So I found the cause of my valve tap [Archive] - MX5 Miata Atlanta Owners Club

PDA

View Full Version : So I found the cause of my valve tap


adjake
01-02-2009, 01:21 PM
Any ideas as to how this happened. I am guessing that the cheap *** wires I had on there had something to do with it. Also just replaced a really dirty air filter... detonation? a/f off a bit? That was a Bosch platinum 2 ie dual electrode also note that the top terminal is completely gone, never found it, disintegrated?

Any way to clean out the chamber and sealing surface of the plugs without getting all the, whatever black stuff is in there into the cylinder? This was out of the #4 cylinder closest to the firewall. The other plugs looked pretty good.

Funny thing is that it did not seem down on power and ran pretty good. It is now only marginally smoother. Really hope that I did not do any other damage.

metalman
01-02-2009, 01:31 PM
Holy moly!

RotorNutFD3S
01-02-2009, 01:33 PM
:eek:

It could have been detonation, but if it was, you're going to have some damage on the piston head as well more than likely.

Doppelgänger
01-02-2009, 01:33 PM
I don't trust all of those "fancy" plugs, I just run the regular NGK plugs.
So how bad is the misfire now that you've replaced the plugs?

metalman
01-02-2009, 01:40 PM
I don't trust all of those "fancy" plugs, I just run the regular NGK plugs.


My thoughts as well. NGK wires too.

adjake
01-02-2009, 01:48 PM
It's running pretty smooth right now. Learned my lesson the hard way, never ever buy cheap ****. Funny how I keep learning that over and over and over and over and......

Put in ngk plugs and wires everything seems ok for now

metalman
01-02-2009, 01:51 PM
Hopefully you have no significant piston damage.

Doppelgänger
01-02-2009, 02:02 PM
^ or valve seat damage...

adjake
01-02-2009, 02:59 PM
Kind of just hoping at this point that everything is cool.

RotorNutFD3S
01-02-2009, 05:32 PM
Find someone with a borescope (make sure it's one with a light!), take the spark plug out and take a look in there. Detonation on the piston will be immediately evident as it looks like chips or chunks missing out of the metal. If the scope is really flexible, you should be able to look up at the valves and seats as well.

MoD_Scotty
01-03-2009, 12:02 AM
It's running pretty smooth right now. Learned my lesson the hard way, never ever buy cheap ****. Funny how I keep learning that over and over and over and over and......

Put in ngk plugs and wires everything seems ok for now

yet the NGK plus are way cheaper than the Bosch ones are

ben91
01-03-2009, 07:39 AM
4 is running hot. Needs at least one of the following
more timing
better coolant flow
better fuel distribution

*I'm assuming it's not detonation because you would have heard it right? Plus car's got a knock sensor.

"cheap" plug wires won't do this.

jester911
01-03-2009, 07:52 AM
I found out that at least on my Pcar the multielectrode plugs are crap.
When I first got the car I let the guy at the parts store talk me into them. I put them in and for the first week the car ran fine. Then it started misfiring like mad. I finally pulled the plugs and reinstalled the old ones that I had removed and the car ran fine.

I took the new ones back and exchanged them for the original spec Bosch plugs. I found out later from a buddy that races Pcars that they found the multielectrode plugs can actually ground out on the head and burn up a piston. This may happen in other cars as well but I have no data to back that up.


I learned my lesson on plugs though.

adjake
01-03-2009, 08:10 AM
4 is running hot. Needs at least one of the following
more timing
better coolant flow
better fuel distribution

*I'm assuming it's not detonation because you would have heard it right? Plus car's got a knock sensor.

"cheap" plug wires won't do this.

Never heard anything other than what sounded like a valve tap. I am going to flush the cooling system today. I'll have to keep a close eye on it. Is there any way to clean the plug sealing surface without getting the crud into the cylinder? Never through a code other than my ongoing egr issue.

jesseealexander
01-03-2009, 01:22 PM
multielectrode plugs are crap for the reasons jester stated, and the fact that you will most likely make less power and the fuel would burn irregularly because instead of one spark in the center, and depending on the plug, there could be up to 4 much smaller sparks that are offset by the placement of the electrode.

GraffitiPanda
01-03-2009, 07:49 PM
i bosh iridiums i will say arent bad with ngk plugs (NEVER HAD AN ISSUE)

(the quad electrode ones) there not sparking in 4 arches jesse its actually accumulates in the center giving it a much more precise shot.

the duel electrodes are very unstable i don't trust anything without a safety measure (2pins to hit vertical and horizontal is better than unguarded duel pin)

but i get hit by trucks... so i don't know anything :facepalm:

Doppelgänger
01-05-2009, 06:46 AM
I tried the Denso Iridium plugs and didn't notice any difference..or at least no difference for a $12 plug.

Grantri
01-06-2009, 10:21 AM
Yup...

The genius at my local Autozone tried to talk me into a $60 set of plugs Saturday (they only had two of the stock NGK's)

" These are really worth it, you'll get a lot more power"

Yeah, sure I will ...no thanks ...

mustangtomiata
01-06-2009, 10:25 AM
and you'll get 40 mpg with these plugs too all while keeping us in business on our big rip off!