Can pinging under load be due to valve lash too tight? I'm just wondering, I had a pinging sound when I was coming up the steep hill near my house. I just broke in the engine, and I hadn't noticed this before.

I hadn't yet adjusted the valves, but I did that today. They seemed a bit tight (I adjusted them hot). After I adjusted them, I drove up the hill again, and I'm not noticing the sound as much, might still be there, but if so it's certainly much quieter than it was.

On a general note, I can't seem to get my valves quiet. My slants have always sounded like sewing machines; but I've seen some videos on youtube where they adjust the lash and it appears to be really quiet after adjustment. Today I purposefully went looser than spec and tighter than spec, just to see what they sounded like - they seem to tick no matter. Is there a sweet spot that I'm just not skilled enough to find?

brian

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On further reflection, this could easily be an exhaust manifold leak...I'll check it out and let you all know what I find.

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After I rebuilt my engine earlier this year, I heard a worrying pinging or clacking noise that did turn out to be an exhaust leak at the head-manifold surface. It went away after we remounted the manifolds with a little bit of high-temp RTV on both sides of the gasket. Does it make the same noise when you give it some throttle in neutral? Mine did.

If it only occurs under high load like going up a hill, I'd say it's more likely to be actual pinging. Not certain, though. Did you mill the head or increase the total timing advance? Maybe try filling up with 93 octane and seeing if it goes away.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

It just started doing it after break in and having driven it for about 50 miles, so maybe the manifold loosened a bit or the down pipe to manifold connections (dutra duals).

Only happens under load, not when in neutral and revving. It's got that characteristic tick of an exhaust manifold leak, but I haven't had time to check it. Up hills is way more noticeable, but also if I punch the gas down on flats. Cruising it can't be heard, at least by me (old ears).

I'll check the connections, I have Remflex gaskets, so it's a matter of a bit more crush if it is an exhaust leak.

brian

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Isn't pinging generally a timing issue ,to much advance. or a hot spot in the cylinder causing preignition ?

pinging is a valve issue, but oftentimes folks mistake an exhaust leak tick or similar sound for valve chatter.

b

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