Where is this exhaust coming from?!

[Rustisamust]

Hello friends,

I’ve been making some headway on my (t)rusty steed. I welded on a new exhaust today, and I am still having this weird issue. On start up, from the passenger side of the vehicle I get massive amounts of exhaust. Usually disappears by the time I’m ready to turn off the clutch. I feel like I’ve done a good job with the manifold, exhaust and crankcase cover... is there a secret exhaust hole I am not aware of? Anything like this happen to anyone else?

From under the vehicle it’s directly under the passenger seat where I see the exhaust (other side of everything exhaust related!!)

Thanks!!

 

[Tancruiser]

Is this a stock engine?

 

[Rustisamust]

Is this a stock engine?

It is. 2F. Mostly stock with some emissions removed.

 

[Shark56]

PVC hooked up?

 

[Rustisamust]

PVC hooked up?

It is...

 

[Solace in Solitude]

What year?

Have you watched for exhaust under the hood... PS... to see if it’s coming from there and following the firewall down to the PS seat area?

My ‘78 has a breather port on the DS-rear of the valve cover.

A hose runs, from that port, to a similar port in the back of the air cleaner.

When I bought my 40, it had quite a bit
of oil accumulated in the air cleaner.

When I disconnected the hose from the air cleaner, I found the engine had so much blow-by that it looked like a smoke out of a (clean) coal-fired smelter stack.

I checked compression and found low numbers... all good, after a rebuild

If you have the same valve cover breather port, is it possibly blocked?

That would cause pressure to build up in the engine and could, potentially, vent out the area of the flywheel inspection cover... or potentially thru some area, like the side cover or the PCV.

That’s the best I’ve got.

 

[Rustisamust]

What year?

Have you watched for exhaust under the hood... .

That’s the best I’ve got.

Thanks for that! Mine is a 78. I had the hood open, so it was definitely coming from somewhere low-ish. I will check the hoses in back, that’s a great suggestion because the PO took a lot out, so it wouldn’t be too surprising if there was an open port or disconnected hose out of sight.

The only thing that baffles me is that it completely disappears when the engine is warm (or at least when the choke is turned off).

Thanks again.

 

[Solace in Solitude]

You’re gonna see smoke, actually more of a mist (like seeing your breath in cold weather), from your exhaust, when the engine is cold and the carb is choked.

But, that doesn’t explain how it presents under the PS seat.

Are you sure you don’t have an exhaust leak, on the tranny side of the pipe?

But, even if you do, unless your exhaust is blocked, I wouldn’t think you would get that much from under the PS seat.

You’re gonna have to watch under the hood and underneath the PS seat and see just where it’s coming from.

Btw do you see or smell anything in the cab, while the “smoke” is present?