anthonym Posted October 27, 2023 Share Posted October 27, 2023 (edited) I am a bit nervous about doing this, since petrol can be a dangerous matter. I am fitting "Gates R14" hose in replacement of "Unknown R6", I would be very grateful for confirmations or otherwise that my connection to the tank appears to be safely done. I know I should replace the clamp, but the ones that arrived are the wrong size not per my order, I can rectify later. I could have ordered the low pressure R14 (BDR on Dellortos is 1.5 to 2 p.s.i not 225 ), but just ordered regardless. Here are the pictures, the Facet pump pic is just the general area, showing evidence of once being occupied by rodents(!): I did not receive any Greenshild stamps with it... I was dreading this task, so got it done tonight. It is very difficult to put any pressure on the hose to fit it, access is highly restricted from above and below. My goodness the pictures handling in this new site is fantastic. Anthony Edited October 27, 2023 by anthonym delete duplicated photos Link to comment Share on other sites More sharing options...
SM25T Posted October 28, 2023 Share Posted October 28, 2023 As you know, jubilee clamps are not good for small petrol hoses. Wait for the correct size petrol hose screw clamps. Link to comment Share on other sites More sharing options...
rj Posted October 28, 2023 Share Posted October 28, 2023 That should not form probems. Mind you the fuel pressure is limited to the gravity pressure Link to comment Share on other sites More sharing options...
Gridgway Posted October 29, 2023 Share Posted October 29, 2023 17 hours ago, rj said: That should not form probems. Mind you the fuel pressure is limited to the gravity pressure I don't really understand this comment. What is gravity pressure please? 1 Link to comment Share on other sites More sharing options...
rj Posted October 29, 2023 Share Posted October 29, 2023 (edited) 2 hours ago, Gridgway said: I don't really understand this comment. What is gravity pressure please? https://www.sensorsone.com/mh2o-metres-water-column-4-deg-c-pressure-unit/ There is no pump in the tank so the pressure will be max what the gravity produces (I think you also use the term "water column" for the pressure the fluid has when lifted above level and 1bar equals to 9.81 meter water column) so even if we count both the tank's level above ground and the height of the tank the top level will be less than 50 cm above ground the pressure will be less than 0.05 bar. No way it can push off the hose. Edited October 29, 2023 by rj Grammar Link to comment Share on other sites More sharing options...
Gridgway Posted October 29, 2023 Share Posted October 29, 2023 (edited) Thanks for the explanation. You are thinking of the feed hose from the tank to the pump? Makes sense. I thought your comment was referring to the pressure side. Edited October 29, 2023 by Gridgway Spelling Link to comment Share on other sites More sharing options...
anthonym Posted October 29, 2023 Author Share Posted October 29, 2023 (edited) I wish I undertood that. I iove the confirmation my hose is safe. I had thought the pump was sucking (ok, atmospheric pressure pushing) the fuel from the tank buit it seems not. Gravity is pushing the fuel downwards, so what's this about it pushing the fuel up and out of the tank? edit: I was readingt this too https://physics.stackexchange.com/questions/599287/what-is-gravitys-relationship-with-atmospheric-pressure but not really much the wiser Edited October 29, 2023 by anthonym Link to comment Share on other sites More sharing options...
rj Posted October 29, 2023 Share Posted October 29, 2023 8 minutes ago, Gridgway said: Thanks for the explanation. You are thinking of the feed hose from the tank to the pump? Makes sense. I thought your comment was referring to the pressure side. Yes, exactly. Or you could say the pressure in that specific hose. Link to comment Share on other sites More sharing options...
rj Posted October 29, 2023 Share Posted October 29, 2023 4 minutes ago, anthonym said: I wish I undertood that. I iove the confirmation my hose is safe. I had thought the pump was sucking (ok, atmospheric pressure pushing) the fuel from the tank buit it seems not. Gravity is pushing the fuel downwards, so what's this about it pushing the fuel up and out of the tank? edit: I was readingt this too https://physics.stackexchange.com/questions/599287/what-is-gravitys-relationship-with-atmospheric-pressure but not really much the wiser I guess it will be a combination. But when the engine is not running it will be the static pressure - which may increase on braking, but it won't form an issue at all Link to comment Share on other sites More sharing options...
