300tdi flogged dampener and crank

horgan · 7th March 2009, 06:56 PM

Hey Guys,

My disco series 1, 97, 300tdi has self-destructed. This time the dampener pulley bolt must have loosened off, and the dampener has flogged itself out and mullered the keyway on the crank

.

Has anyone had experience with patching a keyway on the crank insitu?

We noticed the problem after changing the drive belt - it always had the 1595 until I changed it to a 1575 (and for the first time the tensioner was running within its marks). The extra tension must have been the last straw.

You can see by the photos that the keyway on the crankshaft is burred over.

300tdi flogged dampener and crank-dampener.jpg

300tdi flogged dampener and crank-dampener.jpg

300tdi flogged dampener and crank-crankkey2.jpg

300tdi flogged dampener and crank-crankkey1.jpg

Was thinking about getting a brand new balancer and using some bearing glue to set it on the crank - plus use liquid steel to plug the hole behind the key. There are some pretty good epoxies out there now - I wonder if they are up to this job?

I figure the balancer isn't under a great deal of torque - its just driving the pump, alternator and aircon. It does have a big rubber bit in it anyway - so maybe the bearing glue and liquid steel may do the trick. Anyone had success with this?

Alternatively, I could try to weld the key into the crankshaft insitu - but then there is splatter, and I'll probably stuff the electronics on the car.

I've heard that some people weld the balancer to the crank on the front face - but these welds have been known to crack. Welding onto dissimilar metals plus the shock through the crank is probably too much for the brittle join.

Anyway - that's all speculation. If anyone has any real experience - please let me know.

Yeah, I know that the crank should really be replaced, but the car has done 265,000 - hoping to squeeze another 80,000 out of it before doing a major overhaul. I don't think I have much to loose at this stage.

Any past experiences and advice greatly appreciated.
Cheers

**Blknight.aus** · 7th March 2009, 07:22 PM

you can glue it in place with a loctite bearing mount you can even put it in place and then weld it there.

however you are then in for merry hell when you have to take it off for something else.

Ive done the "remake with hardfacing rod and then machine in situ trick" but its rough and very time consuming to get right and it also requires removing the timing gear (it was off and we had to wait for parts which is why we decided to give it a go the fact that we were in a well decked out maritime marine shop also played a part)

I strongly advocate that you are better off dropping the crank and getting it professionally reworked or replacing.

**roverrescue** · 7th March 2009, 11:23 PM

If you removed the timing cover for access. Maybe you could weld a new woodruff key in the flogged crank. You wouldnt need to put too much heat into it, but either way im sure it will take it. Need a new crank seal though.

Then either pick up a 2nd hand harmonic balancer or just get a new keyway broached into your existing one and bolt her up.

Welding will not harm a 97 disco... disconnect the batt and alternator if you are worried.

Butcher job but should be possible insitu.

Steve

Lucas · 8th March 2009, 12:31 PM

I had a simular occurance with a 200 I dropped the engine and had the crank repaired at out local engine reconditioner and the woodruff slot re machined at an engineering shop, saves buggering around and having it happen again.

I recently did the belt on 300tdi, I asked the mechanic for a woodruff in the timing belt kit and he said they genearlly dont need replacing. For a couple of $ why would you risk it.

**NOFUSS** · 8th March 2009, 02:33 PM

You got a nasty one there
I.ve silversolder keys back in and used metal putty to fill in the hole made by flogged out key. used old pully to smooth of putty, Then used bearring retaining glue loctight with new/second hand harmonic pully to keep slop to a minumin. dont reconmend to weld it on because that will bight back when in the bush touring.
I have a second hand harmonic pully in the shed if you can not find one localy in the big smoke

**sclarke** · 8th March 2009, 05:32 PM

Ahhh yep.... as Puss in boots would say "you are royally #$%#@"

Liquid nails????

Sorry.. my bad....

I would try cutting a new keyway in place on the opposite side and then a new balancer... and then put a new bolt and loctite it and torque it correctly.

**Taz** · 8th March 2009, 06:12 PM

If you do decide to weld her up.. you can always use my MIG with argongas - no splatter.

**Discovery300Tdi** · 8th March 2009, 06:53 PM

i thought when the notches on the tension pulley meet that it is time to change the belt. Well least that what it says im the rave cd

**jimbo110** · 8th March 2009, 07:16 PM

Pull the engine, pull the crank, get the damaged keyway welded up and another cut in the opposite side, new pulley, mains,big ends, front and rear crank seals and do the cam belt while the engine is out, unless it has been done recently.

Remember, every 80,000 km that sucker has to come off to do the cam belt.

horgan · 9th March 2009, 02:56 PM

Big thanks to everyone for their advice. You guys make this forum the best.

Next 80,000 I figure I'll take the engine out and do the lot - just hoping to limp things along until then. Next 80,000 I'd like to recondition another engine block and drop it in (I just did the head). Just don't have the gear, time and $$ to do the overhaul just now.

Yeah, cutting a new keyway would be the way to go - but me thinks I have to drop the engine out for that (correct me if I'm wrong). Will then have to get new seals, regas the aircon, etc - and then fix all my other ****-ups along the way.

NOFUSS - how long has that patch job of yours lasted? It was for the 300TDI balancer pulley? Sounds worth a try for now.

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