Timing chain and oiling trouble fun.

[sheepdog]

Not really a how-to or guide just what has happenned, and what I think may have led to it.


First off, based on what Bmwman91 and my discussion, I  think it is safe to say the M42 pickup screen is worthless. If something gets into your pan, it will end up in your pump. Second thing to remember is that the pump housing on an M42 is aluminum, THIN aluminum. The shitty part is that it is located against the block. Dealer replacement parts will run nearly $1000 by the time you are done.


What you see below is what happens when the timing chain decides it is time to start falling apart, yet not fail entirely. The rollers go bad, end up in the pan, and then get sucked up, the result is what you see below.

Something that was found along with this though, is that all of the sprockets were extremely sharp and worn.

While Bmwman91 and I are not sure (he has doubts), there is a possibility that replacing the timing chain tensioner contributes to this problem. Reason being, both of us had this happen, and had replaced the tensioner a few thousand miles before (probably between 3-5k). Which is probably enough time under added tension that the chain finally shredded apart enough to cause problems. Though we are not sure. Any input form others woudl be helpfull. The bad part is that it could have happenned regardless due to age or stress, plus not changing the tensioner is just as bad possibly..


My best recomendation is change your chain at 120k, I have heard that BMW recomends it at this mileage. If you must do the tensioner, I would recomend pulling teh cam gear cover (very easily done) and popping teh tensioner open before starting the car, rather than use the "rev to 3000 for 30 secnd method". During that 30 seconds, your chain is slapping around an awefull lot.


Also, change your chain. While a pain in the ass, it is FAR, FAR easier than what I now have to do.

What is involved in the T-chain (basic overview, yes, it is a lot):
Drain oil, drain coolant, pull the hood off, remove rad hoses and heater return hose, remove radiator, remove shroud. Remove fan, clutch, all belts. Remove the A/C pump and mounting bracket. Pull the lower and upper pansd, then pull the thermostat and housing, (you may get away without pulling the water pump, but you will have to pull the pulley) valve cover, upper t-chain/cam cover, timing sensor, lower crank pulleys, and lower t-chain cover. The pull the tensioner, upper chain guide, and idler gear. You should be able to pull the chain but you may want to remove some guides to make things easier. I recomend replacing the cam gears, (take a picture for proper bolt placement), idler gear, and crank gear along with the chain otherwise you may end up doing it again sometimes in the future.

Now if you are unlucky and wait too long...
You get to get a ride home and then pull the oil pump/front engine assembly, which you see below. This means pulling the water pump (for sure) as well as dealing with the profile gasket, and possibly the head if you do not figure out how to do it without. Bmwman91 did it without, and I am planning to.

This chunk of aluminum is VERY expensive, and is a shitty design. If you have to do this, buy another motor and cannibalize parts.


What it should look like.


What mine looks like. Notice the crack, about 3-4inches long! and notice the lower chain guide, the plastic is completely gone from the mounting post. Looks like there may be a crack on the other side of teh housing as well.

[bmwman91]

Well, I have replaced tensioners on both cars and I never put it in unspring...for fear of this exactly.  The guides I have read for tensioner replacement call for you to remove the timing case covers and press on the tensioner with the guide rail to release it manually prior to starting the motor...probably for the exact reason Sheepdog has mentioned here.

My chain was missing TONS of pieces because the previous owner had let the tensioner go for a loong time (I am guessing), but did not replace it because it is normal for a lot of older BMW's to be sorta noisy.

[sheepdog]

In the garage, we thought the crack only went across the top area. The pics revealed it was much worse and wraps around underneath. After looking some more though, it looks like it may have another on the opposite side.

[sheepdog]

Yeah, I am leaning toward letting the tensioner go bad for so long is a main cause to the chain going bad, though worn sprockets do not help and mine were bad. I do wonder if putting in the new one did not make things worse after it was going bad already.

At any rate, my engine was noisey and unfortunately I had no idea what actually was "loud". There are no other 318's around to listen to. At a show though a BMW master tech noticed and told me even though I was planning in doing the tensioner soon anyhow. It was more quiet, but still a rather noisey motor.

If in doubt, change your tensioner.

[D. Clay]

A bad tensioner lets the chain flop around causing excessive wear on the rollers and gear teeth. The worn through rail in the photo is worn on the slack side assuming a BMW engine rotates clockwise from the front. The tensioner takes play out of the slack side and drag keeps it tight on the other.  The cam gear teeth and chain rollers are easy enough to check if the engine is noisy - remove upper front cover. A worn tensioner causes a dinstinctive sound. Once you know what it is, it's obvious. Until you know it's baffling. Someone pointed it out to me. Listen to a new 318is. They're pretty quiet.

[sheepdog]

For those wondering about costs to do this...

For me:
$200 used motor
$80 in gas (St. Louis to Chicago and back, yes, I am nuts I guess)
$20 oil
$80 in misc gaskets and such  (I am also doing hoses and belts, but keeping the waterpump as it is in good shape and expensive to replace).
I am also changing to the e36 timing chain, rails and sprockets.

