aNuBiS

iTrader: (25)

Well I think I broke a thread in the crank when removing the pulley earlier on in the build. I screwed out the bolt most of the way and put the 3 arm puller on the bolt to help get the pulley off the rest of the way as recommended in tutorials.

I was putting my new bolt in and I could only turn it half a turn with my hand and thats as far as I could turn it. I then pulled it out and from what I could see on the end of the bolt was a crank thread

Reason why I believe it was a crank thread was because it was almost a full ring rough on the outside and smooth on the inside. So I probably stripped the first most thread in the crank and now it wont allow me to thread in the bolt?

How many turns should I normally be able to turn the crank bolt into the crank by hand?

I did some research on here and Im hoping that maybe I could get away with using a 12mm x 2.0 pitch tap to clean up the threads??

All input would be appreciated!!!

aNuBiS

iTrader: (25)

bump for help

aNuBiS

iTrader: (25)

Up for some advice from those who've done this?

aNuBiS

iTrader: (25)

Would really appreciate some input on wether or not that is the correct size for the crank tap, and on how many turns you would normally turn a bolt into the crank

mmmchickenboy

if all you did was pull out the outer-most thread coil, then you can probably get away with using a balancer installation tool. it sounds like if you use the right tool, you should be able to thread it right in with no tap work neccessary. get the right tool before you make it worse.

see figure 1 in this pdf:

http://www.jasperengines.com/pdf/GMCrankBalancer.pdf

thats what you need.

1sick'98WS6

iTrader: (19)

had a buddy with his vette do this, hes on this forum, he had problems with it till the day he pulled the motor.

black98ws6ta

iTrader: (77)

Get you a tap, lubricate it well, and it will be ok.

mmmchickenboy

IMO there is a good possibility that the threads will accept a bolt right now. I would not mess with the threads just yet. Get the right tool, or a new bolt (you'll need it anyway) and try to thread it in. But DONT use the new bolt to pull on the damper.

I've fucked up crank threads before and it sucks. Good Luck.

TheBlurLS1

iTrader: (8)

The tutorials say to use a longer bolt to push the pulley off, and pull the pulley on. You should not use the stocker, as it's not long enough to have enough threads in the crank. I use a bolt that's about 3/4" longer than the stocker. I can screw it in 'till it bottoms out, then push on it. I may have to remove the puller and back the bolt out a bit to get it all the way off, but the pulley is pretty loose by then.

aNuBiS

iTrader: (25)

Thanks for the replies. I actually have the crank pulley installer tool (basically a long bolt with washers and a nut) and that wont thread in the crank right now at all.

I also have a new crank bolt, and a old crank bolt I found in my toolbox from my first crank removal 3 years ago when I swap'd in my first cam.

I tried by hand threading in that old crank bolt, and the long bolt tool, and it tries to position the bolt sideways while turning, then binds and thats it.

I really dont wanna try with a tool at all and risk doing any more damage. Thats why Im thinking a tap and lots of lube, but willing to do whatever will work.

vettenuts

iTrader: (4)

The threads are buggered and you only choice is to chase them with a tap. Use plent of lube and make sure it stays straight. Go slow. Hopefully it is only the last thread or two that is bad, and once squared away, the tap will go in without too much effort. Next step would be a heli-coil, but try the correct tap first.

aNuBiS

iTrader: (25)

just to be sure what IS the correct tap. Thanks all

2000slpss

iTrader: (27)

my crank threads are screwed! lol the botl pulls out. the correct thread size is 16 mm 2.0 thread pitch. if you get a 16mm 2.0 pitch tap lube it very well and clean the threads you'l be fine. me on the other hand i have to drill and helicoil my crank.

aNuBiS

iTrader: (25)

Sorry to hear that

But thank you very much for the info.

G'luck

aNuBiS

iTrader: (25)

Well I found the correct tap, now I am assuming I can use WD-40 as the lubricant?

TwistedSS

iTrader: (3)

WD-40 is fine...

If its too messed up, you could consider doing away with the bolt and pin it in like some of the blower guys do.

http://www.exoticperformanceplus.com....html?item=458

vettenuts

iTrader: (4)

Buy some cutting oil.

aNuBiS

iTrader: (25)

Always nice to have a plan B, thanks for the info.

aNuBiS

iTrader: (25)

Sounds good, will do. Just ordered a m16x2 in town here, will be in monday, was under 20$, well see how it goes. Thanks

styoung

iTrader: (4)

cutting oil will be best, also what style tap did you order, i hope it was a gun tap or starter tap and not a bottoming tap.