exaust smell in car

[chuck smith]

My CAV seems to have an exaust smell in the cabin especially when going slow. It seems I read somewhere about the tunnel being the source of this. Do you guys have any advice on rectifying this problem? My car also has 4 pt simpson belts and I want to change to modern 3pt retractable belts like on the newer CAVs,do you know where I can source these? I think they are not standard belts you find in street rods. thanks; chuck smith

[Veek]

Hi Chuck,

I have CAV #4 and it has the three point retractable belts. You may want to look and see if the fittings are there in the bulkhead.

As far as the exhaust smell, you may want to check the fit of your door weathestripping. When I changed mine out it made a big difference from a smell factor. You may also want to pull your seats and the rear cockpit access panel and verify the cover fits correctly and there is weatherstrip around the opening.

I also sent you a PM with the other info you asked for.

[Pat Buckley]

Veek -

Can you tell me where you sourced your door weatherstripping?

Thanks.

[Veek]

Sure,
McMaster Carr has lots of choices.

McMaster-Carr

[Tony Hunt]

Originally Posted by 2124

Veek -
Can you tell me where you sourced your door weatherstripping?
Thanks.

The weather strips made for the original cars is still available from:
Robin Batt
Managing Director
C O H Baines & Co
9 Park Road
TUNBRIDGE WELLS TN4 9JP
United Kingdom
Phone: +44 1892 543311
Fax: +44 1892 530682
Web page: Baines Rubber Extrusions and Mouldings
E-mail:

[David Briggs]

Chuck, Auto Futura makes a firewall upgrade that will seal the engine compartment and reduce the noise and heat . The bottom of the doors do not seal properly and I made some small extrusions and moved the bottom weatherstrip outboard so that it sits against the door edge, Also you can adjust the front door weatherstrip by unbolting the plastic trim the strip is attached to(behind the instrument panel) and move it outboard as well.

[Bob Childress]

I guess everyone here on the GT40s forum needs to be the “safety officer” once in a while. In the United States we jokingly call that person “Deputy Barney Fife” (the overly reactive and excitable sidekick from a 1960s TV show).

The structure between the engine and the cockpit should be a firewall. I joint David and others who encourage all of the owners of older CAVs to replace the flammable fiberglass cover with fireproof materials. In addition the firewall should be carefully sealed to prevent all liquids and fumes from getting into the cockpit.

A final consideration might also be the thickness of the gasket material used around the engine cover door. In the event of a fire, a big thick gasket will quickly burn or melt away and allow the fire to breach the firewall.

Adding a fireproof engine cover is not a particularly difficult project and it can conveniently be done at the same time as other engine area work.

Deputy Barney Fife, over and out, 10-4.

[Canuk40]

Hi Chuck,

There's several sources of cabin smells. The firewall panel on early cars is one of them and easily fixed with a filler panel.

Also the side vent windows seem to allow exhaust smells in at low speeds < 45mph so I keep them closed except when parked in the sun.

Weather stripping can be improved by adding more to close gaps especially around the cowl to front of the doors, no exhaust smell there but lots of heat/cool loss.

The single biggest improvement you can make is to provide outside (fresh) make-up air to the Heater/AC unit. There is none as stock meaning as you drive the air bleeding out of the cabin creates a low pressure zone inside and fumes will find a way in.

Directly pumping outside air into the Heater/AC stops this by raising the cockpit air pressure. Also without make-up air the cockpit gets stuffy and humid, not good for long drives. With the A/C on your getting cold, dry stuffy air...

There's no easy way to feed the make-up air, however what we've done on all our cars is plumb the right side NACA Duct on the hood to the Heater/AC through the side of the cowl. Very tricky and time consuming but worth the effort.

There are no doubt other ways to do it, the key is to pump clean air directly into the blower, just getting some into the cockpit is not good enough to ensure fresh make-up air being mixed with the air already in the car.

As the factory CAV unit has four openings on the dual squirrel cage fans and we've dedicated one to make-up air, the ratio of recirculated to make-up air is about 75/25. This is greater than production cars however we need more fresh air since there's no cats and most of the CAVs have bladder fuel cells which are a bit smelly on their own.

Take a look at the pics, you may be able to copy this, just leave yourself lots of time At the end of the day, it will be worth it.

[Canuk40]

Ooops, Columbo moment... here's a pic of the firewall closing panel with the provision for a support bearing for our ZF Shifter Kit. These are stainless or aluminum panels. The sealing gasket is run along the top edge of the panel and all the holes in the lower firewall panel are covered.

Cheers