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Old 10-13-2014, 10:37 AM   #1
Bruce_MO
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Default Tappet noise? Insights needed, please

I asked this question before several months ago and didn't get a lot of insights, so I thougth I'd try again...

I have a rebuilt touring engine that runs great, other than a pretty pronounced "ticking" noise. The noise always completely disappears after a few minutes when the engine warms up, and the engine sounds and runs beautifully after that.

I assume it's a valve lifter that needs to be re-adjusted.

I called the rebuilder (many of you would know him) and his initial reaction was it could be several things, but I wasn't anxious to pull the engine to take it to him if the problem is easily fixable. I'm going to check the valves, and I've seen lots of previous 'Barn correspondence on valve clearance settings and technique. But I got to thinking...could it be a loose valve seat? I would assume that a loose seat would be noisier and perhaps more erratic in sound. And after being hammered, I would think it would get worse over time, and warm-up wouldn't make the noise go away. How would one test for a loose seat? Compression test? Regardless, I'm going to check the valve clearances first.

Thanks in advance for any insights you can provide.
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Old 10-13-2014, 10:59 AM   #2
Jim Brierley
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Default Re: Tappet noise? Insights needed, please

not likely tappet adjustment but it could be a tappet is a little loose in it's bore (the block) i had one once that would change from a little noise to louder then back to little then be quiet for a few seconds. the cure was to ream the block for oversize tappets. in your case, where they get quiet after warming, i would leave them alone.
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Old 10-13-2014, 11:16 AM   #3
Patrick L.
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Default Re: Tappet noise? Insights needed, please

What did your rebuilder say he set the lash at ?
It doesn't take much to check it, the manifolds don't have to come off.
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Old 10-13-2014, 11:21 AM   #4
J Franklin
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Default Re: Tappet noise? Insights needed, please

The reason for tappet clearance is to allow for the elongating of the valve stems. Your clearance may be a few thousandths over and that is why it quiets after warming up. I would not worry too much but you could check the valves for piece of mind. Check first with a stethoscope around the block to pinpoint the tap as other things change dimension from cold to hot.
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Old 10-13-2014, 01:52 PM   #5
Tom Wesenberg
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Default Re: Tappet noise? Insights needed, please

Sounds like piston slap, as that will often go away after the pistons expand from heating up within a minute or so.
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Old 10-13-2014, 04:32 PM   #6
Bruce_MO
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Default Re: Tappet noise? Insights needed, please

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The engine has small block chevy style pistons...would they be more or less prone to experience slap than an orginal style?
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Old 10-13-2014, 09:33 PM   #7
J Franklin
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Default Re: Tappet noise? Insights needed, please

Unless the pistons were not fit properly or you have a bent/twisted rod you shouldn't have piston slap until things are pretty well worn out.
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Old 10-13-2014, 09:53 PM   #8
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Default Re: Tappet noise? Insights needed, please

SBC pistons are way LESS likely to give slap.

Much more likely a valve lash is off somewhere. Like many said sounds ignorable.
Having said that the valve cover comes off very quickly and easily and lash is easy to check. And you don't need to remove manifolds as already stated. Measure several of them (maybe all of them) and see which is too loose. We have always set both I&E to .013 with good performance, but you could match your loose one to the others
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Old 10-14-2014, 10:24 AM   #9
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Default Re: Tappet noise? Insights needed, please

I agree you should check for piston slap. Just short out each plug during the time it is ticking. If the tick goes away when the plug is shorted, most likely is piston slap. Might want to do this easy check before pulling the valve cover.
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Old 10-14-2014, 12:59 PM   #10
Bruce_MO
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Default Re: Tappet noise? Insights needed, please

Thanks to all for your inputs. Larry Shepard stopped by last night to listen (Thanks, Larry!) and he concurs that it's probably valve clearances. But I will do a few other checks before pulling the valve cover. I appreciate everyone taking the time to offer their insights & suggestions.
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