Exhaust Fumes

[andersnd]

Greetings - I'm new to the group and appreciate everyone's input. I've purchased a 1981 3 door Stage 1 in Holland where I presently live, will be exporting back to the states in July.

I've had the truck for 3 months and am noticing exhaust fume smell in the cabin getting worse over time. I've confirmed that there are no leaks in the system itself - it is in good shape and tight. So what I'm left with is length of tailpipe which I've extended by 4 inches to get it out from under the rear left panel, but no real change to the issue. I'm beginning to think that since I've owned the truck the exhaust smell itself is getting more intense ( it is very strong - headache/nausea inducing) but not due to cabin leakage, just the exhaust itself. It has always smoked on startup with choke, but after engine warm up exhaust would thin out. Now, visible exhaust is there always upon idle (white smoke) and I can't help but to think that my issue is engine/carb related as opposed to to trying to figure out a way to keep every bit of it out of the cabin.

Has anyone experienced this?

Thanks in advance for any thoughts.

[map1275]

You are confusing symptoms with cause and effect.

You will always have emissions regardless of visible or not. It is the invisible ones that will kill you.


You probably have a stem seal problem for oily smoke on start up. If you are now blowing white smoke I would be checking brake and coolant fluid levels.

The CORRECT exhaust fitted CORRECTLY doesn't need any tailpipe extensions.

I would suggest you recheck your exhaust while it is running and check all six joints plus all eight flange gaskets and the EGR system.

I would also check that the rear door is closed and the rear left window.

[andersnd]

Thanks for your reply. Maybe I am confused, but are you confirming that it is possible that the intensity of exhaust smell can get increasingly worse over time, and if so is it due to the issues you are referring to?

Thanks for your help.

[map1275]

Smell is another symptom.

So far you have several symptoms, none of which may be related in anyway.

If you have exhaust fumes entering the cabin then you have an exhaust fault and/or a cabin fault.

If you have a smell then you have something causing the smell, like your engine burning brake fluid or coolant, or an oil leak onto the exhaust. Have you properly pressure cleaned the ENTIRE vehicle before you started looking?


If you have smoke on start up then you probably have valve stem issues.

If you have smoke while running then your engine is either burning something it shouldn't like coolant, brake fluid, excess fuel or oil. All have their individual causes.

Most of the above have NO relationship to one another.

You need to stop guessing and apply a logical process, such as do I have an exhaust leak? How do I check it? how many joins are there? NOT JUST guessing and stating that the system is OK and in the same statement insisting it needs an extension on the tail pipe.

So if you think you have an exhaust leak and then engine happens to be smoky; pressure clean the ENTIRE vehicle PROPERLY. After drying, start the car outside and stuff a rag up the tail pipe. You will now have a visual aid to physically checking each and every exhaust joint for flowing gas. Note, flowing gas is checked by the gas applying pressure against the skin in close proximity to the joint, it is not a solely visual check. Audibility is an additional aid as the correct exhaust system is fairly quiet.

[andersnd]

All great points and suggestions. Thanks for your help.

[noexitroad]

check the rocker breather pipes are still on it, they should be plumbed back into the carbs (from memory)for stromberg carbs, possibly via flame traps. if they have been removed (such as mine were when su carbs were installed) then you need to put a hose over the breather hole and run it down under the engine somewhere

[disco2hse]

**sigh**

Since you have copied and pasted your question from Rovers North, I shall copy and paste my replies from the same forum.

there should be *no* exhaust smell in the cabin. If you can smell that, there will also be carbon monoxide that you cannot smell.

Sources of fumes I have found in the past:
Leaking exhaust manifold (leaking gasket and cracked manifold)
Leaking manifold an down-pipe junction. Once upon a time you would wrap a loop of asbestos braid around the junction - guaranteed not to leak and totally heat proof. Unfortunately, asbestos kills.
Leaking rear pipe junctions (they shake loose and whacked when off-roading).
If the pipe finishes under the rear mudguard, fumes can be sucked back into the cabin, especially if you have a station wagon, etc. I found this the case when I had a full rag top.
Otherwise, could be a leaking fume return pipe from the rocker cover to the air filter (mine were missing!).
The exhaust valves are not seating correctly and pumping fumes out the top of the engine (see point above).

then you said:

Thanks for all your replies. The truck is a hard top. Rear seals on the back door are good. Driving with all windows/vents sealed up makes it much better, but in stop and go traffic it can still get bad in the cabin which makes you want to open windows and then the cycle begins. I know there is no cure all for the problem and that some level of tolerance to exhaust fumes is required but i am thinking that I may have a carb adjustment issue due to the truly pungent smell of the exhaust. I have the 123 electronic ignition system for the rover 3.5 v8 which I need to ensure is working properly - but my gut is that my mixture is rich right now resulting in an unusually strong smell to the exhaust. The tailpipe goes out the drivers side of rear panel and I have added about 3 inches of pipe to ensure exhaust is blowing out the side as opposed to the low pressure vacuum behind the truck. Will continue to work through this and will keep you all posted.

and in reply...

As I said, you should not be smelling *any* exhaust fumes. That is not the same thing as smelling oil, etc.

To be smelling exhaust fumes means you are also breathing in carbon monoxide. That can kill you, or it will make you dopey when driving, then you hit something and that kills you instead.

How did the guy confirm there are no leaks in the system? Did he do a pressure test?

Often leaks can be heard as a huffing sound.

If your air-fuel mix is out, in the cab you should not smell it although those outside will.