Metal Tapping Sound from Engine
 

Any knowledgeable mechanics have any insight about the metal tapping coming from the engine of my RX3?

http://vid42.photobucket.com/albums/...pspfsie7ez.mp4

jb

Well done video, JB, picks up the noise distinctly.

I suggest using either a mechanic's stethoscope or a long screwdriver (not joking) to help narrow down the location.

If you've not used the screwdriver trick, press the end of the handle gently against one ear and touch the driver end to different areas of the engine. As you move it around the engine you will hear a difference in the sound.

I imagine you've also sent the link to Gerry at CSC.

Exhaust tight? Sounds like loose or bad exhaust gasket or really loose valve clearance.

Hi Jay,

I used a mechanics stethoscope but still can't pinpoint where the noise is coming from.

Part of the problem is that I have significant hearing loss. One of the reasons I didn't notice the noise sooner is that to protect what's left of my hearing, I put in earplugs before I start the engine.

Emailed CSC a couple of times, with a copy of the video, and spoke with Gerry on the phone.

First suggestion was to check the valve clearances.

He said he couldn't diagnose the problem from the video.

So I did the valve check again....second time in 3 days...:cry:

The clearances are in spec, and the noise persists.

jb

Lee, you don't know how much I wish it is something simple.

I tightened the the header bolts at the first valve check, and pulled and pushed on all parts I could reach to see if there was any movement.

I will check again for loose parts.

The engine starts on the first push of the starter button, and seems to run perfectly, except for the tapping.

jb

Perhaps I'm hearing something else... but it seems rather odd to me that the tapping appears to NOT be related to engine RPM?

Juanro, I noticed the same the same thing.

That's why my ears perked up when Lee thought it might be a rattling of loose parts.

I will take a closer look tomorrow.

jb

I couldn't tell you what that sound is, but it doesn't sound anything like my issue. Mine was much louder and sounded just like what it turned out to be ... a piece of metal bouncing around on top of the piston.

The next time you adjust the valves, take pictures of the tappets and rockers. Out of curiosity, what grade of gas do you fill up with?

I was thinking low octane could cause pre ignition but it shouldn't at idle.

I took photos today.

Gerry asked me to look for any damage to the rockers and tappets.

I looked around the valve galley area with a flashlight, and did not see any evidence of unusual wear or damage.

I alternate between 87 and 89 octane E10. I haven't noticed any pinging, but I may not be able to hear it anyway.

jb

I heard a similiar noise when I had damage to a rocker arm and the camshaft on a different motorcycle. However, the frequency of the noise increased, and decreased, with corresponding engine rpms. The noise was also definitely coming from the cylinder head.

I'm betting Gerry is going to want to pull the rocker cover to get a better look at the tappets, rockers, and camshaft.

It does sound like its in the valve train as the sound alternates like it should as the cam rotates to open and close each valve. It has a different frequency to the exhaust note. tickity tap tickity tap.

Jb, just a shot in the dark here .
Pull the spark plug out and go in with a pencil magnet and see if it pulls anything out with it, slowly rotate motor by hand thru the alternator side hole so piston is way down in the cylinder to give you more wiggle room with the magnet. If you can look down the S' plug hole with a flashlight see if there are dings on the top of the piston. Then with spark plug still out, gently hit the starter button and see if it spits any object out of the S' plug hole by holding a rag loosely over the hole to catch said foreign object. rj

Checked the valve clearances again, yesterday.

Checked for loose parts.

I'm 99% certain the tapping is from inside the engine.

This seems to be where the tapping is the loudest, however after listening to sounds all over the engine for 15 minutes everything begins to sound the same.

http://i42.photobucket.com/albums/e3...psj2gat82x.jpg


jb

Might be a good excuse to get an inspection camera.

http://www.harborfreight.com/high-re...der-60695.html