This is an interesting problem......

[vincechig1975]

Today I installed my balancer (470) and put the bolt in screwed it in as far as it would go by hand and added some antiseize to it but tightened it up then used my impact to tighten it up the rest of the way and now the crank threads are stripped and yes I know that I have to drill n tap it. My question is what is the size of the existing bolt looks like around 1/2" (shank diameter that is maybe metric) I really didn't measure it to be honest but is there another option for meat this point? Hints and opinions welcome ....these threads are stripped about half way inside the crank. I never realized til it was too late :facepalm:

 

[achris]

Re: This is an interesting problem......

Used your impact to tighten??? WHY????

It won't be metric, most likely 1/2"UNF... I would use a Helicoil....

Chris.....

 

[rickryder]

Re: This is an interesting problem......

I'm with Chris on this one....get a helicoil set that matches the oem bolt.... Don't think you'll be able to just send a tap in and chase the threads......

 

[Scott Danforth]

Re: This is an interesting problem......

you need to use a damper installation tool. it has a long hardened threaded stud. you can not simply pull in the damper with the stock bolt, its not long enough.

 

[Pete104]

Re: This is an interesting problem......

Did you the bolt out?

 

[Don S]

Re: This is an interesting problem......

Did you the bolt out?

I was going to say that exact same thing .... I wonder what the missing word is.

 

[vincechig1975]

Re: This is an interesting problem......

yep....it's out and it looks like the bolt was the problem, threads are messed up on it so guess we need to put a helicoil in it and a smack on the back side of the head for me. I can't believe I did this one. I leant my installation tool out and still haven't gotten it back, that was a month ago. Well guess I have to get on it tomorrow....I'll have pics of the culprit and the crank for yas ta see, then ya can say " And what were ya thinkin right? "

 

[picklenjim]

Re: This is an interesting problem......

You say it is only stripped half way down so there should still be enough thread left in there to use. Clean it up in there and get the installation tool and get the balancer on. You can borrow them from most parts stores. Then get the longest grade 8 bolt possible that you can use with out it bottoming out. If necessary get a longer one then needed and cut it off to max possible length. Should be extra threads in there as the stock length bolts don't usually go all the way to the bottom. With the balancer on you can measure to see how long of a bolt you will need. Don't forget to to add the width of the washer!

 

[Pete104]

Re: This is an interesting problem......

Well said Jim!

The bolts are much softer than the crank! Clean up the threads & use the install TOOL!!!

 

[Pete104]

Re: This is an interesting problem......

I was going to say that exact same thing .... I wonder what the missing word is.

:facepalm: "get"

I'm an idiot not a secretary!!!

 

[vincechig1975]

Re: This is an interesting problem......

Thanks fellas, I will have to do that tomorrow. Looks like it might not be as bad as it looks.....I hope at this point. The bolt was .5 unf and measures lil over 1.75 length, bottom of hex to base.

 

[stonyloam]

Re: This is an interesting problem......

It is a 1/2 inch fine thread. It is supposed to be torqued to 75 ft lb after it has been fully seated. You might be able to salvage it with a longer bolt that reaches down to the good threads. As said you need a damper instillation tool. You can borrow one from Autozone, however you need to add a spacer because of the depth of the rotor face. The other thing you could do is get a a section of 1/2 fine thread rod, screw it all the way in add nut and a pipe spacer and some washers. Tighten the nut against the spacer and washers and it should pull the rotor on. That is essentially what the Mercruiser tool does. You do not want to use the internal threads to pull the rotor on, but you already know that. Good luck.

Merc tool:

 

[vincechig1975]

Re: This is an interesting problem......

Thanks Stony, Yep I found it out the hard way:facepalm: