Author Topic: Timing chain and oiling trouble fun. (Read 18748 times)

D. Clay · « **Reply #15 on:** July 20, 2006, 01:45:16 PM »

Quote from: sheepdog

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.

I think the greatest feat of German "engineering" on the M42 is the oil sump in front of the crossmember. Everything is a compromise in design. The M42 is a rather high output for it's day and it does have a chain instead of a belt. To put the sump behind the crossmember would require a redo of the crossmember or raising the motor which is not desirable from a handling standpoint. It would require a separate suspension and crossmember layout for the four cylinder motor - translation $. That may be why the stock ride height is so high - translation $.

sheepdog · « **Reply #16 on:** July 20, 2006, 03:43:54 PM »

Quote from: D. Clay

I think the greatest feat of German "engineering" on the M42 is the oil sump in front of the crossmember. Everything is a compromise in design. The M42 is a rather high output for it's day and it does have a chain instead of a belt. To put the sump behind the crossmember would require a redo of the crossmember or raising the motor which is not desirable from a handling standpoint. It would require a separate suspension and crossmember layout for the four cylinder motor - translation $. That may be why the stock ride height is so high - translation $.

Ford has had it there for years.

My complaint is the aluminum oil pump housing, which is very thin, not tomention aluminum, the pickup screen to stop anything from getting into the pump, that does not stop debris from entering as it goes right through, the excessive number of gaskets used to seal up the front of the engine, the cooling pipe down the side, the rediculous vacuum line shapes (why is the 3 way splitter rubber instead of a plastic "t"?). The fact that they make it so easy to change a thermostat or waterpump, yet attach the fan in a way that it itself is royal pain in the ass.

Things like that.
And it is not just the engine. The entire car is like this. Take the steering rack for example, it is SUPER easy, yet the CSB is somewhat of a hassle.

Anything you mess with on a semi-regular basis is simple to do, anything beyond that, is a royal pain in the ass.

sheepdog · « **Reply #17 on:** July 21, 2006, 05:04:22 PM »

Well, I do take back what I said about the screen, it does seem sufficient in strength, I could not flex it with my hand. That does not change the fact that a peice of timing chain went through it! Makes you wonder what kind of suction is actually going on down there to be capable of that.

Sorry so blurry, it was hard to get decent pics.

sheepdog · « **Reply #18 on:** July 21, 2006, 05:49:17 PM »

Well....

Here is what is left of the inner oil pump ring....
Boom!
All the kings horses and all the king's men... yeah, yeah, yeah, them fuckers could not put this peice of shit back together again either!

Here is the outer ring, still in the housing...
It is seized in there, it took a bit to get it out, as you will see later.
The arrows pount to destroyed teeth from metal getting in between.

Here is an interesting shot:
Arrows 1 and 2 point to cracks in the housing. They are stress cracks from how tight the outer ring was pressing against it. It was so tight when hot, that on each side of each crack, the part is warped. There is still more to see of how bad this truly was in the next picture.

Arrow 4 shows how far around the cracks went. 3 points to the uppermost area undamaged. Odd, since just below that is a rib, hower it cracked the rib and left this. It did still score it though. Look at teh gouges all the way around.

Here we have the misc. parts of the oil pump. The big ring is the oil pump backing plate. Notice the chunk missing!. That lines up with the 2 cracks in the previous picture. You can see the ripped out part just to the right of it, it looks like a washer. Look at the scoring on the back plate.

sheepdog · « **Reply #19 on:** July 21, 2006, 05:56:24 PM »

Anyone have an odd oil or coolant leak they just cannot find the source.

This is the backside of the timing chain case that goes against the block. You can see it had been leaking. Which was probably caused by the fact that some bolts were barely hand tight!

Anyhow, the top area, opens to air, no seal between it and the head, and there is about a 1/16-1/8in gap there. I had all sorts of sand and crap fall out of there.

Thing is, looking at this, you can see I had seepage from the coolant and oil system on the upper right hand side area.

