Crank Dowel Pin - Desperate & Frustrated

[Dorsh]

Hello,

First, thank you guys for all the posts and knowledge everybody shares. Although, I don't post often I spend quite a bit of my time reading everybody's topics.

Alright here is my situation that makes me absolutely sick. If you only knew the entire situation and how excited I've been to get this car back on the road and then this. Honestly, I've been to embarrassed to even post this but here we are.

Please review this and give any advice you may have. Thank you in advance.

Background:
Car's been sitting for almost 1.5 years due to a broken rear window(Targa).
Finally saved up enough money to get the body repaired around the window and glass installed.
Picked the car up and it idles at 3000rpm.
After getting the car back to my garage while checking this out for possible stuck cold start valve, I got careless and let a rag wrap around the crank pulley which stalled the car.
Couldn't remove rag so since I've replaced the crank shaft seal some time ago no big deal remove the rear mount and pulley cover.
Remove rag and pulley falls off.
Pulley is gouged from dowel pin and dowel pin is sheared off. See pictures
Crank bolt and crankshaft threads fine.

Dowel pin is stuck possibly from side load forces or is this pressed in. Lets hope not.

I've created a cone face into the dowel pin with a dremel for drilling.
I've broken several bits that were recommend on here for other dowel pin removal.

If you have any advice on better drill bits then heat/cold treating the metals I would appreciate it.

Thank you
Kurt
78SC

[kodioneill]

Use a GOOD HIGH QUALITY hard center punch. Then a GOOD HIGH QUALITY DRILL bit. Don't mess around or you will ruin your crank. Drill a hole all the way through and extract the pin.

[mholbrook38]

Titanium drill bit. BE CAREFUL, Titanium will drill through almost anything.

[Dorsh]

kodioneill,

Thanks for replying! From you're post you make it sound like the hole for the dowel pin is deeper than the dowel pin itself. I was thinking the hole was only deep enough to house half of the dowel pin but not sure as I've never had the pin out before.

The bits I got from HD are junk. Is there a certain bit I should be looking into possibly from McMaster Carr or similar?

Thanks,
Kurt
78SC

[john walker's workshop]

the pin is tighter in the pulley than in the crank. it comes with the pulley. good luck, as they're kinda hard. maybe use a body shop tool, a stud welder. then use a slide hammer gently to work it out after it's cooled.

[ClickClickBoom]

EDM,
Problem is your engine has to be out. Still would be easier and cheaper than splitting the cases. That pin will be harder than any drill you can buy, good luck post up your results.
eric
P.S. EDM is one of the only(very few) ways to remove broken taps and drills, from expensive castings and forgings.
P.S.S. I don't know if it would be possible to use a stud welder on a piece that small, but check it out. "H and S Auto Shot HSA5500 Stud Starter Welding Kit"

http://www.engineersedge.com/edm.shtml

[dfink]

Here is an off the wall thought. If you can't drill then get a 1/8" diamond bit for a dremel. Grind a hole in the middle of the pin. Then get a steel pop rivet and some JB weld. Insert the rivet along with a little and I mean a little JB weld into the hole. (Do not glue the dowel pin to the crank) Then if possible use the pop rivet tool to just expand the rivet at bit do not pop it. This is the reason for a steel rivet. Once the jb weld has set attach a vise grip or some other gripping tool to the shaft of the pin and hopefully pull it out. If the pin breaks it should drill out and you can try again. If the pin is not very deep and you can get a hole completely through you could get a pop rivet long enough to get to the other end.
Doesn't look like fun in any case. The above might not appeal to you but shows there may be options that just haven't been thought of.

[Dorsh]

Thanks guys for all the responses.

So far I really haven't had the time to put into removing this pin. I've only tried drilling it which proved to be next to impossible even with the titanium drill bits from HD. I don't own or have access to a welder and I'm not sure something could be welded to just the pin considering its size.

The idea with the diamond bit for a dremel and then installing a rivet is worth looking into. I have in laws visiting this weekend and next week I'm out of town on business so I will post up as I move forward.

