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03-19-2015, 05:33 PM
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258 I6
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Join Date: Apr 11, 2006
Location: Mt. Holly, NJ
Posts: 262
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I'm Stumped, please explain these markings!
Tearing down the engine I picked up, I noticed these punch marks on every piston.  I've never seen this before. Someone PLEASE explain the logic to this.
[IMG]  [/IMG]
[IMG]  [/IMG]
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Just Emptying Every Pocket
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03-19-2015, 05:58 PM
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out of order
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Join Date: Jun 08, 2005
Location: Land of froot loops and cukcoo-nuts, CA
Posts: 9,809
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Someone trying/tried to free up a locked engine?
Someone trying to remove the pistons the hard way?
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Tony
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03-19-2015, 06:09 PM
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258 I6
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Join Date: Apr 11, 2006
Location: Mt. Holly, NJ
Posts: 262
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I should mention that I have no clue as to the history of the engine. The guy I bought it from claimed it was out of a 72 J truck. The amount of crud on it made me think that it had not been opened up.
The heads have an 83 code on them. (I'm guessing that's the year)
The cam and lifters had some wear on them, but nothing that looked out of the ordinary for a 30-40 year old motor.
The crank and rods, as well as the bearings were okay, I think I might be able to get away with just polishing the crank. I've never built an AMC motor before, but I'm working with my mechanic buddy who is the Maintenance Manager for my shop.
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Just Emptying Every Pocket
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03-19-2015, 06:26 PM
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232 I6
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Join Date: Jan 10, 2012
Location: Winston Salem NC
Posts: 175
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That is either the highly-sophisticated science of piston balancing or somebody dumped a sack of bbs in the carb.
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03-19-2015, 06:31 PM
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Grease Monkey
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Join Date: Feb 23, 2014
Location: Hollister,Ca
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Quote:
Originally Posted by CheapJeepBrad
That is either the highly-sophisticated science of piston balancing or somebody dumped a sack of bbs in the carb.
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BB's came to my mind also.
What do the heads look like?
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03-19-2015, 07:45 PM
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Long time member
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Join Date: Jan 02, 2015
Location: new bedford ma.
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piston nerl
They do that to expand piston in bore .That is a redneck piston nurl .Works good
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03-19-2015, 09:25 PM
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AMC 4 OH! 1
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Join Date: May 17, 2007
Location: Algonquin (Chicago suburb) Illinois
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has to be "man made" no way something internally caused that on every piston 
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Inferior Chevy
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03-20-2015, 12:41 AM
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Join Date: Feb 12, 2011
Location: Gold Bar, WA
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I haven't seen that done since the '70s!
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 Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
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03-22-2015, 07:05 AM
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327 Rambler
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Join Date: Feb 22, 2008
Location: south jersey
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Punched?
Are there matching marks on the heads,I agree they look to be made on purpose? for some reason? who knows?
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03-22-2015, 07:15 AM
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Grease Monkey
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Join Date: Feb 23, 2014
Location: Hollister,Ca
Posts: 431
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Yep someone could have swaged the tops to try to reduce the clearance.
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03-22-2015, 08:51 AM
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Gone,Never Forgotten.
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Join Date: Nov 22, 2009
Location: Mesquite Texas
Posts: 8,619
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So
If that was going on to expand the piston & it would only expand the top & bottom then the expansion would be egg shaped? Why did they not do the sides. They are gapped. Wouldn't the mark be concentric & not so close to the edge. Just curious I've never seen this done. I would think ball bearings or BB's also. Weakening the edge of the piston can't be good. It would be a great reason to sell the motor.
The fact there are matching marks on the head dispels the piston expansion theory to me. The fact there are marks on the head make me believe they were bearings not BB's. It would have to be something awfully hard to mark the head.
If he still has the vehicle it would be interesting to see what's in the muffler.
I certainly would not trust the rods. This could be similar to Hydro locking.
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03-22-2015, 10:29 AM
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Member
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Join Date: Mar 16, 2011
Location: Newton, NC
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It's braille, for blind engine builders! 
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03-22-2015, 03:44 PM
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258 I6
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Join Date: Apr 11, 2006
Location: Mt. Holly, NJ
Posts: 262
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There are no other marks on the heads; they look pretty good. My father in law also thought that it was a redneck way to fit the pistons in the bores.
I think there was another sign that the motor was rebuilt but didn't think about it until now; the rods were already marked. This wasn't something that the factory did, was it?
I'll find out more later this week when I hear back from the machine shop.
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03-22-2015, 05:37 PM
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Join Date: Feb 12, 2011
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Most of the ones I took apart were already marked in post '70 vehicles.
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 Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
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03-23-2015, 11:39 AM
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Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
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lol. doing that would do nothing to make the piston fit tighter in the bore.
those pistons would go in the scrap bin.
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03-23-2015, 12:01 PM
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Bleedin' Gasoline
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Join Date: Mar 16, 2004
Location: Southwest Wisconsin
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My best guess is the last person to put it together either had no ring compressor, or a poor one and used a punch to get them down in the bores.
But as far as logic....doubtful there was any behind it
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03-23-2015, 12:07 PM
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Join Date: Jan 20, 2006
Location: The Great Googley Moogley Midwest.
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yah,it certainly looks intentionally done. but it wrecked the pistons.
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Quote:
Originally Posted by Hankrod
Ristows right.................again,
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Quote:
Originally Posted by Fasts79Chief
... like the little 'you know what's' that you are.
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Quote:
Originally Posted by Fasts79Chief
I LOVE how Ristow has stolen my comment about him ... "Quoted" it ... and made himself famous for being an ***hole to people. Hahahahahahahahahha!
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→ Where the kids hang out...
fsjbuilder.org come for the mindless chat,stay for the hand drawn emoticons.
It's like you're unraveling a big cable-knit sweater that someone keeps knitting...and knitting...and knitting...and knitting...
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03-23-2015, 04:14 PM
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Join Date: Feb 12, 2011
Location: Gold Bar, WA
Posts: 6,474
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Quote:
Originally Posted by Ristow
lol. doing that would do nothing to make the piston fit tighter in the bore.
those pistons would go in the scrap bin.
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While I agree they should be scrapped, the swedging would increase the piston size slightly so it didn't rattle in the bore and would get a person by long enough to get off the lot. (It's a used car lot trick and I even saw someone do it in a movie. Maybe Used Cars with Kurt Russell?)
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 Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental.
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03-23-2015, 06:14 PM
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hey,does anyone here know how to.......
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Join Date: Jul 30, 2000
Location: WA State
Posts: 4,502
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didnt they have a snake oil engine rebuild fluid with medal balls in it you poured into the plug holes - i think i saw it on JC Whipme many years ago
that was supposed to restore compression - end world hunger yada yada?
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03-23-2015, 07:47 PM
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Join Date: Aug 09, 2000
Location: New Haven, CT
Posts: 6,310
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I must be blind. I didn't see the punch marks (holy #$@#$! Why would anyone do such a thing??)    ... I was talking about the reliefs. My apologies
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