Crankshaft snout snapped

[isedawishy]

Could this have been an installer bottoming out the longer balancer install bolt in the crank and causing a small crack or something that got worse over time? Seems easier to do than installing the balancer without seating it all the way. This thread makes me nervous since I'm about to install my OPG, CG, ATI damper and Whipple.

Are the bolts different lengths? Possible if so. He's installed quite a few before me so I duno

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[sigintel]

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Exactly.

The MMR kit that's going save the world is a gimmick when the balancer is installed properly. At best the giant stepped washer helps square the balancer on the crank when improperly installed. Using a stronger bolt is not the way to properly install any balancer. The install kit Beef shared is best, or those who make their own with all thread.

To OP, sorry to hear your outcome. It can happen to any of us whether manufacturing defect or install issue.

Buy from Terry, value is all in contributing to Beefcake Racing for the support resource he provides to the community. He's part of American muscle car culture at this point. USA USA USA!

It might be difficult to say what caused the issue, but the crank damper install is often suspected. Hope the following is helpful to someone:

Having worked in a machine shop when young and dumb(er), and having damaged various assemblies:
Getting a stiffer/stronger/higher modulus nut/bolt/pin does NOT make an assembly tougher or stronger. It just allows you to create a much higher stress riser where the two parts come together.

If you get the strongest freakn thing you can thread in the snout and torque on it. Where it has interference, the strong will forge a split in the weak.

To know if an installer has previously bottomed out a bolt, just non nonchalantly ask if they know if they got enough threads engaged. If they say I got all you can cause I was able to bottom it... well now you know.
Or ask, "Was keeping track of thread count a pain in the ass?". If no, then prolly just drove the long bolt to bottom and then switched.

You can ask how many threads were in the crank snout. Was roughly xx.xx on my crank. Not gonna post as its one of my test questions and super easy for anyone to learn.

You can learn this yourself on your crank using the Exact bolts to be used. Then keep track and insure a switch from long to short bolt at Least Two threads early. Differences in bolt thread lead in, dogged end, etc. can change the numbers of turns before bottoming.

Get a couple paint pens, bright lighter color, silver or gold.
-After removing bolt, clean bolts and all threads with brake cleaner.
-Thread a bolt in just a couple threads, now slowly back out and Lightly pull outward so you can feel where the very first engagement of thread starts.
-Mark bolt head with a line on just one half pointing up.
-Retest until you are confident you know exactly where the engagement starts where you can line up, insert and turn just a hair and have the bolt hold finger weight pull.
-Screw bolt in by Hand and count turns and partial turns to where the drag starts to increase rapidly due to bottoming. (This is exactly what you are insuring does not happen at 110ft/lb (10,000lbf) with a 190kspi bolt with a hardness 25 points higher than your crank.)
-Paint pen the # turns xx.xx on the engine cover for each bolt.
-During install w flywheel locked, use complete bolt rotations and paint pen tally marks on the front cover while working.
-Stop two or three rotations early if using a long install bolt and switch to final bolt.

You can avoid this by using a threaded rod as a stud for the crank snout and turning a nut instead of a bolt. Leave the snout studded or just remove and final torque the short install bolt.

STACKS OF WASHERS REQUIRED ALL OF THESE!
Rod (cut to length):
Grade B7 Medium-Strength Steel Threaded Rod M12 x 1.5 mm Thread Size, 300 mm Long 95245A115
Nuts:
Use a M12 x 1.5 nut or long lug nut cut open ended. Use w lots of good washers. I use washers and Lisle wheel stud bearing (wheel stud install tool).
https://www.amazon.com/gp/aw/d/B000ETUD22/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8

Dorman 982-020 19mm class 10.9
Dorman 611-312 Wheel Nut M12-1.50 Standard - 19mm Hex, 20mm Length (use backwards or use wheel stud tool)
Bolt(MAKE SURE THE *ACTUAL* INSTALLER UNDERSTANDS THIS IS *ONLY* FOR STARTING THE DAMPER ON):
M12-1.5 x 130mm DIN 960 Class 10.9 Plain Finish Hex Cap Screw


TLDR? No matter what the Beefcake solution costs, its the best way to go for the quality of support.

 

[kcc0521]

Because the ATI balancers are extremely tight fitting if not warmed up before installing.

In all likelihood it was not fully seated, therefore also not sitting on square wobbling the load back and forth. Well metal fatigue constantly pulled back and forth,and snap.

