Thread: 300 TDi crank gear wear

the injection timing would be late as would the valve timing so youd be down on compression and power even before you had to deal with the late injection. Starting, as you've already found would be a right snot of a job.

my guess is it'd easily be costing you 25% of your overall available power assuming you could get it to run reliably and it would only be a matter of time untill the pistons give the valves a touch up if they havent already and crushed the valve cap.


Ive seen some minor flogging of the timing gear before but thats the worst I've seen on a still running engine.

That's really worn, if the crank is ok just fit a new key and gear. Balancer and bolt should be loctited on.
I normally get the bolt out with a breaker bar resting on the chassis, take the wire of the injector pump so it won't start and give it a couple of hitts on the starter, bolt will loosen straight up.

The wear groove looks almost machined!
The gear looks to be an early 300 gear (no belt lip) so probably 1994 original.
The belt appears well lubricated! but no noticeable wear so the belt musnt be wandering to far.

Timing would be out by almost a whole tooth - Im surprised it ran at all!

Id stump up for a modified gear with cast lip (not the pressed tin and spot welded lip).
New cam and crank seals to stop that leak.
And I diagree with 'Balancer and bolt should be loctited on'
Tighten it to specs (bloody tight plus half a turn!!!!) with clean bolt and threads and chemical locking is uncessary - and just a pain at undoing time.

Great pics btw

S

Originally Posted by savage

I recently bought a 94 disco 300TDi which took about 2min of aerostart then high revs on diesel, when off the throttle the engine would run very rough on idle then stall as it could not be revved up with out aerostart.

So i pulled the girl apart and first main thing i noticed was the slop in the harmonic balancer, caused by a loose crankshaft bolt, which was very difficult to get off (a big rattle gun here works well)

Once the cover is off i noticed a lot of slop in the crankshaft gear driving the timing belt. OK this cant be right. this gear is very difficult to get off, for anyone trying make sure the key lines up with the key for the harmonic balancer, and make up a tool to pull using the 3 holes in the gear, mine were 5mm metric thread.

The wear in the gear is considerable i will post some pics to show. this threw the timing to the point where the exhaust valves where touching the piston but no damage yet.

Can anyone comment on how much this would through the timing and influence the running of the motor?

This is without doubt the cause of your engine problems.

Unfortunately that crank is past it. The balancer keyway is dead obvious as it is wider at the top and tapered towards the bottom as the key was rolling side to side.
The nose of the crank will also be tapered as the balancer would be flogging around.

IF you were to reassemble it, it will last until it comes loose again, which isn't going to be long.

Start saving

JC

Originally Posted by roverrescue

The wear groove looks almost machined!
Id stump up for a modified gear with cast lip (not the pressed tin and spot welded lip).
New cam and crank seals to stop that leak.
And I diagree with 'Balancer and bolt should be loctited on'
Tighten it to specs (bloody tight plus half a turn!!!!) with clean bolt and threads and chemical locking is uncessary - and just a pain at undoing time.

Great pics btw

S

I always Loctite them, It stops the balancer moving at all. I've had them with the crank keyway worn as a result of the movement. Loctite in the key way,etc. Crank bolt is no drama to get out regarless, if it has Loctite on it or not. 2-3 hits on the starter to crack them is all it takes.

Three letter solution then JC...
MIG

Steve

If the crank is flogged, you could try Loctite super retaining compound on the shaft, We used to use this on drag bike to stop the pressed on gear on the crank that drive the gearbox from spinning off, worked great. Other wise it's new crank or get that one recliamed. I think we used 638, it wont come move with this. normally you would put 243 in side the balancer, did one on Saturday, new belt and injection pump.

http://au.iloctite.com/en/loctite-64...8-retaining/17