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View Full Version : Help! Crank holes crossthreaded...


jdmking.aj
04-21-2013, 09:08 PM
Well... okay first of all i am a fucking idiot for trying to rush to finish my car for import alliance.
The car is an s14 with an s14 sr20det notchtop/blacktop.
XTD Flywheel and an Exedy stage 1 clutch (ebay prokit bullshit)
I have to change my clutch because it was slipping really bad. So i took everything out and everything went smooth.
UNTIL, i went to go put my new lightweight flywheel on and me being a dumbass crossthreaded two of the crank holes where the flywheel bolts go into.
Now the bolts wont thread all the way into the holes and i don't want to make it worst. So i'm asking you guys for help. What the hell should i do?
I heard about rethreading, heilcoil, and all that other stuff but i've never delt with anything like that and i don't feel like fucking it up even more.

Here's a pic of the bolts, the two are the ones on the bottom left:
http://240atlanta.com/forums/attachment.php?attachmentid=35708&d=1366348663

jr_ss
04-21-2013, 09:11 PM
By a tap and clean the threads up, then use a gallon of red loctite.

jdmking.aj
04-21-2013, 09:59 PM
Would i have to get a different size flywheel bolt?
Ok edit i found this...
http://www.harborfreight.com/40-piece-metric-carbon-steel-tap-and-die-set-39384.html

What size is the flywheel bolt? Does anyone see it in that kit?

jr_ss
04-22-2013, 12:39 PM
Go to a hardware store with one of your bolts and measure the thread pattern and pitch. Buy new flywheel bolts too if you haven't already.

stacksondeck
04-22-2013, 06:42 PM
Helicoil, timesert, etc..

If Jr's advice doesn't work then a threaded insert is the only other option.

People are often fooled that helicoil is junk or "not strong". If you've ever been in a Boeing 737-787 then you were surrounded by about 30k threaded inserts. It is very easy if you take your time and it is often much stronger than the original threads. It is also easily re-inserted if you were to strip out the repair.

stacksondeck
04-22-2013, 06:45 PM
The size is 10mm x 1.0 pitch. Try a tap in that size first. You might be able to salvage them. At 100ft-lbs+ I'm willing to bet they strip further, though.

jr_ss
04-22-2013, 08:08 PM
The size is 10mm x 1.0 pitch. Try a tap in that size first. You might be able to salvage them. At 100ft-lbs+ I'm willing to bet they strip further, though.

He hasn't stripped the threads, just cross threaded two of the eight. However if that doesn't work, he will need to add helicoils to atleast those holes that are screwed.

ShadowMan
04-23-2013, 12:17 AM
He hasn't stripped the threads, just cross threaded two of the eight. However if that doesn't work, he will need to add helicoils to atleast those holes that are screwed.

Curious if this is enough weight difference that would throw the crank out of balance? Or is it not enough that would make a difference?

bussitcustoms
04-23-2013, 12:31 AM
I had a buddy strip out two of his on a Honda beater he was throwing together. He over torqued the rest by 5lbs, and left the other two out. They were not directly across from one another. The car drove fine.

Personally, I thought it was ghetto as fuck, and I wouldn't do that on any of my own cars. But it did run and drive perfectly fine. So idk.

jr_ss
04-23-2013, 07:08 AM
Curious if this is enough weight difference that would throw the crank out of balance? Or is it not enough that would make a difference?

If he has to install helicoils, it very well could add weigh and throw it off. However, if they are directly across from each other it probably cancels it out. If they are side by side, then I'm sure it has some negative effects, but it's hard to tell without actually balancing the assembly. The material removed could equate to the weight of the helicoils.