Wet Sumping Problems

We frequently get asked the question about wet sumping.

We DO NOT recommend fitting any such non return valves on the feed side of the pump as gear pumps are not designed to suck with no oil in the body. This can result in instant engine failure.

The non return valve (A10) sits inside the crankcase (inside this casing the spring and the ball gets dirty with old oil deposits and stops working to the best of its ability and is impossible to reach without a complete strip down of the engine. This is not an issue on the Needle Roller Conversion or the A65 model because the ball and spring sits outside the crankcase and up against the pump.)

We have discovered that when the pumps are worn, oil can either leak past the oil pump drive spindle, or through the scored internal body of the pump and into the return line, or simply a distorted pump body. Later A65 pumps were better because the drive spindle is fitted with an “o” ring inside the driveshaft of the pump. Our new pumps also have this fitted. Due to the inherent design, the problem cannot be eliminated entirely but by fitting our new pump this wet sumping problem can be restricted.
Here at SRM, being a team of dedicated enthusiasts, we have an ongoing commitment to all our customers to get the very best from their BSA’s. Due to the general poor quality of parts available on the market, we like to be able to be in control of our own products by manufacturing them to strict controls with in house testing of all our products. Our latest batch of pumps and special products are no exception, going through a vigorous testing procedure before we bring them to the market.