1982 300 SD timing chain replacement

[richclay]

My timing chain broke as I was cruising along. My cam shaft broke also. I want to replace the timing chain but I have never done it before. I removed the head, the front oil pan, and the oil pump. Is there anything special I should know or any special tools I need to replace the chain. I would appreciate any help.

Richard

[Stevo]

Richard

Check out the archives as there is lots posted about T/C replacement. Do you have a manual? Your gona have to watch the timing of course including the injection pump. A Haynes manual is not bad and should get you through. Anyway check out the archives and get back to the forum if you get hung up.

[ericnguyen]

Dear richclay:

I'm afraid that you will have to replace lots of things in your engine, including blown pistons, broken valves, camshaft etc... They are the consequences of a broken timing chain.

Replacing the timing chain is relatively easy thanks to the article
at http://www.pindelski.com

Best regards,

Eric

[gsxr]

Eric is right - most likely you bent up a bunch of valves, and need to pull the head off to inspect & repair whatever you find. A broken timing chain is *always* a very, VERY bad thing. It's pretty damned rare, too, unless very work (stretched excessively). Most folks check stretch at the 15k valve adjust interval. Sorry to hear about your loss.

[Stevo]

Richard

You removed the head, whats it look like in there?

[gsxr]

Sheesh, how did I miss that part. Yes, what does it look like with the head off, and how are the valves? The pistons might be OK but usually at least a few valves get clobbered.

How about sprocket teeth getting bent/damaged?

[richclay]

Several of you asked how it looked inside the head. The camshaft was busted of course. I have not inspected the valves yet but I have another head to install on it. The one I am going to install, including the valves are good. I did not see any bent or broken gear teeth either. Also, I didn't see any evidence of damage to the pistons.

I pulled the chain out. Was it a mistake to do that without connecting a new chain to what was left?

Richard

[gsxr]

I pulled the chain out. Was it a mistake to do that without connecting a new chain to what was left?

Ummmm.... yes. And at this point I'm at a loss as to what to tell you to do next.

[engatwork]

The next thing I would pull would be the engine. If you have the head off it is pretty straight forward from here on. I would just disconnect everything from the tranny, remove the tranny rear crossmember, disconnect the motor mounts and all the other stuff that has to be out of the way and go at it. Don't forget the oil pressure line at the oil filter housing.
You may be better off $$ trying to find a good used engine because once you start tearing stuff apart you find that you "may as well replace it while I am in there". Not sure about your mileage but if the pistons are damaged plan on spending no less than $120/each.
good luck

[psfred]

If the cam and towers broke, chances are the pistons and rods are just fine -- this was the case with my brother's 300D. He busted the crank, and it blew the cam towers off, we even re-used the cam!

You can fish the chain up from underneath, but you are going to have to pull the IP and injection timer to do it. Much easier with the engine out, although you can do it with the engine in place, just more work. Pull vac pump and timer and IP, then use a wire to pull the chain up from the bottom on both sides, then up through the upper chain guides. Set crank to TDC on #1, then set cam to TDC on #1. Wire chain up, then install injection timer. Install chain on cam gear and install the "master linK" but don't swage it. Set engine to 24 (or 26) degrees BTDC and install IP and check engine and IP timing, then swage chain link.

This is all easier with the engine on a stand...

Peter

[TimFreeh]

I had a chain break on a 220D - my experiences were the same as those noted by Psfred. Two cam towers were broken, I reused the cam and did NOT even remove the head. I was able to snake the replacement chain back into place with a couple of coathangers but I did have to remove the IP pump and injection timer.

All this was done with the engine in place - not alot of fun but I think I had it all back together in one day.

Of course your mileage may vary...

Tim

[richclay]

Thanks fellas...I was able to snake the chain up with a wire. I took off the injection timer but not the IP. One tower broke but I used the others. No damage to the valves. I worked with it about half of the day Saturday. I'll finish up Sunday afternoon. Thanks.
Richard