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Does any1 know the diameter of the exhaust ports on a 03 LX?
If not, can I remove the exhaust manifold, measure port size, and then reuse the gaskets when I reinstall manifold, or will I need new gaskets?

-Thanks

 
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any time you remove something and break a gasket seal, you are supposed to replace the gasket. i know some ppl say not to to, but better safe then sorry. gaskets are cheap....and i would not recommend removing the manifold w/o proper knowledge and equipment.

• new gasket, either fel-pro or oem
• torque wrench
• shop guide, either oem or haynes or chilton

alot of fasteners by manufacters have been to use for the engine have are referred to yield to torque. meaning that you torque, then you use a special guage (known as an angle guage) to finish the torquing. when removing the fasteners, you will need new fasteners. i always believe and using new fasteners regardless of what anybody says. then you have to follow hondas tightening sequence to make sure the gasket is crushed properly. also if you attempting to just measure the exhaust ports sizes, look it on the internet. it must be there somewhere.



ps. if you attempting to measure the exhaust ports, i would recomment removing the cylinder head and not the exhaust manifold <----which is commonly referred to as headers

 
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also, if u want to port the header ports, i have been told time and time again that they are engineered well to begin w/ and that they on import engine they should be slighty larger than exhaust manifold/headers......dont know if that helps....however just polishing couldn't due any harm..just dont port (ie make it bigger)......you also want to be careful when having this work done and make sure that a shop is familiar w/ aluminum engines because iron block are much less delicates and allow room for error

 
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are you nuts??? take off the whole head just to measure exhaust ports that are staring you in the face when you take off the exhaust manifold? sorry but no.
I have my stock cylinder head sitting here. no need to take anything apart. i'll post the port size in a bit. also the exhaust gasket is probably the only one besides the valve cover gasket that i would re-use.

 
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a little less than 1 1/4 "

 
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Thanks for the help guys. I wanted to know the size so I would know what tube sizes to look for in a header. There's no point in going larger than the exhaust ports, right? I'm stock and looking for low-midrange torque (I understand headers by themselves will probably give minor if any gains on D17).

 
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i must be nuts, i meant to say i recommend removing exhaust manifold and not cylinder head my bad, if you looking for header, i recommend getting ceramic coated as they due not discolor and keep temps down better than the polished versions. spend the money on a proper socket to remove o2 sensor, will save you a lot of time and hassle...when its come to 4-2-1 vs 4-1....ppl recommend the 4-2-1 due to it having better torque...one final thing is that if a turbo is in your near future, dont get headers because you need a new one w/ turbo anways

 
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I found when taking off the exhaust manifold on my 2001 Civic DX not only is replacing the gasket necessary but so is some of the bolts that mount it.

The service manual recommended this and I carelessly ignored it because I was in a hurry. I used a torque wrench to tighten one of the reused bolts to Honda’s specifications and the bolt head snapped right of the damn thing. I guess on some of the newer blocks this may not be a problem because they use posts already mounted to the block and all that is needed are the nuts to tighten the manifold back down. Luckily I have a friend who is really good with a tap and die.

Anyway most gaskets are 10 - 20 dollars with exception to the head gasket. I recommend replacing them and anything else that wearable any time you pull something apart. Save yourself the headache later.