Fixing Crankshaft Threads

[DuckRyder]

I must have gotten a friday afternoon crankshaft.

When installing the damper (with a rental Tool) the treads came mostly out with the tool. there were enough to hold the bolt with locktite but don't really trust it and want to fix it.

From my reading my 2 choices are tap it larger for a Hemi Bolt or helicoil. Either is going to require drilling it out, is there any solution to doing so with the crank it the engine and in the truck? Or do i need to resign myself to pulling it all out?

[jayb]

I'd be concerned about the heat treat on that crankshaft, those threads should be plenty strong to get the damper installed.  Unless of course the ID of the damper was way undersize, it would be worth checking that.  Shouldn't be more an about a 0.001" press, and a lot of engine builders prefer a slip fit.

If you have to drill and tap the crank, I think you could do it in the vehicle with a drill guide.  You would need a steel sleeve that would have a bore that would allow it to fit closely over the snout of the crank, with a hole in the other end for the diameter of the drill.  Any good lathe operator should be able to make that up for you.  Assuming the shank of the tap is smaller than the drill, a donut over the shank would allow you to use the same tool to guide the tap.

Of course, if you took it out a crank shop could do the repair for you.  Good luck with the repair.

[cleandan]

I'll second Jays concern about the crank heat treat....as well as the inner bore of the damper.
It's too bad but that inner bore must be checked prior to installation because many of these parts are NOT correct right out of the box.....and it stinks.

Some questions for you;
1) By number, how many threads were pulled out?
2) How much force was used to seat the damper?....assuming it was seated in the process of pulling the threads out.
3) Were the threads of the rental tool in good condition prior to using the tool?
4) Are you certain the damaged threads are from the crank hole and not from the rental tool?....In other words, did you look into the crank hole to verify those threads are damaged?
I say this last part because I have had rental tools fail and my first reaction was....Oh crap, my stuff is damaged, when in fact, nothing of mine was damaged in the least...the tool had failed.

[GerryP]

...
3) Were the threads of the rental tool in good condition prior to using the tool?
4) Are you certain the damaged threads are from the crank hole and not from the rental tool?....In other words, did you look into the crank hole to verify those threads are damaged?...

These two seem most likely.  For those who are not aware of how the tool works, there is a threaded adapter that screws into the crank snout and the installation tool threads into that.  Once the installation tool is fully seated, the hub is set in place and on the shaft of the installation tool, a bearing and the nut are threaded on.  The only part of this process that turns is the nut on the installation tool and it rides against the bearing as it pushes the dampener on the snout.  The weak point in the tool is in the adapter that threads into the snout and if something was to break, it seems it would be that adapter.  The threads in the snout would probably be stronger than the tool.  That assumes it was properly machined and had the correct heat treat.  And, of course, something like a metric adapter wasn't being used on SAE threads and it didn't fully engage the threads.

[MeanGene]

I made my own installer, actually just the center of and old puller that lost its end, and is the same size and pitch as the crank threads. I cut the square end off and beveled it a bit, so you can thread it into the crank, start the dampener, add a big, thick flat washer and a nut, and it works very well

[pbf777]

I must have gotten a friday afternoon crankshaft.

     That may be so, but is this the Ford O.E. soft cast iron crankshaft, that perhaps someone previously may have just abused the treads of?    As if this is, particularly one of the "import" steel examples, I might start to get nervous as I have found some of these that definitely exhibited over heat-treated treading surfaces to the point of being brittle, and if so may prove quite the task to repair.   

From my reading my 2 choices are tap it larger for a Hemi Bolt or helicoil. Either is going to require drilling it out, is there any solution to doing so with the crank it the engine and in the truck?

     I would not suggest going to the larger "Hemi Bolt" as that would require a larger diameter drilling process which would increase the likelihood for failure in the endeavor; yes the Heli-Coil process also does require drilling, but the sum is greatly relegated to just the removal of the original treading (which you imply is already greatly missing!  ) therefore the drill does tend to a great degree to self-pilot, and only with a rather deft touch can one really F.U.!   

     As far as in the truck, with the Heli-Coil process, if one can make enough room to work, then I surely wouldn't hesitate.   ;  though yeah, still dread the thought of having to do it!   

     Scott.

[DuckRyder]

I'll second Jays concern about the crank heat treat....as well as the inner bore of the damper.
It's too bad but that inner bore must be checked prior to installation because many of these parts are NOT correct right out of the box.....and it stinks.

Its a DSC spacer and a ATI damper both were in use on the prior Ford crank and fit well.

Some questions for you;
1) By number, how many threads were pulled out?

I don't remember, all but 3 or 4 is my recollection, at least that the bolt could get to.

2) How much force was used to seat the damper?....assuming it was seated in the process of pulling the threads out.

Too much apparently, but it did not seem too bad - i used a ratchet and not an impact

3) Were the threads of the rental tool in good condition prior to using the tool?

To the best of my recollection. it seemed to thread in fine.

4) Are you certain the damaged threads are from the crank hole and not from the rental tool?....In other words, did you look into the crank hole to verify those threads are damaged?
I say this last part because I have had rental tools fail and my first reaction was....Oh crap, my stuff is damaged, when in fact, nothing of mine was damaged in the least...the tool had failed.

