slightly blue pipe

[Guest]

I had one head pipe that started to blue a little, just looking to see what you guys have used to get some blue off
I'll have to take a further look at my airbox for leaks, as well as the mixture screws again

[Nessism]

Vacuum sync the carbs too.

Bluejob is the best stuff I've found. It's expensive and if the blue is really burned in the pipe nothing will remove it.

[steve murdoch]

A valve clearance that is tight can also be a cause of too much heat.

[tkent02]

As can retarded timing or a stuck spark advance.

[eil]

A valve clearance that is tight can also be a cause of too much heat.

Can it? I know you can burn valves due to too little valve clearance, but that's because the valve stops contacting the head and can't dissipate heat... the temperature in the combustion chamber doesn't increase in this case, does it? Or does a leaky valve make for a leaner burn?

Not trying to argue, just want to understand the mechanics.

[jprice90]

These pipes literally looked new, it just happened Saturday when i had it out, it was a 94 humid day.
I'll try that, and do some adjustments

Thanks alot guys

[tkent02]

A 94 and humid day should make it run richer, not leaner. Something is wrong in there. It would be a lot leaner and run a lot hotter on a cool dry day. One pipe only is odd, did some fuel passage get clogged up or something? An intake leak would likely blue them both, if everything else like fuel level and mixture screw was the same.

Wait, is the one with the blue pipe the one with the petcock vacuum line or the other one?

[tkent02]

One more question, is this the stock double walled pipe or an aftermarket one with a single thin wall?

[tkent02]

Can it? I know you can burn valves due to too little valve clearance, but that's because the valve stops contacting the head and can't dissipate heat... the temperature in the combustion chamber doesn't increase in this case, does it? Or does a leaky valve make for a leaner burn?

Not trying to argue, just want to understand the mechanics.

I think only if the valve has already burned and so flames are leaking out into the pipe. Not sure though.

[steve murdoch]

To my backyard mechanical mind...agreed, it can't get rid of some the heat which used to go to the bucket so the heat has to go somewhere which is out the exhaust port.
Even still burning mixture might be exiting the exhaust side.

My thinking pointed to a valve clearance because the o.p. mentioned only one pipe was turning blue.

[tkent02]

OK, could have some effect, dunno. Something is going on in that one, could be the vacuum line split and is leaking in air into it.

It takes a lot to blue the stock pipes, not much to blue an aftermarket one. Like majorly lean vs just a skosh lean.

[Lorenzo]

Can you show us something about the relevant spark plug?
It may hold clues on a less than optimal mixture.