Exahust Leak

[Fordication]

Will an exhaust leak make the engine run rough?

 

[72HCODE]

depends where the leak is, If the leak is at the exhaust manifold before the collector, it can lead to a burnt valve. A burnt valve can make the engine run rough since the burnt valve(exhaust valve) will not be able to make a seal in the combustion chamber.

if the valve is burnt then fixing the exhaust leak now will not change the damage. you could do a compression test and see if you are losing pressure in one or more cylinders.

otherwise if the exhaust leak is further down in the system then its just you inside breathing in exhaust.

the burnt valve is caused by a build up of heat from the exhaust not exiting the cylinder correctly due to the leak not allowing undisturbed exhaust flow. the heat builds up and melts the valve a little causing sealing problems and can make an engine run badly. So you do a compression test to see if one or more cylinders are very low compared to the others which might indicate a problem with valves.

 

[Fordication]

Oh damn, here goes pulling the plugs. I think the leak is further down but I will check the compression anyways.

 

[72HCODE]

well you don't have to go crazy try a vacuum gauge first and see what the engine is doing.

and check firing on the plug wires, make sure all the plugs are firing.

http://www.secondchancegarage.com/public/186.cfm

look at example 6 for a burnt valve

 

[Fordication]

Oh. You must not have read that thread yet. Yeah, um, none of the hairs on my junk has any curls left in it thank you. Thats what I get for checking spark at the plugs.

 

[cobrajet99]

Wow, I never realized how much a vacuum gauge can tell you about engine internals. That is a great link,,,, Thanks 72HCODE

 

[c9zx]

Oh. You must not have read that thread yet. Yeah, um, none of the hairs on my junk has any curls left in it thank you. Thats what I get for checking spark at the plugs.

Be glad you don't have a CD ignition system installed. It sounds like you learned one you will remember. Everyone has done this at one time or another. LOL Chuck

 

[OLE PONY]

depends where the leak is, If the leak is at the exhaust manifold before the collector, it can lead to a burnt valve. A burnt valve can make the engine run rough since the burnt valve(exhaust valve) will not be able to make a seal in the combustion chamber.

if the valve is burnt then fixing the exhaust leak now will not change the damage. you could do a compression test and see if you are losing pressure in one or more cylinders.

otherwise if the exhaust leak is further down in the system then its just you inside breathing in exhaust.

the burnt valve is caused by a build up of heat from the exhaust not exiting the cylinder correctly due to the leak not allowing undisturbed exhaust flow. the heat builds up and melts the valve a little causing sealing problems and can make an engine run badly. So you do a compression test to see if one or more cylinders are very low compared to the others which might indicate a problem with valves.

Great info!