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Anyone broke an LY or 6 pack rod?
#1723191
01/06/15 01:32 PM
01/06/15 01:32 PM
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Joined: Jun 2006
Posts: 5,167
CT
GTX MATT
OP
master
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OP
master
Joined: Jun 2006
Posts: 5,167
CT
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Just for fun - the small block rod thread got me thinking. I have a 400 shortblock with a bent connecting rod, it is bent slightly in the non thrust direction.
I also have a friend with a 67 HP 440 sitting on his garage floor that he grenaded around 74, it has a couple of broken LY rods and a few that actually bent about 90 degrees and did not break. The engine is so screwed up that you can't get it apart. He shifted it around 6500-6800. Obviously he broke it with excessive RPM. And it had heavy TRW 6 pack slugs in it.
What stories do you guys have?
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Anyone broke an LY or 6 pack rod?
[Re: Twostick]
#1723200
01/06/15 07:17 PM
01/06/15 07:17 PM
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Joined: Nov 2003
Posts: 5,160
Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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Yes I have. Ly. Will I again? No after market rods are too cheep and blue printed short blocks are too expensive.
Getting old just means you were smarter than some and luckier than others.
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Re: Anyone broke an LY or 6 pack rod?
[Re: GTX MATT]
#1723202
01/06/15 07:39 PM
01/06/15 07:39 PM
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Joined: Jan 2003
Posts: 6,531
Jacksonville, FL
Chris2581
master
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master
Joined: Jan 2003
Posts: 6,531
Jacksonville, FL
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Never broke a LY rod,but had one that a bolt snapped in...engine had 27 runs on it. New engine has a brand new set of LY's with ARP bolts and 6 pak slugs,but it will never go over 6000 rpm.
Nautilus Racing-
We use Superformance gaskets and Turbo Action converters/products.
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Re: Anyone broke an LY or 6 pack rod?
[Re: Chris2581]
#1723203
01/06/15 08:25 PM
01/06/15 08:25 PM
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Joined: Feb 2005
Posts: 20,203
PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,203
PA.
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I put a lot of of high 9, low 10 second passes on stock 440 rods with upgraded rods bolts,and polished and shot blasted beams. Some broke, some didn't. Would I do it again with whats available now? HECK NO. Another thing to remember was that back then most of us were running stock cranks and HEAVY TRW or Sealed Power pistons.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: Anyone broke an LY or 6 pack rod?
[Re: GTX MATT]
#1723212
01/07/15 11:15 AM
01/07/15 11:15 AM
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Joined: Jan 2003
Posts: 13,408
Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,408
Marion, South Carolina [><]
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Not me personally, but I bought an old Duster drag car once that had the top 1/2 of a 6 pack rod laying in the trunk. The rod had broken, but surprisingly hadn't hurt anything else except for hitting a piston skirt. I never saw the crank or the other 1/2 so I can't say if it was a broken bolt or a turned bearing that caused it.
They swapped in a set of LY rods and kept on going, lol. Had the old 2295 TRW slugs in it.
Friend of mine had a 600 hp 440 w/ a stock crank and six pack rods that ran high 9s in a back half cuda bracket car for a long time. I bought the motor and ran it for a little while, but then tore it down for a rebuild and put some Manley H beams in it.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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Re: Anyone broke an LY or 6 pack rod?
[Re: gdonovan]
#1723213
01/07/15 02:53 PM
01/07/15 02:53 PM
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Joined: Jun 2006
Posts: 5,167
CT
GTX MATT
OP
master
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OP
master
Joined: Jun 2006
Posts: 5,167
CT
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Quote:
Quote:
He shifted it around 6500-6800. Obviously he broke it with excessive RPM. And it had heavy TRW 6 pack slugs in it.
What stories do you guys have?
You are making me cringe.
GTX still has "old school" 440 that I built in the mid 90's. Mcandless ported heads with oversize valves, battleship springs with titanium retainers and max wedge rocker gear with a 590 cam.
Forged six pack slugs, LY rods that are shot peened with ARP bolts.
On its best pass (11.2 at 124) it went through the traps at 7200. I remember looking at the tach as the needle was rising wondering if the blow shield would hold if the flywheel let go...
Motor still runs great though I bet the ring seal is not as good as it once was and she marks her spot time to time.
