vito 108d timing chain snapped! Please help.

anthony evs

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hi all,

the timing chain snapped today on my 1998 vito 108d. Removed the rocker cover and all the chain was located around the tensiner area, and not around the pulleys.

Any advice on how to thread a new chain around the system please.

Had alittle look, was thinking to remove the vaccuum pump to expose the sprocked of the injection pump drive and get it to the sump, somehow got to get it around the crank sprocket then back up to the top to rejoin.

I am praying that there is sufficient clearance between the pistons and the valves....... as its an old design engine..... hoping.....

Any help is greatly appreciated,

many thanks, Anthony.
 

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First I would check that the valves are all good , you can do this with the rocker cover off
 
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anthony evs

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Hi malcolm,

thanks for your contribution.

I have already rotated the cam a frw revolutions and checked that all the cam lobes are pressing on the hydraulic followers ok. All followers are the same height when not in contact with the cam lobe, and all hydraulic tappets press down ok when being pushed by the cam, i am hoping no damage has occured......

Any ideas on the threading of the chain?

Thanks,
 

Number_Cruncher

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>>I am praying that there is sufficient clearance between the pistons and the valves

Sorry - no chance whatsoever. The valves will have hit the pistons, and you will find damage.
 

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>>I am praying that there is sufficient clearance between the pistons and the valves

Sorry - no chance whatsoever. The valves will have hit the pistons, and you will find damage.

Rotating the crankshaft should prove this point
 

Number_Cruncher

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Rotating the crankshaft should prove this point

That depends upon exactly how well the valves have been mashed into the head!, but, the general point is that because of the higher compression ratio, there is never sufficient clearance on diesels when the valve timing is lost.

With a belt driven petrol engine, it might be worth putting a belt on, and seeing if you have good compressions, but, that approach isn't worth trying with a chain driven diesel - if I were the OP, I would be either scrapping the vehicle or looking for a good second hand engine.
 

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That depends upon exactly how well the valves have been mashed into the head!, but, the general point is that because of the higher compression ratio, there is never sufficient clearance on diesels when the valve timing is lost.

With a belt driven petrol engine, it might be worth putting a belt on, and seeing if you have good compressions, but, that approach isn't worth trying with a chain driven diesel - if I were the OP, I would be either scrapping the vehicle or looking for a good second hand engine.


Why did the chain break in the first place ? they are a double block chain and I've never heard of one going .I've used theses engines for years and done truly outstanding mileages without ever having to replace the chain . There isn't even a recomended replacement time in the servicing schedules .
I've recently replaced one of these engines and the gearbox, the original engine being literally worn out @ 620k miles (piston slap, smoking, worn valve guides fuel pump worn out), yet the chain did not need replacing .
 
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anthony evs

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Thanks for the replies gents.

The head gasket was changed 2 weeks ago due to oil smoking. When the head was removed, the gasket between the timing chain compartment and cylinder 1 was eroded way, allowing oil thro into cyl 1. Skimmed the head, put on a new gasket and decoked the head, lapped in the valves.

Engine started and run fine. Day before yesterday, started to rattle, removed the rocker, and noticed the tensioner was alittle weak. Ordered one at the dealer at £65 + vat, not in stock. Had to use the vito yesterday to pick up my disabled child from my parents, and on the way it snapped. Gutted.

I can source duplex chain form a chain manufacturer i used to use just to see if the engine is recoverable, but as the head has just ben off, if i have to, i`ll have to take it off again.

Its the threading of the chain is the problem, cant see how to get it around the crank.

Thanks for you help.

Anthony.
 

Alex Crow

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hello again anthony, sorry to be one of the bearers of bad news but we are just relaying the facts - the valves will be bent - look again at tappet clearence, as i said 1mm will be too much (telling you there is damage). i understand you want to thread a new chain through and for everything to be OK. so do i, but having great experience in these matters (full time MB mechanic for many years) i can confirm that trying to thread the chain is a waste of time. the valves themselves meet the pistons straight on, this being a 'heron' type head, i have known them to punch holes in the pistons on a 601 engine.

even if you did manage the impossible and thread that chain round andget the engine running, you still have not answered why the chain broke!! perhaps when the head was done the chain was split? either way, a broken chain will usually bunch up somewhere and break something - so how ARE you going to replace those broken guide rails without removing the front case?

please don't mistake our negative attitude as anything less than objective. and also note you have advice here from a high level astro engineer, a guy with a fleet of these that has done a zillion miles and myself.

if you want to take this further, tell us what went wrong with the head gasket job, and what rpm you were doing when it went belly up.

sorry again to be another bearer of bad news, but it is what it is.
 

