it sounds different

[eric-France-]

Hello everibody !
Bonjour à tous !
My engine is now making a metallic noise that it didn't make before. I wonder if this noise is worrying. The engine seems to be running very well. Could the noise simply be coming from the exhaust manifold?
This video after 1 minute cold start but the noise is the same after a while.
https://youtu.be/wHDQCd-_7VE

Thanks !

 

[Big hammer]

Sure sounds like an exhaust leak to me, I wonder if you could pressure the tail pipe and then use soapy water and spray around the manifold and look for bubbles ? A shop vacuum or compressed air to pressure the exhaust

 

[CT Jack]

With the engine cold try retorquing the 4 manifold nuts to 61Nm. If the ticking sound diminishes I would change the manifold gasket.

 

[nkaminar]

Take a small diameter hose and hold one end up to your ear and move the other end around the manifold areas to find the exhaust leak. Use the copper clad gaskets. The paper ones burn out in a few miles.

 

[Benson]

A very common problem called "drooping manifold" where manifold is warped from weight of tail pipe over 90 years AND from folks running engine with spark retarded which gets manifold red hot..

Remove manifold and you will find that the rear (#4) exhaust port is about 1/8 in or so lower than the others and #4 port gasket area has been burned out.

IF you run straight edge across the bottom of the 4 ports you will find # 4 lower than the others.

 

[Jim Brierley]

Do what https: NKAMIMAR says, it could be timing gears or ???

 

[Benson]

...

 

[nkaminar]

Cast iron naturally grows when heated. It grows more if heated more. I have restored the compression on model airplane engines by heating the cast iron piston for a few minutes. Because the Model A manifold is not symmetric it will warp at the #4 port. The weight of the exhaust pipe may exacerbate the warping.

 

[eric-France-]

thanks very much to all of you for advices ! Très content de faire partie de ce forum ! I have a manifold gasket among my stuf in my shop. I ll try to change it next week.