If you have mystery leacks, this could be your cause. Some things to keep in mind, when I worked on aircraft, we hessitated to just tighten leaky lines and such, because while you may stop it, you may also make things worse. This gasket is a royal BITCH to get to. It takes A LOT of work.

For those unsure of what you are looking at, this is the back side of the timing chain housing. This is the block side. It is also one expensive chunk of aluminum. This one is now worth about 25 cents to a local recycler.

sheepdog · « **Reply #20 on:** July 21, 2006, 05:58:49 PM »

This is one of BMWman91's pics from when his went. This mounts on the front of the block in this picture.

That is also shows how much you have to do to get this off.

Berlin · « **Reply #21 on:** July 21, 2006, 09:25:50 PM »

im sorry for you pains mate. if it helps id like to say this is a very informative thread, keep us posted with the great pics and details

D. Clay · « **Reply #22 on:** July 21, 2006, 10:34:36 PM »

It looks as if the culprit is either the timing chain and plastic guides or the lower sump gasket and pan bolts.
1) Any ideas on what would be the recommended "M42club.com" service interval for replacing the lower pan gasket and the timing chain and guides?
2) Does BMW have a recommended srvice interval for any of this?
3) Also would it be worth it to go ahead and take the timing case off the block and replace that gasket?
I'm starting to worry as I am at 196,000+ miles and have only done a chain tensioner at about 140,000. Parts are pretty much $300 for the chain, tensioner, guides, and gaskets. Or maybe I should just wait and use the "what's that noise" method.

sheepdog · « **Reply #23 on:** July 22, 2006, 02:00:17 AM »

The destruction was certainly caused by the timing chain roller(s) getting through the pickup screen, plastic could not do this. What caused the chain to destruct is partially open for debate. The chain was certainly in bad shape due to being run too loose. The second half is that changing the tensioner while in the condition it was in, may have acclerated its destruction. For those wondering, there was nothing ever came out in the oil (I watched and listened for anything) and nothing was in the filter when the oil (and filter) was done just before (2000-3000 miles previously). The tensioner had been in for maybe 3000-4000 miles. It may have also just decided it was time.

Honestly, I am just amazed any of these motors are holding together. I am not sure I want to even check my rod or main bolts for fear they will be loose. On the other hand, I do not want to risk disturbing them or distorting the bearings. I have been told that unofficially, the t-chain is due at 120k miles. Is it true? I have no idea, but it tends to go with most other timing chain replacment times. Though I have also heard of many chains going 500k plus despite this recomendation from manufacturers. I have also heard the tensioner should be changed every 40k miles. If this engine blows after all this I am buying another motor and dropping it in. I am NOT doing this again. There is a good side to this, I think (hope).

Here is what I will do, or do over again (preferably while it is out, or never):
Which by the way, I would probably just pull it next time, seems like it would be simpler.

First pull the pan, and check the bolts and sump, all bolts removed one at a time and locktighted and retorqued 15% over stock torque numbers.

Then the front of the engine, pull the covers off. Check the sprocket teeth and chain, if bad, pull the housing and replace the gasket while there, you already have 90% of the work done, may as well. Better now than later. If the chain and sprockets are fine, replace the tensioner, and Re-torque the entire t-chain housing, and work my way back out from there re-torque'ing and locktight'ing everything.

Consider replacing all vaccuum lines, coolant hoses, belts, waterpump, and t-stat as well as plugs and wires. A lot, yes, but so much is easily accessed at this point that requires so much removal to do again later, it is rediculous not to. You may not think so now, but trust me, by the time you get the t-chain husing off, and the engine is very easily accessed and you realize what it took to get there.

sheepdog · « **Reply #24 on:** July 22, 2006, 02:24:48 AM »

Quote from: Berlin

im sorry for you pains mate. if it helps id like to say this is a very informative thread, keep us posted with the great pics and details

Thanks, glad someone is getting something from all of this.

