Catastrophe

[jdh00]

Ok, I am really stupid. Yesterday while pulling the crankshaft dampener I ran the puller bolt into the crank hole... Now I've got threads that are god knows what, all I know is the bolt does not even come close to starting. What are my options? Tap it to a different size? I am really panicking frown

 

[fredhurderjr]

I don't know if you'd be able to find another size crank bolt. Have you tried chasing the threads to clean the up?

Bummer! & Good Luck!

 

[jdh00]

Chasing with a tap? What size/thread pitch is that bolt?

 

[munkee]

There is usually a guage in a tap and die set if you had access to one.

 

[jdh00]

Man, I don't have a whole kit. In the CPS procedure on shotimes there is a guy who says this " I had bought an M14 bolt to use for this task but the threads are NOT M14. I'm not quite sure why they use a standard thread or worse, a rare M13 bolt, but I didn't bother to measure it"

<small>[ August 04, 2002, 11:35 AM: Message edited by: jdh00 ]</small>

 

[RStalveyARFF]

are you close to a napa or home depot? They have bolt gauges, and you could tell right off. That's definitely a fine thread btw.

 

[CharlieSHO95]

You should be able to tell what the threads are from the crank bolt. Be careful with tapping the threads. My one experience with that is it is easy to accidently cut out the remaining threads.

A fallback option might be to install a helicoil insert, which is just a set of threads made of high quality material. You would have to drill the hole out, tap it for the helicoil thread size, then thread in the helicoil. The helicoil becomes the threads for the crank bolt. I have a helicoil holding in one of the rear main bolts in my SB chevy (an LT1 355 that has seen 7k rpm). I believe they are also used in some aluminum blocks. If you have to do the helicoil, you might want a shop to do that, as you would really want that to go properly.

Good luck.

 

[jdh00]

The bolt is a 14mm x 1.5, no one around here has that size tap. They're all 14 x 1.25. There doesn't look like enough area to drill any material out in there... I called a place and they have a 14 x 1.25 helicoil but then that leaves a problem with a new crank bolt. Can I just use a bolt with a tight-fitting washer that's the same size as the collar on the original crank bolt?

 

[CharlieSHO95]

I would wait until I could get the correct size tap. That maximizes your chances of getting a good repair, IMO.

 

[jdh00]

Alright, the car is put up for the day. I'll get the correct tap tomorrow and see what transpires... Thanks for all of your input guys.

 

[jdh00]

Patience is a virtue... I got the correct size tap today and it put a wonderful new set of threads in my crank. I can now sleep again

 

[pete c]

jdh00:
..... and it put a wonderful new set of threads in my crank. I can now sleep again

Ain't no way I'm sleepin' with something in my crank.

 

[billyshoe]

Helicoil. I'v seen the damage that occurs if the dampner & timing pulley is'nt seated. It will start eating timing belts. The belt will cut right thru the timing cover. If it reaches this point the crank damage is beyond reasonable repair.