ejparrott Posted September 22, 2015 Share Posted September 22, 2015 Project fuel tank.Not sure if this is the right board, but it was either here, fabrication or Series, and I thought this might get the biggest exposure for interest, and maybe any pointers and suggestions along the way. I think I've mentioned already that The 109 appears to have sprung a leak in it's fuel tank, probably as a result of me having it out to do the welding on the rear cross-member, so it's time to make a new one. I figured making a new one would result in a quicker turnaround than repairing the old - if even possible - and in any-case I do need another tank for the other 109, as the one that came with it was the narrow low capacity one for working with a rear PTO.So, one flat pack fuel tankI've increased the capacity a little by widening it by about 30mm, and there won't be the flange that the OEM tanks have so probably say 50mm extra width would be more accurate. I've also added some to the bottom, and a short extension to the front which goes over the axle - I can do this as The 109 won't ever be getting extreme axle articulation, nor does she need such a good break out angle as previously.This is the pickup pipe sitting on the narrow tankand this is it sitting on the new tank in about the same position, showing just what I've added to the bottomI'm intending to make all the fittings on the top to accept OEM fittings, should just be able to transfer the old return pipe and the old sender unit over, just fitting a new longer pick up. I'm hoping I can just silver solder an extension onto the existing tube which is steel. My spare sender unit has enough reach to cater for the extra length so hopefully the current one is the same.The filler tube is a length of 1.5"BSP tube, for which I have a pipe bender to suit. Turns out the outside is just right for the rubber connecting tube - provided you out a bit of a lead on - I chose to put it in the lathe and turn a bit of a collar on it to aid the jubilee clip....probably aid the hose fighting me when I want to get it off some point in the future.... At this stage I haven't planned to put any baffles in, and I'm not sure if I should be or not. It seems like there is currently baffles in the spare tank, it sloshes and I can't get anything out of it....might have to borrow the bore-scope and have a looksi. Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 22, 2015 Share Posted September 22, 2015 Very nice wee project here, I've often pondered making my own tank after replacing a couple of them on 110's and not really been overly impressed with the quality of them. Did you cut them out and bend the sections yourself? Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 22, 2015 Author Share Posted September 22, 2015 No. I created the CAD drawing for the side panels, starting with the existing tank then overlaying a new one, sent these off for laser cutting. The foldings I had done by a friendly sheet metal company. I would really really like to be able to do foldings like this myself, but I haven't got the room for the kit Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 22, 2015 Share Posted September 22, 2015 Interesting - the 109's tank is not a million miles off that for reasons of rear winch-tray. What are you doing about baffles? Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 22, 2015 Author Share Posted September 22, 2015 Currently no plans, I'm looking for suggestion on that matter. Well, I say 'no plans', I have been thinking about it, but have not yet come to any conclusions. I was going to get the main body done, and then install something before the tops go on. I was thinking about putting one in under the dropped section for the cross-member, then something further forward but clear off the sender unit, but I'm not too sure what the requirements are - there's still some googling to be done!! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted September 22, 2015 Share Posted September 22, 2015 Please don't delete those CAD plans, I've been planning a long range tank for my 109 for sometime, and it looks like you've done most of the work for me. On the subject of baffles then I'd say you should put them in: you never know what engine you may fit. You may need a swirl pot in the thing someday. Here is an interesting link: http://www.mig-welding.co.uk/forum/threads/modifying-a-clean-and-new-fuel-tank.29629/ http://www.mig-welding.co.uk/forum/threads/modifying-a-clean-and-new-fuel-tank.29629/ G. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 22, 2015 Author Share Posted September 22, 2015 Haha..don't worry, I've got CAD files going back a long way, never delete any!! Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted September 22, 2015 Share Posted September 22, 2015 If its any help here's how i did the baffles in my tank about 5 years ago. I can run it as good as completely dry offroad without any pickup problems. And its quite easy to make: Oh and pickup tube sits right in the middle of the center (smaller) square container Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 22, 2015 Author Share Posted September 22, 2015 I knew it would be a good idea to post this for all to see! Ok, I wasn't aware that anything like this was required in a fuel tank! My 88's tank doesn't have anything in it, it's just the 6 sides, consequently I hadn't planned on fitting anything inside. I'd thought about baffles to stop the fuel surging around in the tank under braking or accelerating, thinking that it would be potentially problematic when the level was getting low. I'll perhaps add something in the area where the pickup eventually ends up - I can add that at any stage before the lid goes on though. Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted September 22, 2015 Share Posted September 22, 2015 Definitely fit some baffles. The custom tank on my hybrid doesn't have any and the fuel light flashing every time I go round the slightest corner drives me nuts. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 22, 2015 Share Posted September 22, 2015 Clever baffles Soren! Quote Link to comment Share on other sites More sharing options...
