Help! Crank holes crossthreaded... - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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:

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-piec...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

Quote:

Originally Posted by stacksondeck

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

Quote:

Originally Posted by jr_ss

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

Quote:

Originally Posted by ShadowMan

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.

04-21-2013, 09:08 PM	#1
jdmking.aj Zilvia Member Join Date: May 2012 Location: my house Posts: 161 Trader Rating: (0) Feedback Score: 0 reviews	Help! Crank holes crossthreaded... 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:

04-21-2013, 09:11 PM	#2
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,052 Trader Rating: (34) Feedback Score: 34 reviews	By a tap and clean the threads up, then use a gallon of red loctite. __________________ My SR20VET

04-22-2013, 12:39 PM	#4
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,052 Trader Rating: (34) Feedback Score: 34 reviews	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. __________________ My SR20VET

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04-21-2013, 09:59 PM	#3
jdmking.aj Zilvia Member Join Date: May 2012 Location: my house Posts: 161 Trader Rating: (0) Feedback Score: 0 reviews	Would i have to get a different size flywheel bolt? Ok edit i found this... http://www.harborfreight.com/40-piec...set-39384.html What size is the flywheel bolt? Does anyone see it in that kit?

04-22-2013, 06:42 PM	#5
stacksondeck Leaky Injector Join Date: Mar 2013 Location: over yonder Posts: 66 Trader Rating: (0) Feedback Score: 0 reviews	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.

04-22-2013, 06:45 PM	#6
stacksondeck Leaky Injector Join Date: Mar 2013 Location: over yonder Posts: 66 Trader Rating: (0) Feedback Score: 0 reviews	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.

04-23-2013, 12:31 AM	#9
bussitcustoms Zilvia Junkie Join Date: Jan 2012 Location: philly pa Posts: 409 Trader Rating: (5) Feedback Score: 5 reviews	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.