I don't see how it is possible for the balancer to not be seated squarely due to the tight tolerances. I would also think the car would throw the belts off if it were not on all the way. If I had to guess the bolt probably came loose.

 

[TooSoonJunior]

Exactly.

The MMR kit that's going save the world is a gimmick when the balancer is installed properly. At best the giant stepped washer helps square the balancer on the crank when improperly installed. Using a stronger bolt is not the way to properly install any balancer. The install kit Beef shared is best, or those who make their own with all thread.

Not advocating for the MMR stuff, but until you actually measure the full depth of the ATI damper and then measure the area on the crank where it is to be installed you cannot be certain it will 100% seat so that a standard washer will sit flush with both the crank and the damper.

I have NEVER installed an ATI damper and have it seat 100% flush to the snout of the crank, NEVER. Always out 1/16 - 1/8" from the end.

 

[Super Werty]

Maybe when you guys are applying the torque you are lifting up or pushing down on the snout of the crank. I could see that stressing the snout enough to bend. A few rpm later it could snap.

 

[Excelerater]

Bad crank,simple.

I would rebuild the short block with aftermarket parts and add more boost

 

[Slamdcoop0428]

Not advocating for the MMR stuff, but until you actually measure the full depth of the ATI damper and then measure the area on the crank where it is to be installed you cannot be certain it will 100% seat so that a standard washer will sit flush with both the crank and the damper.

I have NEVER installed an ATI damper and have it seat 100% flush to the snout of the crank, NEVER. Always out 1/16 - 1/8" from the end.

Isnt the balancer suppose to press up against the timing gear?

 

[Jay-rod427]

Isnt the balancer suppose to press up against the timing gear?

Yes. Where it sits to the end of the crank is irrelevant...

 

[TooSoonJunior]

Isnt the balancer suppose to press up against the timing gear?

Yes, my point is the tolerance of the factory crank from the front of the timing gear to snout of the crank can often times be less than the depth of the ATI hub.

OR in most cases the ID of the ATI hub is too tight and you will NEVER fully seat it up to the timing gear. This is where honing the hub is necessary, is specifically called for by ATI, but is RARELY done by the installer.

 

[Slamdcoop0428]

Yes, my point is the tolerance of the factory crank from the front of the timing gear to snout of the crank can often times be less than the depth of the ATI hub.

OR in most cases the ID of the ATI hub is too tight and you will NEVER fully seat it up to the timing gear. This is where honing the hub is necessary, is specifically called for by ATI, but is RARELY done by the installer.

Well even the stock balancer doesnt sit flush with the end of he snout.

 

[TooSoonJunior]

Well even the stock balancer doesnt sit flush with the end of he snout.

LOL right, exactly my point. Everyone chimes in and says "wasn't fully seated" as a possible cause. Define "fully seated"...to the same depth as stock, which isn't fully seated?

And to my original post, since almost no setup, stock or ATI, is "fully seated" and sitting flush to the end of the crank, I actually think the MMR ARP bolt and washer is a wise upgrade. Eliminates this argument some make.

 

[Slamdcoop0428]

LOL right, exactly my point. Everyone chimes in and says "wasn't fully seated" as a possible cause. Define "fully seated"...to the same depth as stock, which isn't fully seated?

And to my original post, since almost no setup, stock or ATI, is "fully seated" and sitting flush to the end of the crank, I actually think the MMR ARP bolt and washer is a wise upgrade. Eliminates this argument some make.

Well i just installed an ATI 20% balancer on my car. It was my first ati install. I havent thrown a belt or even jumped 1 rib yet but i honestly coudnt tell you if i was for sure up against the timing gear. I just ordered the installer tool and arp/mmr washer and bolt setup as i want to remove it and do it again just to make sure.

 

[isedawishy]

MPR is beginning to break down the motor. In a quick email he mentioned the heads are destroyed and that the cam caps are even broke.

He's going to dig further in tomorrow and I asked that he take some pics. I'll post them up as I get em!

 

[kcc0521]

Sorry to hear that. You will forget about all this pain when you spool up those new turbos.

 

[isedawishy]

Sorry to hear that. You will forget about all this pain when you spool up those new turbos.

True that! I'm waiting to see what all broke and what the final bill is. The initial estimate was about 500 more than another builder, but the other builder's setup comes with a new block and heads.

If I have to completely replace the heads, then it may make more financial sense to go with builder #2.

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