Badwolf Posted January 16, 2019 Report Share Posted January 16, 2019 One day I intend to fit an in line fuel line tap in the boot. Extra security, unless I forget that I turned it off, but very useful for doing work on the main pipe runs, Link to comment Share on other sites More sharing options...
dougbgt6 Posted January 16, 2019 Report Share Posted January 16, 2019 BW, My brother has just done this on his Spitfire, he has a toggle switch and relay operating the valve. The toggle switch is on the dash, it has a tiny blue LED on the end, very cool but not very secure. But I suppose if the tea leaf doesn't know what the switch is for, it's OK. Unless your brother's already told everybody. Doug Link to comment Share on other sites More sharing options...
Badwolf Posted January 16, 2019 Report Share Posted January 16, 2019 Doug - Nice idea especially if you link the switch through another isolator but that's total paranoia. You could simply put the switch in the glove box or somewhere out of sight. I might just try that when I put in the new fuse link box Link to comment Share on other sites More sharing options...
jondhm Posted February 3, 2019 Author Report Share Posted February 3, 2019 Andy Cook must have been reading this thread, because on page 34 of February's Courier is a picture of a fuel hose being changed. Really useful article on fuel pipes, thanks, Andy. 2 Link to comment Share on other sites More sharing options...
daverclasper Posted February 3, 2019 Report Share Posted February 3, 2019 (edited) Hi. That is a good article. I wasn't aware that the suck bores (tank to pump) were larger than pump to carb bores. He sited GT6, though wondering if that is same for Vitesse?. Just wondering the reason for this (larger bore needed to deliver enough fuel as a longer run from tank to pump)?. I just bought a metre of the smaller 1/4", thinking this would do the whole run!. Cheers, Dave Edited February 3, 2019 by daverclasper Link to comment Share on other sites More sharing options...
NonMember Posted February 4, 2019 Report Share Posted February 4, 2019 I don't know about Mk2 Vitesse but I think the Mk1 had 1/4" bore all the way. The Mk3 Spitfire certainly did. The larger bore from tank to pump is done for the same reason inlet valves are bigger then exhaust valves. Whether pushing or "sucking", the real physics is that the fluid is passing through a restriction under the influence of a pressure difference. On the inlet / tank-to-pump side, the higher pressure is only atmospheric at maximum. On the exhaust / pump-to-carbs side, the pressure is much higher, and thus so is the difference. Link to comment Share on other sites More sharing options...
PeteH Posted April 3, 2019 Report Share Posted April 3, 2019 Hi There is also the consideration that the flow can be reduced by the internal pipe friction, dependant on length. Most "Suction" pipe/hose is larger dia than that of the pump outlet. It applies especially in marine practice, often in a effort to reduce or eliminate cavitation and erosion on pump components. Pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 3, 2019 Report Share Posted April 3, 2019 I recently had a fuel leak from the rubber section in the passenger side rear wheel arch (GT6). I replaced it with Barricade from the club shop, I thought the pipe was all 1/4", the short section from the tank was, but the section to the pump was slightly larger, not as big as 5/16" but metric? Doug, Link to comment Share on other sites More sharing options...
JohnD Posted April 3, 2019 Report Share Posted April 3, 2019 "Can be reduced"? WILL be reduced! Poiseuilles Law. Flow = (Pi x Radius^4 x DeltaP)/ (8 x viscosity x Length) You will note that the radius is raised to the Fourth Power - Radius x Radius x Radius x Radius. Double the radius and the flow is increased SIXTEEN TIMES! (2^4) Sure, length affects flow, directly (and inversely), but you can't change the distance from the tank to the engine. You can change the radius of the tube you use! John Link to comment Share on other sites More sharing options...
PeteH Posted April 4, 2019 Report Share Posted April 4, 2019 Thanks John, I couldn't remember M Poiseuilles. But it comes up in Naval Architecture and Ship Construction. But that was 50 years ago!. 12 hours ago, JohnD said: "Can be reduced"? WILL be reduced! Poiseuilles Law. Flow = (Pi x Radius^4 x DeltaP)/ (8 x viscosity x Length) You will note that the radius is raised to the Fourth Power - Radius x Radius x Radius x Radius. Double the radius and the flow is increased SIXTEEN TIMES! (2^4) Sure, length affects flow, directly (and inversely), but you can't change the distance from the tank to the engine. You can change the radius of the tube you use! John 15 hours ago, dougbgt6 said: I recently had a fuel leak from the rubber section in the passenger side rear wheel arch (GT6). I replaced it with Barricade from the club shop, I thought the pipe was all 1/4", the short section from the tank was, but the section to the pump was slightly larger, not as big as 5/16" but metric? Doug, 5/16 = .3125" : 8mm = 3149" : 7mm = .2755". All approx. Pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 4, 2019 Report Share Posted April 4, 2019 Looks like I've got 0.25" into 7mm then. So I have a constriction of 0.0255" out the tank. Which means a flow reduction of...…………………. How did that happen? I've never had fuel starvation, so I'm not going to worry about it. In the words of the Guru Mark Smith "If it ain't broke, don't fix it." Doug Link to comment Share on other sites More sharing options...
