Exhaust fumes

Before I do anything about having my car checked is it normal for a 246 to have very noticeable exhaust fumes especially with the windows open? I have to admit it's a long time since I owned a non-cat equipped car and even longer since I had a car with carb's but I don't recall the smell being as strong. I also get a strong smell of fuel around the rear quarter of the car where the gas cap is. I know there are no fuel leaks as the system was thoroughly checked through. Is this simply down to the design of the system with no breather system like modern car that allows vapour release?

 

There are many causes of a strong fuel smell. If, indeed, this is exhaust related then I would first check the carb mixtures to make sure that you are not running too rich. Best to remove the intake plenum to gain acess to the mixture screws. If you have not adjusted them before, let us know and we can walk you through the process.

Second cause could be timing (retarded).

Third, and quite common, is a leaking or perforated cross-over tube. There are several, some more hidden then others. The obvious cross-over tubes are the clear one behind the engine lid hinges (filler cap to opposite tank), the lower cross-over mounted against the bottom of the firewall, and the hidden one, a metal pipe running on a frame ledge in front of the rear storage firewall. This is the roll-over valve and cannister tucked way up in the passenger wheel well (assume your car is right hand drive).

Unless someone really knows these cars, having it "checked" out might not be sufficient.

Jim S.

 

You might also want to check around fuel filter, especially if it may have just been changed.

My car arrived completely 'dry' underneath and then I changed the fuel filter and the smell started. It was a small fuel leak around the fuel filter. I thought it was a leaking seal on the filter body but then found the fuel was leaking past the washer on the bolt that holds the fuel filter in place. For a short while I thought it was the copper washer on the outlet pipe.

Put clean newspaper under the car just in front of the passenger rear wheel (on a RHD drive car or drivers side on a LHD - same place but different seating). Turn the ignition on for 30-60 seconds to build up pressure, don't start it, turn the ignition off and see if you have any drips. For some reason it took about a minute for my leaks to show up. As far as I can see it should leak even with the system unpressurised but mine only really shows up as described above.

I managed to ruin the rubber seal on the filter body whilst investigating all of this (tip - make sure it is correctly seated before tightening the securing bolt) and have just received a new filter and seal from Superformance in the UK and will fit them tomorrow.

In the meantime I did a bit of research and I am hoping my problem is caused by hardened washers. I have annealed the copper washers on the outlet and the aluminium washer on the filter bolt. I could explain annealing here but have a look at this site which does it much better - http://www.motorcycle.co.uk/reference-material/annealling-copper---aluminium-washers.aspx

Please note that copper and aluminium need different temperatures to be annealed effective. The article explains this and tells you how to easily achieve the correct temperature over a gas flame on a cooker using Fairy Liquid believe it or not.

Also please see his notes at the bottom. They are amusing. Especially the one about being careful of the hot pliers. It made me smile, at least until I did exactly what he said not to do - ouch !!

I'll report back tomorrow on how it has gone.

 

Many thanks for the replies and pointers.

 

Thanks for that link, real home mechanic stuff, took me right back to the back yard and my mother complaining of the dirty shoe marks leading from the back door to the gas cooker, across the tiled floor, as my brother and I tried to squeeze an Arial square four into a Norton featherbed!

 

Well it all went well well and I have no more fuel leaks

 

Does thAt mean you can start smoking again?