Crank pulley shenanigans

macleanflood

I break sh!t
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So on my trip down the Rubicon the only issue we had was belt splitting. Lost a rib on two belts and when we removed the rib @CMBD noticed the belt would ride forward on the crank pulley and rear on everything else.

For reference the crank pulley is Napa sourced and installed a couple of years ago when I did my timing chain. From the face of the pulley to the block next to the bolt below the timing marks I have 2 1/16". Guessing this is proud by 1/16 to an 1/8".

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Checked torque on the crank bolt and it was correct at 100 ft lbs. Went to pull the pulley this morning and discovered this oh shit moment...

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Assuming at this point this is the smoking gun. I cross threaded the crank bolt and that fucked up torque numbers and that in turn didn't get the pulley to the right spot.

I have a 1/2-20 tap. I assume chase the threads best I can and hope there is enough left on the crank to hold a new 1 1/2" bolt?

Thoughts? Yes, yes I fucked up.

-Mac
 
Living up to your motto I see.... Hopefully the crank threads are not torched as well.... But hey, only another reason to get a stroker build going right?
 
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Ok...thread chasing didn't take much resistance and not much came off with the tap...

I test fitted a long 1/2-20 and as predicted it goes in 3/8" no issues and then gets crunchy. Chased the tap a few more times.

As it happens...I have a perfect replacement bolt. Happened on a garage sale last summer and bought up a metric shit ton of bolts and hardware at an estate sale for $50. Mostly for the bins. Whomever they were they clearly were building engines.

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-Mac
 
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It's not stupid, I've seen this many times. It's a learning process right up to the moment you die... Next time, 'start' the pully with the longer bolt so you have assured thread alignment & purchase when pulling the pulley/balancer onto the shaft.
 
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I hav used a longer bolt with stacks of washers to pull them on nearly all the way before using the regular bolt.

If you want to get fancy, put a nut above the washers on the bolt and you have an install tool.

View attachment 563122

Even after advising a lawyer (too smart) against using the hub bolt; I watched him try to press the harmonic balancer onto the crank snout using the bolt. He stripped the bolt and buggered up the internal threads. The guy was mad at me when I said, "I told you not to do that" !!!!
Several years before I created one of those tools for a Mopar dealership technician friend using Grade 8 all thread after seeing me use the tool to replace the harmonic balancer on my '98 XJ 4.0L.
 
And we have a winner...clean threads = proper torque. Pulley drawn in to 1" 15/16". 1/8" more.

View attachment 563090

Now please lambast me for being an idiot. =)

-Mac

Mac,

Glad to see you used a Bottoming Tap to chase the threads and recover several threads at the bottom of the crank snout.
Congrats on getting the threads repaired and the harmonic balancer hub fully seated.