AtLast Posted June 1, 2016 Report Share Posted June 1, 2016 Hi all I recently moved my just restored 3A to my garage and have noticed a strong smell of petrol. Trouble I've got a room above the garage and I can smell it, to a lesser degree, in their too. Previously it was in a very large barn in a air tent so I think the smell quickly dissipated and wasn't so obvious. I've checked all the pipes I can see and fuel filler cap and can't find any leaks. Engine bay and all around carbs all seems fine. The smell appears to be mainly coming from the metal tank breather pipe that comes out near the back on the drivers rear wheel side. I've noticed the smell is much worse afterjust putting thirty quids worth of petrol in and wonder is there any issue with putting some electrical tape or a bung over the pipe whilst it's sat in the garages so long as I remember to remove it when driving? I intend to use the car fairly regularly (once a week). Or is that dangerous? Cheers Archie Quote Link to post Share on other sites
Lebro Posted June 1, 2016 Report Share Posted June 1, 2016 You need a vent on the tank somewhere or else it cannot draw air in to replace the petrol you use. Are you sure the smell is coming from the vent, & not just from the bottom of the tank - which may be rusty, & seeping very slightly ? Bob. Quote Link to post Share on other sites
AtLast Posted June 1, 2016 Author Report Share Posted June 1, 2016 Hi Bob pretty sure it is the pipe. The tank was treated and tested during the rebuild but I will strip out the carpet and look again. For now I've covered the vent pipe with some electrical tape and will check again later. Yep I'll remove it when I use the car so air can breath in as well as out when filling up with petrol. My concern was more that by blocking the breather whilst the car is standing are there any risks of gasses building up in the tank and that being dangerous? Thanks for your reply. Quote Link to post Share on other sites
AtLast Posted June 2, 2016 Author Report Share Posted June 2, 2016 Well blocking the breather pipe with some tape seems to have made a big difference. Hardly any smell when I opened the garage today. So that's good news.... But would anyone be able to chime in to put my mind at rest that there is no danger having the breather pipe sealed whilst the car is standing so long as I remove it before driving or putting in more petrol? Thanks Quote Link to post Share on other sites
RobH Posted June 2, 2016 Report Share Posted June 2, 2016 No problem and no danger Archie - as Bob says the vent is to let air in not to let fumes out. Have you never carried petrol in a sealed can? Its exactly the same. Quote Link to post Share on other sites
AtLast Posted June 2, 2016 Author Report Share Posted June 2, 2016 Hi Rob thanks (and to Bob) yep have indeed done just that and it makes sense - just wanted that extra bit of certainty before I took out the garage!! Cheers Quote Link to post Share on other sites
boxofbits Posted June 2, 2016 Report Share Posted June 2, 2016 Hi Archie My only concern is that you can smell petrol simply because the tank is naturally venting and some vapourization is taking place. Are you sure that your garage itself is vented properly, with air blocks or metal vents in place of a couple of bricks for instance, as this would surely be a better option than blocking the tank vent? Regards Kevin Quote Link to post Share on other sites
AtLast Posted June 2, 2016 Author Report Share Posted June 2, 2016 Hi Kevin... there is a bloody great gap under the front doors that provides plenty of circulation! I spend quite a bit of time in the garage and the room over it as also have a PC and some musical equipment in there and the smell was very noticeable. Popping so tape on the breather pipe whilst it's in there has definitely reduced (if not quite eliminated) the smell. Cheers Quote Link to post Share on other sites
foster461 Posted June 2, 2016 Report Share Posted June 2, 2016 Are we doomed to having to live with this problem or do some cars do it, some cars not and we just need to figure out why ? Stan Quote Link to post Share on other sites
Graham Harris Posted June 3, 2016 Report Share Posted June 3, 2016 Over filling is one of the main reasons i have found if i push the pump nozzle all the way in up to the triger and stop filling when it clicks off the first time, thats full enough. Graham Quote Link to post Share on other sites
AtLast Posted June 3, 2016 Author Report Share Posted June 3, 2016 So Graham are you saying I should stop work immediately and go out for a nice long drive to use up some petrol sounds a good plan even if it doesn't work! I think you may be onto something though because the smell definitely worse since I filled her up. Cheers Quote Link to post Share on other sites
