"chugging" sound under load...

[amaurer]

I just replaced the head/intake/exhaust gaskets on my 3B, and ground some major divits out of the rockers and set valve adjustment. With everything back together, it runs great but I have a slight "chugging" sound (like a steam engine, only much faster) under load that speeds up with RPM. Not very loud, and it only occurs through the middle RPMs. I don't remember it doing this before.

Something says "exhaust leak" to me, but I don't know for sure. I couldn't *see* anything leaking, even when i tried to drag the clutch a bit and run up the RPM in the garage. I don't know if this is a realistic assesment, or if I'm just dwelling on my concerns about the replacement exhaust donut and the bent flange on my exhaut pipe....

Sound like anything to you?

 

[Pin_Head]

Yes, exhaust leak. Try using a piece of tubing with one end up to your ear to listen for the leak to localize it.

 

[lostmarbles]

Could hold a piece of paper tissue around the manifold and see where it gets "blown about" by escaping exhaust too Andrew

 

[amaurer]

Traced it to the flange; the donut is leaking. That tube trick works well, gonna have to remember that.

What do you guys think about doubling up on exhaust donuts? The donut just isn't thick enough to seal due to my bent flange...

 

[badass]

double up the gaskets and use some high temp silicone and it won't leak.