Hi James,
I really shouldn't be doing this,however,there is some thing you could do if you're game to give it a whirl.
A new crankshaft would be the answer and if you want to do that send it up here to Brizzy,and i'll do it for you. (Through my business of course.)
Getting back to the point,what I am going to describe for you is something I would do to one of my own vans,to,as you say extract a few more K's until it stopped completely. It is not a permanent fix,however,it's as close as you will get in the predicament that you find yourself in.
You need to remove the cambelt and anything that stops you getting at the crankshaft gear. Then you need to remove the washer in front of the gear. First hurdle- some crankgears have holes in their outer face to attach a puller to remove the crankgear from the motor and some don't. Some gears have a hole with no thread. You need two holes with thread to attach a harmonic balancer puller to, or you can drill a row of holes along any one tooth and simply break the gear with a cold chisel(don't drill into the crank, it's already weak enough.) You can purchase a puller from any Repco store for 30-70 dollars.(The gear has to be removed to get to the key- it's a long one). Using a very small file you need to remove the burr in front of the gear to facilitate its removal and refitting,If you damage the gear or even have to destroy the gear getting it off,replace it(new or good secondhand.)
Now you should have access to the key. I am hoping that once the gear is off you will still have a piece of key sitting proud of the crank (sticking up).If so you get hold of that protruding piece with sidecutters or pincers and pry the key up out of the crank. If there is no protruding piece of key it will be necessary to drill down into the key, approx 6mm from one end, a hole big enough to take a reasonable self tapper into the key without touching the crank on the sides or the bottom. Use that self tapper to hold onto to pry the key out.
Once the key is out you will need to find some emery tape(fine grade)and polish the crank(where it's not damaged) back to new condition(shiney). Where the crank is damaged do not worry too much,as long as there is no sharp burrs to hinder refitment of the new pulley. Clean the area with a solvent like carby cleaner which will remove all traces of oil and air dry by itself.
Next, if the crank is ok under the crankgear, you will now need the replacement parts, this is up to you but if it was mine,I would be aiming at not having to look in there again for 100,000k so I would be obtaining & replacing the following parts:- Timing belt kit(new),crankgear(if damaged)(new or good secondhand),crankshaft key(new or good secondhand NO SIGNS OF BEING LOOSE),Crankshaft pulley, bolt & washer (new or good secondhand NO SIGNS OF BEING LOOSE)(rust around the bolt or where fits is an indicator.) Water Pump and coolant, unless you replaced it in the last 10,000k's.
Last but not least you need a tube of either Loctite liquid metal or Loctite bearing fit. Check the specs on the tubes or pamphlets and see which product fills the largest gap and use that one.(I think the bearing fit will fill up to .003"wear)(Liquid metal would be the harder compound of the two.)
WARNING, DO NOT USE THE BOLT OUT OF YOUR MOTOR!!!
Time now to reassemble, remove the old water pump and fit the new one. In the new cambelt kit you will find,(hopefully), two seals. These are for the crankshaft and the camshaft, again, up to you, but fitting them now could save you some grief later. Fit the new crank key by centralizing it in the hole it has to into and tap it into place with a small ball pane hammer(flat side of the hammer not the ball pane side).When the key is in place make sure it looks level along the crank,not too high or too low at the front or rear.(I hope you have cleaned these parts)Do NOT use any oil or sealants on the key.
Fit the new cambelt tensioner,locking it back(off)until later, idler gear, crank gear and timing belt whilst aligning all the timing marks. Release the tensioner and set the belt tension and retighten the tensioner.(Setting cambelt tension-This is achieved by placing the cambelt on its gears with all timing marks aligned and releasing the cambelt tensioner bolt(leave it released)and fit the crankshaft pulley bolt into the crankshaft and screwing it all the way in until it locks,turn the motor over (2) revolutions until the timing marks are almost realinged again and stop just before top dead centre.While the belt is still tight on both sides of the motor, tighten the camshaft tensioner bolt - correct tension has now been achieved. Recheck your timing marks, if not aligned, do it all over again until you get it right. Now refit all the plastic covers and don't forget the washer that goes on the crank after the cambelt?Whoops -- good thing it fits through that plastic cover!!eh.
Now, you have to remove the crankbolt again, if you haven't already.Next is the trick, place the damaged section of the crank to the bottom(before you do make sure there is no dirt or grease on the nose of the crank or this will all be for nothing.Same goes for the inside of the replacement pulley you are about to use.CLEAN AND DRY<RIGHT!!Most important.) With aclean finger wipe the liquid metal into the damaged area and around the nose of the crank. Apply enough above the damaged area that it has a tendency to run down toward the damage.Apply the same inside the pulley a little heavily so it also tends to run to the bottom as you quickly assemble the pulley onto the crank and tighten the bolt into the crank as quickly and as tight as you can.(within reason,don't break it off.)
I think I can leave you here because you already have it apart and should know your way from here.
One other thing-- if you put it all together in less than a day do not start it untill the next day-- give that compound a good length of time to harden.
Cheers,
Greg Page.
