- This topic has 11 replies, 4 voices, and was last updated 13 years, 5 months ago by
.
- Topic
2002 Accord LX (4 dr) 5MT with 200k km or 120k miles.
I just did the valve adjustment as per Eric’s video and other DIY threads on the net. I found that many of the valves were too tight and so loosened them slightly, to the clearance per spec (same as what Eric mentions in his vid). Is this normal? I found that everyone else seems to talk about tightening valves that were loose.
While I was at it, I inspected the wires and found one to be discolored, rusty in color. No sign of oil, though. See pic:
And here are the corresponding plugs: Left to right: cyl 4-1
Since I had it all out, I replaced the spark plugs with NGK platinum plugs that I had on hand (I think OEM spec calls for the iridium plugs, IIRC). Does anyone know what the rusty colour means? The corresponding plug also looked more burnt / rusty around the bottom of the ceramic area:
Overall, the engine feels much better and sounds smoother, except when you pull the gas cable and let go. The engine revs up and as it comes down to near idle, it makes some slapping (is that knocking?) noise, as it did before the valve adjustment / spark plug change. The slapping comes from behind the exhaust manifold, so I’m guessing it’s the exhaust valves making that noise.
Thanks for looking,
Josh
- Replies
I sometimes see that brown color when moisture gets into the spark plug well either due to someone washing the engine or when the wire is not installed all the way.
As for the plugs the marks on the porcelin are normal and from someting called the ‘corona’ so that is not a concern however it does look like your buring some oil on a couple of the cylinders so keep an eye on your oil level especially after a long highay drive.
The noise your hearing could be a loose timing belt so you might want to check the tension there.
Lastly with the valve adjustment I often find that the intakes are loose and the exhaust are tight. If you felt the valves were all tight you might want to go back and recheck them and your work just to be sure because if they are not adjusted correctly it could mean damage to the valves. It could be nothing as they may have been misadjusted in the past.
Quoted From dreamer2355:
Those spark plugs look pretty normal. As for the rust, well that could be down to moisture building up around the lower of the ignition wire. Have you tried dielectric grease?
Do you have the ability to post a video of this ‘slapping’ noise? Piston slap sounds like a hollow sound that is most noticeable on acceleration.
Have you tired to isolate the engine noise by disabling 1 cylinder at a time to see if your engine noise disappears? Thatis one way of checking for a rod knock and so forth.
If it’s just moisture, that’s reassuring, as I wondered if that was a burnt color (and not just rust). I did install the new plugs with dielectric grease (on the ceramic end), as well as a touch of anti-seize on the threads.
I will try to post a vid on youtube regarding the noise.
I didn’t know I could safely disable one cylinder at a time. (I thought it would cause the engine to stumble and trigger a code and the CEL.) Do I do this by just removing the ignition wire off the spark plug, one at a time with the engine running and then listening while giving some gas?
Eric, I double checked all the valves by swiping the feeler gauge while pulling the valve up with the other hand. I thought your comment in the vid was that it was better slightly too loose, than slightly too tight. So while pulling up on the valve, the gauge had drag but without getting jammed up. I made sure that it wasn’t so loose so that the feeler gauge had vertical play (up and down).
Also I did put a dab of gasket sealant (though not Honda brand, Permatex I think) on the corners around the cam arches. There was no mention in the vid if this was required, or if I could even reuse the old gasket. Some DIY treads mentioned to dab the corners. I hope that was the right move…
Thanks for the replies folks.
JoshAnyone know why the pics aren’t showing, I imbedded them as:
“[IMG]http://tl.acurazine.com/forums/picture.php?albumid=9865&pictureid=47711[/IMG]”
“[IMG]http://tl.acurazine.com/forums/picture.php?albumid=9865&pictureid=47712[/IMG]”
“[IMG]http://tl.acurazine.com/forums/picture.php?albumid=9865&pictureid=47713[/IMG]”I could see them during the preview, but nothing now…
Those spark plugs look pretty normal. As for the rust, well that could be down to moisture building up around the lower of the ignition wire. Have you tried dielectric grease?