Gridgway Posted October 29, 2023 Share Posted October 29, 2023 6 minutes ago, anthonym said: I wish I undertood that. I iove the confirmation my hose is safe. I had thought the pump was sucking (ok, atmospheric pressure pushing) the fuel from the tank buit it seems not. Gravity is pushing the fuel downwards, so what's this about it pushing the fuel up and out of the tank? edit: I was readingt this too https://physics.stackexchange.com/questions/599287/what-is-gravitys-relationship-with-atmospheric-pressure but not really much the wiser No it's not a gravity feed pump as such. The facet can and does "suck". If you look at the pump spec it says how much. Something like 12" iirc. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted October 29, 2023 Leadership Team Share Posted October 29, 2023 Yes but the maximum pressure in the feed pipe will be that provided by gravity plus an increased amount under braking. When the pump sucks it reduces the pressure in the feed pipe to the pump. Link to comment Share on other sites More sharing options...
rj Posted October 29, 2023 Share Posted October 29, 2023 13 minutes ago, Gridgway said: No it's not a gravity feed pump as such. The facet can and does "suck". If you look at the pump spec it says how much. Something like 12" iirc. True. I've just realised that the feed is taken from the top of the tank 😮 Link to comment Share on other sites More sharing options...
Gridgway Posted October 29, 2023 Share Posted October 29, 2023 I think we're all violently agreeing here! Link to comment Share on other sites More sharing options...
Gridgway Posted October 29, 2023 Share Posted October 29, 2023 2 minutes ago, rj said: True. I've just realised that the feed is taken from the top of the tank 😮 Effectively it's not taken from the top off the tank. The feed pipe goes to the bottom of the tank. So in fact there is a very small net column of fuel to provide pressure in the feed pipe. Link to comment Share on other sites More sharing options...
anthonym Posted October 29, 2023 Author Share Posted October 29, 2023 so it works the same as the coolant overflow "tank" return mechanism - except in the overflow system the "vacuum" is natural not induced by the/a pump. So atmospheric pressure is pushing fuel from the tank bottom feed tube in to the pump. i i u c Link to comment Share on other sites More sharing options...
rj Posted October 29, 2023 Share Posted October 29, 2023 1 hour ago, Gridgway said: Effectively it's not taken from the top off the tank. The feed pipe goes to the bottom of the tank. So in fact there is a very small net column of fuel to provide pressure in the feed pipe. Exactly Link to comment Share on other sites More sharing options...
anthonym Posted October 29, 2023 Author Share Posted October 29, 2023 (edited) it's a siphon! edit: without the unpleasant taste Edited October 29, 2023 by anthonym Link to comment Share on other sites More sharing options...
anthonym Posted October 29, 2023 Author Share Posted October 29, 2023 (edited) seems relevant to mention I have fitted one of these (regulator with "edit: non permanent" pressure guage) and corrected my fuel pressure from 3psi to between 1.5 and 2 psi, a 50% reduction, which I am hoping/expecting to help getting my float chamber levels right: Edited October 29, 2023 by anthonym added non permanent Link to comment Share on other sites More sharing options...
OldAndrewE Posted October 29, 2023 Share Posted October 29, 2023 Anthony, do you leave that gauge permanently in place? This from the Demon Tweeks site: The Sytec in line fuel pressure gauges have been developed to monitor fuel pressure when making final adjustments to the fuel system. The in line gauges are available in two pressure range types, with the 1-7bar range glycerine filled, and each including a male thread for attaching to an adaptor (available separately). The gauges are designed for setting up of the fuel system only and not recommended for permanent use. (my bold). Blanking plugs are available 1 Link to comment Share on other sites More sharing options...
anthonym Posted October 29, 2023 Author Share Posted October 29, 2023 (edited) no it is for pressure setting only edit: it comes with the blankiing plug in place and states temporary only - it came from Demon tweaks. In any case the car is static now for Winter. edit I have added that clarification. edit I think it would vibrate to bits if left in place during car use. Edited October 29, 2023 by anthonym Link to comment Share on other sites More sharing options...
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