Some sort of water pump pulley holder?
Spot on, Eric. I didn't think it would take long for someone to get it. When I get back to my PC I'll post a pic of it in its working environment.
All this was instigated by the fun and games I had getting the water pump pulley off the (broken) engine in France. I swore that I would fab something to avoid going through that particular circle of hell again.
For anyone that's interested, distance between bolt centres is 36mm and a 15mm hole allows a 13mm bolt head to pass snugly through. I used a pillar drill and 15mm blacksmith bit to make the holes and a die grinder with cylindrical burr to make the ellipse. It had its first test when removing the cap head bolts I had foolishly used to secure the pulley to the pump on the 'new' engine. Having done battle with those bolts in situ I quickly realised that using cap head screws was madness - you'd never have clearance to remove them.
I'm pleased to report that the tool did its job without any dramas.
