T1N timing chain replacement

[skyeg3]

Has anyone ever heard of a timing chain breaking on the T1N? My uncle has a NCV3 and his timing chain just broke. And because that engine is an interference engine ( the valves come in contact with the top of the Pistons if the timing chain breaks) it destroyed his engine and he had to buy a new one... For $17,000. ouch.

Does anyone know if the t1n has an 'interference' engine? Is replacing the timing chain something that would be smart, or overkill?

 

[photogravity]

While I do not know for sure, I think that most diesel engines are of the design you mention. Diesel engines run at much higher compression rates than gasoline engines and it seems that dictates the cylinder and head design which causes interference between the two in the case of a catastrophic failure of the timing chain.

I am a fan of gear to gear setups, foillowed by chains and then belts. The old pushrod Volvo engines (B18, B20, B30 and probably others) had gear to gear drives between the crank and camshaft.

If I'm way off here about diesel engine design, someone correct me please.

 

[EZoilburner]

I remember reading a post by Doktor Andy saying the chain on the t1n's should last for the life of the vehicle, or was it the engine. No need to put a new one in I believe, so many other things can go wrong before that, vibration damper and key, egr, injectors, black death, broken glow plugs come first to mind to name a few.

 

[lindenengineering]

I remember reading a post by Doktor Andy saying the chain on the t1n's should last for the life of the vehicle, or was it the engine. No need to put a new one in I believe, so many other things can go wrong before that, vibration damper and key, egr, injectors, black death, broken glow plugs come first to mind to name a few.

Basically he is right!
That stated if the engine has suffered a failure where pistons have whacked valves then it should be replaced since it will have suffered some due shock/stress treatment due to the chain bending the valves; since it is connected to the crankshaft and the camshafts.

The clearance on most diesels are minimal hence they are almost always interference designs.
The Sprinter like many other engines uses a version of the toroidal cavity piston and cut out pockets are provided in the piston crown to accommodate the valve heads as they sit proud of the head face.
Here is a view of Sealed Power's Sprinter piston ans you can see the valve cutaways quite clearly.

If you are interested in piston design over the years, here is a good symposium on the subject

http://www.gruppofrattura.it/pdf/ext/MS&T/Vol.5 No1/The piston.pdf
Good bedtime reading
Dennis

 

[jackbombay]

I don't know of any diesel engine that isn't an interference engine.

 

[hkpierce]

I remember reading a post by Doktor Andy saying the chain on the t1n's should last for the life of the vehicle, or was it the engine. No need to put a new one in I believe, so many other things can go wrong before that, vibration damper and key, egr, injectors, black death, broken glow plugs come first to mind to name a few.

Source: https://sprinter-source.com/forums/showthread.php?p=222923&highlight=timing+chain#post222923

 

[Boater]

I don't know if it applies to the NCV3 but I have heard of diesel cars where timing chain failure has been linked to how the tensioner works. For some reason the timing chain tensioner has oil pumped through it on these cars, and failure was traced to a blockage in the oil supply starving it of oil and causing it to seize.
I know my T1N engine does not have oil actively pumped into the tensioner, and the same appears true for the OM611 engine used in non-NAFTA T1Ns, so I'd say if your tensioner is just pre-loaded with oil and does not rely on a pumped supply, you can probably ignore any rumours of failures on other engines, the caveat being that I don't know whether the NCV3 tensioner is passive or pumped. Almost certainly this sort of thing will be specific to an engine series and I haven't read about a failure in T1N yet so wouldn't worry about it.

 

[icarus]

I don't know of any diesel engine that isn't an interference engine.

Not to pick nits, but lots of older stationary diesels with compression release levers are non interference engines.

Icarus

 

[jackbombay]

Not to pick nits, but lots of older stationary diesels with compression release levers are non interference engines.

Icarus

Interesting, I was thinking through the various automotive diesels I have knowledge of. A friend used to have an old bulldozer, it started on gasoline and ran till it was warmed up and then you switched it to diesel with a raise in the compression, I never got to check it out before he moved away though...

 

[skyeg3]

It makes sense that diesels are interference engines with the compression and all. Thanks everybody..

 

[ManWithDog]

oh God could you imagine buying a sprinter, having the chain break then having to spend another 17k? I would probably quit everything, leave everything and move to some island and eat fish for the rest of my life if that happened to me.

