timing chain replacement

E28 technical advice asked and given! Troubleshooting, modifications and more.
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secondratehero
Posts: 11
Joined: Jul 05, 2012 12:47 PM
Location: milwaukee, wi

timing chain replacement

Post by secondratehero »

First off its an 86 535i m30.

Ive hearing a lot of rattling coming from what I'm narrowing down to be my timing chain. It's loose enough to cause a slight misfire. Ive been doing all my own work of this car since I've bought it and would love to tackle this problem myself also (especially after the $1500 quote I received).

Just wondering if anyone has any advice on the topic to help me through what looks to be a tiring and lengthy job. Any and all help would be greatly appreciated.

Thanks
Eric
ElGuappo
Posts: 8128
Joined: Feb 12, 2006 12:00 PM
Location: Sacramento, CA
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Post by ElGuappo »

Check your chain guides, and change the tensioner before you think about replacing the whole chain.
ahab
Posts: 6174
Joined: Jun 11, 2006 9:12 AM
Location: Chalfont, PA

Post by ahab »

Assuming it's not a failed tensioner, which isn't that common but worth checking as pointed out by ElGuappo, here's my advice.

Buy a new tensioner, guide set, upper and lower timing cover gasket set (including seals) and chain.
Set the motor on TDC before you do anything. Take the time to read up on this if you're not familiar.
Drain the cooling system and remove the radiator for the extra room.
Don't remove the water pump pulley until you've removed the fan clutch, which is reverse threads. If you use a large crescent wrench on the fan clutch it helps to remove 2 pulley bolts. Hand tight only on fan clutch reassembly.
The crank nut is a bitch. A flywheel lock is a huge help.
Use the 10mm ring spanner from the tool kit to remove the two vertical M6 bolts on the upper timing cover.
You have to slit the ring on the headgasket to change the guides. I do it on a corner furthest from the head at a 45° angle (so it overlaps when you re-seal it).
Don't forget the oil pan bolts when you remove the lower cover.
Change the seals when you have the timing covers off.
Reinstall the covers with Permatex #3 Aviation Gasket.
Follow the torque specs in the Bentley closely for this job.
This job is a lot easier with the motor out. :cool:

Some while-you're-in-theres:
Change your water pump if you don't know the history.
Same for the cap, rotor and belts if they're worn.
If you use a flywheel lock, you may want to upgrade to a B35 starter at this time.
Flush the cooling system while it's drained.
craigb93
Posts: 718
Joined: Feb 12, 2006 12:00 PM
Location: Cumming, GA

Post by craigb93 »

ahab gave you a world of good information.

Some things to add:

A good Air Wrench makes the crank nut a non-issue.

Toyota makes a black sealer that is superior to the 3M stuff for sealing the various corners. A tube is abt $12 but worth it.

If you change the chain, which I recommend, also change the sprockets. New chain + old sprockets = fast wear.

If the pan gasket is not completely dry plan to change it as well. You have to raise & block up the front of the engine but it's not a biggie.

The Chain Guides can be replaced w/o cutting the head gasket ring.

-Craigb93
xaviervp
Posts: 9
Joined: Sep 18, 2011 2:36 PM
Location: Miami FL

Post by xaviervp »

I would also check your water pump bearing it also could make a similar noise, it happened to a friend with an E30 M42 motor we all were sure due to milage timing chain and/or guides were shot, when it was taken apart all it the noise was made by a water pump bearing, what was strange it was not leaking coolant.
WesfromTas
Posts: 23
Joined: Nov 25, 2021 4:21 AM
Location: Tasmania

Re: timing chain replacement

Post by WesfromTas »

I'm contemplating this as I'm replacing all the cooling system, so halfway there. I'f I'm reading this right then the 36mm crank nut has to come off to release the pulley? I had secretly hoped it was just the ring of 13mm bolts inside the pulley. Assuming the crank nut needs to go what's the best trick given the motor is still in the car and I don't want to drop the stater to use a lock on the flywheel?
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: timing chain replacement

Post by Mike W. »

Yes, to remove the hub, you need to remove that 36MM nut. You can remove the harmonic dampener with out removing the 36MM nut, but if you're looking at doing the timing chain that doesn't do any good. How to hold it in place? Yeah, that's the tough part, with the engine in place.

On an E39 with a M5x engine I had to replace the front main seal. Different pieces, but pretty much the same concept. I took a piece of steel bar stock, cut a "C" into it, then drilled 3 holes for the 8MM bolts. I then bolted it onto the crank hub, attached something to keep it from turning against the frame rails I think, then a 36MM socket with a cheater pipe for leverage. I didn't need all 8 (or is it 6) bolts, just 3 was enough to loosen it, although I am in a non rust area which could complicate things if you are in a rusty area. But it worked well, just as easily as I had hoped, once I got the tool made, which took an hour or so.

But... after all that, how many miles are on it? The guide actually seems to be the most failure prone part, but it isn't really a common failure. Anything less than 200K miles/350KM I personally wouldn't bother.
Rust Bucket
Posts: 109
Joined: Dec 27, 2020 1:06 PM
Location: Montreal

Re: timing chain replacement

Post by Rust Bucket »

I cracked two of these 36mm nuts recently,engine out of the car.I made myself a tool to hold crank in place using some
of the 8 holes on the front of the crank.This bolt is torqued to 330 foot pounds.To give you an idea,I'm 200 pounds and had to swing myself a little on the breaker bar,about 3 foot long.
I wedged a piece of wood to make sure the socket would'nt tilt and strip the nut.

Some peoples secure the crank with the homade tool,put
the breaker bar on the nut and actually crank the car.The
starter is powerful enough but it is VERY DANGEROUS as
in throwing the bar 100 ft in the air.Make sure to unplug
spark plugs and plan accordingly.Idle at 900 rpm does'nt
sound like much but it's an hole other story with some
sh*ts attached to the crank.

It's doable,it's not the meanest bolt I ever encoutered but
it need torque to get cracked.Good luck,keep us updated
topher800
Posts: 446
Joined: Nov 24, 2009 9:44 AM
Location: Marshall, CO

Re: timing chain replacement

Post by topher800 »

Out of curiosity, is there a rule of thumb for when to change a chain. I am coming up on 200,000 miles.
Blue Shadow
Posts: 10195
Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Re: timing chain replacement

Post by Blue Shadow »

topher800 wrote: Jan 07, 2022 9:30 AM Out of curiosity, is there a rule of thumb for when to change a chain. I am coming up on 200,000 miles.
check back in a another hundred thou or two.

But you can check the condition of the cam sprocket when you do a valve adjustment.
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