[vishwaschettri]

My ever trusty 550 suddenly broke down by the side of the road. There was a poof! sound and it died. I could immediately tell something big is wrong.

Didnot try to crank again and coasted to the side of the road. On popping the hood found timing case cover broken and oil spilled all over the engine bay. The lower pulley had jammed against the case




Towed it with a friends help to a trusted mechanic. On opening the case we found that timing chain has broken and it has broken/sheared everything inside the case including the case it self.

I don't know the nomenclature of the most of the stuff inside and it was dark to click pics with my phone cam.

I have found these pics on TBHP itself and marked what all is broken (which is a lot). I think the head of camshaft (marked) is broken as well




I am heart broken. Not because of the expense in pipeline but the fact that my jeep broke down for the first time and had to be towed.
I had done complete mechanical restoration from a mahindra authorised workshop in 2009 and everything and everything's uncle were replaced. Timing chain, tensioner, pulleys everything were put in brand new other than new liners, pistons, guides, valves, oil pump, fly wheel, clutch and what not.

After the rebuild it has run flawlessly for 25,000 kms which include numerous OTR and a trip to spiti.

What is done is done but I want to know what could have been done to prevent this disaster. AFAIK timing chains are designed for the life of engine and should not fail before 1.5~2 lakh kms.

Anything that I might have done to reduce its life?

My poor jeep waiting for my friend to come and tow us.



cheers
vishwas

[vishwaschettri]

My Jeep with its heart wrenched out.


Engine was dismounted for better access and ease of work. Below is the BoM for the repairs. Need input from gurus

1. Timing chain - new
2. All Pulleys - new
3. Tensioner - new
4. Timing case - Old one from Mayapuri
5. Cam shaft - Old one from Mayapuri if we can find a good one from a sealed engine
6. Engine mounts - New
7. Fan belt

I am not in favour of old cam shaft but my mechanic says new one will be very expensive.

Please advice.

cheers
Vishwas

@ Mods - May be we can move this thread to 4X4-technical to attract more relevant eyeballs?

[Jaggu]

Really sorry to see this, did the engine seize by any chance? which then resulted in timing chain failure? Very odd to see a chain failure, unless it was really a very old one (not changed last time) or a spurious part. Maybe one of the pulley's gave away and resulted in other damages.

Its very difficult to diagnose what all needs replacements without actually taking a look at it. Dismantle and ask mechanic to do a complete check and then rebuild. Hope the damage is limited and do keep us posted on the rebuild.

[humyum]

All 4 stroke diesel engines are interference engines because of the high compression ratio. How badly are the valves damaged ? what about the pistons ?

[vishwaschettri]

@ Samurai - Thanks for moving in 4x4 section. Finally some traction.

Originally Posted by Jaggu

Really sorry to see this, did the engine seize by any chance? which then resulted in timing chain failure? Very odd to see a chain failure, unless it was really a very old one (not changed last time) or a spurious part. Maybe one of the pulley's gave away and resulted in other damages.

Its very difficult to diagnose what all needs replacements without actually taking a look at it. Dismantle and ask mechanic to do a complete check and then rebuild. Hope the damage is limited and do keep us posted on the rebuild.

@ Jaggu - I think, rather hope that XD3P is old school with low compression and thus non interference. So hopefully no damage on the engine side other than cam. The chain has stripped the cam head towards timing case.
I am also surprised at timing chain failure so early (25K kms). I am positive it was changed last time and was original (work was done in a mahinda authorized workshop and owner is very reliable). All pulleys were changed as well. I know for sure because I took the old parts back. Trying to relocate the bill. I have listed the damage in previous posts.

Originally Posted by humyum

All 4 stroke diesel engines are interference engines because of the high compression ratio. How badly are the valves damaged ? what about the pistons ?

I hope this is a non interference engine. Top side looks OK. Will only know the full picture when I fire the engine again.

Can some one confirm whether XD3P is interference or non interference

If there are chances of damage on engine side I wont be able to sleep tonight!. The engine had barely started to open up at 25K kms and had beautiful power delivery.

cheers
Vishwas

[Sutripta]

Originally Posted by vishwaschettri

I am not in favour of old cam shaft but my mechanic says new one will be very expensive.

