HELP!!!!!!!!! tonight i noticed that my crankcase seal had a slight leak so since i had a new seal i decided to replace it. while doing this for some unknown reason i put a wrench on the bolt at the end of the camshaft gear now i didnt put very much force on it so what happens next came as a surprise. put everything back together and started her up in the garage she ran for 30-45 seconds then CRACK!!! tried to start her a couple of more times and nothing. so i removed the crankcase againd and found the first section of the camshaft broke in two a very clean break.. the timming chain was also broken. so my question is now what? is it ruined? should i just buy a new chain and camshaft? and what is involved in doing this?? what else could have broken in the process? i am at a loss and in dire need of some good advise..thanks in advance for your help...

Doesn`t sound good. The engine was idling when this happened?

The engine is an interference engine. meaning, when the timing chain breaks, then the valves are out of time with the rest of the engine.

So when a piston is coming up, a valve might be in the open position, the the two connect real hard, this bends valves, cracks the head ( but not always) and breaks the cam shaft and snaps off the cam towers/bearings.

If you were only idling the engine, then maybe not too much damage. will need a cam shaft, chain, tentioner and rails. probably have to pull the head to check for bent valves etc...


I went through this 2 yrs ago, but was doing 65mph at the time, bent every valve and cracked the head, broke 2 cam towers, and bent the heck out of the last rocker arm. also broke the valve cover.

At least you are home, I was 500 miles from home.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Your description of what you did is not precise.

1. Did you replace the front crank seal?

2. When you put a wrench on your big 27 mm front bolt which way did you turn the crank?

3. It seems like you did not actually remove the crankcase (which I am pretty sure is impossible), so what was it that you actually removed?

If you can please answer these questions accurately perhaps we can help figure out what happened (other than something caused your cam chain to break).

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Tom I bet he ment the Valve cover.

Turning the bolt on the end of the cam shaft gear is a No No. turning it to
the left could have caused slack on the chain and problems with the chain
tentioner. maybe it could have jumped a tooth?

Should always turn the eng to the right standing in front of the car, (and
facing the car of course ). Using the crank shaft bolt.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Yes, I'm thinking by 'crankcase' the OP meant valve cover. This may be an example of turning the engine backwards and the problems it can cause.
Why did you have a wrench on the camshaft bolt? Which way did you turn it and how far?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

yes sorry i meant valve cover, sorry, i turned the camshaft gear to the right and it was only a little bit maybe a degree only..dont ask me why i did it because i have no idea, just one of those things. now i dont know what to do. should i just buy a new camshaft and chain? how much work is this and if i am going to do this is there anything else i should be changing out? i really appreciate all of the help you guys are giving.. i feel like an idiot.

If your camshaft broke, I would strongly suggest replacing all the camshaft towers as well.

On an '85 creating slack in the chain should not be an issue if everything is in proper working order. The fact that it started well and ran fine for almost minute tells us that you most likely did not skip a tooth somewhere.

The broken timing chain - which is shocking - and camshaft suggest interference as Charmalu mentioned.

Try retracing your steps clearly and answer Kerry's question

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we can speculate forever on what happened. Its almost irrelevant now.

I would definitely drop the lower oil pan and remove debris and inspect all the gears I could see (on the crankshaft mostly) after removing the chain.

If it was me, I seriously consider pulling the head to inspect the pistons and valve train. This will also allow you to inspect all the moving parts in the timing cavity without removing the engine and tearing it down.


Replace:

chain
camshaft
camshaft towers

Depending on what you find from other visual inspections, replace other items as necessary. If you have the money, have a shop inspect the head.

You are probably better off getting an entire used head from a junkyard and eliminating any guesswork as long as your pistons are in good shape.

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another thing i just noticed is that the chain guide rail looks like it had already been broken, there is a chunk missing from the top portion of it. apears to have been like that for awhile cant find any traces of the debris anywhere. could that have caused some of the problem?

which guide rail?

the tensioning rail? or the guide rail on the driver's side of the engine?

either way, if any large, solid object obstructs the chain from mating with the teeth on any sprocket it could break the chain and the pistons interfere with the valves.

don't forget that when that chain broke, for whatever reason, it whipped at a pretty high velocity bouncing off everything in its path.

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yes the tensioning rail.

Why is this such and issue, wouldnt it just seat the cam tighter on the tapered fit? What is the proper torque spec for the cam gear?

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Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

after further inspection tonight i found that the camshaft sprocket was missing a couple of teeth. also of note one of the rocker arms was bent, does this mean there is valve damage? do i need to remove the engine to gain access to the tension rail that is definatley damaged, still think this was already broken before all this happened. and does anybody know what size the 12 point socket head bolts are that hold the camshaft i am thinking 12mm? once again thanks for your help and advice. i am going to try and get a used camshaft tomorrow at the pick a part, any thoughts?

Look up the DIY on removing the Timing Chain Tensioner Rail (I believe you need to remove the Crankshaft Dampner to use the tool to pull out the retaining pin). See pics.

If you find out it e repairable I would get a used Camshaft and Camshaft Bearing Towers. Camshaft Gear if not costing too much; new.

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84 300D, 82 Volvo 244Gl Diesel

When this happened to me I had the head pulled to check for damage on the pistons and valves. I don't think there was any though. I guess it wouldn't hurt to assemble it with a new cam etc. and try it out. Disassembling the motor is a lot of work (removing the head I mean).

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.