Author Topic: 1178 Crank Question  (Read 1104 times)

Dusk_Blue_Z

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1178 Crank Question
« on: March 03, 2018, 02:12:16 AM »
I have two 1178 cranks that haven't been ground. Brought them to a crankshaft shop and they magged both of them and found many small hairline cracks. Is that normal for these particular cranks? Thanks.

1969 X77 01B 51 51 flat hood

69Z28-RS

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Re: 1178 Crank Question
« Reply #1 on: March 03, 2018, 04:36:58 AM »
I would guess that the 'hairline cracks' are only in the surface of the journal, unless the machinist had a better idea... turning them 0.010 might totally take care of them?   
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bcmiller

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Re: 1178 Crank Question
« Reply #2 on: March 03, 2018, 03:21:53 PM »
They found hairline cracks, but what else did the say or recommend?
Bryon / 1968 Camaro SS 396 coupe - now 468 cubic inch BBC/M21
67 RS/SS 396 coupe L35/M40 - 4 generation family project
Looking for 68 Camaro with body # NOR 181016

Dusk_Blue_Z

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Re: 1178 Crank Question
« Reply #3 on: March 03, 2018, 06:14:33 PM »
They said I could have them ground but they won't warranty/guarantee that they would come out clean. I'll get one of them ground and see how it comes out.

I just found it odd that cracks were prevalent in both. Makes me think small hairline cracks are 'normal' for these cranks. Thanks for the replies.
1969 X77 01B 51 51 flat hood

69z28302

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Re: 1178 Crank Question
« Reply #4 on: March 14, 2018, 01:42:21 AM »
I would get a second opinion from a different shop and see what it say's

Tx-Z 302

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Re: 1178 Crank Question
« Reply #5 on: March 15, 2018, 01:48:00 AM »
I'm curious if it isn't heatchecks vs cracks, I would get a second opinions to the value of the cranks.
Chris W

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Re: 1178 Crank Question
« Reply #6 on: March 15, 2018, 02:37:51 AM »
It could be a function of 'heat' and the tufftride surfaces put on those cranks;  I think cutting a few thousands will eliminate both... :)
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

Stingr69

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Re: 1178 Crank Question
« Reply #7 on: March 15, 2018, 12:59:11 PM »
50 years of 1178 cranks and you have TWO outliers????  Second opinion is warranted. 

L78 steve

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Re: 1178 Crank Question
« Reply #8 on: March 16, 2018, 01:55:27 AM »
Thump the flange end of crankshaft on a concrete floor. It will have a distinct sound if its cracked. Your crank shop should know this.
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bcmiller

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Re: 1178 Crank Question
« Reply #9 on: March 16, 2018, 09:56:13 AM »
Find a different shop.
Bryon / 1968 Camaro SS 396 coupe - now 468 cubic inch BBC/M21
67 RS/SS 396 coupe L35/M40 - 4 generation family project
Looking for 68 Camaro with body # NOR 181016

Kelley W King

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Re: 1178 Crank Question
« Reply #10 on: March 16, 2018, 03:14:36 PM »
I think I would look elsewhere also. I have had 2 sets of heads deemed worthless by two different people. Running both today.
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Arch Stanton

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Re: 1178 Crank Question
« Reply #11 on: March 16, 2018, 11:22:41 PM »
Did he say they were junk, but still offered to take them off your hands?
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