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So the incorrect fitting of the timing chain tensioner cased this to happen, once taken out it should have been returned to its fully closed state. You are not alone and this has happened many times.

The timing cover will have to come off to fit a chain, if it is the 601 engine,,I should hav the details of fitting the timing chain correctly
 

Alex Crow

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i think that actually this tensioner is not the ratcheting type.
 

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Hi, sorry to add to the negative reply's but the guys are right, i have worked on the truck and van side for many years before leaving to go to the car side, im afraid but it needs a full strip down to revive your engine, not sure why its snapped poss somthing to do with the way its been built up the other week, the tensioner is not the ratcheting type and there is no need to reset them, there was a batch years ago where the chains were stretching and even snapping, but these were all recalled and delt with. sorry for confiming what others have said but it needs a full strip down, not a bad job to do, used to love them jobs, good luck and just post if you need any info, some good guys on here.

rob
 
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anthony evs

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Hi all, thanks for all your input.

OK, i did the head job myself, with the help of my garage friend to use his tools and equipment, ie torque wrench, valve spring compressor etc...

I dont think these type of tensioners need resetting, but i am no expert. I am a mechanical engineer(manufacturing) with 4 years mechanical apprenticeship (44 yrs old now so getting on abit) not auto, but can use tools and examne/ inspect equipment.

Sayin that i am not an auto engineer, just using my own experience and knowhow to get me thro, as i would not hsve been able to afford the amount to get it repaired in a auto mechanics workshop.

If i cannot easily thread the chain thro the casing by either dropping the sump etc... then it may be easier to try to locate another engine. Not sure. Whichever the easiest and most cost effective.

As i have only just removed the head, maybe it may as well come off again to fullyh examine the extent of the damage and reassess from that point, but if the chain is an impossible job, then a repalcement engine may be easier to do in the long run.

Again, i will have to try to do it myself, as being on income support caring for my disabled child, funds are not easily made available without someting else being sacrificed.

Any further help is greatly appreciated.

Thanks again, Anthony.
 
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anthony evs

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Small update,

it is a 601 engine, not turbocharged, very little access around the timing chain side, any advice on whats got to be removed, or a work instruction on how to do it would be very useful.

Used to have WIS on my old pc, that was very handy, not sure if it would have shown this in detail though.

Thanks.
 

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Alex the vito uses the 601 942,, the 202 uses the 601 913 and the 124 the 601 902 I wonder what the difference is
 

Alex Crow

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differences are minor, the vito will probably have minor details to suit a transverse application like the mounting for the intermediate o/s drive shaft bearing housing. i believe the 202 used different engine management to the 201, never seen a 124 with the 601 but it would be slow!! i suspect also that the vito has a larger displacement. i myself have driven about 60,000 miles in our vito 108d over the last 8yrs and i adore this van!! what pleases me most is thinking that the engine is bullet proof, and generally they are. then we have the cdi engines, superb power and economy at the expense of poor reliability and high repair costs, not MB's best upgrade...
 

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differences are minor, the vito will probably have minor details to suit a transverse application like the mounting for the intermediate o/s drive shaft bearing housing. i believe the 202 used different engine management to the 201, never seen a 124 with the 601 but it would be slow!! i suspect also that the vito has a larger displacement. i myself have driven about 60,000 miles in our vito 108d over the last 8yrs and i adore this van!! what pleases me most is thinking that the engine is bullet proof, and generally they are. then we have the cdi engines, superb power and economy at the expense of poor reliability and high repair costs, not MB's best upgrade...

But OK for cheap spare parts what I was thinking as you can pick them up really cheap, but then the OP may only need a couple of valves, with luck
 
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