Curious smell of gas.....

[CliffBeer]

When I put my CAV (mono #8) back in the garage after a drive I smell a relatvely strong smell of gas. Using a gas sniffer tool (my nose) I can't seem to pinpoint the origin. It doesn't seem any stronger in the engine bay than it does anywhere else. Obviously, this situation is a bit concerning as I'd hate to see my car go up in flames.

Anyone had any kind of similar problem with their CAV?

[Jac Mac]

Cliff,
First check to ensure that the smell is not residing in the garage already due to a can of gas for a lawnmower or other vehicle etc. If you drive into a garage with a car that has electric cooling fans etc, these tend to lift and blow any fumes etc up to the level where your super sensitive gas sniffer can detect them. If you need a second opinion get a feminine version of the gas sniffer on the case, they apparently have a more highly developed detection system!
Jac Mac.

[Gary Gibbs]

Hope you have installed the cap retrofit to put a modern gas cap under the LeMans.

[MK -IV J6]

Gas especially winter gas has additives that are designed to smell to alert owners to leaks.

Carb cars after being shut down emit fumes. Cars that run rich and most of these do emit fumes. These fumes are not good to sniff but may not be indicative of a leak. Garages should be well ventilated esp. if storing cars like these. If there is a fuel vent open to the air you could try a charcoal canister. Make sure there are no leaks and if there aren't still air out the garage before starting your car.

Best

[Veek]

As mentioned, it's probably your carb innards that were wet with fuel when the car was running that are evaporating. If you topped off the car it may also be slosh on the interior of your cap. See if it's wet.
But to be sure, check all of your fuel lines and I'd feel under the car under each fuel cell to see if your cell is leaking. If so, you'll need to inspect the cell and repair. For the breather, my engine also had water hose installed instead of emissions hose and that degrades over time and leaks.

Good luck!

[JCoop]

My family always complained that the garage smells like gasoline; and my clothes reek of gasoline whenever I'm working on or driving the GT40. I have vented fuel caps on it (no upgrade). Now my garage houses the Cobra and 2 Mini Coopers as well - all carburetted and the Mini's have vented tanks. My wife and 2 girls are all used to fuel injected cars that have sealed systems and have no smell at all. On days that I drive to work in my regular commuting car (fuel injected) and not fool with the "toys" I can hug the girls without any complaints.
So I think it's just the carbs in your car. The bowls are full of gas and the smell kinda vents through. And as mentioned, if you don't have the fuel cap upgrade like me, it would smell. I'm so used to it I don't even smell it anymore.
Unless there's really a leak somewhere, then it would really be evident.
Dunno if that helped but my 2c

[CliffBeer]

Thank you all - very good suggestions. I'll do as suggested and check all the lines and tanks for leaks and, if none, then see what I can do about managing the evaporation from the carbs.

Much appreciated. My wife thanks you for assisting with changing my cologne from eau de garage to something more sophisticated.

[Tony Hunt]

One final point, it's a good idea to flip the fuel pumps off about half a mile from home, then run the carb dry. It's also good fun seeing how finely you can judge it!
My garage smells of fuel - I thought it was my unmodified caps too, but putting cling film over the hole before closing the cap didn't fix it, so I assume it's coming out of the Holley.
Once the car has settled down after its last run, the smell abates somewhat, but it's always a good idea to open the garage up on a dry day and get the air circulating through it.

[Ricky]

Are your fuel lines the stainless braided type, like Earls or similar?

I seem to recall that fuel smell issues were raised previously on the old forum and could be attributed to braided fuel lines where the aroma of fuel tends to emminate (sp) out of the hose.

I think this is why people like earls have a clause in their tech data about modern fuel additives possibly not being compatible with their hoses.

My car (RF) has no fuel leaks. I have checked very thoroughly but I also get a fuel smell from the engine bay. Funnily enough it's the only place fitted with braided lines.

[Ron Earp]

Originally Posted by ricadona

Are your fuel lines the stainless braided type, like Earls or similar?

I seem to recall that fuel smell issues were raised previously on the old forum and could be attributed to braided fuel lines where the aroma of fuel tends to emminate (sp) out of the hose.

That can't be, unless the hose is leaking. A braided hose is a normal rubber hose underneath (or other material depending on what the hose carries) with a SS braided overlay and a permanent fitting on the end of the hose that mates up with the AN adapters. If the braided hose is releasing fuel vapor, then it is leaking due to a hole in the hose, or a improper connection at the AN adapter, or the AN fitting is not tight.

R

[Pete.]

I had similar smells and concerns when I first took delivery of #48 even though it is fuel injected. I checked all the lines etc about three times and took the car back to DRB for them to check as well. No fault found.
I asked my brother in law who has been motor racing all his life to come over and see if he could find anything. His comment as he walked into my garage was "smells just like a race car".
I have never worked out where the smell emanates from, I suspect that there is enough residual fuel in the stack pipes after engine shut down to cause the smell. Even half a teaspoon of fuel will stink up your garage if it is not well ventilated.

[Mark Charlton]

My Pantera and my GT40 share a garage, both have Holly carbs and braided lines and the ONLY time I ever get a smell of gas is after filling the GT40 tanks full. I've learned not to top it up and no problem. In my case I'm pretty sure it is a poor seal at the top of the flip caps and I don't have the recommended modern fuel-cap upgrade (sure would appreciate more info on if there is a GTD retrofit...), which I am confident would eliminate the problem altogether.

[Bobski]

On my previous car, I had a alloy serge tank mounted in the boot and the car had a heavy smell of fuel inside. After checking and rechecking all the fuel lines and connections, couldn't find where the smell was comming from. Spoke to a few people about the proplem, and one sugested that it may be the alloy tank itself. He said that fuel vapors can actually leack through the alloy and by painting it, the smell would go.
So I did just that, I painted the surge tank and the smell was gone (maybe thats why race cars always smell on fuel).
So the problem could be our tanks themselves? Just a thought.

Bob.

[Canuk40]

Hi Cliff,

A couple of things to consider, the obvious which is to make sure there are no leaks and proper gas caps under the Monza fillers is a good start.

There can be quite a bit of standing vapours from carbureted engines, Webers in particular, especially when the heat soak from the engine raises carb temps when you first park the car.

Try turning off the fuel pumps before you get in the garage. This will drop the fuel level in the carbs and should help.

Also, unique to CAV GT40s are bladder fuel cells fitted as standard equipment on the pre s/n 100 cars. These cell are made to aircraft specs and have FIA recognition. Most of the other cars have aluminium or poly tanks so the following won't apply:

According to ATL: "Due to the elastomeric nature of fuel bladders, a certain amount of vapour permeation or "diffusion" will occur. Always allow generous ventilation around the cell and vehicle so as to preclude the accumulation of fuel vapours." from pg. 27 of the ATL Racing Fuel Cell Catalogue.

As always, great advice on the GT40 Forum. Enjoy your ride

Cheers