Talk:Boiler feed pumps and injectors/@comment-43984939-20191001095243

I'm not sure if anyone is following this but if so then my thoughts on axle pumps might be of interest. My Speedy is fitted with two injectors which I dislike. The tanks are just not adequate for feeding injectors so I have to use a driving truck fitted with a water tank which is fine but having to constantly refill is impractical, perhaps a bigger water tank? The other problem is trying to get the injectors to pick up reliably whilst driving, maybe OK on a merry go round raised level track but not so easy on ground level where leaning over to check the drain outlet can be interesting. So I wanted to refit the axle pump. I have heard reports that the 1/2" pump as specified is a bit of a beast and massively oversized, if running at low speed it can actually stop the engine if the bypass is closed and even at high speed the extra load is significant, enough to badly affect driving performance. I calculate that a 5/16" pump would more than keep up with steam throughput at full speed, regulator and gear so have sleeved my pump down and am currently refitting it to use water fed from the loco tanks. I have used 1/8" square graphited PTFE gland packing to seal the plunger which fits perfectly and gives very low friction resistance, no O rings! I am also fitting a balance pipe between the two tanks and plan to fit a handpump in the bunker, winter job! Does anyone else have similar experience?