OK, this continues to drive me crazy, need your ears, it won't be easy

[My427stang]

My 445 has a noise, and has had a noise for a long time.  It won't blow up, it's been apart twice since the original build for the noise, and I have found nothing.  The only thing I haven't done is Zyglo the pistons.  Heads magged, multiple cams, multiple rocker sets, multiple valve covers, clearanced the timing chain, multiple fuel pumps, nothing hitting down below, with or without PS, even reblocked to have tighter clearances because I originally built it loose, new balancer, clutch, flywheel, you name it. 

In the video below starting at 25 seconds, you hear a tapping that sounds like a loose valve, it's much worse when cold.  After all of this, my hunch is I have a bad piston, but I did not see anything on multiple inspections and it is silent at idle.

First request, listed to the video until you hear the minor tapping between 25 and 30 second point. Many people say they can't hear it, and it is tough, but once you tune into it, it sounds like valvetrain, although everything has been gone through multiple times.

After you hear it, generate ideas.  FWIW, I have been in pure parts replacement mode for over a year, the absolute only engine I have ever been in this situation.  The only things not magged or replaced are the pistons and rods, but my eyeball couldn't see or measure anything.  The crank was magged and checked.  All new parts,and it has made the noise since the original build without change

Thoughts, prayers?    Been doing this a long time and haven't ever ran into one like this.

About ready to put the spare 390, or maybe buy an LS off Craigslist LOL

https://youtu.be/VlHIl9hafYA

[Drew Pojedinec]

Doesn't do it at idle, you think it's a piston but consider it at valvetrain speed.
Can you replicate the sound without the engine under load?  (like running 2,000rpms in the driveway?)
If so, have you done the ole "remove a plug wire" and see what it sounds like trick?

Other random thought:
On every Ford truck I've ever put headers on they all seem to just barely touch a crossmember somewhere.  This often makes a random tick/tap sound, especially under load as the engine moves and twists.

[fryedaddy]

if its not the headers do you have floating pins in your pistons,i have a sbf that makes a noise,i was told it was a wrist pin.i also had a hole in my headers where it was hitting a cross member and i couldnt find it till i took the header off.it sounded like a medal tick or knock to me,but it wasnt

[Heo]

Hard to hear on a video but sounds "hollow" like
a loose piston pin bushing or piston slap
Have you checked the pistonpin bushings?

[My427stang]

Thanks guys,

Absolutely not anything touching, had one tube originally close to the pan, but it has since been reshaped and I cannot make the noise in the driveway, wish i could, it takes a load.

I visually inspected all the wrist pins and small ends, and measured them too, everything looked good.  They are full floating dual spriolock Probes.  My hunch is, if it's a piston, it's only one. I wish I would have swapped sides last time it was apart, at least I could have heard it from a different direction.

[Heo]

You turn left and accerelate lightly when the sound
is on the video....is it always under light Accerelation
mayby something hit somewhere when the torque
twist the engine and gearbox?  something hits when
you turn left?

[My427stang]

Heo, good ears.  I think it is always there under load, but when I open it up the engine barks pretty loud and you don't hear it.

When the engine is cold it is significantly louder and gets quieter with engine temp, so I believe it is internal. To back up since the build, I originally has a 270H cam and stock rockers, the noise started immediately an I found an odd lifter that I didn't trust, assumed that was the noise.  Replaced it with a solid lifter Bullet and Erson rockers.  No change in noise. 

Tried a new set of Harland Sharps, found some loose tips on the pushrods, each time thinking I found it.  Then I finally decided that I knew my bore was on the large size for that style piston, to I reblocked it to exact specs per Probe.  Again no change.

Put some miles on it, it did not seem to get worse, but I didn't like it, so tore it down again, verified any potenital exhaust leak, had the heads and crank magg'ed, replaced the flywhee, clutch and pressure plate (mostly because it was designed for a lower perf engine, but also because I saw some heat checks on the flywheel) Had the block decked, magged, and checked closely, assembled yet again, but found a balancer that didn't look as great as when I installed it.  No change.

It almost has to be a piston, however I never heard a wrist pin get quieter with higher temps. 

[Joe-JDC]

IF, and IF, I hear what you are talking about, it sounds like the timing is too advanced for an instant, and then the rpm catches up.  I had a hard time selecting which video you had intended because each time I clicked on your link, I got a different video.  I personally would check the advance rate just off idle and try to slow it down just a couple of degrees and see if it helps.  Joe-JDC

[My427stang]

IF, and IF, I hear what you are talking about, it sounds like the timing is too advanced for an instant, and then the rpm catches up.  I had a hard time selecting which video you had intended because each time I clicked on your link, I got a different video.  I personally would check the advance rate just off idle and try to slow it down just a couple of degrees and see if it helps.  Joe-JDC

Thanks Joe, and I chased that the other day as an experiment, tried everything from 4 degrees initial to 14, and it didn't change.  Ran with and without the vac advance too.  It's a pretty repetitive steady beat during acceleration.  Additionally, it did it zero decked with the old block, .010 below with the current block and 1020s, and it's doing it now with 8554s and a zero deck.

