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Header cracked, could hurt valves?

Jeff-97XJ

NAXJA Forum User
Location
Atlanta, GA
My header has cracked close to a valve port. Noise makes the XJ sound like a piece of junk. New header is being ceramic coated but not back yet. A buddy tells me not to drive the XJ as the crack in the header will hurt my valves due to back-pressure issues. Does anyone know if this is true? How many miles will it take till it hurts the valves?
Appreciate any thoughts on this-
Thanks,
Jeff-97XJ
 
Idk but i had the same problem and drove a couple houndred miles and i just got it fixed. It runs better then ever. So I think you will be ok. Just dont push it. I babied mine. And all ports were cracked almost all the way around
 
i hear what your buddy is saying but i drove mine for atleast a month with my header cracked before i got my Borla on and i never noticed any long term effects...running with NO header would be bad but a crack isnt gonna throw off pressures that much...
 
One of the ones I have has had a crack in it for 3 years. It's still running just fine. Except for the crack of course. I should probably fix that one day.
 
The idea of a cracked header causing valve problems came from a bye gone era. Back when I was a kid people would run very short pipes on hot rods. The problem with the valves was that if you shut the engine down when it was really hot, the cold outside air could get back to the valves and cause them to warp. With newer metals this isn't a real problem anymore.
 
i ran mine like this for maybe a month

it was uber annoying but didnt cause any issues

45247_508769117714_226300669_213851_3833534_n.jpg
 
Technically it can be bad for the engine. It could pull in outside air and mess with the O2 sensors, causing a rich condition. It won't hurt valves due to back pressure issues.

However, I have never seen a problem caused by a cracked manifold on a 4.0L.
 
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