Thanks again,
Kurt
78SC

[john walker's workshop]

the body shop stud welder loads what looks like a nail with a rounded head. you position the head against the spot you want it to adhere to, pull the trigger for 2 or 3 seconds, the nail (stud) gets red hot and welds itself to the object. then you loosen the chuck and remove the welder tool. then you attach the related small slide hammer after it cools to touch, and carefully tap it out, hopefully. probably can rent one at rental places. the pin is real hard, so hopefully the stud will stick sufficiently. it's a tough issue to deal with, even professionally, so go slow and don't get crazy.

[kodioneill]

Originally Posted by john walker's workshop

the body shop stud welder loads what looks like a nail with a rounded head. you position the head against the spot you want it to adhere to, pull the trigger for 2 or 3 seconds, the nail (stud) gets red hot and welds itself to the object. then you loosen the chuck and remove the welder tool. then you attach the related small slide hammer after it cools to touch, and carefully tap it out, hopefully. probably can rent one at rental places. the pin is real hard, so hopefully the stud will stick sufficiently. it's a tough issue to deal with, even professionally, so go slow and don't get crazy.

I like that idea the best.

[Gunter]

+1.

A partial drop would help and give the room required to work on the broken pin.

Replace the cracked oil seal as well.

[1990C4S]

Toolmakers trick: drill and ream a hole, then fill it with a bit of oil, drive in a dowel and the hydraulic pressure will force the larger dowel out.

Or drill and tap (I suspect it is too hard to tap) and use a slide hammer.

Or loctite a pull dowel in and use a slide hammer on the new dowel.

Make a drill jig and move the dowel 180 degrees. Modify the pulley to match.

[klaucke]

You can also try a carbide drill bit (not cheap). This will be hard enough to cut the dowel, but it will require an extremely high spindle speed to work correctly.

JW's tip is great (per usual), but you'll have to do some leg work to scrounge up the stud welder.

[tctnd]

There is an old hot rodder's trick that actually works very well. Pick a hex nut that just fits over the exposed pin. Weld to the pin through the center of the nut. Use a wrench to twist the pin out. The weld will cause the pin to shrink and it will likely slip right out.
regards,
Phil

[1990C4S]

There isn't any part of the pin exposed, from what I can tell.

And you can't weld a dowel pin with any strength, the material is too hard. I think JW's suggestion might have the same issue.

[Gunter]

Good point.

I would first try to grind a small indent into the center of the pin and then use a center punch and hammer it sideways to loosen it a bit. The dowel is not press-fitted into the crank, AFAIK.

[1990C4S]

It is likely designed as a slide fit, but has corroded, essentially making it a press fit. I am still inclined to say rotate it 180 degrees and start over with a new hole. This is not a simple repair, it is more suited to a machinist than a mechanic.

Dorsh: where do you live? You don't have any location info posted....

[Gunter]

No way.

The picture indicates 2 things:

The pin was sheared off squeezing it over to one side in the hole. It looks to me that the bolt wasn't tight enough to hold the pulley and it worked on the pin for a while.

And, enough of an oil-leak is showing to prevent rusting the pin, I think.

Machining a new set-up at 180 degrees cannot be done in situ and is way too involved and costly.

I think the dremel-center-indent, a center punch and some hammering might get it loose. It's worth a try before any major surgery.

[boyt911sc]

Originally Posted by tctnd

There is an old hot rodder's trick that actually works very well. Pick a hex nut that just fits over the exposed pin. Weld to the pin through the center of the nut. Use a wrench to twist the pin out. The weld will cause the pin to shrink and it will likely slip right out.
regards,
Phil

This is something I'll try if I have this kind of problem with my engine. Spot weld the nut and the nut itself will prevent the weld material to spread out. Do it slowly bead by bead until the nut stays put on top of the broken dowel. Then fill the hole (nut thread). I bet you could use a flier or vise grip to pull it out. What ever you decide, keep us posted. We could all learn from your experience.

Tony

[Gunter]

Consider the size of the pin/nut to be welded and a few other things:

This is not on a bench or easily accessable.
This is on a vertical plane, very restricted area with the bumper etc. right behind.
How would one hold the nut precisely over the pin, get the stinger in there, get the crank grounded, get the head in there so one can see???

Please, this is taking on a utopian character.