Lotus Elan

Exhaust smell

PostPost by: Lotus54 » Sat Mar 16, 2024 9:08 pm

I think this has come up before, but now I can’t find it.

66 Elan drophead.
With top off, windows down, I still get exhaust smell (including on clothes).

I know there are some small exhaust leaks- I plan on replacing the whole works.
I also saw some mention of making sure tailpipe goes out past bumper- but mine (with new muffler) will not unless I put some sort of extender on it.

I speculate it is swirling around behind the car and getting back to passengers.

Suggestions? (I know, replace exhaust, but will that solve it?)

Mark
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PostPost by: richardcox_lotus » Sat Mar 16, 2024 10:02 pm

If your exhaust is leaking, then also check for holes in the the gear lever gaitor, and the grommet for the temperature gauge sensor, as gases can get through there from the engine compartment

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Richard
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PostPost by: Lotus54 » Sat Mar 16, 2024 10:58 pm

Thanks.
I will check all those.

I think I will just replace exhaust now, or I will never be sure. The header system had some odd joints and since I have a new one seems best to just replace everything. Original owner replaced studs with bolts, I have new studs and will go back if I can.
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PostPost by: ericbushby » Sat Mar 16, 2024 11:51 pm

Hi Mark,
I only drive my S3 with the top down and I was getting exhaust fumes coming back at me from the tail pipe. I had no leaks on the rest of the exhaust system.
I extended the tail pipe only by one inch and it cured the problem. I used a piece of brass shim inside the tube and only one pop rivet.
It is not pretty but it works and nobody has noticed it so far. I am sure there is a better way of doing this and I may improve it some day.
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PostPost by: Lotus54 » Sun Mar 17, 2024 12:40 am

Thanks, I will come up with a good way to extend.

I just pulled the exhaust off (header was fun). I am not looking forward to putting the motor mount back in.

I think I can come up with something that will look nice. I tried expanding the tail off the old muffler (still looks nice) but my pipe expander of that size would not do it.

Thanks for the tips.

(Now if anyone wants to come over and install that motor mount…)
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PostPost by: types26/36 » Sun Mar 17, 2024 1:23 pm

Where does your head breather exit to? Later cars have the breather going into the air box. Early cars had the breather to a tube down under the car and crankcase fumes/blowby could possibly get drawn into the car.
Brian
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PostPost by: Lotus54 » Sun Mar 17, 2024 1:50 pm

Mine goes into aibox
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PostPost by: Lotus54 » Mon Mar 18, 2024 2:19 am

I replaced entire exhaust and sealed up well.

With muffler as far back as I could get it- I think the smell is gone. I will test further, and extend tip if needed.

Thanks for the tips.
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PostPost by: Lotus54 » Wed Mar 20, 2024 2:28 pm

The exhaust smell is gone. I did bore an aluminum tube I had to snuggly fit over exhaust tip, so I could extend just past bumper (ok, I did not try it without yet). But with that in place, new exhaust system with no leaks- no more smell. Yay!

Car also runs better, different header system than what was on their (original owner claimed ‘factory racing’). It likely we fine when new, but it was pretty tired, has two joints that were very difficult to seal. New one is a LOT better in that way- and easy to fit with LH engine mount removed (that was the most work).

Sounds great, not loud, but a nice sound to it.

Mark


IMG_8241.jpeg and
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PostPost by: Keith Scarfe » Thu Mar 21, 2024 9:04 am

Any chance you could post before and after pictures. I think I might try this but I am afraid it might look a bit silly. I have always had this problem and have made it better over the years (by sealing the boot etc) but it is still there.
https://lotuselan.net/forums/viewtopic.php?f=19&t=31213
The only thing I haven't tried yet is extending the exhaust pipe. So I will give this a go I think.
Thanks.
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PostPost by: ericbushby » Thu Mar 21, 2024 10:06 am

Hi Keith,
Can I make a suggestion.
First establish if the length of the exhaust pipe is causing the problem. Make a temporary extension to the tailpipe using something that will stand the temperature. Maybe even aluminium foil or a piece of a bean tin fixed by a wire twisted round it. At this stage it does not matter what it looks like.
If that works then you will have established that the problem is there. Then shorten it a bit until the smell comes back. You will now have a minimum dimension to work to. Only then should you consider buying or making a modification. I used brass shim because I had some but use whatever you have.
Run it for a few weeks until you are satisfied with the result then modify it with confidence that it will work.
best of luck
Eric in Burnley
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PostPost by: Elseezed » Thu Mar 21, 2024 2:52 pm

Had to extend the tail pipe on my +2.
The new silencer exhaust tailpipe was way too short, causing the fumes to dirty the back of the bumper and bodywork.
Extended tailpipe using copper pipe and a self tapping screw.
IMG20240321143230.jpg and
Tailpipe extension
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