Patrick L

The engine is just under 65kmiles (100k Kms). Had some compression issues a few years ago in this cylinder, had the piston head replaced.

Form what I gather the whole piston head would have to be removed, the rings changed, then everything put back together. Probably a pretty serious issue I assume?

Also, for what its worth, I haven't seen smoke coming out of the exhaust. (I did some quick searching and that seems to be a symptom of worn piston rings)

YELLOW JACKET

that's the stuff. try it. what do you have to loose. worked for me. as for valves, it is possible a retainer could be cracked. if so I would at least pull the valve cover and inspected the valve spring retainers for cracks. cause if one is cracked and it lets a valve drop, then you got some serious trouble. I would also do a valve adjustment to ensure they are at spec. run that restore till your next oil change then do a compression check again. but check those valves first.

Billman250

Even a mega crack in a retainer will not cause compression to differ like that.

Your next step is a leakdown test by someone who knows how to follow the audio signal of the leak (provided the valve adjustment is good)

Full diagnosis should take one hour tops. I can do it in 15 minutes.

10 hrs is absurd (based on 100/hr)

chubbys2k

Billman is right. Just went to Honda to see how much it would be to diagnose my smoke out of my exhaust. $103/hr at Honda. I had a previous master Honda tech do it at his house for $65/hr. Took him 1 hour to do a compression and leak down and gave his opinion. Find someone else to diagnose your problem.

Car Analogy

Is 'the mechanic' the Honda dealership? If so, I'm not surprised they want $1k to do almost nothing.

You had a problem with this cylinder before, and it was the cylinder head? Well maybe at that time some damage also occured in the cylinder itself, to the cylinder wall, and its only gotten worse and now its causing issues with compression. This would jive with the change in wet vs dry comp test results, as well as with misfire issues (whereas, unfortunately, wet vs dry results point away from being an easy valve adjustment fix).

So it would seem whoever did the repairs last time missed something big, and now you (probably) have to rebuild the motor. A leakdown test is going to tell you if its a problem with the rings sealing.

Was it this same mechanic that did the work last time?

windhund116

Do a leak-down test on the cylinders.

How often do you adjust the valves?. My WAG would be a burnt exhaust valve(s) on Cylinder 1.

Billman250

Test parameters:

-Engine warm
-test performed within 15 min of shutdown
​​​​​​-injectors disconnected
​​​​​​-all spark plugs removed
​​​​​​-throttle WOT
-crank engine about 6 pulses per cylinder

If these parameters were not met, do the test again. Whichever cylinder was the lowest during your original test, do this cylinder first. Then do the second lowest cylinder, etc, etc.

If test still shows problematic cylinders, only a PROPER leakdown test can pinpoint the cause.

Proper means following the comparative audio leak signal on all cylinders, across all points of possible noise discharge.

jyeung528

call up the shop that replaced the piston head. they messed up somewhere.

jyeung528

you completely hi-jacked this thread, and i get confused whether you are the OP or not.

OP seems to have a problem with his rebuild of cylinder #1 with low compression due to rings/piston head rebuild.

hi-jacker has issues with bent valves. you should have compression tested the car before you bought it. you don't necessarily need to throw a code for low compression in one cylinder. $2,000 seems to be a fair price.

suggestion is to get the head repaired.