Devs Posted June 3, 2016 Report Share Posted June 3, 2016 You could block that breather up permanently and instead, opt to drill a small hole in the filler cap (not in the chrome of course, in the sealing cap beneath). I had to complete this action when my breather became blocked after I sealed my tank, however I'm aware of other individuals who have completed this action due to 1/ excessive fumes and also petrol slopping out of the breather when hard cornering. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted June 3, 2016 Report Share Posted June 3, 2016 (edited) No visible leaks at the tank sender or anywhere else? Genuine or repro tank? I have seen a repro tank that had the internal breather arrangment all to cock/missing - It should have an internal vent pipe to stop self syphoning ( think original Metro problem here, that would empty its fuel tank all over the RH rear tyre on a warm day if parked on a sideways slope or swerved round a RH bend) Peter W Edited June 3, 2016 by BlueTR3A-5EKT Quote Link to post Share on other sites
harrytr5 Posted June 4, 2016 Report Share Posted June 4, 2016 A mate of mine has a TR3a which suffers from the tank vent and stank out my garage. I looked at the non return vent valves and thought that might work but, as the TR lives in a council lock up which is well vented and not a problem he gets on and just drives it. If it lived in my garage I would try the valve as I could not put up with it. Regards Harry. Quote Link to post Share on other sites
AtLast Posted June 4, 2016 Author Report Share Posted June 4, 2016 Hi, its an original tank. I'm going out for a long drive tomorrow so hopefully just having less fuel in there when I get back will help but certainly covering up the pipe has helped a lot. Does anyone have a link for the vent valves you mention? Thanks for all the input. Archie Quote Link to post Share on other sites
foster461 Posted June 4, 2016 Report Share Posted June 4, 2016 My cap seems to already have a 1/16 hole drilled through the bit that seals against the tank filler hole. I blocked off the end of the vent tube and will see if that makes any difference. It seems odd that they would design that elaborate vent tube mechanism if a small hole in the lid would serve the same purpose. Stan Quote Link to post Share on other sites
harrytr5 Posted June 4, 2016 Report Share Posted June 4, 2016 (edited) Hi, its an original tank. I'm going out for a long drive tomorrow so hopefully just having less fuel in there when I get back will help but certainly covering up the pipe has helped a lot. Does anyone have a link for the vent valves you mention? Thanks for all the input. Archie www.demon-tweeks.co.uk Try this and scroll down. Regards Harry. Edited June 4, 2016 by harrytr5 Quote Link to post Share on other sites
BrianC Posted June 5, 2016 Report Share Posted June 5, 2016 My cap seems to already have a 1/16 hole drilled through the bit that seals against the tank filler hole. I blocked off the end of the vent tube and will see if that makes any difference. It seems odd that they would design that elaborate vent tube mechanism if a small hole in the lid would serve the same purpose. Stan I thought the vent tube was also to allow for overflow in the case of expansion on a hot day if the tank is full. Better than having it leak out of the filler cap hole all over the rear of the car and into the boot. Quote Link to post Share on other sites
foster461 Posted June 5, 2016 Report Share Posted June 5, 2016 I thought the vent tube was also to allow for overflow in the case of expansion on a hot day if the tank is full. Better than having it leak out of the filler cap hole all over the rear of the car and into the boot. That makes sense Brian. I guess it is not a good idea to totally fill the tank. Gasoline creates holes in my blacktop driveway. I'm hoping that modern pumps shut off before the tank is that full assuming you have the nozzle fully inserted. Stan Quote Link to post Share on other sites
TomMull Posted June 5, 2016 Report Share Posted June 5, 2016 At the risk of beating a dead horse with this, wouldn't the tube render the pinhole totally redundant? Tom Quote Link to post Share on other sites
foster461 Posted June 5, 2016 Report Share Posted June 5, 2016 At the risk of beating a dead horse with this, wouldn't the tube render the pinhole totally redundant? Tom It would Tom but perhaps that cap was also used on cars that didnt have the vent tube and so some cars got both the tube and the hole in the cap ?. My current solution is to put a plastic cap over the end of the tube but leave a small hole in that plastic cap just in case any fuel gets into the tube. Now I have two small holes for ventilation/drainage and a greatly reduced smell of fuel in the garage. Quote Link to post Share on other sites
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