TR2/3/3A TR3 Engine Noise

[TFR]

Piston slap can come and go. Heat decreases the cylinder OD tightening the clearances.
Also, if you are concerned it might be rod bearing clearances then use 50 weight oil and see if the niose clears up.

 

[sp53]

Hi Dave I just thought I would throw this out. Many years ago I had a tr3 problem that was a knocking noise close to where you described and it turn out to be the inner rod of the steering column. Please keep us posted because personally I enjoy diagnosing knocking noises from thousand mile off.
Steve

 

[Deleted member 8987]

To me, experientially, the key piece is the broken insulator on the sparking plug.

"The spark plug on #3 cylinder had a damaged ceramic insulator around the center wire."

Now, too much side load with the socket and you can do that, or, something floating around in the comustion chamber, like a screw out of the butterfly shaft, a bolt from the air cleaner, or, a ring that broke and worked up through the top land.
It may now be wedged (or part of it) in the top of the piston, contacting the bottom of the head.

I've got a bore light, if you are careful, with piston down, semi-dark shop, you can see the top of most of the piston.

Dave

 

[TexasKnucklehead]

I agree that the broken plug is very concerning.

I also agree it's fun to diagnose from 1,000 miles away -especially when it's not my car!

But, the suspence is killing me. Dave has been quiet and I hope it means he's figured it out and is out driving around, but my thoughts are elsewhere. You could always clean out your shop-vac and see if you can vacuum anything out of the plug hole. I think if it were wedged into the top of the piston, the noise would stop.

 

[DrEntropy]

Not if it's a big enuff piece to hit th' roof of th' chamber.

But due to the description as a more syncopated noise I'm leanin' to th' damper keyway.

 

[ekamm]

Pull the plug and run a magnet through it.

 

[Deleted member 8987]

If it's wedged into the piston, that won't help.