mikey7134 Posted March 29, 2013 Share Posted March 29, 2013 Quick question. Is it possible to tee the leak off (return line) from Inj pump into the filter, to be circulated back into pump, without going to tank first? Or would lift pump pressure / return pressures fight against each other? Cheers Quote Link to comment Share on other sites More sharing options...
western Posted March 29, 2013 Share Posted March 29, 2013 IIRC the spill return goes back to the return side of the fuel filter then to the tank. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted March 29, 2013 Share Posted March 29, 2013 Quick question. Is it possible to tee the leak off (return line) from Inj pump into the filter, to be circulated back into pump, without going to tank first? Or would lift pump pressure / return pressures fight against each other? Cheers In the hope of gaining what? The injector pump never uses all the fuel sent to it from the filter, just like the injectors dont use all the fuel the Pump sends to them. Quote Link to comment Share on other sites More sharing options...
mikey7134 Posted March 30, 2013 Author Share Posted March 30, 2013 Dual tanks, with just the one x-over tap.. To save having to plumb in and mechanically link another tap so they change at the same time... Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted March 30, 2013 Share Posted March 30, 2013 Dual tanks, with just the one x-over tap.. To save having to plumb in and mechanically link another tap so they change at the same time... Have a look at small aircraft change over taps, they work both lines in 1 unit. When i twin tank my 110 i plan to do just that. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted March 31, 2013 Share Posted March 31, 2013 Do you mean the injection pump return to tank line or the injector leak off line? IIRC the leak off line goes back to the pump. You can connect the pump return to tank line back to the pump inlet, but it's an absolute bugger to get the air out of the system, and the lift pump ends up 'dead headed'. It's happy like that for a short while, but I wouldn't want to run like that for an excessive number of miles. Do it properly - get a twin change over valve. I had one on an ex mil series 3 - shouldn't be that hard to source. Quote Link to comment Share on other sites More sharing options...
mikey7134 Posted March 31, 2013 Author Share Posted March 31, 2013 Do you mean the injection pump return to tank line or the injector leak off line? IIRC the leak off line goes back to the pump. Yeah, sorry, should have been clearer. The pump to tank return line - the fitting where the return line connects, is also banjo'ed to the leak off line, which is why i had said that - apologies. What do you mean by dead headed? I had looked at a de-aerating filter to go in place of the standard filter, tee-ing the return into this, with the thoughts that it would get around the twin change over issue, and the air in the line issue, and also generally help keep the line air free, if, say, it has been sat for a little while.. What would be your thoughts on this? In the mean time, i'll start trawling t'interweb for a twin x-over tap. Cheers Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted March 31, 2013 Share Posted March 31, 2013 Dead heading a pump is blocking the outlet. Even though the injection pump would be using fuel it's such a miniscule amount in relation to what would normally travel through it and return to the tank, you're effectively blocking it. A de-airating filter would do the job, but it's still a bit of a bodge IMHO - and would likely cost more than a proper change over valve. Twin changeover valves are a fairly standard setup for those that run on vegetable oil - there are cheap solenoid valves around for this purpose. Something like this? http://www.oilybits.com/bio-fuel-equipment/valves-all-types-/fuel-tank-selector/pollak-6-port-fuel-selector-valve/prod_328.html Quote Link to comment Share on other sites More sharing options...
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