All,

I just pulled my Evo's head and noticed that the exhaust valves on cylinder 1 had some residues of corrosion. Please take a look around the valve seat area. I verified the head gasket and there were no signs of water leaking from the top or bottom layers of the gasket.

The car has not been running for about a week, so not really sure if the buildup was due to that reason. Weird thing is that only those two valves were the only ones showing that!

Here are some pics:








A few months ago, I did a compression test and these were the results:

Piston1


Piston 2


Piston 3


Piston 4:


Any ideas as of to what may have caused that residue on the EX valves on cylinder 1 only?

Will appreciate your help on this matter!

 

do you run race gas?race gas has alot of moisture,can cause some surface rust on exhaust part.just an idea.

 

nos,

I never ran race gas on the car before! Thanks for the info!

Just curious why in two valves only thou!

 

All your numbers look really low...

Head gasket would explain rust issues and the low numbers.

Why did you pull the head off in the first place?

 

codean,

Remember that on a IX, the range is 92-145 psi with a max variance of 14 PSI between cylinders. However, I do agree that they are too inconsistent! I would expect all of them to be in the 140 PSI area which is not the case.

I revised the gasket and could not see any visible damage(s) or leaks! Weird haaa!

As for, why I pulled the head..... well, a long story short. I was replacing clutch, conrods, a new ported ex manifold (Swain Coat was peeling), fuel rail with FP gauge and intake manifold! Due to the amount of work involved, my friend that it is helping out suggested that we were fairly close to replace pistons/rods. It took us 20 mintes from where we were to pulling the head!

 

This makes me worry as I am getting Cylinder #1 missfires and people are saying exhaust valves could be the problem.

 

How do you know it was misfiring? Spark plugs reading?

 

P0301 Code, actually hear it, narrowband and wideband going nuts....

Spark plugs looked very close to yours. #2 was a little browner than the rest. Kind of confused me because the #2 is suppose to be the hottest cylinder.

 

My plugs look very lean because the car was turned off after a few minutes of been idling (Turbo Timer). At idle, my car oscillates between 15.4 and 14.6 AFRs.

However, mine always look like brownish if I do not let idle for a while.

 

all 4 cylinders are within 10psi, did you count the number of cranks it took to get each reading? if you let one crank a few less cranks the reading can be lower. if one takes more cranks just to get up to the same value as the others, that can indicate a problem.

 

I did the same test about 3 days ago and all of mine read 140psi all the way across, cranked each the same amount aswell.
How much boost do you run?

 

KevinD,

I hear you! Cylinders 2 and 3 were able to reach their max in a few cranks. However, pistons 1 and 4 had to be cranked a few more to reach 10 PSI difference on the down side.

I verified the compression tester with another set of cars to determine the "accuracy" and my Civic was pumping almost 290 PSI across the board.

 

I used to run 25 PSI!

 

Look at the marks made by your headgasket around the cylinder. It seems as though it is an inconsistent ring around where it sealed around the chamber. Specifically, right next to where your nasty valves are...

 

maybe HG is starting to give,, the reason why you were getting inconsistent redings


looking at the pic if you look at your head,,, look in between the two valves where the rust is ocuring this would be on the right hand of the pic then look below the 2 valves right where the HG markes are you can see a ding mark it doesnt seem to be a flat surface,,, and it makes sence because thats exactly where the rust valves are, meaning water might be getting in there ,,,,,