Harmonic Balancer problem on LC 80

Submitted: Monday, Jan 16, 2006 at 20:50

ThreadID: 29762 Views:9595 Replies:5 FollowUps:1

This Thread has been Archived

techo2oz

Just returned from a trip to sunny QLD and got stranded about 200 klm's from home. On investigation it turned out to be the harmonic balancer on my 92 model 80 series LC had developed a bad wobble and in fact was no longer on good contact with the crankshaft.

While I hoped it was just a simple matter that the rubber binding had separted (as is common in older holdens and fords), I was dismayed to find that it had stripped the key way on the crankshaft. I now have 2 options, one get the front section rebuilt, or replace the entire crank. (either option is not that cheap)

I have done a few searches and there doesn't appear to be any problems like this discussed previously. Has anyone had a similar problem? If so how did you go about rectifying it? Also for future reference, is there a telltale to indicate this sort of problem is developing so it can be nipped in the bud early instead of letting us down out in the middle of no-where?

Cheers

Peter

Back Expand Un-Read 0 Moderator

Reply By: howesy - Monday, Jan 16, 2006 at 21:10

Monday, Jan 16, 2006 at 21:10

The keyway on the crank is a piece of steel wedged tightly into a groove machined along the crank. This gives you the raised key. Unless you have a chunk missing out of the crank shaft it is more than likely that you only flogged out the key that is wedged into the groove which is not so uncommon and usually caused by the retainer bolt being loose. Remove the balancer (and the timing cover if you have to) and you should be able to get a hammer and suitable drift to knock the key out of the groove in the crank and relace it. I had one that broke out a piece but there was still enough groove left to take the key and balancer. Failing this you can turn up the MIG and line it up and weld it on but not all in one go so as to keep the heat down a little.. Lets face it if it wont take a new key the crank is rooted anyway and the only other things you might need are balancer and seal if it dont work but try the key first welding is a last resort.

AnswerID: 149022

Reply By: Member - Nick (TAS) - Monday, Jan 16, 2006 at 22:11

Monday, Jan 16, 2006 at 22:11

One of my mates 80 Series T/D 92' did the same thing and he had to replace his crank.On the 4wd monthly forum awhile back there was a topic going on this problem and quite alot of guys had this happen.Most seemed to think it happened because of the crank bolt not being torqued/tightened up right.A few tried repairing the crank but endedup having to replace or remove,have built up and machined back.

AnswerID: 149045

Reply By: Billowaggi - Monday, Jan 16, 2006 at 23:03

Monday, Jan 16, 2006 at 23:03

Hi all , check with a good engine/machine shop I think that there is a cone lock set up to repair the crank, it is a two piece double cone that goes inside the harmonic balancer and is locked together onto the crank as you do up the bolt, it is designed to repair a damaged crank nose or flogged out key groove.
Regards Ken.
PS. prob is caused by the balancer retaining bolt being incorrecly tightened.

AnswerID: 149055

Reply By: Member - Hughesy (SA) - Tuesday, Jan 17, 2006 at 05:14

Tuesday, Jan 17, 2006 at 05:14

Hi Peter,

I had mine go on my old rig whilst on a trip thru outback SA (never happens at home - and took me a while to work out what the problem was). Mine was the front pulley that powered the A/C and so I left the belt off and crossed the fingers until I got home. If yours has done the same part there is only 4 bolts holding the pulley/harmonic balancer on and I simply replaced it with a second hand one for $100 and about 20 minutes work. Mine was on a 1HZ. Yours must have done some more damage if its done what your talking about.

AnswerID: 149079

Reply By: techo2oz - Tuesday, Jan 17, 2006 at 06:31

Tuesday, Jan 17, 2006 at 06:31

Thanks for the replies. It would seem this kind of failure is quite common. (as mentioned as well by the toyota repairer who now has the vehicle.

They are to remove the crank and send it to a local repairer who has done (hundreds) of these where he builds them up then machines back.

However had I caught it earlier, it might not have been such a major repair. My problem is, what to look for? (short of pulling things apart on a regular basis.)

Also Now I need to decide do I go the whole hog and get the rings/cylenders and head checked while I have all the bottom half dismantled? it has only done 270,000 but it has the usual problem of the TD series where it blows grey smoke especially under acceleration. (in for a pound, in for a dollar)??

Cheers

Peter

AnswerID: 149080