Sub Frame Damage
 

This sub-frame damage might be familliar to some of you drag racers - I had never seen it before:

Re: Sub Frame Damage
 

Wow, Crazy rod throw..

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Bet they heard that! Might even have felt it! [img]<<GRAEMLIN_URL>>/headbang.gif[/img]
Peter

Re: Sub Frame Damage
 

Don't fix it..... Battle scar [img]<<GRAEMLIN_URL>>/headbang.gif[/img] I wish mine had a cool scar like that... All I got is jack stand crush marks. I used to have hundreds of bumper jack marks on both sides of the rear bumper but in a moment of stupidity I fixed it... What's the only reason for hundreds of bumper jack marks ??? Yeah, swapping slicks and street tires out each weekend... Someday fixing battle scars will be as regretful as throwing away dealer badges or manifolds....


Tommy [img]<<GRAEMLIN_URL>>/3gears.gif[/img]

Re: Sub Frame Damage
 

Cool battle scar. Made me think about one that happened to my old drag wagon's engine.
Pieces of a main cap were in the crossmember, but I didn't take a pic.
Here's what the crank looked like though.

http://i36.photobucket.com/albums/e4...nengine001.jpg

Re: Sub Frame Damage
 

Ouch $$$$

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Cast[casting] crank,not a forged crank, that's why the cast crank brakes like that. *Paul

Re: Sub Frame Damage
 

Wow!

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Have one on my chevelle like that rod let go at 9400. Kept it there for a reminder lol.

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Funny - we are working on Benjamin's frame right now, and are finding some unique battle scars. We've decided to leave them alone - they will prompt some good story telling at shows.

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[quote=Rixls6]Cool battle scar. Made me think about one that happened to my old drag wagon's engine.
Pieces of a main cap were in the crossmember, but I didn't take a pic.

Rick, how fast were you spinning that Cast crank when it let go,

Re: Sub Frame Damage
 

It was right at the 1-2 shift, so 6800RPM. Funny thing is the only sound it made was a &quot;POP&quot;, then quit.
Yeah that cast crank was a problem waiting to happen, but I wasn't having any problems up to that point.
Here's what the bottom end of the block looked like.

http://i36.photobucket.com/albums/e4...nengine004.jpg

Re: Sub Frame Damage
 

Wow...to the original picture and wow to Kurts picture! [img]<<GRAEMLIN_URL>>/crazy.gif[/img]

Re: Sub Frame Damage
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rixls6</div><div class="ubbcode-body">It was right at the 1-2 shift, so 6800RPM. Funny thing is the only sound it made was a &quot;POP&quot;, then quit.
Yeah that cast crank was a problem waiting to happen, but I wasn't having any problems up to that point.
Here's what the bottom end of the block looked like.

http://i36.photobucket.com/albums/e4...nengine004.jpg </div></div>

That'll buff right out. [img]<<GRAEMLIN_URL>>/grin.gif[/img]

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Wow....both pictures are amazing. [img]<<GRAEMLIN_URL>>/eek.gif[/img]

I'm running cast crank and shift at 7k at the strip and sometimes on the street. [img]<<GRAEMLIN_URL>>/hmmm.gif[/img] Guys have running them for years and haven't had problems as long as everything is balanced.

Kurt

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See that Rick, should have balanced the motor and none of that would have happened!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 69 Post Sedan</div><div class="ubbcode-body">Wow....both pictures are amazing. [img]<<GRAEMLIN_URL>>/eek.gif[/img]

I'm running cast crank and shift at 7k at the strip and sometimes on the street. [img]<<GRAEMLIN_URL>>/hmmm.gif[/img] Guys have running them for years and haven't had problems as long as everything is balanced.

Kurt </div></div>

Re: Sub Frame Damage
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rixls6</div><div class="ubbcode-body">It was right at the 1-2 shift, so 6800RPM. Funny thing is the only sound it made was a &quot;POP&quot;, then quit.
Yeah that cast crank was a problem waiting to happen, but I wasn't having any problems up to that point.
Here's what the bottom end of the block looked like.

http://i36.photobucket.com/albums/e4...nengine004.jpg </div></div>



Ship that &quot;Puppy&quot; off to Nu Yawk........That would be considered a Mint Survivor Engine out on Long &quot;I&quot;Land......

Re: Sub Frame Damage
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pxtx</div><div class="ubbcode-body">See that Rick, should have balanced the motor and none of that would have happened!</div></div>

Well....let's not go that far. I'm sure his motor was balanced. Although, looking at the dome of the piston in the picture, I'm sure he was running more than 10.4 compression. Rick will chime in and give us more details.

My point is that a lot of motors have been run hard on a good GM cast iron crank without issues.

Kurt

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Awesome. I grenaded a Subaru once, and a rod broke the intake in half and ended up on top of the spare tire. Gotta love carnage.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TORONADOXS</div><div class="ubbcode-body">Awesome. I grenaded a Subaru once, and a rod broke the intake in half and ended up on top of the spare tire. Gotta love carnage. </div></div>

Yep, carnage is kinda cool. Too bad it cost so much.

We're not sure why my engine grenaded, but it was balanced, etc. Others have told me the crank may have had a crack we didn't know about, but it's a moot point now.
I would never build an engine like this again to begin with, but it's what came in the car and we ran it 3 seasons. Just 1 run too many I guess. [img]<<GRAEMLIN_URL>>/hmmm.gif[/img]

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Another thing to keep in mind about cast iron is that it doesn't propagate fatigue cracks like steel does. After cast iron exceeds 1,000,000 cycles (which doesn't take long for a crank shaft) it has unlimited fatigue life. Steel, however, is always suseptible to propagating (growing) cracks. The bottom line is that steel has higher yield strength, but old steel cranks can have some pretty bad fatigue issues - and don't assume that small cracks that show up on crack detection will stop growing.

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A little JB weld and that block will be good for another 100k miles. [img]<<GRAEMLIN_URL>>/wink.gif[/img]

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I had a Nova drag car I shifted at 7k with a cast crank. Never had a problem. Detonation is what kills them whether a cast or forged.

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At some point horse-power and stress can cause trouble. I believe that a forged crank and four-bolt block can take more.