steve b Posted September 22, 2015 Share Posted September 22, 2015 Is that MIG'd Aluminium Soren ? Your baffle layout is like mine in the main tank where the pickup is , basically a open box with some small notchs in the base edge . I also have larger baffles to stop surge with a larger gap at the bottom cheers Steveb Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 22, 2015 Author Share Posted September 22, 2015 Baffles it is then! I'd like to get hold of some perforated sheet, somehow knowing the local stockists I think it'll be out of pocket range! I think a piece of that under the dip would be functional. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted September 23, 2015 Share Posted September 23, 2015 Yes it is, so much easier to MIG in Ali, the gaps doesn't have to be so perfect. I did TIG the outside of the tank though, TIG is better for making sure it won't have any leaks Quote Link to comment Share on other sites More sharing options...
miketomcat Posted September 23, 2015 Share Posted September 23, 2015 You could do something like soren out of tube with some strategic holes. Mike Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 23, 2015 Author Share Posted September 23, 2015 I've been looking at that and wondering....I can bend 1mm myself up to about 4" long, that I would have thought would be ok for the pickup issues, especially when you consider that we won't be offroading with this one, not more than gentle laning anyway. She's our camper and currently the tow vehicle, the 88 being a bit poorly and I prefer the extra length and weight of The 109 for towing anyway. Won't help with the level reading though, not sure how much I'm bothered about that though, need to think some more on that one. Quote Link to comment Share on other sites More sharing options...
Carloz Posted September 23, 2015 Share Posted September 23, 2015 Sörens baffels are no baffles, it's a clever anti surge trick! The pick up pipe AND return pipe has to be in the center. Basically two C's with a liitle different diameter in eachother with the opening 180 opposite from eachother Baffles are big sheets of metal almost as big as the side walls which are welded in the tank in a way that the tank is devided in for excample three sections. In the corners the deviders (baffles) are left open. This prevents excessive fuel movement in the tank which can make damage like broken welds. Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 23, 2015 Author Share Posted September 23, 2015 Why does the return pipe also have to be in the centre? Quote Link to comment Share on other sites More sharing options...
Carloz Posted September 23, 2015 Share Posted September 23, 2015 Because you can see that area as a sort of tank in a tank: when you are in a steep angle this area is separated from the rest of the fuel (which is in a far corner in your almost empty tank) the return pipe fils this area up again, only the fuel what is used by the engine disapears. Otherwise the fuel pump pumps this area empty in no time with fuel surge as a result. ;-) When the car is level again this anti surge "tank" in the tank will be filled up again. The openings must not be to big: in that way the level of the fuel will always be higher than in the rest of the tank (in case of a quite empty tank). Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 23, 2015 Author Share Posted September 23, 2015 Right, I get you, that makes sense yes. I've just had another look at the narrow tank with the sender unit out. With a decent torch I can see there is actually a single baffle in there. It's actually very large, comes about half way up the tank and it's 'wings' are actually only about 2" in from the edge of the tank, way way larger than Soren's. Also checked the busted 88" tank again - nothing in there at all Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 23, 2015 Share Posted September 23, 2015 I'm guessing it's more of an issue for V8's as they have electric fuel pumps that hoof quite a lot of fuel through the system constantly. Certainly my tank we baffled (as in a couple of big plates across the tank) to stop fuel sloshing fore & aft too much, but didn't create a nice pickup area like Soren and I regretted it, the (external) fuel pump would run dry very easily, I added an external swirl pot with the return line teed in but always intended to re-do the tank with better baffling etc. and a bit more capacity. Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 23, 2015 Share Posted September 23, 2015 The EFI V8 in-tank pumps have an integrated bowl like that as well. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted September 23, 2015 Share Posted September 23, 2015 I have also seen a horizontal baffle in an engine sump. (BMC B Series). The baffle plate had three holes, one for the oil pump pick-up strainer bowl, one for the dipstick, and one in a rear corner, furthest from the other two. I recall the largest hole (oil pump pick-up) as having a flanged edge. This was more to ensure continuous oil pick-up, rather than stop the liquid sloshing about. Although the two requirements overlap, the engine sump wasn't trying to control 5 gallons in a 20 gallon space. It was the horizontal design feature I was offering as an alternative consideration. Regards Quote Link to comment Share on other sites More sharing options...
ejparrott Posted September 23, 2015 Author Share Posted September 23, 2015 It's a thought. 200 ladder frame is rather like that, can't remember how many holes are in it Quote Link to comment Share on other sites More sharing options...
Maverik Posted September 24, 2015 Share Posted September 24, 2015 I'm ot sure this has been mentioned as such as most have been concerned with continued fuel supply (which is of course important!) but from a stability side I'd want something to retard the liquid slopping around front to back and side to side, although the inherent position of the fuel tank isn't so centre of gravity critical, i'd argue that you coud easily have 40ltrs ~ 40kg of mass moving around above the rear axle which if you've ever experienced shifting loads when cornering, its not perticulalry pleasant... I'm not overly familiar with a 109 tank but i'd maybe consider fitting an inspection hatch that you could easily get your hand in, on the one occasion you'll need to look in the tank to inspect or clean it due to some contaminant, it might come in handy...? Quote Link to comment Share on other sites More sharing options...
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