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I have a question about the valves on a 97 DOHC EJ25. I'm currently rebuilding a 99 motor with these heads and have found that I could remove 99% of the junk that was coating the Exhaust valves. I thought it was carbon build up because it wasn't very uniform in thickness or appearance. Some of it was gone when I began cleaning the heads up.


Are the valves coated with a heat control substance from the factory? If they are, I just ruined these valves by removing the stuff.


Also, I began cleaning the heads by soaking them in Toluene for a few hours before bristle-brushing the gunk out of the chambers and around the valvesprings, etc.... By doing that, did I just ruin the valve seals? I wasn't planning on doing a valvejob before bolting the heads onto the block.....Now I'm not so sure I should puth the heads on until I replace the valve seals, guides and maybe even the valves if I screwed them up.


Any info is helpful!


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The only thing new valves are coated with is a small amount of some antirust stuff. So, no damage there. However, unless you relap the valves, they won't seat as well as they did initially.


Your valve stem seals are TOAST now! Even solvent or really high temp water will damage them, but toluene...man, are you sure they even still exist!? :eek:

I'd expect to see a little puddle of goo.


The valve guides should be ok.




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Thanks Emily! I'm definately pulling the valves and getting the rest of the carbon buildup off. I'll make sure to re-lap them and install new valve seals too.


There goes another week of the car being motionless..... :0

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