I ain't gonna lie to ya Gary 7200 on stock rods would scare me, but lots of people have done it. I built mine to turn 7K with Scat H beams, studded mains, and 525 gram forged pistons and I'm a little scared to bring it up that far.
What are you using for bearings out of curiousity and how do you like that 590 on the street?
If it makes you feel better the same friend bought a 67 GTX brand new and for 2 years spun the stock short block (never opened, so factory clearance on everything) to 7K, that was brand new of course though but the car saw street duty as well, never broke it.  I'm guessing like many others the one on his garage floor started with a rod bolt.
Last edited by GTX MATT; 01/07/15 02:54 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Anyone broke an LY or 6 pack rod?
[Re: dogdays]
#1723215
01/07/15 04:45 PM
01/07/15 04:45 PM
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Joined: Jun 2006
Posts: 5,167
CT
GTX MATT
OP
master
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OP
master
Joined: Jun 2006
Posts: 5,167
CT
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I don't think they were in love with heavy pistons, I think they were in love with tall pistons, for greater stability in the bore. They were heavy as a product of being tall. They were pretty strong for factory cast slugs though. Unfortunately it also makes aftermarket parts selection harder. Aftermarket rods are all .008 inches short, lots of short pistons, etc. And also so that we could stroke them easy later.
Last edited by GTX MATT; 01/07/15 04:49 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Anyone broke an LY or 6 pack rod?
[Re: GTX MATT]
#1723216
01/07/15 05:01 PM
01/07/15 05:01 PM
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Joined: Feb 2005
Posts: 20,203
PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,203
PA.
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Years ago I had a local coal company that would sell me the 440 engines off their old generators for 50 bucks for a complete forged crank engines. Man I miss those days
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: Anyone broke an LY or 6 pack rod?
[Re: GTX MATT]
#1723217
01/07/15 05:50 PM
01/07/15 05:50 PM
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Joined: Nov 2007
Posts: 277
MN
Willie68coronet
enthusiast
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enthusiast
Joined: Nov 2007
Posts: 277
MN
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Quote:
I ain't gonna lie to ya Gary 7200 on stock rods would scare me, but lots of people have done it. I built mine to turn 7K with Scat H beams, studded mains, and 525 gram forged pistons and I'm a little scared to bring it up that far.
Which 440 pistons do you have that 525? Lightest I've seen advertised are CP at around 625. My late 1990's JE's I have on the shelf are 645. I'm curious of what you have, if that wasn't a typo?
'68 Coronet 500 w/ Indy EZ-1 headed 446, 727 trans, 9" rear
First day at the track with SUV street tires and no traction: 1.688 60', 7.24 @ 101.79 in the 1/8 mile
Great customer service from: DominicThumper Carbs, B3 racing engines, Porter Racing Engines, A-1 torque converter's, Quick Performance, Racer Brown Cams, R&R Performance, Manton pushrods
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Re: Anyone broke an LY or 6 pack rod?
[Re: RSNOMO]
#1723223
01/08/15 12:10 AM
01/08/15 12:10 AM
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Joined: Jul 2006
Posts: 684
toronto
6PAK70CUDA
mopar
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mopar
Joined: Jul 2006
Posts: 684
toronto
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Quote:
Got 20 years going on LY's with ARP bolts, under forged, six-pak TRW's...
I bought a used bracket 440 off a buddy and heavy (2350P I think) pistons, LY rods, solid lifter cam and usually buzzed it 6500-7000 rpm and it did go when I bent a pushrod and lifter popped and then low oil press and you know the rest...
I remember going to a Herb McCandless seminar back at the Nats in the 80's and asked him what could be done to improve RB bottom ends and he replied "they are strong enough; it's usually an oiling problem. If you put beefier parts in you just do a better job of sawing the motor in half when it lets go due to the oiling problem"
Now that was well before aftermarket heads and power adders that have us pushing them to power levels previously unattainable but words to consider for those of us running "old school" combos.
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Re: Anyone broke an LY or 6 pack rod?
[Re: CHAPPER]
#1723224
01/08/15 01:43 PM
01/08/15 01:43 PM
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Joined: Jan 2003
Posts: 21,086
Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,086
Niles , Ohio
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I have a LY in the garage that is bent pretty good.My machinst asked if the motor ran.I said yes it did and was spun over 6K many times with the bent rod.Its not a slight bend either.Rocky
Chrysler Firepower
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