Do you have the ability to post a video of this ‘slapping’ noise? Piston slap sounds like a hollow sound that is most noticeable on acceleration.
Have you tired to isolate the engine noise by disabling 1 cylinder at a time to see if your engine noise disappears? Thatis one way of checking for a rod knock and so forth.
You can do a cylinder balance test if you have a scan tool.
If not, you can disable the ignition or fuel injector on one cylinder at a time checking for a change in noise. It may be easier just to disconnect a fuel injector harness connector on one cylinder and see if you hear a notable change, if not, reconnect and go to the next cylinder. If the fuel injectors are hard to get to, you could disconnect an ignition wire, ground it, then again check for a change in noise while at idle. If you are unsure on how to do that, just Google it. And don’t get zapped….
Do you have a mechanics stethoscope that you could use to help locate this particular noise? Also, make sure your ruling out any other noises coming from the engine bay from accessories and so forth.
I really doubt its a rod knock or anything that major. Its possibly just excessive lifter noise.
Hi guys:
For years I have noticed this brown stain on my high voltage, large gap spark plugs. It worried me, and eventually discovered it is called a “corona stain”. See this link.
http://www.ngk-sparkplugs.jp/english/techinfo/qa/q17/index.html
If this link goofs up, just google “spark plug corna stain” and you will get it.
I believe this is correct, because oxidized oil readily dissolves in acetone, and acetone wipes this stain right off.
I think that the long plug service combines with a very high electric field to oxidize oil vapor in the plug well, and then electrostatically deposit this “fried” oil onto the plug porcelain.
See if your rust colored deposited wipes of with acetone, methanol, or nail polish remover (aka methylethylketone).
Sorry about all the technical vocabulary.
If you know the valves are good then I would check the timing belt tension as I suggested in the last comment. I do believe I did mention to put a little sealant on the corners of the valve cover gasket at the arches in my video as that is actually Honda service procedure, you can reuse the gasket as long as it’s still pliable and not hard and brittle. I don’t recommend anti-sieze on the plug threads, just a drop of oil is much better in my opinion but it’s not going to hurt anything. Here is a link to my ‘power balance’ video.
http://www.youtube.com/watch?v=bAOmUjAjNjE
If you do it for a prolonged period of time it might set a CEL but if it does you can just clear it and ignore it. I would be checking the belt tension first however.
Eric – How come your not a fan of applying anti-seize on the threads of spark plugs? Ive never thought of using oil instead.
Interesting…
Dreamer:
Good question about spakplug antiseize.
The first thing I do when buying a vehicle, new or old, is apply a bit of antiseize on the sparkplug base threads. Lawnmowers too, come to think of it.
However, these antisieze coumpounds have metallic copper, lead, maybe zinc, which will poison your catalytic converter……so apply very little. I own a fair number of engines, and two tubes of antisieze are still about half full.
Quoted From WDHewson:
Dreamer:
Good question about spakplug antiseize.
The first thing I do when buying a vehicle, new or old, is apply a bit of antiseize on the sparkplug base threads. Lawnmowers too, come to think of it.
However, these antisieze coumpounds have metallic copper, lead, maybe zinc, which will poison your catalytic converter……so apply very little. I own a fair number of engines, and two tubes of antisieze are still about half full.
This is ‘kind of’ the issue. My philosophy has always been ‘if they didn’t put it there at the factory what makes me think I know better?’ With antisieze on plugs especially the copper type you are basically putting a conductor on the end of the plug, get too much on and you could short it out. Lastly I like oil better because it doesn’t leave a mess in the spark plug tube and for me seems to work much better at getting the plug threaded in correctly, I really haven’t seen any benefit from useing antisieze on spark plugs.
- You must be logged in to reply to this topic.