Oh yeah

I must have gotten a friday afternoon crankshaft.

     That may be so, but is this the Ford O.E. soft cast iron crankshaft, that perhaps someone previously may have just abused the treads of?    As if this is, particularly one of the "import" steel examples, I might start to get nervous as I have found some of these that definitely exhibited over heat-treated treading surfaces to the point of being brittle, and if so may prove quite the task to repair.   

It's a Scat Stroker. It also had an out of round oil slinger

From my reading my 2 choices are tap it larger for a Hemi Bolt or helicoil. Either is going to require drilling it out, is there any solution to doing so with the crank it the engine and in the truck?

     I would not suggest going to the larger "Hemi Bolt" as that would require a larger diameter drilling process which would increase the likelihood for failure in the endeavor; yes the Heli-Coil process also does require drilling, but the sum is greatly relegated to just the removal of the original treading (which you imply is already greatly missing!  ) therefore the drill does tend to a great degree to self-pilot, and only with a rather deft touch can one really F.U.!   

     As far as in the truck, with the Heli-Coil process, if one can make enough room to work, then I surely wouldn't hesitate.   ;  though yeah, still dread the thought of having to do it!   

Good Point

     Scott.

I guess i will try the helicoil when i get a chance, Plan B would be a new crank and hope i could have the balance matched. Plan C might make me persona  non grata on the FE Power Forum

[Rory428]

I wonder if there are still some good treads left further back in the crank snout, if one could make a stud, that will thread further into the crank than the stock bolt does, and then use a nut at the balancer? To be honest, I have never had any issues installing balancers on FE cranks over many years , although I always tapped the balancer on with a hammer, with a piece of wood or steel between the balancer and hammer. I have never used an aftermarket FE crankshaft, are the aftermarket cranks a bit larger OD, making them tighter fitting for the balancer? I know a local guy that built a FE stroker, with an aftermarket crank, not sure of the brand, and when he went to install the spacer behind the balancer, rather than being a hand slip fit, like factory stuff, he had to tap it on with a hammer, and it cracked the spacer, so I have to assume the snout of the crank was a bit larger, or there was a problem with how the non OE style crank key fit.

[My427stang]

How much thread do you have left?  If you have the bolt diameter worth of thread, it torqued OK, and you Loctite it, it isn't going anywhere.

Secondarily, I like the idea of going deeper if you have to (assuming there is more thread).  I would have to think you could find a longer bolt somewhere, but might take some searching

[pbf777]

Its a DSC spacer and a ATI damper both were in use on the prior Ford crank and fit well.[/b]

2) How much force was used to seat the damper?

Too much apparently, but it did not seem too bad - i used a ratchet and not an impact


It's a Scat Stroker. It also had an out of round oil slinger
 

      Even though you stated that it didn't "seem too bad", I would suggest that one establishes the interference fitment sum; as the Scat crankshaft and the ATI damper actually prove to be unknowns, and although someone else already commented on the possibility of the crank being oversized, I can assure you that ATI dampers 'most often' must be I.D. honed to size as they 'most often' are undersized in their I.D. bore   

      Scott.

[winr1]

Have always threaded a cut off bolt almost bottomed out in a crank and used a nut and washer to install a balancer

I think using a hammer or such to drive a balancer on would not be good for the main thrust bearing or the main cap and block as well

Seen a bunch use an impact wrench and the balancer bolt to install a balancer

As mentioned above, perhaps always check for proper clearance on balancer ID and crank snout OD.. ( everything else as well )


Ricky.

[Rory428]

As mentioned, an aftermarket balancer on an aftermarket crank may have potential fitment issues, I have used ATI Super Dampers on a couple of my FEs in the past, and they did fit a bit snug on the factory Ford cranks, but not bad enough to require honing the damper, ATI wants them to be rather snug. As for the use of a hammer, I have used that method on factory and ATI balancers  on factory crankshafts for over 45 years, and have yet to have any thrust bearing issues, even on stickshift drag cars that routinely enjoyed years of 6000+ RPM clutch drops.

[DuckRyder]

Thanks for the input.

This happened a while back which is why i'm not real clear on some of the questions.

It did torque but it did not feel great, the trigger for my bringing it up is i'm considering changing a camshaft and i have low confidence it will torque again, that being the case i will either have to leave it alone or deal with it.

I no longer have a very good place to pull the engine so i may just leave it alone, though it bugs me.

[pbf777]

It did torque but it did not feel great, .................. and i have low confidence it will torque again, that being the case i will either have to leave it alone or deal with it.

     If your operating a Used Car Lot, and the "No Warranty" sticker is posted in the window, I guess, not that I would agree morally, but I understand where your coming from; but for ones' own treasure, I'd suggest addressing the issue, as the if your "feel" was right, the possible resultant damages and costs if a failure does take place might prove quite unappreciated!   

     Scott.

[Heo]

A friend had a 70 or 71 Camaro Z28, I was passenger when he lost the damper
He shifted down and enginebraked in an intersection and there was a rattling noice
and i se something careering across the road on the driverside, hitting the curb, and takeof
straight up  no damage to the car