broken keyway

[bad88u]

hi all

my old man has a mitsubishi pajero 3.5L petrol. i have taken it apart and the harmonic balancer keyway is broken. all people i have spoken to said the motor is stuffed and cant be fixed. is this true? can it be fixed? also been told its a common problem

[planetdavo]

Might be worth a read of this bad88u.
http://www2.pajeroclub.com.au/forum/showthread.php?t=3480

[Tre-Cool]

drill another keyway?

just make up a kit similar to what capa does the ls1 crank.

[LS1-5.7]

Most will tell you at least a new crankshaft is required but there are some engineering shops that will refill the keyway with weld and just remachine it.
You can put a new keyway anywhere you like on the crankshaft as long as you adjust the pulley to maintain TDC where it should be in relation to the engine and the timing marks. In any event it will be crankshaft out to say the least :(

[mjrandom]

Generally the crankshaft tail will also be damaged so it is not as simple as cutting a new key in a different location in the crank and pulley. A mate of mine had this same problem on his Pajero several years ago and ended up winning the 'extended' warranty battle with Mr Bishi on the basis that the pulley retaining bolt wasn't tightened sufficiently to prevent relative movement between the harmonic balancer and the crankshaft. This is the whole reason why torques are specified on bolts. You need to make sure that during operation there is no chance for the joint to become unloaded and fret or allow movement.

His may have been a special case though as there was warranty work done on the harmonic balancer during the warranty period. I know at the time I did some research for him and the problem is fairly widespread. Having said all that I would think a new crankshaft and harmonic balancer and key would be the minimum bits you would need along with bearings and seals but you could chance having a shop build up (spray weld) the crank and cut a new keyway and machine the taper again but there is a lot of stress there so be careful.

Michael

[maginoodle]

i have had this happen in the past. what i did was drill and tap the harmonic balencer in four spots equal around the balencer. i then drilled dimples into the crank to match those holes and i used grub screws to hold the balencer in place.
this was on one of my old small cars(think charade but am not sure). it didnt have a lot of power so it never stuffed up while i had it.
this will work if you are able to get access to a suitable spot on the balencer. i wouldnt recommend this on a powerful car but i wouldnt that a pajero would have enough power to break the grub screws.

[blnls1]

I have had this happen before on a customers Mitsubishi challanger (same engine). I asume that the groove for the keyway in the crankshaft itself has been made wider and the key itself damaged? The customer wanted the absolute cheapest fix. We sat the key in the keyway and filled around it with "liquid metal" and did the balancer bolt up REAL FT with locktight. Left it to set overnight and told him no guarantee that it would even work or last very long. He drove that car for 6 months before trading it in.

I wouldn't recommend it if you want to keep the car, and it may not even be an option depending on how bad the damage is. But if you just want to patch and trade in?????? I just feel sorry for the poor basterd that gets it next.