timing chain replacement-jammed?! - PeachParts Mercedes-Benz Forum

laidbback · #1 02-24-2010, 03:59 PM

Ok so my experience with the timing chain was very similar to this post http://www.peachparts.com/shopforum/showthread.php?t=150337&highlight=timing+chain+jammed

I can not turn the engine over by hand at all. It feels jammed. A few people said it could be the piston hitting the valves. If that is the case, they say to remove the rocker arms. How can I remove the rocker arms when they are depressing the valves. Normal procedure is to rotate the camshaft so that the cam is facing away from the rocker arm, then remove that one and go to the next one. I can't rotate the camshaft without taking the chain off of it.

Should I mark the camshaft and chain and take the chain off and rotate and take all the rocker arms and hopefully be back where I started so I can put the chain back up where it lines up. Would this cause any problems.

A little info: I avoided removing the glow plugs and injectors and I built up too much compression and I couldn't rotate the engine any more. I asked a diesel mechanic and he said to remove the glow plugs. After I did that i was able to move the camshaft sprocket about one turn and then it was stuck. After that my supersmart helper dropped the chain down in. I was able to fish it out and it lined up on the camshaft sprocket where it was supposed to be so I figured I was ok. Also I decided to drop the oil pan so I could get a look from underneath. The chain appeared to be on the bottom sprocket as it should.

Now I am stuck, so i want to try to remove the rocker arms and see if I can reel in the new chain with no interference with valve/pistons.

babymog · #2 02-24-2010, 04:04 PM

Model and year are helpful, we'll assume it's a Mercedes.

laidbback · #3 02-24-2010, 04:06 PM

Also,

If I take the old chain off the sprocket,(the end exiting on the pass side)

I can rotate the camshaft bolt with little resistance but the old chain doesn't want to come out of the pass side. I only did this slightly because I didn't want to throw off the timing.

What could the old chain be hung up on.

Again, tensioner is out and the pass side slide rail is as far left as possible.

From the bottom it looks like it is on the bottom sprocket.

Where is another possible spot it could jam.

laidbback · #4 02-24-2010, 04:07 PM

sorry 1984 300cd turbo with 300k

Alastair · #5 02-24-2010, 04:55 PM

Sounds like the timing is off now anyway!

Best way forward, pull the sprocket off the cam.

remove those rockers that are not opening valves.

Move cam, (carefully) to allow the other rockers to be removed.--IF the cam wont turn that far, try the other way, IF still no go, turn the crank around 1/4 turn and try again.

Now we'll need to re-time engine--Assuming 0M-617...

With no rockers in there, It'll be safe to turn engine, pump, and cam.

Align the Crank with the timing marks on ballancer to '0' degrees.

Align the Cam notch with the notch in the cam-bearing-tower.

Re-fit Cam-Sprocket and chain with the engine in this position.

Engine should now turn by hand, do this for a few turns of the engine to insure nothing is blocking it. Best with glow-plugs out for ease of turning!--Any resistance felt should be investigated. After this, Re-check the timing of Crank to Cam...

Now, remove the Injection-pump....

Align the 'dot' on the case flange near the splined drive, with the gap in the splines. OR, remove the plug in the Governor case and locate the timing-pin. (Check with Your WSM specific to Your IP)

Turn engine In The Normal direction Of rotation until the 24 degrees Before TDC lines up on the Ballancer--Make sure you turn the Crank TWICE from the initial setting where you fitted the cam-sprocket and chain (Nos. one-pot Firing-stroke...)
(Check your WSM specific to your IP type.)

re-fit Injection pump and do a proper drip-timing of the pump.

All now should be OK. The WSM shows how to remove the IP and how to re-time this part specific to Your car....

.

laidbback · #6 02-24-2010, 05:06 PM

ok this is really weird. I tried cranking it from the power steering bolt and It reeled the new chain in and old chain out about 3 links. Then it stopped and won't budge again.

How do I remove the sprocket off the camshaft?

I feel like I am not too far off timing or it wouldn't have moved at all. I tried advancing the chain one notch one way and one the other and it didn't change anything.

Alastair · #7 02-24-2010, 05:12 PM

Ahh...

Right!

You got a chain halfway in!

now it comes clear!

Take that big bolt outta the middle of the sprocket! The sprockety will come off...Take a Note of its position, its possible to fit backwards by mistake!

Lay the chain out the way for now.

Turn the Crank sufficiently Backwards to allow you to turn cam to remove the rockers....

Whatever you do, You gotta get those rockers out first before getting the new chain rolled in there, as it looks as though it slipped a couple of teeth when attempting earler...

When the rockers are out, Roll in the chain all the way, and then re-time cam, before fitting rockers....

laidbback · #8 02-24-2010, 05:32 PM

ok to remove the sprocket i assume that bolt has to be turned ccw. How can I avoid cranking everything ccw when trying to remove that bolt.

laidbback · #9 02-24-2010, 05:33 PM

and how do I turn the crank backwards if the bolt/sprocket aren't there. What do I turn it with?

leathermang · #10 02-24-2010, 07:01 PM

You need a Factory Shop Manual to be doing the things you are attempting..
There are a lot of warnings in it which there is no way to communicate on a forum...

laidbback · #11 02-24-2010, 07:41 PM

thanks for nothing leatherman i got a shop manual so save your unhelpful comments for yourself

barry123400 · #12 02-24-2010, 08:13 PM

Remember to label each rocker as to it's location when removing. They have individual wear patterns.

vstech · #13 02-24-2010, 10:16 PM

leathermang is trying to be helpfull, don't get upset yet. just wait until we start poking fun at you!

WARNING!!! before you loosen the cam bolt, and pull off the sprocket, stuff a towell in the chain area, because you will drop the washer that's under the sprocket. try not to drop it, but I drop it nearly every time I remove the sprocket. also, there is a woodruff key in there that can fall out. best if you have something in the big hole to catch the parts that fall off.
the cam sprocket has holes in it, wedge something in one, and turn the bolt CCW.
be extra careful turning the crank until you have all the rockers out. you don't wanna force anything and bend or damage a valve or piston...

laidbback · #14 02-24-2010, 10:50 PM

ya i know he's just being smart. No worries

Ok so I got the rocker arms off and was able to rotate the new chain in with no problem.

Old chain is off and the new chain is vice-gripped on the the camshaft sprocket for now.

Now I need to get her timed.

I was going to follow alastair's advice and...

first line up the crank with the balancer at 0, then advance the camshaft sprocket until the line and notch line up.

next install the rocker arms

then remove the ip pump and reset( not sure exactly how to do this but I will search around)

install ip pump and do drip test,

adjust valves

Is this correct so far?? Also at what point do I cycle the engine over a few times to make sure I am not hitting pistons with valves?

Again thanks for all the help so far.

leathermang · #15 02-24-2010, 11:20 PM

I should have said you need to READ THE FACTORY SHOP MANUAL..
I assumed from the half dozen mistakes you have described making which are clearly warned about in the FSM that you did not own one...