1 possible theory to M42 breakdown...

[Alpine003]

Well after swapping in my replacement motor and having that one start to go south, I think I have one possible theory leading to M42 disaster. I feel this can be a common occurance as I always hear about some owners thinking that the ticking sound is "normal" and that's just the way 318i's are. But of course that isn't suppose to be that way.

Symptoms: ticking, rough running, oil light staying on a bit longer during startup,  coolant temp increasing or staying at the half level while cruising, rough idle.

These can be signs of your engine not getting the proper flow of oil. This can be due to debris blocking your oil pickup. The BMW design for oil pickup can be sensitive to even minor obstructions as I've found out.

It all starts with a flaw from BMW in which case, the upper pan bolts tend to come loose and fall in the lower oil pan. This restricts oil flow and can prevent the timing chain tensioner from working fully. This in return will cause slack on your timing chain causing ticking sounds. If this is driven long and hard enough, the chain can eventually stretch prematurely or cause damage to your chain guides. The chain guides can break apart from the repeated chain slapping against it and cause the broken pieces to end up in your lower oil pan. This debris will further suppress proper oil flow from your oil pickup and can lead to oil starvation which can prematurely wear out your engine. If this happens, you might see fine metal particles in your oil pan from the lack of oiling and the metal on metal rubbing.

Prevention or to play it safe: I feel if you track your car or run your car hard at high rpm's for extended times, you should check for loose bolts at least once a year. First check your upper pan bolts. If any of them are loose, it is very likely the rest within the lower oil pan are also loose. Drop the oil pan and check for the additional bolts including your oil pickup bolts.

I also feel that anytime a timing chain is done, you should check your lower oil pan and all the bolts at the same time. These should go hand in hand.

Just my observation and $.03

[sheepdog]

While that can happen, and I have seen the evidence, it is not the only problem with these motors.

Trust me, the pump has PLENTY of suction.



List of problems I have found with this motor. Some are personal, you decide:

The oil passages are too small, combined with poor maintenance, allows them to clog easily. Old oil leads to this as well. High detergent oil could help.

Another problem with this motor is vibration, leading to a lot of the end results.

2 Peice pan... Disaster waiting to happen, not just because of what you mention, but gives two failure points in the pan. Also you cannot notice missing bolts, which is the root of another problem here, see the next entry.

Bolt falls out, pan gets bumped and pushes bolt through the intake screen. Anything in said pan is then sucked into the oil pump shelling said pump. I know of at least 2 cars and possibly a third that this has hapenned to. Mine was one, and is documented here. Bmwman91 also had similar happen.

Bolts also fall out and allow the pan gasket to shift, cutting of flow entirely by blocking the pump and allowing an air hole. Febi had this happen to him. This was well documented on this site.

Another problem is the pump and housing setup. The pump in on the rear of the housing, meaning you have to deal with taking apart a huge portion of the motor to access it. It also has a VERY fragile aluminum housing, which happens to cost a small fortune. It takes a long time to replace the oil pump. On a Chevy, it is a 10 minute job on some cars.

Profile gasket... We all know this one. Bad part is, to replace a pump, due to the above situations, you have to mess with the dreaded profile gasket.

Motor assembly itself. Pull the oil pump you will see what I mean. Not only is it like a jigsaw puzzle, but getting multiple edges to line up properly so gaskets seal properly, is a total pain in the ass. Good luck getting this thing oil tight after pulling it apart.

Setting cam timing. Seems easy enough, except that there is enough slack to be off by a tooth.



Typical German engineering, great ideas, poor execution.

[Febi Guibo]

I think both posts are a great summation of the general problem (which I have experienced personally)

every person has experienced the following at one time or another

Symptoms: ticking, rough running, oil light staying on a bit longer during startup, coolant temp increasing or staying at the half level while cruising, rough idle.

Thinking back to my old engine... I would periodically have weird stuff happen... it was highly intermittent, and I was sort of like, 168,000 miles on the engine... maybe the oil pump lost prime for a moment, no big deal.

Meanwhile, looking back each instance was an upper oil pan bolt falling out, bounding into the oil pickup screen, etc etc.

so, check your oil pan bolts and oil pickup every so often!!

[badboypolar]

Great post. I'll definitely be watching these while I'm racing. I'm glad that I used loc-tite on all the oil pan & pump bolts.

[e9nine]

Great post. I'll definitely be watching these while I'm racing. I'm glad that I used loc-tite on all the oil pan & pump bolts.

If you're going to be running Spec E30 as your sig - crank scraper, pick up baffle and shimming the pump for more pressure is what a buddy of mine is doing to his. I'll most likely do the same prior to my next HPDE. I am not to sure of the shimming process yet but I'll post updates when/if I get it done

[bmwman91]

Very good posts so far.  The upper pan bolts ARE a real pain in the ass.  One of mine is actually stripped...the threads in the bottom of the timing case are toast.  Unfortunately, I REALLY do not want to have to pull the upper pan again, but it is inevitable.  If I do that, I will probably drill out ALL the threaded holes for the upper pan in the timing case and put steel inserts in.  Still debating helicoils versus the actual solid sleeve dealies.......

