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Custom fuel tank building, help with baffles + fuel pickups please


bobtailrangie
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Hi everyone

Building a bobtail off road toy at the moment

Will have 1 fuel tank either side in the rear so i keep as much boot space as poss as im keeping the rear seat

The bit im stuck on is baffles + fuel pickups

How is best to have the baffles, horizontally, vertically etc?

Also fuel outlets, rather than having a fuel pickup from inside the tank i was thinking more of having just a fuel outlet on each tank going to a t piece then to an external pump with a filter before the pump

Would 2 or 3 outlets on each tank then all t'ing together be ok or cause problems?

cheers for any help + suggestions, i only want to do it once + do it right

James

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when i built my bobtail i thought about making my own tank and decided against it. it hasto be so clean inside as some contaminents will cause serious problems (sillicone) and tbh, i diddnt really like the idea....i can weld alli fine but at the time wasnt confident enough to weld up something that size. so i opted for a custom alli one from allisport, i knew it was going to cost but i got a nice sized tank that weighed nothing and did the job very well.

if i were to do it again i would have used the tank from a 90, it would have been half the price and a bit smaller.if your putting your tanks in the boot have you thought about mini cooper rally tanks? they had a tank on either side joined up. wouldnt know how much they are but just a thought.

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single tank would be easier in a 4x4 and probably cause less issues,if you did have 2 tanks why not use them seperatly with a valve or something to swap tanks,as for the fuel pick use a length of silicone or ptfe pipe with a small ball weight on the end (drilled and pipe running through),whatever angle the trucks on the ball will follow the fuel round the tank,if you did run 2 tanks at the same time do this in both tanks and fit non return valves near each tank,1 tank cant bleed into the other then on side slopes and should empty evenly

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single tank would be easier in a 4x4 and probably cause less issues,if you did have 2 tanks why not use them seperatly with a valve or something to swap tanks,as for the fuel pick use a length of silicone or ptfe pipe with a small ball weight on the end (drilled and pipe running through),whatever angle the trucks on the ball will follow the fuel round the tank,if you did run 2 tanks at the same time do this in both tanks and fit non return valves near each tank,1 tank cant bleed into the other then on side slopes and should empty evenly

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when i built my bobtail i thought about making my own tank and decided against it. it hasto be so clean inside as some contaminents will cause serious problems (sillicone) and tbh, i diddnt really like the idea....i can weld alli fine but at the time wasnt confident enough to weld up something that size. so i opted for a custom alli one from allisport, i knew it was going to cost but i got a nice sized tank that weighed nothing and did the job very well.

if i were to do it again i would have used the tank from a 90, it would have been half the price and a bit smaller.if your putting your tanks in the boot have you thought about mini cooper rally tanks? they had a tank on either side joined up. wouldnt know how much they are but just a thought.

The 90 tank isnt a bad idea, wouldnt be perfect but would be probably the easiest + cheapest + the shape they are i would be able to get it over + still have some decent space, good thinking

Is it for diesel or petrol, carbs or injection?

The problem with connecting the outlets with a T piece is that when the level is low you may draw in air if driving on a side slope.

Its petrol injection, yes i did wonder about air but today i have thought i could just use a 2 litre swirl pot so there will always be fuel for the engine + a not injection pump would keep it topped up

http://www.ebay.co.uk/itm/Race-Rally-Performance-Alloy-Fuel-Swirl-Pot-2Lt-A030-/190474588949?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c592b9315

Ive made them before + wont need a baffle due to the shape

single tank would be easier in a 4x4 and probably cause less issues,if you did have 2 tanks why not use them seperatly with a valve or something to swap tanks,as for the fuel pick use a length of silicone or ptfe pipe with a small ball weight on the end (drilled and pipe running through),whatever angle the trucks on the ball will follow the fuel round the tank,if you did run 2 tanks at the same time do this in both tanks and fit non return valves near each tank,1 tank cant bleed into the other then on side slopes and should empty evenly

I like the idea of a weight on fuel pick up, never would have thought of that, just trying to think of how id make it + stay on the pipe, ive had a search but all i can find are small ones for rc helicopters

The non return valves are something to think about too, nice one

Mine has a foam filled plastic tank in an Ali case. The pickup & return are pipes going to two cone shaped devices. The vent just goes to the top of the tank.

Never looked into the theory though :)

Someone else suggested foam filled today too, also another good option

cheers everyone for help on this, given me some food for thought, once ive cut the body about + finished it ill see what ive got left to work with + ill put pics in the build thread

cheers again, geat help :D

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I believe Whitebread do an ally tank that is made to take the original Rangie in tank fuel pump and sender, and is sized to fit between the chassis rails in the rear. Can't remember the cost but I sure it wasn't silly money.....

MIne was built by MJ Lee and also sits between the chassis rails, but sticks up so the boot floor is about 6 inches higher than normal, but it also allows the rear seat to be retained.

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I did mine as a tank in a box with a 2mm ally tank inside a 3mm walled 'bund' box with a 4mm base. (underside protection) With a bolt on lid on the box, I mounted the tank inside with foam. Hopefully water won't get into the box, let alone the tank, so I hope for a good fatigue life? Should also reduce sweating?

Because it had a tough base I went to the bottom of the chassis rail, so I got a deep tank but short. So no baffles required :)

But when we repair or make tanks the baffles are usually a virtical plate, with corners cut off and the odd hole. The edges are usually bent at 90 to make the weld easier.

I was considering that a sealed tank would siphon fuel from another as it empty'd, but I think if I really had to go for it I would chuck on another pump to load the primary tank from a secondary part way through the day.

And if I did that I think I would run primarys breather back to the secondary, so over filling wouldn't cause any harm :)

So far 6 gallon has done us, with a check at lunch time, so theory has never been tested.

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