It has me stumped, I don't think I have ever gone to pure parts replacement like I have with this in over 35 years of building. I appreciate everyone's input, at this point I am trying to rule out a set of pistons because it's a pretty steep experiment.  Even had all the guide areas in the head magg'd to see if something cracked when Les Schmader pushed them in. 

I am doing a little solid lifter 396, will likely swap it in and start Zyglo-ing pistons.  Truth is, pistons and rods are the only things that haven't been touched, looked close at, but I'd hate to window a block if a piston comes apart

[Heo]

I had a customer one time with a 59 impala sounded
like it had a missfire and a knock in the engine. The plate
in the distributor was frosen solid. So i rebuilt the dist
still missfiring still a knock sounded like the fuel pump
changed that ,still knocking and.... missfiring
chased my own tail for a while  I finaly had it up on the lift
to trye to listen under it if i could locate the knock.....The
bottom of the right muffler oilcanned up and down i hit
it with a ballpen hammer and the impala run like a Dream
The knock gone the "missfire" gone

[Drew Pojedinec]

Just take the mufflers off. 

[cjshaker]

Listened to the video at least a dozen times and I can't hear a thing.

Stuff like this can drive you crazy. I've had a bunch of these older trucks, and one thing I CAN say for sure is that they can get rattles, squeeks or undefineable noises that are hard (ie: near impossible) to track down. Are you sure it's not something inside the truck? As a for instance...when the wife and I were going to the FERR this year, out of nowhere, my '70 F350 picked up a squeek, actually more like a hard rubbing noise, inside the interior. It was rather obvious that it was inside (or so it seems, again, they can be deceiving because the cab basically amounts to a 'sound amplification box'  ), and as you know, there isn't a whole lot of stuff in those interiors. BUT, there is a bunch of metal parts inside that cab that can give metallic sounds, and inside the cab it can sound hollow, tinny, or solid. She and I spent a LOT of time, pushing, pulling, shoving, tweaking...with our hands, feet and anything else we could use, against EVERYTHING inside that cab. NOTHING stopped it. Like yours, I noticed that it only happened during acceleration. As soon as I let up or evened out, it went away. Just the LIGHTEST application of throttle and it was there. Abso-freakin-lutely was driving me NUTS (I HATE rattles and squeeks!!)!! Now my only option is to strip the interior and re-do it piece by piece, making sure that everything along the way is solid and mounted good with no parts touching or rubbing. Luckily I was planning on stripping it this winter for a paint job.

I could give a list of dozens of places, inside and out, of things that have caused noises that drove me nuts on these old trucks. And inside the cab, they always sound worse. When I restore the '70, I will spend most of my time putting in sound deadener, mounting stuff super solid, making EXTRA sure that nothing can touch or rub, and even applying some sort of rubber or silicone isolators to metal parts that bolt or mount together. I know it will be the ONLY way to avoid those annoying noises.

May seem like that has nothing to do with you, except that noises can be, umm, irritating, to put it very VERY mildly. And old trucks are notorious for that. Good luck!!

[Heo]

Yes that take care of many ticks and knocks

[chris401]

My 445 has a noise, and has had a noise for a long time.  It won't blow up, it's been apart twice since the original build for the noise, and I have found nothing.  The only thing I haven't done is Zyglo the pistons.  Heads magged, multiple cams, multiple rocker sets, multiple valve covers, clearanced the timing chain, multiple fuel pumps, nothing hitting down below, with or without PS, even reblocked to have tighter clearances because I originally built it loose, new balancer, clutch, flywheel, you name it. 

In the video below starting at 25 seconds, you hear a tapping that sounds like a loose valve, it's much worse when cold.  After all of this, my hunch is I have a bad piston, but I did not see anything on multiple inspections and it is silent at idle.

First request, listed to the video until you hear the minor tapping between 25 and 30 second point. Many people say they can't hear it, and it is tough, but once you tune into it, it sounds like valvetrain, although everything has been gone through multiple times.

After you hear it, generate ideas.  FWIW, I have been in pure parts replacement mode for over a year, the absolute only engine I have ever been in this situation.  The only things not magged or replaced are the pistons and rods, but my eyeball couldn't see or measure anything.  The crank was magged and checked.  All new parts,and it has made the noise since the original build without change

Thoughts, prayers?    Been doing this a long time and haven't ever ran into one like this.

About ready to put the spare 390, or maybe buy an LS off Craigslist LOL

https://youtu.be/VlHIl9hafYA

I could not make out the sound. Going by your wording I would suspect wrist pin or piston slap. Backing your timing low will add heat to the cylinders. If hotter cylinder temps make it quieter then it is likely piston slap or wrist pin. Removing a plug wire of course takes the heat away and will make a piston problem noisier.

[Joe-JDC]

Not talking about initial setting, but the rate of advance just off idle.  Seems too fast to my ears.  I have experienced that with FEs and stroker sbfs.  Slow down the rate off idle.  Since the oil pump is driven by the distributor gear and shaft, you may be fighting yourself for an instant with the oil pressure.  Just an observation.  Joe-JDC