Author Topic: Timing chain replacement (Read 9232 times)

m42mccabe · « **on:** November 16, 2007, 04:26:56 PM »

I've got a 91 318is that has 160000 miles on it. The timing chain is about done for and I've been dreading the replacement job. I talked to a local mechanic and he told me it might be possible to roll the new timing chain on by getting one with a master link and cutting the old one at the top. Then I could link the new chain to the old one and keep tension as I crank the engine over manually. Once the new chain is on I just link the two ends together with the master link and I'm done. The only problem is, I'm not sure if a master link even exists for the M42 timing chain. I've been looking around and I can't find anything. All I really need is the master link and I can cut the new chain manually

Anyone even heard of this procedure?? :confused:

sheepdog · « **Reply #1 on:** November 16, 2007, 05:58:57 PM »

Do NOT do that.

The chain goes along with the sprockets because the teeth are meshed perfectly when the chain is new, once stretched the teeth must deform to accommodate the chain, wearing the sprockets. When you use worn sprockets and a new chain suddenly very few teeth and only a small amount of material are contacting between the sprocket and chain, making everything stretch rapidly.

At minimum expect new crank, cam, and idler sprockets, as well as the timing chain tensioner and of course the chain. Do not forget the associated gaskets and fluids that will need to be changed. May want to also do the thermostat while you are there, and if you can the waterpump, hoses and belts.

Oh, and I would find a new mechanic.
His ideas are downright scary.

rob_e30 · « **Reply #2 on:** November 16, 2007, 06:00:49 PM »

I don't think I'd try it. I've found that often the "work around" is more work and hassle than making the effort to do it correctly. It would also allow you to check the lower guide, idler and crank gear.

Oh, and I just checked the old chain I replaced and there is no master link.

KenC · « **Reply #3 on:** November 16, 2007, 06:05:04 PM »

What makes you think the chain is done?

sheepdog · « **Reply #4 on:** November 16, 2007, 06:09:46 PM »

Quote from: KenCopperwheat;37812

What makes you think the chain is done?

At 160k, it is done.
I would pretty much put money on it.

m42mccabe · « **Reply #5 on:** November 16, 2007, 06:36:05 PM »

Sounds like I'm in for an expensive job. I've taken a subaru engine apart and I'm in the process of a subaru engine swap right now. Is the timing chain for an M42 exrememly difficult or can it be done in a home garage with Mitchell On Demand? Is there need for any special BWM tools or can I get by with a simple set?

sumyungguy · « **Reply #6 on:** November 16, 2007, 08:47:08 PM »

I think the only "difficult" part is the crank pulley. I know having some of the special bmw tools help with the cam placement and such.

PaulC · « **Reply #7 on:** November 17, 2007, 12:43:10 PM »

Mitchell On Demand is a pretty thorough manual. But nothings perfect, right. Any chance you'd be willing to share some procedures / diagrams?

sheepdog · « **Reply #8 on:** November 17, 2007, 01:02:02 PM »

Not too difficult, just a bit of work.
The timing chain housing itself is a different story. Which is why you need to fix this before it comes to that.

rhogg · « **Reply #9 on:** November 17, 2007, 08:06:18 PM »

Here you go:

http://www.esatclear.ie/~bpurcell/318ismaintenance.html#timingchain

Brendan is sometimes is on here. This also my next job, well after the E46's brakes.

OKTAY · « **Reply #10 on:** November 19, 2007, 08:51:16 AM »

What about E46 brakes?

Royalratch · « **Reply #11 on:** November 22, 2007, 04:01:38 AM »

You'd be crazy to try that!

You've got to chain the sprockets, chain, tensioner and nylon chain guides too. BMW sell this as a complete kit with all the bits, including the timing case gasket.

sheepdog · « **Reply #12 on:** November 22, 2007, 01:05:46 PM »

Quote from: Royalratch;38145

You'd be crazy to try that!

You've got to chain the sprockets, chain, tensioner and nylon chain guides too. BMW sell this as a complete kit with all the bits, including the timing case gasket.

Got a part number?

Royalratch · « **Reply #13 on:** January 12, 2008, 05:28:55 AM »

There is no one part number but you can ask for the whole kit and they'll put it together for you.
Below is everything that should be changed when doing it - all the little bits too!

Jak318 · « **Reply #14 on:** January 12, 2008, 08:31:12 PM »

I would not go to the dealer unless you want them to own your wallet. Here is the list of parts I replaced when I did mine. My total cost was $670.00
http://www.r3vlimited.com/board/showthread.php?t=96062&page=2

You may be able to skip replacement of the deflection wheel, mine looked like new when I took it out and I could have saved $70 by reusing it.

Author Topic: Timing chain replacement (Read 9232 times)

m42mccabe

m42mccabe