I'm looking at a t1n tomorrow with 220k miles. it is 1/3 of the price of your friends engine and that is a ton of money for me. If I buy it and it's a good van I'll be taking it fishing in south florida!!

I always thought the t1n was gear driven for some reason. Now I know there is a timing chain does anyone know how often they should be changed or are they nothing to worry about as mentioned above?

Merry Christmas!!

 

[Lotus54]

I have not seen the timing chain system on the T1N-'and I have not even looked at the Manuals to see how it is setup.

I did just do the chains on my 2000 VR6 Eurovan.
The problem on it was not really the chains, but the tensioners. Three of them were broken- the chain was starting to wear against the case. The hydraulic tensioner appeared just fine.
Poor design for extended longevity I think. It wouldn't be so bad, but it is a pain to R and R the transaxle to get to them.

 

[lindenengineering]

Well I have just fixed one!
The timing half gear spokes sheered on the exhaust camshaft.
Really buggered it up!

The pistons clashed with the valves, bent all of 'em and busted five valve guides in the process of coming undone. The exhaust camshaft sheered off at the 1st lobe, and all that collision activity before it stopped reduced the valve train it to junk; tearing up the cam lifters in the process.

I took the engine down and checked the pistons for damage, rods for bend and twist but found nothing so I rebuilt it using some new guide rails, chains,and recovered the head by installing some new guides and a set of good used valves reworking the head. Then installed a complete used valve train from another used engine that had been severely overheated.

With all that stated the timing chain set up on these is traditional Mercedes and very reliable and this is the first time I have seen one really come apart in decades of working on MB engines.
Really if you were contemplating buying one this would be my last area of worry.
Dennis
Mechanic

 

[ManWithDog]

Well I have just fixed one!
The timing half gear spokes sheered on the exhaust camshaft.
Really buggered it up!

The pistons clashed with the valves, bent all of 'em and busted five valve guides in the process of coming undone. The exhaust camshaft sheered off at the 1st lobe, and all that collision activity before it stopped reduced the valve train it to junk; tearing up the cam lifters in the process.

I took the engine down and checked the pistons for damage, rods for bend and twist but found nothing so I rebuilt it using some new guide rails, chains,and recovered the head by installing some new guides and a set of good used valves reworking the head. Then installed a complete used valve train from another used engine that had been severely overheated.

With all that stated the timing chain set up on these is traditional Mercedes and very reliable and this is the first time I have seen one really come apart in decades of working on MB engines.
Really if you were contemplating buying one this would be my last area of worry.
Dennis
Mechanic

Dennis i'm moving to Denver soon maybe I'll meet you. I am wondering what you charged to do all of that?

 

[lindenengineering]

Dennis i'm moving to Denver soon maybe I'll meet you. I am wondering what you charged to do all of that?

That job was $6000 incl tax.
Dennis

 

[owner]

What was the actual engine in the OP? Was it the v6 or om651?

 

[lindenengineering]

Well in my posted case it was an OM647.
Dennis

 

[wlauberds]

I have a 2006 Sprinter 2500 and the van died while driving down the hwy on the 4th. Had it towed to the closest trusted Sprinter repair location (luckily in Portland, OR, so there are a few to choose from).

Got a call from the shop today that the timing chain snapped and that the engine needs to be replaced. 8k for new engine and 3k for the install.

Van has 125k on it and has been babied, so this comes as a huge shock. Aside from replacing some hoses and other standard stuff, van has been a great runner. All fluids, filters, etc, replaced to a T.

Question for you all, any idea on what questions I should ask to see about rebuilding over replacement? At the cost I was quoted, putting in a new engine is likely out of the question.

Any advice on what route would be advised and what questions to ask the shop would be very greatly appreciated. Super bummed to have them happen. Van has been fantastic otherwise with lots of great trip my family has shared in it.

 

[lindenengineering]

Well I did one similar recently at around $5000 but adding a lot of stuff that needed replacement other than just the engine repair , like water pump, accessory belt, tensioner etc that added another $1000 to the bill.
Still not a cheap job but better than 11 Grand.
Dennis

 

[Patrick of M]

So why are the t-chains failing? Are the tensioner loosing it thus causing chain failure. My money is always on the tensioner in t-belt failure, but with t-chains...?