This will be a great car by the time I get done with this, however I am almost ready to move on. Not a perfect car yet, but it will have had a lot gone over by the time it is done and should be mechanically sound for a while. I love this car, but I have too much time underneath it, which will not improve much considering how much I drive it.

Last 2 years or 20k miles, which is when I got it, I havereplaced or upgraded:
6 tires (Yokohamas)
steering rack
tie rod ends
guibo w/new bolts
center support bearing
fuel tank (that was as much fun as this)
all belts
main hoses (May do the rest)
lots of vaccuum lines (may do the rest)
air conditing
stereo (Alpine)
speakers
brakes (Axxis Ultimates)
Headlights (Hella upgrade) h1 100w. high / h4 Silverstar lows (bright as hell)
Shift knob
2 rims
rearview mirror and mount
Drivers window
Lots of knobs and switches
Fog lamps (cheap Piaas, not great looing, but necessary)
fixed winsheild washer splitter
fixed wipers (one blade would not stay tight)
replaced bottlecap spare with bbs (no idea why it was like this)

Got the parts and plans to fix central lock system, re-paint the lower black body area, and straighten the bumper alignment. Probably put a chip soon too.

m42 fan · « **Reply #25 on:** July 22, 2006, 07:42:20 PM »

Like everyone else has said, at least the silver lining is that 1) you know it's been done right now, and 2) This has been a very informative and helpfull thread for the rest of us. I, for one plan on putting this information to good use, as time and $$ allow.

Unfortunately, it'll have to wait till after I move to Pensacola here in about a month. I'm sitting right near 150k right now, so everyone cross their fingers that it'll make it!

Keep the updates coming. I may not be posting much with everything on my plate (new baby, graduating, commissioning, transfering to P-cola), but I'm reading every day.

Brian

sheepdog · « **Reply #26 on:** September 04, 2006, 02:23:22 PM »

Just a heads up to those who end up replacing the timing chain housig,
you do NOT have to lift the entire engine or remove the engine.

Unbolt the passenger motor mount from underneath, place a 6in x2in block of wood against it (vertically), then use a floor jack to gently lift the motor up a bit. This will give you the clearance necessary to clean out the gasket and remove the bolt above the steering rack.

Make sure to check that things are secure before shoving your fingers up in there. Also use a mirror to check that all of the old material is removed.

You should be able to slide in the new gasket from the front.

Oh, a bit of advice, if you buy a lower end gasket kit, be sure to also purchase a profile gasket, as they are not included. Ask how I know... :mad:

Try finding one at 4pm on Sunday of a 3 day weekend...

e9nine · « **Reply #27 on:** October 05, 2006, 12:22:56 PM »

I experienced this on my sedan a while ago. Started her up on my way to work one fine morning...Oil light comes on...shiet :mad: noticed car was low on power and rattles like a tractor. Oil pressure is very low. The car can still be cranked but its VERY LOW on power.

I have a lower mi. used motor to swap it out with. I might just salvage some parts from the old motor to keep as spares since I have no desire at the present time to rebuild it considering time and resources available.

This issue seems to be random depending on the history of the car along with partial servicing (e.g. when doing the timing chain tensioner alone too late) versus complete complete timing chain case items being replaced (e.g. when doing the profile gasket)

Dunno how I missed this post earlier on!

Euro Nation · « **Reply #28 on:** October 05, 2006, 12:30:59 PM »

Excellent thread. I feel lucky that mine made enough noise in the driveway when the previous owner brought it to my house for me to replace EVERYTHING prior to even driving the car. My lower guide was broken in a couple places and my chain was about to fail. I also found that while I had no bolts in the sump none of my internal oil pan bolts required a wrench to remove.

denious · « **Reply #29 on:** November 11, 2006, 12:23:47 AM »

Hey guys, the m42 I got in my car is a 1994. I know BMW made some modifications to it compared to the 1991 one, so does anyone know if it still has all the problems mentioned here and in the oil pan thread??