Engineering Question

[Rossodino]

Hi everyone, I am a newbie and a car nut. I also enjoy racing a lot and track my cars whenever I get a chance. I am wondering if someone can help with an automotive question or direct me to a technical publication/paper where I can see scientific/engineering explanation of the following question.

I am wondering if excess backpressure created by clogged catalytic converter on a high performance passenger car can cause exhaust valve failures. The car has a v8 where a compression and leakage tests were performed and while the right bank shows no leakage (0-1%), the left bank shows anywhere from 4 – 14% on different cylinders. The car has less than 19000 miles.

Can anyone point me to an engineering paper discussing this cause and effect? I appreciate your help.

Cheers,

Matt

[Rossodino]

Hi everyone, I am a newbie and a car nut. I also enjoy racing a lot and track my cars whenever I get a chance. I am wondering if someone can help with an automotive question or direct me to a technical publication/paper where I can see scientific/engineering explanation of the following question.

I am wondering if excess backpressure created by clogged catalytic converter on a high performance passenger car can cause exhaust valve failures. The car has a v8 where a compression and leakage tests were performed and while the right bank shows no leakage (0-1%), the left bank shows anywhere from 4 – 14% on different cylinders. The car has less than 19000 miles.

Can anyone point me to an engineering paper discussing this cause and effect? I appreciate your help.

Cheers,

Matt

[Daves]

I currently have a clogged catalytic converter (party due to oil consumption), and it causes my '91 Honda Civic to overheat when traveling over 60 mph. I easily remedy this by turning the heater on nearly 100%.

It's logical that the exhaust valves could be one of the first parts to be damaged from such overheating. Also, here is a website that may have some more info:
http://www.all-catalytic-converters.com/techtip3.html

[Rossodino]

Thanks for your post. Believe me I am an expert in what kills a catalytic system by now. I have worked with the epa to figure out the root cause(s) and they have done extensive failure analysis not only on my catalyst system but on my fuel and cam timing. It turned out that the cam timing was off in my car causing an excessive rich A/F mixture, which eventually caused the cats to fail.
I have talked with many experts in engine building and cam/valve train manufacturer. While everyone agrees that excess backpressure can cause exhaust valve damage no one can show me why and how. I also investigated the hydraulic lifters and a pump up phenomena. If the lifter was pumped up and didn't have time to drain and come back while at high rpm the valve would not be able to rest on the seat and transfer the heat and eventually will burn. So far this is the best theory I have.

Anyone with access to data and research papers that can chime in?