After dismantling my two-speeder engine I have found some corrosion which has crumbled away to reveal a hole in the base of the cylinder water jacket (this engine has been stood for a very long time). So, i’m thinking about how to repair the hole which is quite near the exhaust port (therefore quite hot in use). The corrosion is on a gasket face so that’s not particularly helpful but on the positive side any repair will be supported by the face of the crankcase. I am wondering if I could get away with something like JBWELD metal resin filler which can withstand temperature upto 300C – anyone else tried this before ?
You need to get rid of any oily deposits that might have got in the water jacket
Clean face, Make temporary seal over hole with adhesive tape. Pour in to water jacket some good cleaning spirit. If you do not have any, pour in some reasonably strong solution of warm water and “Flash” cleaning detergent and shake barrel to agitate. Next put in some small stones and shake to try and remove any more friable pieces on the bottom inside face, then repeat the cleaning with detergent, then wash out with clean water. Now put somewhere to dry out thoroughly. When perfectly dry, replace temporary patch if is not secure, then buy some slow setting epoxy, I recommend the product made by “Plastic Padding Co” as their products have more natural elasticity than some others. I used 2 off PP slow epoxy LCT-00141M
2 off mixer nozzle LCT-20945B from J&L Ind. Supply. Just pour in enough to give at least 4mm depth all over the bottom face of the water jacket. Rock the barrel slightly in all directions about 10 degrees to be sure the epoxy covers the entire floor area. Being a slow setting epoxy, you have time to be sure it covers the bottom surface before it sets. Stand on horizontal surface and allow to dry 24 hours, preferably in a warm place. Take off temporary tape patch and your block will be ready for use.
The water at the bottom of the water jacket does not get very hot so do not worry about the epoxy insulating the heat path. I have used this method on racing blocks with total success. The core on your casting was not in the correct place. The Scott castings are not easy and they had some problems with suppliers failing to produce to the quality required. In 1916, they had so many problems with crankcase castings that they started to produce cases in two halves bolted together. This was a big complication and expense, so they managed to solve this problem and we have had one piece cases ever since. Hope this helps. Let us know how you get on if you use the method. Kind Regards Roger
Hi Roger, thanks for that really helpful and encouraging answer. I will try it and let folks know how i get on.