Crankshaft Keyhole Damaged - will devcon do the job?

Hello Andrew,
This happened in my old FJ40, you've taken me back in time here.
Luckily I caught mine before it came right off.
What I did was rotated the crank until the keyway was uppermost. I filed the rounding out of the keyway and back to square. With the engine in place, all I did was removed the radiator and support panel, also bullbar if fitted. Climbed straight through the front of the truck.
I then filed the keyway in the pulley back to parallel.
Next step was to make a custom woodruff key (woodruff is crescent shaped on one side and square on the other, the shape of the installed key.)
Put the whole thing back together with some Loctite, exact variant was recommended by the local bearing shop.
Devcon should do a similar job to Loctite.
All worked great, think I kept the old truck for nearly 5 years after this.
One thing I did notice, there is a tab washer designed to keep the bolt that holds the pulley on from loosening. On mine the washer was broken.
If you work it out, this washer MUST be in place and intact or the bolt will work loose under engine rotation.
The bolt also doubles as a crank start dog, thats the reason it is made like it is. (Under crank start the bolt is tightened, the greater force)

Hope this helps,
Geoff.

Gday Andrew,one of my mates had a similar thing happen on his T/D Cruiser 92.The bolt that holds the harmonic balancer to the crank came loose and slogged the key way out.He got a new key and locked everything together with a filler/loctite but it only lasted 3 months when everything came loose again but bolt was still tight.In the end he bought a new genuine crank,harmonic balancer and all worn bits to fix it once and for all.All up cost was $3000

Thanks guys for the real quick response.

I must admit I am very skeptical of the devcon as a solution, but my friend (a farmer / bush mechanic) reckons he has done this before and made it work.

I was just chatting with him and he reckons I need to fill the gap, file it back to square and then locking it all up will hold it in place.

This is the $200.00 solution... and I've got to admit, this one is much more tempting to at least try in a $4000.00 car.

To haul the motor out and replace the crank is freaking me out a bit.

Any other input would be valued. I'll let you all know what happens, what we try and what works.

I did also consider rnigng an engineering company to see if they could recut a keyway'pulley and key similar to what Geoff suggested.

I'm not sure it'd real easy for them though...

Your replies are very much appreciated!!

Hi Andrew, Mate the devcon idea will not be a long term fix. and making a new cutom key is not either as woodruff keys are hardened, you need to have the crank removed and the keyway welded and recut . The 2 f is a petrol right so this keyway deetermines timing for the harmonic balancer so it must be recut in the same spot . If the crank is cast iron the engineering shop will T.I.G weld up one side with 99% nickel filler or a stainless steel and recut it , if the crank is steel it will be a little easier . I am a fitter and turner by trade and have done similar repairs on earthmoving machinery etc before and have had no dramas . Don't panic about the heat from the welding as the tradesman will know how to do it so the crank will remain cold . This fix requires a little time and effort but will be cheaper than a new crank.

Would you risk it as a long term fix? You would hang yourself if you saved $1000-2000 now, adn then in 12 mths time it shi+itself in the middle of the Simpson...

Fix it right, fix it once.

Another reasnable fix , is to bronz it in place and to file the exess off

Devcon make a product called 'liquid titanium'. We sell about 1 a month to varous mechanics to fix the problem you have. Like most things I spose, done right it's OK.

Andrew,

Had the same problem on a Subaru a few years back, its just bad luck. I am a mechanical fitter by trade and can tell you from experience that Devcon will NOT work in your case.
It won't last, bite the bullet, get another crank (from wreckers)and new big end and mains bearings and fit them. Especially if you want to keep the car. Its not a big job, not as big as you think...

If you want to sell it, and decide on the devcon way, make sure you let the people on this forum know so they can avoid your vehicle.

cheers
mike

Thanks again all who have responded.

It seems the jury is out on whether Devcon will work or not. The answer is clear that it is not a long term fix.

Then again the car is worth only $4000.00

Those who have used it seem to think it will work...

Most mech fitters would seem to consider it a waste of time. I fully understand that. It will not give the original strength.

However given the other expenses incurred on our recent holiday and the age of the car I am thinking I'll give it a shot and see how it goes. Its $200.00 spent for the total repair v $2000.00. It seems like its worth the gamble.

Maybe it'll last 5 minutes maybe 5 years. I originally bought the old beast for just dropping the boat in and out and hitting the local sand dunes. If it does that for the rest of the time I own it I'll be happy.

Thanks again!

There are a few pics up here if you are interested...

We are in process at pres...

link text

After looking at the pics I would be tempted to pack a key in the slot with some devcon to set it in the right spot then try and hit it with a welder.
Keep us posted on how it goes.