Ha! If I'm seeing what I think I'm seeing,,,,
Damn good work! You're not far now, though it may not seem that way... Good job, on a no fun job. Good stuff!

 

I'd be tempted to try modifying a bolt first as there's less chance of doing any further damage, is the old bolt in good condition? Use plenty of lubrication. If that doesn't work you can use a regular tap, just be very careful to make sure it starts correctly and is perfectly square to the crankshaft.
Looks like you are making good progress.

 

call these people.

https://drillsandcutters.com/

800-870-3201

They will have the proper tap you
need. Using a cutting tap is asking for trouble given the extremely high torque involved for a proper installation. Any metal removed by a cutting tap is going to reduce the safety margin. But how much is too much is that not something I’d be comfortable gambling on.


Your car, your call.

Z

 

The original bolt is in good condition, I will start by adding flutes to it to clean the threads...when I get there!!

 

so the original bolt is not the broken one ?

Z

 

The short one without the thread lock is the original.

 

how can a shorter than stock modified bolt be used to clean up threads all the way to the bottom ?

Or is that not an important consideration.

Z

 

Who woulda thought one lousy broken bolt would gather so much attention?? It's an important bolt but holy geez.
DJP, this was indeed the best place to come to with your troubles. As you mention the support has been plentiful. Not one snide comment and every single poster was concerned and looking to help find a solution. THAT is this forum. Don't let an enthusiast go down the road of too much money spent for something or let something get ruined unnecessarily.
Everyone knew you could do it and wouldn't let you down. So glad progress is being made. These guys are the best!!!

Now back to normal programming. :P) TM

 

I could not agree more!!
Now for the greatest news ever...This post is the last!!....Job completed this evening....could not believe it was ever going to happen...through the dark days when the tap broke and had to be drilled out...to the slow, so slow job of grinding the captive bolt out!!...That was the KEY to the success, using those carbine cutting tools to grind it out, bloody flake by flake!!
Once I had cleaned out the threads the new bolt went all the way in finger tight...Job Done!!
You guys are the BEST....The Jaguar Forum Rules...I can never thank you enough!
I have cracked open a bottle of Prosecco, plus orange juice, this will be a late night...who cares...
Let The Games Begin......

Those carbide burr cutters must be does something inside to that bolt!

Great some of the threads coming out already!

That looks wonderful...how can one get so emotional over crankshaft threads??

I cannot believe it!!! after so many weeks, days, hours, the new bolt finally ran in finger tight...What do you know!!

 

Congrats! You must be feeling ecstatic! Nothing like finally getting that problem bolt out!

 

If you are worried about the condition of the thread or that such a short length of it is taking the load you could put in a long set bolt ..that would use all the threads available. then chop off the head and secure balancer with a thick washer and nut. If you needed to remove in future that would give you two options . Make sure its 8.8.
It looks to me like only the last 6 or so threads of the bolt are being loaded.

 

Wondering aloud; perhaps there’s no answer for this since the motor designers are likely not focused on their work of 20+ years ago…..

​​​​​……but, why does this balancer require such a high fastening torque ?

I’m familiar with much larger engines that turn higher rpm’s that make do somehow with an equally sized or ever larger balancer that’s bolted on using 50% of the torque that these X-100’s are asking for.

Seems like many of the assembly's fastener specifications are so extreme that it’s just asking for trouble. Especially these some 20 odd years later. In particular the cylinder head bolt torque spec comes to mind.

what gives ? I’m admittedly no engineer, just an long time engine builder / mechanic with more decades of experience than I should admit to. But there’s no lightbulb coming on upstairs to help me “get it”.

Z

 

They are expecting the load to be taken by the taper I think and as it not very shallow it needs a high torque.
Make shure you clean the taper well before re fitting.

 

Most automobile and m/c’s with balancers have a tapered attachment / interface with the crankshaft. At least all Fords have since the 1960’s and earlier. Those call for only 75-90 ft lbs.

Z

PS not trying to 2nd guess the engine designers, just understand them.

 

Lose the red bolt locker and use blue or one could probably use an old fashioned lock washer. they worked fine for the last 100yrs. It seems most mfgrs. have gotten away from washers and gone to cheaper thread locker. Little do they care about future problems.

 

BeauTtiful,,, amazing job sticking with it! I'm glad you didn't take my advise! Honestly.

And to the question posted above,,, I don't think the bolt needs to be torqued as tight. It's insane - a disaster waiting to happen. I have often thought it a misprint,,, that just kept being - misprinted and reproduced til it became lore. I feel the same about a few other torque specs on the car... Then that glob of red loctite,,, heck no!

Happy endings Man... And glad you shared the journey with us all... Good stuff

 

red threadlocker /=/ loctite 271

you would not be getting it out if it was