Projects Exhaust Smell Inside Car - Seal Firewall?

Thanks,
This 53 Chevy was chopped, shaved, c-notched, frenched.. so a lot of custom body work to get rid of some things and the fuel door is gone. I'm about to take some more photos.

 

Here are some more pics. I took the rear seat off to take a closer look. Cardboard separates some parts of the wall between the trunk and the cab. I can also see the ground in a couple of areas behind the piece of cardboard when I look down. The fuel vapors must be seeping right through the cardboard from the trunk. Does this seem like the cause of the gasoline smell? I can't believe I didn't know about these kinds of issues when I was looking at the car. I don't have a welder and was really trying to avoid metal work. Ugh!

 

Relax man ... you need to be patient. That "cardboard" is/was used by manufacturers and trim shops for door panels, and areas like that "bulkhead" in your photo between the p***enger compartment and trunk. Don't worry about having a welder, I have one, but it's not very likely that we'll need to use it on your car. From the photos that you've posted, I'm certain we can get you tuned-up in no time. Trust me.
Seriously, this is relatively simple stuff, and I got you covered ...
I'll help you out with all of this stuff as soon as I get back from Bonneville. Don't get it in your head that it's a bigger deal than it is.

 

Ed is spot on.

Have you ever bought gas in a gas can for your mower and set ot in your cabin of your car, it stinks bad. You are kind of experiencing the same.

I think you are getting really nice response from this thread do to your at***ude and willingness to listen to the advice being offered. Most young guys, I am 34, are ****y and arrogant and it really just doesn't work here.

Believe me, if a few lines and a trunk seal gets you back up and running and you have the right help being offered, you are waaay ahead!

FWIW we have a 56 wagon with the stock engine that has a road draft tube, it stinks bad. I have a late model engine that has a PCV system that will be much appreciated.

 

Thanks so much for responding and I'm grateful for any help (no rush at all!). It feels so much better hearing others say these are small issues. Thanks again.

 

Thanks. I agree with you and am definitely going to be patient and learn as much as I can from others.

 

Watch out for Ed. He's on the FBI "watch" list.....

 

Good on you Ed! I guess I might have to change my opinion of you.

 

That Ed he's Special ya know.
-Pat

 

As for getting rid of your air ride leaks, get a bottle of Snoop. I think you can find this at your local welding supply or Grainger. It is basically a bottle of soapy water, but I think it works better, plus it is pretty cheap. Spray a little of that on the various fittings of your air ride setup to find the leaks. It will bubble up when there is a leak. Fast leaks will just blow it out of the way -so watch for that.

Kelvin

 

Okay ...
Got a peek at his Chevy today. We spent a couple of hours going over it, and going for a short drive so that I could try to figure out the aromas. The "gasoline" smell appears to come from the fact that once the car has sat for awhile, it needs a few minutes of running the compressors to fill the airbag storage tank. The compressors are wired into his ignition switch (on position), which also causes the electric fuel pump to run. Without the engine started or running, that pump is sending gasoline through the lines, and you can smell it. Not sure if there's a return line or what, because I couldn't get underneath the car enough to check. I did NOT see any obvious leaks or drips though... but it did smell of gasoline. Should be a relatively easy fix to simply wire that switch differently to eliminate the fuel pump from operating like that.
The exhaust smell he reported was also present once we drove for a bit. Undersized exhaust system might be contributing to little bit of a back pressure issue. I didn't have tools to check tightness of exhaust manifold bolts, but that's where I'll begin next time. He does have several small holes and unsealed seams on his firewall. We'll start at the engine and work back, checking for exhaust fastener issues, and potential entryways into the p***enger compartment.
Engine has a pretty good miss that I need to find too, other than that it's a decent car that he can enjoy for many years to come. We'll need to find that air leak soon, too. Very nicely chopped car. Gonna be nice ...

 

Thanks so much Ed!

 

Spent a few more hours on this today ... We found one pretty decent air leak at the fitting connecting to the air pressure gauge. We wrapped some teflon tape on the rascal, screwed it back together, and that was that ... Also found a few other fittings that needed a little bit of re-tightening. We ran the compressors to re-fill the tank, so now we wait and watch and see if we solved that issue.
While I diagnosed the air system, Dan got underneath the hood and re-torqued his exhaust manifold bolts. He found four of 'em that were loose. This might be all he needs (for now), and we will need to see how today's work pays off ...
Stay tuned ...

 

Ed, you exemplify what the HAMB is all about.

 

Poking around underneath the hood, we found that a few of the sparkplug wire's insulation was cracked and broken in places. The wires were tightly bound together. No looms or separators either. A set of fresh plugs, a complete new set of sparkplug wires, along with a set of separators should clean up that miss that we heard. We'll bleed his brakes, and we should have this car ready to roll this Saturday, and then he can enjoy it while taking care of the other odds and ends that could use some attention.

 

Good to hear you are getting him on line man.

 

Yep this is a good call right here.

One thing that makes a car have exhaust smell as well is exhaust not properly routed. Make sure that the pipes dump outside of the body and not under it.

 

Yeah ... He's aware that his current exhaust system needs replacement. It looks like a homemade type of deal, not even any mufflers used, just basically two straight pipes run the entire length of the car, underneath the crossmembers, making it the lowest point on the car.

 

Good on you for helping out,might of made the difference of him giving up the old car bug,which is a good hobby for someone with kids.

 

Good man, Ed!!!!!

 

The "miss" appears to be a thing of the past after Dan installed a new set of plug wires and a set of sparkplugs from Napa. Now that we have it running well, we can concentrate on some of the other issues. Some pretty hokey-*** stuff goin' on with his gas tank. A few bungs welded shut. Mismatched delivery hoses (some 3/8" and a few inches later some 1/2"), and the strangest (and most dangerous) fuel tank vent that I've ever seen. There's a 7/8" bung welded into the aluminum tank near the top. A 7/8" hose goes from that bung and terminates inside the left-rear wheelwell. Just a wide-open hose connected directly to the tank. Open to water, sparks from the brakes, gravel, ANYTHING ....

 

Hoping this can be fixed, I'm not too surprised there are a bunch of things that were done really weird. I didn't have the eye to check these things before I bought the car but hopefully the vent fix isn't really difficult.

 

Very cool! One step at a time. Find an issue, fix it up and move on to the next. They are never truly finished.

Welcome to the world of hotrods

 

It's been a few weeks but I'm still having the same problem. A couple of things have been fixed like new wires sparkplugs, and the airbag system leak. I've checked and tightened the exhaust manifold bolts.

The cab still smells like exhaust or gas (I can't tell which one) when I drive it long enough (about 15 minutes). When I bring it back in my garage and turn the engine off and let it sit, I can still smell the fuel/exhaust for a couple hours. I'm not sure if this is from the smell that ac***ulated inside?

When I adjusted the idle yesterday I could smell fuel close to the carburator while it was running (on the side with the valve cover that has the breather on it). As someone with limited knowledge on engines, I'm guessing this is to be expected?

I already know the exhaust pipes need to be redone and would ask the shop to change the donuts too, but should I do this as a first step anyways and see if the problem is solved and go from there? I know sealing up the firewall is just a bandaid to the problem so I'm thinking of solving the source problem and then sealing up the firewall.

This is for sure the biggest issue I want to solve. There are others but I don't care about them as much as this one. I intend to keep this as a local zip code driver and have AAA and a fire extinguisher and hope that bails me when something goes wrong. I'm working to fix unsafe things like wiring, etc and maybe changing the fuel tank out. Thanks.

 

And if you ever get rear-ended, you are gonna HATE the outcome... given that your fuel fill tube is in the trunk. Going to look like a rocket.........maybe.......

 

Unfortunately I don't see what I can do to fix this easily on my own. My option is to live with it and keep a fire extinguisher in the cab or p*** this project on to someone else.

 

Does anyone think getting the exhaust replaced is a good first step since I need to anyways?

 

Yes, new exhaust, then seal up the firewall. Then check all the door and window seals, and any air vents.

Old cars and engines smell, and people used to driving Hondas are usually not used to the things we smell every day.

 

A fellow HAMB'er that lives up the street came by to take a look. Basically there is an exhaust leak near the area the pipes were crushed/s****ed by the previous owner. The fuel lines coming out of the tank are a joke, and the fuel line by the exhaust manifold running into the carb is dodgey.

Here's my plan to correct all this:
1. Add non vented fuel cap (the vent in the tank goes high up by the rear wheel well.. that's plenty good enough for me!)
2. Add anti-roll fuel valve (I can't remember the exact name).
3. Replace all the rubber fuel lines coming out of that tank and replace the fuel filter.
4. Replace the rubber fuel line going to the carb with a longer length and route it above the air duct so it doesn't go near the exhaust manifold like it does now.
5. Add mounts to keep the lines/hose fastened properly.
6. Add an inexpensive fuel pressure regulator on that line going to the carb.
7. Get the exhaust completely redone from the manifolds back with 2" pipe and 22" brockman mellowtone gl***packs.
8. Seal the region between the trunk and cab with sheetmetal, screws, silicone, and some type of stick and seal (I think that's what it's called). I'm not welding anything, and can do this the right way later when I have nothing to do.
9. Add Rubber trunk seals that are missing.
10. Seal the firewall in a similar fashion but from the inside of the cab.

Optional in the future:
- Cut out the fuel tank in there and replace with something smaller that can fit inside the trunk.
- Add breather with outlet that can connect back to the PCV line (I think this is what I was told may help)

This should hopefully fix up the smell!

 

Holes can easily be filled with plastic hole plugs from the little parts bins at most hardware stores (Yes even Home Depot and Lowes). They are available in a regular depth and a thinner version and also available in metal and chrome. Measure the holes or just buy a bunch for stock. Drill out irregular holes to plug size. Get some grommets while you are there.