Knock Knock Who Is It?

Well my previous post regarding lifters rattling and knocking was off base. Although I did have collaped hyd. ifters after replacing them I still have the knock.
1965 273 Commando motor
Mid speed knock 2000 rpm, stopped when I pulled the #1 plug wire. Rod bearing? Wrist Pin?
Drained the oil and cut the filter apart, all is clean no pieces parts or shiny flakes. ???
The motor has 600 miles on a freshen up rebuild, rings, bearings, new cam. etc. no machine work, all tolerances seemed OK.
I will know more later this week when I have time to drop the pan, but it is driving me crazy thinking about what might have happened.
Can the rod bolts loosen up and knock with out spinning a bearing? or mains?
Loose flexplate knock, been there before, but why would it stop knocking when pulling plug wires.
I did not pull the intake when I swapped out lifters so I never had a good look at the cam, but if it is self destructing where would be metal in the oil, right?
So let me know what I am missing.

Flex plate noise will not change with a deadened cylinder. Rod will.

Wrist pin is a double knock, will quiet down when the plug wire is pulled

It sounds like a rod bearing.

Rod bolts do not loosen by themselves if they are torqued properly. But something had to go wrong. You've got to take the engine apart and find out. It isn't going to get any better.

R.

Does it sound like this???



If so.... Its a rod bearing

Knock Knock.
Whos there?
Rod.
Rod who?
Rod Bearing. Want to go for a spin?

Sorry.

Drop the oil pan and check the rod bolt nuts. I've seen this happen on new builds, sometimes the rod bolt head isn't fully seated even after torquing. Once you run it the head finally seats that last few thousand but now you've got a loose cap, making it knock. You may get lucky and not hurt anything. But just to be safe remove that cap and bearing to be sure you didn't damage the crank journal.

If it turns out that it is loose bolts I will go nuts.. Can't deny that I was hoping against all odds that that would be my issue, given the "history" of the build up on this car.

History you ask? OK for yor amusement I will spill my guts.

I originally pulled the motor out of the Barracuda in 1980. It sat until 1985 when I tore it down and rebuilt it in my basement of a rented house after I got divorced.
I assembled it and wrapped it in heat shrink plastic. I moved it from Cleveland OH to Richmond VA, to Cincinati OH, to St Paul MN over the next 10 years. Finally in 2002 I reinstalled it and finished restoring the car.
Thats some history.

You've got to take it apart and see for yourself. You have a good idea of which cylinder has the noise. You will probably be replacing a bearing shell if you're lucky. If not it'll be time for a crank and bearing set.

R.

How'd it happen? You put all the rod caps in with nuts finger tight. Started torquing and got called for dinner. Came back, put on the pan and there you are.

Well I dropped the pan to find the obvious trashed rod bearing on #1 piston. The crank "looks" OK no deep scrathes.
Not knowing the real cause I am going to pull the motor and go thru the bottom end again.

Have a look at the photos, The bad bearing is obvious, but the #2 bearing does not look like it was new 600 miles ago. I pulled #4 just to compare and it is slighly better but not by much.

http://i152.photobucket.com/albums/s195/frozen_bohemian/273/DSC06448.jpg

http://i152.photobucket.com/albums/s195/frozen_bohemian/273/journal12.jpg

http://i152.photobucket.com/albums/s195/frozen_bohemian/273/DSC06449.jpg

Well at least you caught it before it windowed the block or did too much to the shaft.

the metal from #1 migrated over to make #2 look like that , tearing it down to check it is a good idea

I would also make sure to flush that block good. A lot of metal is still floating around in there. Clean or replace the pump wouldn't be a bad idea nor would a shaft polish.