So if I’m hearing that sound just in cold start, the 2.7 uses forged pistons I think, so there’s the answer.
So if I’m hearing that sound just in cold start, the 2.7 uses forged pistons I think, so there’s the answer.Piston slap (not to be confused with detonation or pre-ignition) is most likely to be heard in an engine that has forged pistons or one that was set up with the wrong piston to bore clearance or flat worn out. If they have the wrong clearance they can make noise from the get-go. Which one of these fits the bill? Just sayin'
I don’t hear any odd sounds while driving around. It’s just at startup. For all I know it could just be the timing chain a little dry for a few seconds till oil lubricates it.I wouldn't even venture a guess without listening to it firsthand. No guarantees without looking at piston skirts and then measuring the pistons and bores. I'm not suggesting this but bearing knock and piston slap can also sound like one another at first. Worn rod bearings soon get a very distinctive sound and are most often noticed at a lower RPM.
Both of my motors have done this under these exact conditions, under no other conditions is there the typical piston slap that I am accustomed too.Piston slap (not to be confused with detonation or pre-ignition) is most likely to be heard in an engine that has forged pistons or one that was set up with the wrong piston to bore clearance or flat worn out. If they have the wrong clearance they can make noise from the get-go. Which one of these fits the bill? Just sayin'
I wouldn't even venture a guess without listening to it firsthand. No guarantees without looking at piston skirts and then measuring the pistons and bores. I'm not suggesting this but bearing knock and piston slap can also sound like one another at first. Worn rod bearings soon get a very distinctive sound and are most often noticed at a lower RPM. The second video in this thread was hard for me to hear what I wanted to hear except in one certain spot. It sounded to me like it had some top-end noise (valve-train) but from underneath I could hear a noise that I couldn't distinguish.
Years ago, I was building 400 Ford engines with 351 Cleveland parts. These were real runners they'd put down 500 usable street HP. These engines would really run with large port, big valve, closed chambered heads on them. We tried parts from several manufacturers including cams pistons etc. We had one that was running a TRW Forged Piston/Piston Ring pack.
This engine was built as well as human hands could put it together following parts manufacturers very closely. It developed a noise (later confirmed as piston slap and beyond) very early in its street life, just a couple of thousand miles. I saw serval of these go beyond 70,000 miles (that was respectable back then for a forged piston engine), including my father-in-law's F150 4X4. It had been broken in properly. Its cylinder-to-wall clearance was perfect according to TRW's specs.
This engine was disassembled it had literally broken the skirts in two cylinders but the break (upside-down triangle break) was such that the skirt was still going up and down with the piston. The cylinders were undamaged. After many discussions and mailing some parts back and forth, TRW re-designed this piston including additional skirt ribbing and a "thicker" ring pack. We ended up using custom Mahle's after this happened. I don't know if the problem was resolved.
I'm telling a long story here but the thing is you could barely hear this noise at first and it ended up literally being broken pistons. Without revving it to a couple of thousand RPMs and backing out, most simply couldn't hear it. I couldn't hear it at a sustained RPM. It got louder but it wasn't like it was just slapping one day and broken the next, very subtle over a few weeks' time. These noises don't go away, they'll get louder. I'm sure that's more than any of you wanted to read.![]()
I stand corrected.I wouldn't even venture a guess without listening to it firsthand. No guarantees without looking at piston skirts and then measuring the pistons and bores. I'm not suggesting this but bearing knock and piston slap can also sound like one another at first. Worn rod bearings soon get a very distinctive sound and are most often noticed at a lower RPM. The second video in this thread was hard for me to hear what I wanted to hear except in one certain spot. It sounded to me like it had some top-end noise (valve-train) but from underneath I could hear a noise that I couldn't distinguish.
Years ago, I was building 400 Ford engines with 351 Cleveland parts. These were real runners they'd put down 500 usable street HP. These engines would really run with large port, big valve, closed chambered heads on them. We tried parts from several manufacturers including cams pistons etc. We had one that was running a TRW Forged Piston/Piston Ring pack.