About $380


Normal cost for this (based on real OEM) this is bare minimum:
$300 Timing chain case
$53 oil pump
$120 chain
$55 Guide rail (for some reason the same one broke on me and Bmwman91's)
$100 gaskets and such, buy a bottom end kit
$20 oil
$25 oil pump pickup

You may also need to replace sprockets, mine were very sharp which is not good. $220 A full guide rail set is about $220.

Basically if you need it all, About $1000.
Do yourself a favor, find a slightly used e36 engine to cannibalize.

[bmwman91]

My cost:
 $80 Used Timing Case & pump gears, Shipped (from some guy on Bimmerforums)
 $60 for all gaskets (Pelican Parts)
 $30 New Pump Sump Screen Boom
+
-------------
 $170ish

Now, I had just rebuilt the whole timing case about 2 months prior.  All those parts through Pelican Parts cost me about $450.

[sheepdog]

My cost:
 $80 Used Timing Case & pump gears, Shipped (from some guy on Bimmerforums)
 $60 for all gaskets (Pelican Parts)
 $30 New Pump Sump Screen Boom
+
-------------
 $170ish

Now, I had just rebuilt the whole timing case about 2 months prior.  All those parts through Pelican Parts cost me about $450.

I think we both got off cheap.

I cannot even imagine paying a dealer to do it all with new parts, YIKES!

[bimmerlover]

I may have a similar issue. What I know so far about my "new" cabrio is that about 40k miles ago it had the hydraulic lifters and chain tensioner replaced.
The latest service record (2/06 - last time car was driven) from the previous owner shows that they found a lot of metal and plastic in the oil pan that was clogging the pump pick up. They removed the debris, re-installed the pan and filled it with oil. They wrote "engine noisy. parts in oil pan may be from timing chain tensioner guide rail coming apart."

What do you guys think? Does it sound like I have the same thing going on?

Thanks

      Rachel

[Eurospec]

How many miles on the engine?

[bimmerlover]

How many miles on the engine?

115k

[D. Clay]

It sounds like guide rails at least may be the problem. The guide rails are the only plastic I know of in the motor that are likely to disintegrate. The metal would be the chain and gears. You'll have toi pull the covers off to tell for sure. You might park beside another M42 and see just how loud it is. You may not need to do anything. I think M42's are just plain noisy!
If you do the work yourself, a good used motor would probably cost what the parts would if it looks like the pic above or even needs guides, chain, and a few gears.
Where do they get those parts prices? The main cover is $300 by itself.

[sheepdog]

I may have a similar issue. What I know so far about my "new" cabrio is that about 40k miles ago it had the hydraulic lifters and chain tensioner replaced.
The latest service record (2/06 - last time car was driven) from the previous owner shows that they found a lot of metal and plastic in the oil pan that was clogging the pump pick up. They removed the debris, re-installed the pan and filled it with oil. They wrote "engine noisy. parts in oil pan may be from timing chain tensioner guide rail coming apart."

What do you guys think? Does it sound like I have the same thing going on?

Thanks

      Rachel

Not good.

I would stop driving. Pull the lower pan, and pull the upper timing case cover (cam sprocket cover) and valve cover. Takes all of 5 minutes, you will need some new gaskets. Take a look at your chain, look for missing rollers, all you will see is the pin. Mine was showing only the pin in some cases, and parts of rollers were missing.

Be prepared to order up a new chain (bend over), gasket kit, lower and right side guides immediately.

That is exactly what you will find in there when it goes.

Be prepared, you may find a cracked pump, though not punched though, you may also find very worn sprockets. Better to get it now before the timing case/pump housing gets damaged.



Take a look at my pan when I pulled it...
The black chunk is plastic is from the guide. The bolts were from the upper pan, and bits of metal are rollers from the chain. Also lots of aluminum.  Whoever pulled that pan and did nothing should be shot as ANY time you find metal in the pan it is a bad thing unless it is fine metal shavings from a recent rebuild.

Check this picture.
http://www.m42club.com/forums/vbgarage.php?do=getimage&id=4

[D. Clay]

What did it sound like. Did you pull the pan for checking out what happened to Febi with the gasket/loose bolts problem or was it because it was noisy?

[sheepdog]

What did it sound like. Did you pull the pan for checking out what happened to Febi with the gasket/loose bolts problem or was it because it was noisy?

Well before I changed the tensioner, I had a lot of ratle from about 3000-4500rpm. Afterwards, the rattle was muffled and from 3750-4250 or so.

The problem is, I have never heard a stock m42 in proper condition run, so trying to tell you how different it sounded is difficult.



I was planning to pull the pan that weekend to check for what happenned to Febi. When it happenned, I assumed I had suffered the same fate.  I wish. This is far more expensive, and a whole lot more work. Had it been what happenned to him, I would have been running again in a couple hours rather than weeks.


I have to admit, the more I work on this engine, the less impressed I am with it. It runs good, but the engineering behind it is crazy. Some of it is genius, other portions of it seem to be designed by a moron.  German engineering my ass.