Petrol tank issues/ design.
Discussion
Hi guys hows it going on this rainy bank holiday Monday?
I've finally decided to bite the bullet and Ive taken the body off my 350i so I can refurb the chassis and hopefully mod the mounting points to fit coil over shocks at the same time (if anyone will still sell them by the time im done). Ive been thinking about the petrol tank while I was under there, is it just me or does anybody else have issues filling the two tanks? petrol pumps seem to be to quick now to decant into the second tank, it does seem a strange design with a small pipe at the bottom of the two tanks and a large one at the top, I would have thought it should fill the second tank from the bottom with the air bypass at the top (maybe wrong though). Has anybody here thought about making the tank in one piece sort of bridge shape with the two tanks joined at the top for the full width instead of just with the rubber tube (should fit over the chassis), maybe with a bigger tube joining at the bottom if it will fit between the chassis tubes? Or is this a daft idea, thoughts please lol.
......or maybe just one tank on the filler side.
This brings me to the other problem I used to have (when the car was last on the road), if I parked on a kerb or similar the petrol (when I managed to finally fill both tanks) would run back into the first tank then up the filler pipe, down the overflow tube and onto the floor on the rear nearside corner, this happened when I drove off the kerb or took the filler cap off. unfortunately it also happened once, much to the owner of a B&B's horror as I ruined his newly laid but unfortunately slightly slopey tarmac drive with unleaded petrol, not a good mix and not the only time it happened either (hot sun, full tanks and expanding fuel do the same). From then on Ive never put more than about 15 litres in at a time, problem solved but seriously cuts the miles between fills down.
Is this just a problem with my car? and any advice on what to do would be great, sorry about the essy. Have a good rest of the day.
regards
Jon
I've finally decided to bite the bullet and Ive taken the body off my 350i so I can refurb the chassis and hopefully mod the mounting points to fit coil over shocks at the same time (if anyone will still sell them by the time im done). Ive been thinking about the petrol tank while I was under there, is it just me or does anybody else have issues filling the two tanks? petrol pumps seem to be to quick now to decant into the second tank, it does seem a strange design with a small pipe at the bottom of the two tanks and a large one at the top, I would have thought it should fill the second tank from the bottom with the air bypass at the top (maybe wrong though). Has anybody here thought about making the tank in one piece sort of bridge shape with the two tanks joined at the top for the full width instead of just with the rubber tube (should fit over the chassis), maybe with a bigger tube joining at the bottom if it will fit between the chassis tubes? Or is this a daft idea, thoughts please lol.
......or maybe just one tank on the filler side.
This brings me to the other problem I used to have (when the car was last on the road), if I parked on a kerb or similar the petrol (when I managed to finally fill both tanks) would run back into the first tank then up the filler pipe, down the overflow tube and onto the floor on the rear nearside corner, this happened when I drove off the kerb or took the filler cap off. unfortunately it also happened once, much to the owner of a B&B's horror as I ruined his newly laid but unfortunately slightly slopey tarmac drive with unleaded petrol, not a good mix and not the only time it happened either (hot sun, full tanks and expanding fuel do the same). From then on Ive never put more than about 15 litres in at a time, problem solved but seriously cuts the miles between fills down.
Is this just a problem with my car? and any advice on what to do would be great, sorry about the essy. Have a good rest of the day.
regards
Jon
I discovered a new technique to fill up the other day, as I had to top up the reserve gallon I keep in the boot while I was filling:
- Fill up at full speed to the filler clicks
- Wait 30 seconds
- Fill up to brim
I'm not use if it's overall any quicker than running the filler at half speed after the first click but there you go.
As for expansion, yes if you know you will have to park up soon after filling then don't brim the tanks. Any more than 10 miles though and you should be safe. Luckily where I live in East Anglia we don't get many slopes!
- Fill up at full speed to the filler clicks
- Wait 30 seconds
- Fill up to brim
I'm not use if it's overall any quicker than running the filler at half speed after the first click but there you go.
As for expansion, yes if you know you will have to park up soon after filling then don't brim the tanks. Any more than 10 miles though and you should be safe. Luckily where I live in East Anglia we don't get many slopes!
Must admit I did a similar thing, on the near side tank at the top in the arch is a small pipe with a bolt in the end, so I think "maybe this is to let air out the tank while filling, why else put a hole in it", so like a bright spark I take it off then fill the tank, only to hear some one shouting "petrol pissing out", I then think I'll push something in the hole but without the car jacked up can't get my hand up in the arch. doh! very embarassing, I got the sand out, paid and never went back lol.
My first wedge had twin fillers, I once filled the car happily, so happily it was running out the lower second filler as SLOW as I could dribble fuel into the higher filler, I only stopped when I saw the HUGE wet patch.
My Turbo has twin alloy tanks from the factory, I can fill it as fast as any pump can deliver, The pipework seems fairly standard 16mm bottom connecting pipes and a 6mm top pipe all via a swirl pot, a 50mm pipe at the top of the two tanks, and I think most importantly, another 6mm pipe from the top of one tank, up to the top of the B post then back down to the neck of the filler. I guess this could be prohibitive with a DH, but something similar must be possible.
Regards,
Chris.
My Turbo has twin alloy tanks from the factory, I can fill it as fast as any pump can deliver, The pipework seems fairly standard 16mm bottom connecting pipes and a 6mm top pipe all via a swirl pot, a 50mm pipe at the top of the two tanks, and I think most importantly, another 6mm pipe from the top of one tank, up to the top of the B post then back down to the neck of the filler. I guess this could be prohibitive with a DH, but something similar must be possible.
Regards,
Chris.
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