Anyway, anyone who has not had their oil pump blow, take these guys' advice.  I had mine grenade itself along with the front of the timing case ($$$).  Not only was it somewhat costly, but the labor was a real pain.  Just FYI though, you do not need to pull the cylinder head to reinstall the timing case. Some  putty knives, silicone RTV and patience can get the thing back in.

[badboypolar]

If you're going to be running Spec E30 as your sig - crank scraper, pick up baffle and shimming the pump for more pressure is what a buddy of mine is doing to his. I'll most likely do the same prior to my next HPDE. I am not to sure of the shimming process yet but I'll post updates when/if I get it done

I saw a thing about the baffle, however I have not heard anything about shimming the pump for more pressure or a crank scraper. PM me please with more info.

I Heli-coiled my stripped bolts. I had 4. Heli-coil done correctly is quite strong and doesn't generally unseat if installed correctly.

I think as with any engine, age will creep up on it. And preventitive maintainence will help. I know prev main sucks and is can be alot of work, however look at the alternative of rebuilding. On my Spec car I will probably check every bolt in the engine at least three times a year (pre, mid, post). It may be alot of work, but it beats breaking down on the track.

[rhogg]

Sorry to hear about your woes David.  Type of oil and frequency of change could certainly be a contributing fator.  Do you know the history on the replacement engine?

Question.  I've seen sheepdogs post on his rebuild and I'm a little confused about the warning signs.  I bought a 91 318i with what I thought were chain noises and it turned out to be a water pump bearing.  With the much quiter engine, I can now hear though a faint shhhh sound like running water or a very quiet sewing machine (for you ladies or confident guys) above 2500 RPM  No ticking or other noises.  I am thiknig this is a chain tension issue but your posts have me scared of just replacing the chain tensioner without looking at the sprokets guides & chain.  

So the question(s): Is there a way to inspect the chain for potential failure, Can you measure it like a bike chain for stretch?  I don't want to do half a job, but I would like to avoid the expense of rebuilding the timing case if I can.  I have just under 112K miles on the car.

Thanks - This a great site and was instrumental in my buying the 318.

[1991 E30 M42]

The last two engines that I had in my car stated out with I slight ticking. As I put more and more miles on my car it got worse and worse, so I had to keep putting thicker oil in. Eventually the ticking got really bad and then spun rod bearings. In my first engine the rod bearing on one of the cylinders shreaded into what looked like pencil shavings, which were then sucked up into the oil pickup, which starved the engine of oil and caused the rest of the rod bearings to drop. it also tore up the lower timing case, oil pump, and oil pump cover.

[pepe m42]

i had problems like these ones....

i had my timing chain and sprockets and all the things changed at the BMW dealer. And they left the old broken parts of the timing chain rail in the oil pan.....   so if you have the time and the knowlage, its better to do it yourself! I was traveling few times accros Europa with those things in my oil pan and once it blocked my oil pick up. so when i looked inside the pan ............ yes its good idea to have a look.

here is my thread, its not a best at all because i was new to forums and also i haven't got the best English knowlage.... but its use full to run through quickly

i added some link to the beginning for EASY TIMING ADJUSTMENT!!!

http://www.m42club.com/forums/showthread.php?t=1786

Thanks for the help you guys gave me that time!!!

[Alpine003]

Trust me, the pump has PLENTY of suction.

I don't think anyone is saying the pump doesn't have enough suction but suction is only good if the passage isn't blocked.

[e9nine]

I saw a thing about the baffle, however I have not heard anything about shimming the pump for more pressure or a crank scraper. PM me please with more info.

I Heli-coiled my stripped bolts. I had 4. Heli-coil done correctly is quite strong and doesn't generally unseat if installed correctly.

I think as with any engine, age will creep up on it. And preventitive maintainence will help. I know prev main sucks and is can be alot of work, however look at the alternative of rebuilding. On my Spec car I will probably check every bolt in the engine at least three times a year (pre, mid, post). It may be alot of work, but it beats breaking down on the track.

I have no direct input on how we would shim our pumps or if a kit exists. I'll update accordingly when I find out. You can check with any race shop/shop that knows about bimmers as it's a pretty common mechanical "trick" to increasing oil pressure done by many others.

[johna]

Has anyone looked into whether BMW improved any of the above problem areas in the later M42 engines as fitted to the E36 or the M44 successor? Maybe there are parts from these later engines that could be interchanged?

[e9nine]

Has anyone looked into whether BMW improved any of the above problem areas in the later M42 engines as fitted to the E36 or the M44 successor? Maybe there are parts from these later engines that could be interchanged?

A quick scan of the ETK showed the m42 & m44 being identical except for the oil pick up parts.