SStolen

iTrader: (22)

I was one hour from finishing my cam and header install tonight when I stripped the freaking crank! All I had left to do was bolt on the pulley and water pump, slap the radiator in and fill it up. Instead, this happens!

I printed off the instructions from LS1-how-to for my cam swap. The part explaining how to put the pulley on says nothing about possibly cross-threading the pulley. It says to use a longer crank bolt if you bought one to pull on the pulley. I didn't and everyone I have ever seen has just used a mallet to get it started on the snout until you can catch a few threads and start the bolt. Well, I used the mallet and hit it top, bottom and side to side until I could hand-thread it about two turns, then I start to torque it down with my ratchet. After about three full turns I think, 'this is way too hard' so I pull the bolt out. It is ate up on all three threads! I figure maybe the bolt just didn't go on right because it is stretched out... torque-to-yield. I start threading in the new bolt thinking I will just buy a new one tomorrow for the final install after the pulley is pulled on. Well it threads in very smoothly so I think I'm in the clear, it was just the bolt. I pull the pulley on about an inch with about a half inch to go when it is getting so hard to turn my breaker bar is bending. I pulled out my torque wrench just to see how hard it was and it was clicking on 240lbs! I decided this bolt is probably red hot, weak and ready to snap so I just pulled it out, barely... I thought it was going to snap unbolting it. When I pull the bolt out the first three threads are gone, just completely missing! I ran a magnetic tool inside the crank-bolt hole and pulled out all kinds of shavings, including a few half-inch long pieces of thread. What happened? Was the pulley just not seated right and started the bolt ****-eyed? It looked/looks even...?

What should I do now? I'm thinking I could just cut off the first inch of the bolt thats ate up and pull the rest of the pulley on, get a new bolt, cut it and torque it to the 240lbs less that last half-inch. I mean cross-threaded or not it should stay in there right? All its doing is holding on that pulley, or is it a big deal?

Do I have to bring it to a machine shop and have it tapped now? That is going to cost me $200 by the time I have it towed and worked on. God, I was half an hour from an extra 70rwhp!!! I think I'm going to puke.

TaTommyWS6

That sucks man, but it should not be too difficult to fix.

FIRST OF ALL, one way or another you need to retap that bolt hole and clean all that crap out of there. Finding a tap that size will probably be a pain, but it has to be done. DO NOT put any more bolts in there until you get it cleared up.

First pull the pulley back off...

If you can't find a tap that size, try getting another (NEW) crank bolt and shave two sides off the threads like what guys do for cleaning there head bolt holes. Insert it as straight as possible and turn on a little a time removing it often to remove the residue inside. Keep doing that until you can insert a new crank bolt by hand. The crank bolt should spin freely until it is near bottom. If it is hard, keep cleaning...

Don't just try to crossthread it and tighten it! There is no keyway on our crank pulley, so it has to be done right.

Don't despair, 70rwhp is coming soon for you!

Good luck and keep us posted.

Tommy

ZDOG

iTrader: (13)

that sucks! definately try to find a cleaning tap for it. even if there is nothing local order it. think of the damage that could be done if that puppy fly's off especially at 5000+ rpms! a new bolt for sure and maybey a little of that magical loctite. im sorry to hear this. man two of the next mods i want to do, and people are having problems! i just read that an electric water pump failed after 8 weeks and now this! gives me the shivers! good luck and keep us posted.

SStolen

iTrader: (22)

Maybe this is stupid but I'm going to clean it out, grab two or three crank bolts, lube em' up and bolt them on with an impact gun. A guy I emailed last night said this is what he did on a Neon he had and it worked fine. Last night, the first bolt I had went in a half-inch and got stuck. I cleaned it out and the next bolt went in another half-inch. Hopefully the third or fourth bolt will push it on flush and I can lock it in with a final bolt. Opinions? I asked him about tapping it out and he said that if it gets tapped an at angle then I WILL be forced to pull the engine and crank. I guess this is my best bet. I'm going to call a machine shop today and see what they say. Thanks guys.

Vents

iTrader: (9)

well, this isint th first time i've seen this happen. you cant drill and tap it out bigger, there's not a good viable bolt size to go back with. trust me i know. what you could do, is make a crank bolt stud out of some good threaded rod, and a jamnut. other than that, good luck man.

jmX

I think I'm going to start selling longer crank bolts on my site for a few bucks for people that are about to do cam swaps. You wont muck up threads with a longer bolt. You gotta be REALLY careful with the stock bolt and get that pulley on really far or you just wont have enough threads to start pulling the pulley on.

I cant even count how many swaps I've done with the longer bolt and I've not had any issues. Your situation is very unfortunate.

It will be possible to find a tap that can be inserted all the way into the crank, then enlarged to fit the threads, and then you back it out. That'll clean the threads back to stock. At the same time, you need to buy a longer crank bolt since you'll be missing the first couple of threads. I imagine it'll all cost $100 or so because those huge taps are very rare (gotta go to a machine shop, they can order it), but at least you'll be back up and running.

Magnus

iTrader: (4)

I would definatley not do the impact method.

Use the cleaning method described by people.. and be careful... the original threads should be left at least a little bit, those are the ones you need to catch.

TaTommyWS6

DITTO.

DO NOT USE AN IMPACT GUN TO CURE THIS PROBLEM. YOU WILL CAUSE MUCH BIGGER PROBLEMS.

Assassin

iTrader: (3)

get the right size tap, use pleanty of lube, go slow, keep cleaning, the crank is stronger than the bolt, have a beer and work on it in the mornin, must have faith everything will be allright!

SilverGhost

iTrader: (53)

The stock lenght bolt is fine is you do it right, I've done it a bunch of times.