Measure it. Check for scuff marks on the lobes. If OK, should not be a problem. Do check out OE prices though.

Originally Posted by Jaggu

Really sorry to see this, did the engine seize by any chance? which then resulted in timing chain failure?

Engine seizure should not cause timing chain failure.

Originally Posted by humyum

All 4 stroke diesel engines are interference engines because of the high compression ratio. How badly are the valves damaged ? what about the pistons ?

Agree. The head should be taken off for assessment.

Regards
Sutripta

[vishwaschettri]

Update

Pics of inside of timing case. Today we will hunt for parts.

Old timing case cover and cam shaft if we can find a good sealed engine in Mayapuri and get it removed in front of us. Still clueless about cost of new.

Rest will be bought new.

Busted timing case


Outside view of timing case


Cam shaft


Stripped head of camshaft


Catastrophe inside the timing case



Valves look fine from top. Mechanic also says they look OK. I am thinking of not opening the head and see the movement by rotating the pulley by hand after installation of cam.

cheers
Vishwas

[Jaggu]

Originally Posted by Sutripta

Engine seizure should not cause timing

I agree, I meant something else (not the piston) seized up resulting in load on chain from moving bits and it broke? Just guessing, and now seeing the pic of crank end and cover does seems like something really messed up leading to chain failure? Something inside the timing cover?

Edit: was it that pulley wheel that started it?

[Sutripta]

^^^
I too am puzzled about the root cause.

Regards
Sutripta

[Timson]

@vishwaschettri

It would be advisable to dismantle the entire engine clean it and reassemble. At least inspect the condition of values, piston crown and check for traces of metal fragments in the sump.
The failure could be due to various reasons, I have seen some mechanics setting up the timing chain tension very high.

[vishwaschettri]

Originally Posted by Jaggu

Edit: was it that pulley wheel that started it?

I don't think so, though one cannot establish it either way with certainty.

On closer inspection of timing case I found scuff marks of chain on the inner top side. This side also has a plastic/teflon slider to protect metal as per my mechanic. That too has been stripped completely.

I have highlighted the area with red where scuff marks are there.

I am inclined to infer that timing chain was not replaced with the engine rebuilt. Thus it got elongated beyond tolerance and was slapping against the inside of the cover. Hence the catastrophic failure.

Time to dig out the old bills and see whether I was charged for it or not.

cheers
Vishwas

[DirtyDan]

Chains break with age for sure. Contributing factors might be badly set tension making the chain too tight or too loose. Either will make a chain wear faster. Just speculating here. Scuff marks are coming from chain?

[svsantosh]

Would you be inclined to go the DiTurbo way? Anyways you are looking at nearly a full 50k xd3p rebuild, might as well look at bigger or later engines?

[ex670c]

Hi Vishwas,

Sorry I couldn't reply earlier.

The please pick up the part yourself and be there when the installation is being done.

The Brand New camshaft cost 4-5K.

Is there any chance the Lower Pulley hit the differential while off-roading?

Also could be a case of improper assembly.

My Guess is one of the Gears inside the Timing Case Broke, stripping the Timing Chain and breaking other gear in the process.

Or the Chain Tensioner broke, binding everything inside and stripping the Timing Chain.

Any pictures of the timing case and internal parts before they were removed.

Regards,

Arka

[motocamp]

It will make sense to remove the head and have a look at your valves, guides and tops of your pistons, the chain snapping could have been a caused by incorrect valve timingto start with.

In any case even if the valve timing was correct to start with and the chain snapped due to some other cause the valves in some of the cylinders could have made contact with the pistons and would surely be bent as this is an interference engine.

Also check the pushrods, you might find a few bent ones too.

Make sure your mechanic disassembles the head while you are at it, it will be well worth it in the long run.

Ensure valve timing is done in respect to cylinder 1 ( the closest to the radiator) at TDC and all the marks align.

Shortcuts now and repent at leisure