PeteH Posted April 4, 2019 Report Share Posted April 4, 2019 37 minutes ago, dougbgt6 said: Looks like I've got 0.25" into 7mm then. So I have a constriction of 0.0255" out the tank. Which means a flow reduction of...…………………. How did that happen? I've never had fuel starvation, so I'm not going to worry about it. In the words of the Guru Mark Smith "If it ain't broke, don't fix it." Doug IMV. Sound advice!. Lots of people tinker with stuff, and then regret doing it!.😢 Link to comment Share on other sites More sharing options...
Adrian Saunders Posted April 14, 2019 Report Share Posted April 14, 2019 This short section of rubber is a sod to fit. Has anyone used a lubricant to make it easier? Link to comment Share on other sites More sharing options...
Paul H Posted April 14, 2019 Report Share Posted April 14, 2019 6 hours ago, Adrian Saunders said: This short section of rubber is a sod to fit. Has anyone used a lubricant to make it easier? Vaseline Paul Link to comment Share on other sites More sharing options...
daverclasper Posted April 14, 2019 Report Share Posted April 14, 2019 (edited) Doing water traveling hoses I've often dipped the ends in boiling water to soften. For fuel, maybe gentle heat with a hair dryer/paint stripper gun and don't forget the vaseline, very good. Dave Edited April 14, 2019 by daverclasper Link to comment Share on other sites More sharing options...
Adrian Saunders Posted April 28, 2019 Report Share Posted April 28, 2019 This Gates Barricade 5/16 is still evil to fit. I can’t get any further than 10 mm on, and that’s with the hard line off the car! With it fitted its even less, with lubricant. Anyone else struggled with Gates Barricade R9? Link to comment Share on other sites More sharing options...
Paul H Posted April 28, 2019 Report Share Posted April 28, 2019 I warmed up the Gates with a hot air gun , plus Vaseline Paul Link to comment Share on other sites More sharing options...
Adrian Saunders Posted April 28, 2019 Report Share Posted April 28, 2019 At the risk of many, many jokes, did you find it difficult to insert to anything beyond 10 mm? Even with heat and Vaseline? 1 Link to comment Share on other sites More sharing options...
Badwolf Posted April 28, 2019 Report Share Posted April 28, 2019 19 minutes ago, Adrian Saunders said: At the risk of many, many jokes, did you find it difficult to insert to anything beyond 10 mm? Even with heat and Vaseline? I don't think anyone is brave enough to follow up from that!!! Maybe on Doug's other website!!!! Link to comment Share on other sites More sharing options...
Paul H Posted April 28, 2019 Report Share Posted April 28, 2019 46 minutes ago, Adrian Saunders said: At the risk of many, many jokes, did you find it difficult to insert to anything beyond 10 mm? Even with heat and Vaseline? 15mm for the joint at the front of the chassis . Paul Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 28, 2019 Report Share Posted April 28, 2019 Adrian, (Serious face on) it sounds like you have the same issue as me. Despite the specs saying the pipes are 5/16 some are 7mm, slightly bigger. I boiled and greased the Barricade and got 1/2" on the 7mm. With the hose clamp I think that's enough. Doug Link to comment Share on other sites More sharing options...
Adrian Saunders Posted April 28, 2019 Report Share Posted April 28, 2019 1 hour ago, dougbgt6 said: Adrian, (Serious face on) it sounds like you have the same issue as me. Despite the specs saying the pipes are 5/16 some are 7mm, slightly bigger. I boiled and greased the Barricade and got 1/2" on the 7mm. With the hose clamp I think that's enough. Doug Thanks Doug. I’m going to get some 8 mm Gates and test it at work. I can do some vacuum and pressure decay testing on it secured with some ABA clips. I’ll publish the results. What’s this “other website” that Badwolf mentioned? Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 28, 2019 Report Share Posted April 28, 2019 It's a web site for the discerning gentleman, there are stringent entry requirement, but Pete Lewis can probably sign you in. db 2 Link to comment Share on other sites More sharing options...
Clive Posted April 29, 2019 Report Share Posted April 29, 2019 12 hours ago, dougbgt6 said: Adrian, (Serious face on) it sounds like you have the same issue as me. Despite the specs saying the pipes are 5/16 some are 7mm, slightly bigger. I boiled and greased the Barricade and got 1/2" on the 7mm. With the hose clamp I think that's enough. Doug Doug, are you sure you don't mean 8mm?? 5/16"=7.9375mm Rubber hoses seem to work OK on a slightly smaller pipe, but if the pipe is too big for the hose, they are almost impossible to fit. Especially in fuel hose sizes.... Link to comment Share on other sites More sharing options...
dougbgt6 Posted May 4, 2019 Report Share Posted May 4, 2019 Clive, You may be right, I was relying on dimension supplied by Pete, to lazy to verify the facts myself! And yes very difficult to fit. Doug Link to comment Share on other sites More sharing options...
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