the block. This involved drilling out and countersinking the pilot holes.

image 1

drilling out and countersinking the pilot holes

Next step was to find two 5/16 BSF nuts and silver solder them to the back of the plate. I then used the nut as a tap guide to extend the thread through the plate. Hey presto, the studs can be screwed in. My preference was for stainless steel so no rusting problems (I hope).

The final step was to mill (or hacksaw) the remains of the fixing points out of the block and to drill and tap 8 fixing holes using the repair plate as a template.

For simplicity I used silicone sealant and a thread lock to ensure it does not become incontinent when filled with water. The block was then pressure checked with boiling water.

Result: the saviour of a very ropey, but original block from my shared 1930 Fabric Saloon. “Want not, waste not”, as my Grandma says.

Colin Danks

image 2

plate complete and installed

Thanks to Terry Griffin for these photographs.


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