What I do is keep an old crank bolt. I put that in the center of the pulley and into the crank and the take a sledge hammer and lightly tap the head of the crank bolt. This pushes the pulley on, when it quits moving it is plenty far on for the new crank bolt to grab and pull the pulley the rest of the way on. This works like a charm every time..

JeffJeff

I had a similar issue with my H/C swap, I thought for sure I stripped the crank. Couldn't sleep well that night. You need to make sure you clean out the crank with brake cleaner, and chase the threads to clean them. Then use a longer bolt so you can grab as many threads as possible when pulling the crank pulley on. I also used ARP lube on the bolt when I was seating the pulley, and cleaned it out before torquing with the new bolt.

The crank is very strong and it is doubtful the weak crank bolt would be able to do a lot of damage. In my case it was just the first few threads that were slightly damaged. I would definately stay away from the impact wrench method.

Camaroholic

iTrader: (1)

(I know this is in hindsight, but it may be useful to others)

For under $20, you can buy 3 feet of crank-bolt-size metric threaded rod, 2 nuts for that rod, washers, and a piece of pipe fitting.

Use a hacksaw to cut the rod in to 3 pieces. One about 6" long, and one about a foot long.

The 6" long one, you use to 'push' against when using a puller to get the dampener and/or timing gear off. This way you don't damage anything useful, and nothing wobbles around in or on the crank.

The foot long one - you thread in to the crank, slide the pulley on the crank, and use the piece of pipe, washer, and a nut to 'push' the crank pulley (or timing gear) on to the crank.

I bought this stuff at a local industrial nut/bolt shop (not a Home Depot). I just took the crank bolt with me and they matched it up to threaded rod.

FWIW.

Andrew

66ImpalaLT1

I did the same as Andrew, bought my threaded rod at Fastenal.

Tally TransAm

iTrader: (17)

i went out and spent 2 bucks on a long bolt and a bunch of washers just so i would have to deal with any of this

quickWS6

I've done 3 cam swaps, and I've never had to use a longer bolt or tap the pulley on. The pulley just slides on the snout enough for the original bolt to thread on, with no lube. Also had no problems with Rollmaster timing chain and ASP pulley like many did. Just lucky, I guess.

SStolen

iTrader: (22)

Does it matter than I have cross-threaded almost all the way through? Like I said I am almost all the way to pulling the pulley on, less than a half-inch to go. The first time it only pulled to a half-inch, the new bolt took it to a full inch and I'm thinking the third bolt will take it the rest of the way. Maybe I shouldn't use the impact gun but this sort of worked so far. I can thread the new bolt to the spot where I last left off so it is kind of like tapping it since I'm making new threads with the new bolts each time. Isn't it kind of the same thing??
I'll do what I have to do to get it right and if you all say that tapping is the only way to go then I will do that but what about tapping it in crooked like my friend mentioned? I guess a machine shop can get it dead-on right?

JMX: Are you saying a machine shop can order it for me to do the tap myself or order it and them do the tap for me? I don't even feel comfortable doing my own oil changes after this.

Camaroholic: I did a search and see you had a friend at a machine shop take care of you. I wish I were as fortunate. But, do you really think your method with the 6"and 12"rod is completely necessary? It's as easy as using a longer crank bolt to pull it on isn't it? I appreciate all your help so please do not consider this as me questioning your style, obviously I have no room to judge.

Camaroholic

iTrader: (1)

To me (and GM), the method I used is *safer* than pulling it on with a bolt.

Why? Because with the threaded rod, you put it all the way in to the crank first, and the nut does all the work. The stress on the crank threads is minimal - you are not turning the threaded rod at all in the crank threads (while under stress).

With the longer bolt, you're pulling on the crank threads and turning at the same time.

My 'tool' is a $20 version of the GM balancer installation tool (that works the same way).

As for machine shop, no, noone helped me out in this situation. My hacksaw, my labor, etc. No friends involved, just the local bolt shop (which I'd never been to before, or since). That's not saying I haven't screwed other things up tho. I have.

-Andrew

TaTommyWS6

You must have a magical stock pulley or be one strong **** to get that pulley to start without tapping it on a bit!

The ASP pulley on the other hand goes on fine with a stock bolt...

Tommy

jmX

I'll reply to a few things.
1) An ASP pulley usually doesnt need a longer bolt to go on. Just a stuck pulley.
2) I wouldnt sledgehammer a pulley on, but thats just me.
3) A bolt that is 20mm longer than stock will work fine, and I *prefer* this to a threaded rod, but that is all personal preference. It doesnt take much force at all to pull the crank pulley on once it is started, so its really no big deal IMO that the bolt is threading in at the same time. Either way works fine tho, of course.
4) I'm saying get a tap from a machine shop (not gonna find a tap that huge anywhere else), and tap it yourself. As I said, they make special taps that are small, you put them in the hole, and then you "expand" the tap out by screwing something into it and it grows to fit the thread. Then you back it out and it cleans the threads on the way out. It is much easier than having to start tapping in already messed up threads. This way you start in the clean section of threads and just back out. Simple! Expect to pay $70 to $100 for the tool though.

Disasters happen, its part of modding a car unfortunatly. I have had bolts break off, threads strip, whatever over the years, but in the end stuff ends up working out and you learn a good lesson. Once you get this all fixed up, you'll make sure you buy a longer bolt next time (I never do it without one!) and you'll be happy with your new horsepower.

I will change the webpage to stress getting a longer bolt or allthread, as I *highly* recommend it. I'll go buy them in bulk as well and send them out to people cheap if they want, since not everybody has a local bolt shop.

quickWS6

Actually, I had an ASP pulley, didn't realize there was any difference in how difficult they were to get on. I didn't think anyone ran stock pulleys too much anymore by the time you get around to doing a cam swap.