Need Help -- Knocking 440 Sound

[PRHeads]

It’s obvious the real culprit for the noise has been pretty elusive thus far....... but I’m thinking it will be pretty obvious when the head comes off.

 

[4406bbl]

All I know is if I had one that sounded like that I would not start it again until I found the problem.

 

[mvandale]

Well.... head came off & there are no new leads. Despite knock clearly coming from #1 cylinder when spark plug pulled.... Nothing in the head, nothing damaged on the head, nothing out of the ordinary with the head (a little carbon build up, but nothing excessive).

Pulled the piston out...same. No cracked skirt, no damaged wrist pin, no cylinder wall damage (the cross hatch is still clearly visible), rings all there & good. Everything checks out.

I'm tapped.

Guess I'll keep pulling pistons out one by one to see if there are any issues.

 

[69Bee]

That piston wear is "Abbey-Normal"... I will bet that the rod is bent. Take a pic of the rod like your second pic, but get the full rod so we can see if it is bent. Then post a pic like the third pic so we can see the complete rod in the other plane. Pistons just don't wear like that normally, let alone in 1000 miles like you say the motor has.

 

[69Bee]

Also, ... piston askew?? Post edited.

After checking, the pistons look more like Icon FHR (forged) piston. While they have an accumulator too, just not as large, and not a high silicon piston like the KB Hypers are.

ICON FHR Piston - Chry 440, Rod 6.768, Flat Top +5.6cc 2V Piston Set (uempistons.com)

 

[mvandale]

Also, ... piston askew?? Post edited.

After checking, the pistons look more like Icon FHR (forged) piston. While they have an accumulator too, just not as large, and not a high silicon piston like the KB Hypers are.

ICON FHR Piston - Chry 440, Rod 6.768, Flat Top +5.6cc 2V Piston Set (uempistons.com)

Pics as requested. They are icon pistons apparently, but I don't see anything significantly askew with the rod.

 

[fastmark]

I’ve had more customers come in with piston problems and scuffs like that using KB hyper pistons. I don’t know what those are but those cheaper pistons are very sensitive to piston to wall clearance. That pistons has some issues with that scuffing. I don’t use Icons either. Check your piston to wall clearance. Might as well pull the motor.

 

[fastmark]

What does the bore look like?

 

[Mark Barnes]

With that somewhat triangular, possibly excessive wear on the piston skirt it kinda looks like the piston is rocking in the bore too much. Could you have gotten an undersized slug in your kit, or is the bore dia. too large or out of round? 2 cents...

 

[mvandale]

Bore looks like you'd expect with the piston skirt scuffing... It corresponds to marks on piston.

View attachment 1095558

Piston is stamped properly for ,030 over, which is what it should be.

 

[fastmark]

I’ve had so many problems with bores moving around on these blocks. If you don’t hone them with a honing plate, these critical piston skirt clearance can be compromised and you are looking at the result. Most non performance shops don’t have plates and even some performance shops don’t have mopar. I’ve had bores go out of round as much as .002-.003 when you bolt a plate on.

 

[Mark Barnes]

Bore looks like you'd expect with the piston skirt scuffing... It corresponds to marks on piston.

View attachment 1095558

Piston is stamped properly for ,030 over, which is what it should be.

View attachment 1095561

Hate to ask the obvious question, but if it was ME, I'd be mic'ing the bore and piston. I think that may be where the issue is. Hope I'm wrong....

 

[fastmark]

I agree. I bet that is where the problem is. Last three fresh rebuilt motors I had to fix, looked just like that with low miles. One had less than 100 miles.

 

[Fran Blacker]

Any wear on edge of for bearing, probably not but worth a look.

 

[PRHeads]

That piston is f’d.

“If it were me”, they’d all come out to make sure arent more like that one.

Frankly, I’d just pull the motor at this point.

 

[mvandale]

Any wear on edge of for bearing, probably not but worth a look.

No bearing wear of note, plus I replaced them as a precaution.

I'm resigned to have to pull the engine and bring it to the machine shop for measurements (and probably extensive work).

 

[Fran Blacker]

Neighbor rebuild 87 Turbo GN had some problems with oil pressure. Looked at the speed shop screw up resizing the rods. Owner kid did the rods they weren't square with wrist pin.

 

[Mark Barnes]

No bearing wear of note, plus I replaced them as a precaution.

I'm resigned to have to pull the engine and bring it to the machine shop for measurements (and probably extensive work).

Good luck! BTW...hope a different shop can identify it quick!

 

[Moparnocar]

I've got the same noise in my 413! I'll be watch this thread..

 

[zyzzyx]

Sorry for your predicament! Hope you can get away with .040+ pistons. you won't know until
you Mic it and then it gets set-up and bored. Hopefully it's just one cylinder! Arais makes
pistons any size you want. Good luck, and thanks for sharing all of the details!