engine and drivetrain Timing Chain Clatter or Where Old Towels Go To Die

[PaulTWinterton]

Following a previous thread from a couple of weeks ago I offered to share my experience if I was successful in eliminating an annoying issue with my car.  I've had a rattling/knocking/clattering come from the front of my engine for a year.  Imagine driving with the windows open and you can hear a bicycle chain spinning at high speed.  When idling there was an erratic knock/slap, and revved to 2000rpm would set up a cacophony of metal-on-metal  arrhythmic  percussion.

I should clarify that these sounds are not really loud, only at a volume that is annoying TO ME.

My veteran BMW technician buddy , Rick Stephenson encouraged me to dig in and replace the chains etc in the front of the engine.  So, three weeks ago, after a fast run from Vancouver to Tacoma and back (BMW Centennial Celebration) I put the car up on stands and went to work.  Being an amateur I was nervous throughout the whole process and spent a lot of time in contemplation before doing each job.  I really didn't want to screw up and wreck something.

I used an engine hoist to raise the engine, remove the pan and then supported it with 2x4chunks so I could work on the front more easily.  At this point I confirmed that the engine/cam/KF were at TDC.  From this point forward I would keep that pinned for re-assembly.

If you're going to do this job, make sure you have the right tools.  Pullers are fantastic!  I used generic ones for the KF pulley and crank hub.  Both popped off in seconds. 

Cleaning old parts is something I really enjoy.  Make old look new(er).  Some blasting and clearcoat.  New water pump by the way.

I wasn't surprised to find the tensioner piston was fully extended, and the tensioner and guide quite worn.  The timing chain was quite sloppy near the crank sprockets, and the oil pump chain had at least 1/2" of deflection in each side of the chain.

Now here is where it gets interesting.  I measured the old chains against the new chains and found very

little difference (in length) UNTIL I installed the new ones on the engine.  Much less deflection.   I learned that worn "links" loosen the chain, not "chain stretch".    I know, I know.  I could have replaced the sprockets too, but they only showed moderate wear.  I'll do that next time. :-)

Re-assembly was uneventful.  Chains went on in the same orientation as the old ones, albeit with more tension .  The guide and tensioner slipped on easily.  Lower cover shaft seal fit nicely.  

Guiding the lower cover into position was a bit of a challenge.  Block/gaskets/sealant/tensioner lever/cover are all in play at the same time.  Thank you BMW for the guide sleeves on the block.

It would be easy to get into a "how to" article here, but I'm not really qualified, so I'll leave it at "read everything you can on this process ".  It's not difficult and I was rewarded with a smooth running (and sounding) car after approx. 40 hours of methodical plodding.   I bet I could beat 12 hours next time.

Started up immediately.  No more ugly sounds coming from the engine.

Thanks to my wife for donating all the linen to keep everything clean, and to Rick for coaching me through this process.

 

 

 

 

 

Edited June 3, 2016 by PaulTWinterton

[ray_]

Nicely done, Paul!

 

Cheers,

[cda951]

Nice work, I am glad to see that this thread was not the culmination of a horror story about an old towel somehow getting sucked into the timing gear of your engine . . . .

Edited June 3, 2016 by cda951

[Rxforfun2002]

I will be attempting that same job...soon, thanks for the details. Very clean parts and components- "blasting then clearcoat" ? More on the "blast"...water?degreaser? Thanks again.

[ingramlee]

Nice job. I wish I had the cajones to try this on mine.

[PaulTWinterton]

5 hours ago, Rxforfun2002 said:

"blasting then clearcoat" ? More on the "blast"...water?degreaser?

 

The timing covers, especially the lower, have many contours that are hard to clean.  I gave up on degreaser and scrubbing.  Took the parts to my local DIY blasting shop and glass-bead blasted them.  Afterward I used a high quality clearcoat.

 

CAUTION: plug the hole for the tensioner piston.  It's a machined surface that you don't want to blast.

 

I did use degreaser on the engine block after removing everything.  I wanted a clean mating surface for the covers and also wanted to clean the backside of the KF pump, which rarely sees the light of day.

Edited June 3, 2016 by PaulTWinterton

[saaron]

That is great!  So glad you did it, and it solved your woes!  You must feel great about it.  

 

Scott

[PaulTWinterton]

6 minutes ago, saaron said:

You must feel great about it.  

 

I was scared to turn the key the first time.  I spun the engine without spark plugs or coil to lubricate the engine before start up.  With the plugs and coil inline it caught immediately.  A relief and exciting too.

 

I notice the idle is a lot more steady.  My shifter is near motionless.  I didn't expect much of a performance change, but I guess a "timing" chain is pretty important to timing and steady ignition.

[TobyB]

Quote

I learned that worn "links" loosen the chain

 

THAT is truth with nice quality German chain.  And it wears quite a bit faster/more than the sprockets, especially the cam sprocket.

 

Nice- yes, you are quite qualified to write up a DIY.  I think you just did...

(and I too thought a towel mad a few trips through your timing case)

 

t

 

[jgerock]

Um- no mention of replacing the head gasket. Did you just cut the front off???

[PaulTWinterton]

56 minutes ago, jgerock said:

Um- no mention of replacing the head gasket. Did you just cut the front off???

 

Well, on advice from my veteran BMW mechanic buddy, I trimmed-off the head gasket end with side-cutters.  He said that was common practise at the dealership back in the day.   I preserved it and cleaned it with brake cleaner.  In the re-assembly phase I made sure that there was an extra blob of Permetex Right Stuff in the cut corners before I put the upper cover in place.

 

I have about 4 hours of driving in the car and so far no oil leaks.  Here's hoping.

[TobyB]

I've done that, and it works.

I've also left it floating, and that works too.

 

As long as there aren't any gaps, you'll be fine.

 

t

 

[arminyack]

I'll be doing this very thing this weekend in attempts to clear up my clackity clack clack at idle. It's looking more like a oil chain problem, but as taught as my timing chain was, I have an alternate new one to put in as well to compare. I am just going to drop the whole subframe, and suspend the engine with a 4x4 across the engine bay with tied down straps.

[kaptanoglu]

Fantastic job, Paul.  Thanks for posting it.

 

On the other hand, I now need to clean things up a bit to "keep up with the Wintertons"