This engine was built as well as human hands could put it together following parts manufacturers very closely. It developed a noise (later confirmed as piston slap and beyond) very early in its street life, just a couple of thousand miles. I saw serval of these go beyond 70,000 miles (that was respectable back then for a forged piston engine), including my father-in-law's F150 4X4. It had been broken in properly. Its cylinder-to-wall clearance was perfect according to TRW's specs.
This engine was disassembled it had literally broken the skirts in two cylinders but the break (upside-down triangle break) was such that the skirt was still going up and down with the piston. The cylinders were undamaged. After many discussions and mailing some parts back and forth, TRW re-designed this piston including additional skirt ribbing and a "thicker" ring pack. We ended up using custom Mahle's after this happened. I don't know if the problem was resolved.
I'm telling a long story here but the thing is you could barely hear this noise at first and it ended up literally being broken pistons. Without revving it to a couple of thousand RPMs and backing out, most simply couldn't hear it. I couldn't hear it at a sustained RPM. It got louder but it wasn't like it was just slapping one day and broken the next, very subtle over a few weeks' time. These noises don't go away, they'll get louder. I'm sure that's more than any of you wanted to read.![]()
Awesome input,Upload video to YouTube and then post the "share link" in your post here.
The videos you see on this forum aren't actually hosted on the forum.
I wouldn't even venture a guess without listening to it firsthand. No guarantees without looking at piston skirts and then measuring the pistons and bores. I'm not suggesting this but bearing knock and piston slap can also sound like one another at first. Worn rod bearings soon get a very distinctive sound and are most often noticed at a lower RPM. The second video in this thread was hard for me to hear what I wanted to hear except in one certain spot. It sounded to me like it had some top-end noise (valve-train) but from underneath I could hear a noise that I couldn't distinguish.
Years ago, I was building 400 Ford engines with 351 Cleveland parts. These were real runners they'd put down 500 usable street HP. These engines would really run with large port, big valve, closed chambered heads on them. We tried parts from several manufacturers including cams pistons etc. We had one that was running a TRW Forged Piston/Piston Ring pack.
This engine was built as well as human hands could put it together following parts manufacturers very closely. It developed a noise (later confirmed as piston slap and beyond) very early in its street life, just a couple of thousand miles. I saw serval of these go beyond 70,000 miles (that was respectable back then for a forged piston engine), including my father-in-law's F150 4X4. It had been broken in properly. Its cylinder-to-wall clearance was perfect according to TRW's specs.
This engine was disassembled it had literally broken the skirts in two cylinders but the break (upside-down triangle break) was such that the skirt was still going up and down with the piston. The cylinders were undamaged. After many discussions and mailing some parts back and forth, TRW re-designed this piston including additional skirt ribbing and a "thicker" ring pack. We ended up using custom Mahle's after this happened. I don't know if the problem was resolved.
I'm telling a long story here but the thing is you could barely hear this noise at first and it ended up literally being broken pistons. Without revving it to a couple of thousand RPMs and backing out, most simply couldn't hear it. I couldn't hear it at a sustained RPM. It got louder but it wasn't like it was just slapping one day and broken the next, very subtle over a few weeks' time. These noises don't go away, they'll get louder. I'm sure that's more than any of you wanted to read.![]()
LOL!!So if you drive it normally no noise?
Sounds like an easy fix…
In the video I sent ?Where was the microphone positioned?
Torque converter?Just throwing this out there. Something loose in the cats? Hope it’s not in the new engine. Bad tolerance or not perfectly rebuilt correctly, the engine usually lets you know fairly soon. Happened to me once on my 67 fastback 289. Started knocking 250 miles. Feel like it’s got to be something in common with the old engine that you swapped onto the new one.
If you haven't done so yet,Torque converter?
I did give it a once over, but I didn't go over it with a fine tooth comb.Cracked flywheel?
This was my first thought as well, flywheel, flex plateCracked flywheel?