M103 Timing chain snapped

[gvanhouten]

Wow what a dissapointment. I just got done installing a new headgasket on my 91 e300te wagon. The head was resurfaced and new valve seals where installed and I put back the old timing chain 188,000 miles due to the longevity of the chain. I was sitting in the vehicle and then all of a sudden the car shut off. Timing chain snapped. Tore the head off and noticed the ditributor cap new as well was cracked. So four of the valves are bent and I am not going to spend more money to have the valves replaced on a 188,000 mile motor. SO I AM SHOPPING FOR A NEW MOTOR. THIS S_CKS!!! I used the same tensioner and did not replace any of the guides. ANY INSIGHT WOULD BE HELPFULL>

[Moneypit SEL]

Did you remove the old tensioner and reset it?

[Arthur Dalton]

Well, That is a bad break.. but, as my earlier posting advised.. not such a good idea using parts with that kind of miles on them, even ones considered 'Bullit Proof"

No parts are bullit proof.. they ALL wear out

...a chain pushing 200K has wear, I don't care what motor it came out of.
..and for $50 ?? ...and you had it torn down that far anyway ??

Sorry , but not surprised.

[gvanhouten]

Unfortunatly I did put the tensioner back the original and my original tensioner did not release so I put it back the way it came out. I think the tensioner was to tight and this probably did not help. Any idea on where to finda a used engine from a reputable yard?/

[Arthur Dalton]

Originally Posted by gvanhouten

Unfortunatly I did put the tensioner back the original and my original tensioner did not release so I put it back the way it came out. I think the tensioner was to tight and this probably did not help. Any idea on where to finda a used engine from a reputable yard?/

The tensioner has to be reset . so that is prob more a cause than the old chain/rails, but you will never know..
You prob have seen post here where guys break cams right in half 10 min after doing a new chain cuz they did not reset the tensioner ..

I will ask about an engine and get back to you is I have any leads.

Bad break , but never to be forgotten ..and don't feel alone ....seen it happen even when you have it done at a shop.
Et al..
A good thing to ask when anyone is having this kind of work done is to ask the guy doing it explain to you how those chain tensioner work... it he doesn't mention the Ratchet design , question him on it or print out one of these sad post to bring with you.

I am very sorry this happened, but this is why I have been repeatedly telling people to remove the tensioner, push the plunger through and then restart the plunger. Maybe my instructions weren't very clear.

I don't know if I said this in your thread or if you even had a thread, but this has been discussed repeatedly for the last five years that I've been on this forum.

Please read thoroughly. It is sort of like carpenters rule except instead of measure twice, cut once, it is read twice, do once.

I hope others learn from your misery. I have had similar misery before and posted here in an effort to help others.

Doing a job like this without a manual is false economy. Having a manual and not reading it is I don't know what.

Again, I'm sorry for your misery.

BTW, it would be much less trouble to pull the head again, replace the bent valves and whatever else it needs and put it back together, than it would be to find another engine. If the oil has been changed even a little bit, the bottom end of that engine should be barely broken in. What did the cylinder walls look like when the head was off? At 176,000 miles I still had crosshatch on my 103 cylinder walls.

I personally would fix that motor LONG before I would put a used engine in that I had no history on.

BTW, don't consider this the fault of the chain. Had the tensioner plunger been restarted and all guides inspected the chain would have gone forever.

Good luck,