e36 m3 vanos system

jterp · 09-26-03, 03:04 PM

I've been talking to someone about buying a 99 m3... Sometime in the cars' life the driver missed a shift and over revved the motor. Engine didn't blow, but he bent the valves. The head was removed and all the valves/valve stem seals were replaced. The head was put back on and the vanos system was put back on as well.. From what he says though, it is not lined up correctly beacause only a bmw mechanic can put it on and line it up... He seems very trustworthy and a lot of people have vouched for him so i don't doubt that he did the work correctly... my question is this: Bmw told him that it is not nnecessary to have the vanos lined up perfectly-- that the car will run the same and it will not do any damage to the motor. Does this sound right to you guys?

LateNightCable · 09-26-03, 06:12 PM

Isn't there some kind of rev limiter anyway? Well, you should ask around yourself, simply because the operation of these kind of cars is so much about close tolerances. I don't see how only a BMW mechanic could line it up properly though. I'm not too familier with VANOS mechanically, so thats' my two cents.
You seem to be taking your own sweet time about finding the right M3, thats' good.

thepolarfoxqx · 09-26-03, 07:15 PM

yeah, how did he over-rev, the computer won't let you, something pretty odd would have had to happen to bend valves. The VANOS system needs to be properly aligned, here's why. The cam in the M3 slides back and forth, the lobes on the cam taper from a flatter cam for low end to a lumpier one for high end, the computer monitors a number of things to adjust this, but it primarily uses a lookup table, if throttle=x and rpm=y, then cam position =z, one of those deals. If the VANOS isn't aligned right, it will run, but the computer will keep trying to adjust to get the right result, which it won't because it isn't ligned up, it will always be a bit off. As a result, the performance of the car might be compromised a little bit.

My advice, have the BMW look the car over, and have them pay special attention to that.

jterp · 09-26-03, 08:10 PM

He was looking for fourth and he found 2nd

I think the rev limiter prevented him from blowing the motor completely, but couldn't help the valves. I assumed that the vanos not being lined up properly would affect the performance... but then i thought that maybe to be 100% perfectly lined up you need a special BMW tool or something and maybe without the tool you can only get it 99% perfect -- and the difference is negligible.. From what the guy has told me, he had a very reputable machine shop do the head work and he was going to get BMW to adjust the vanos but it was expensive and he was told that its a waste of time... Anyone work for bmw that can shed some light on tuning the vanos system?

Yes, LNC, I am taking my time.. I've looked at 8 now... I'm pretty picky..

thepolarfoxqx · 09-27-03, 08:27 AM

i'm not sure what the tool is, i think it isn't even a tool so much as people trained in how the VANOS system works. Again, if it looks worthwhile, just pay the local bmw dealer their 150 dollar fee to look over the car for you, if they say it looks good, go for it.

And if the transmission synchronized the shift into 2nd, it couldn't have been revving TOO high, those 3.2L I6 motors are tough as nails, i'd be a little weary as to if something else may not have happened as well to have caused that.

LateNightCable · 09-27-03, 05:17 PM

Yeah, really. I've seen others rev the hell out of their M3s' for extended burnouts with no such damage that I know of. Being choosy myself, I think I would pass on a car with a history of valve damage and unauthorized VANOS maintenance. Paying out 150 dollars for a once over could really add up if you're checking out multiple cars.

In fact I would be much more inclined to buy a car from the lady who freaked when you took it to 70. Nice shape, complete records and maintenance - and you know it hasn't been abused. What more could you ask for?

Is that guy the original owner? He may not be sure himself what happened. Bent valves, thats strange.

thepolarfoxqx · 09-28-03, 05:51 AM

like i said, i think more happened to the car than overwinding. I think he did something wierd. I've looked into it, i can't find a single service brief even on bent valves on that motor. What i'm saying isn't have EVERY car looked over for 150 by BMW, but if this car is a deal, it would be worth it because if the car is good, you would have saved yourself a good chunk, and if the car iss bad, you wouldn't have been stuck with an expenisve probem.

but yeah, i'd pass on this one most likely, there are tons of E36 M3's out there, find a better one.

jterp · 09-29-03, 05:06 PM

I hear ya.. From what i can tell this guy is telling me the truth.. I imagine if you're running hard and you pull the shifter hard enough going from 3 -4.. you could accidentally pull it into 2 and rev it to all hell. But i havent had a chance to look at that car yet... I may go see it next week and a test drive will help me understand the performance a little better.

Another question for you guys -- since we're on the subject. I drove a car this weekend. A 99 M3 with 77,000 miles.. CPO warranty to 100k. Car is beautiful and is priced REALLY well... BUT (always a 'but') .. I found out when i went to look at it that it was in an accident a few months ago. SOmeone hit the driver side door... COnsequently the whole side of the car was painted... I am getting my buddy to run a carfax for me to get the details.. He (who is a car salesman) says that if its been hit I should walk away.. Do you guys agree? It runs great (the guy was at work when i went to see the car-- he couldnt leave to go on a test drive so he just let me take it on my own

) and it is priced well below what a 99 M3 with a warranty would normally be. (he's asking 20k) I told him that I would need to have a Pre-purchase inspection done by a BMW dealer and that i would want them to pay attention to the frame to make sure it had no frame damage from the accident... Any fellings on cars that have been in accidents ?

Also, have you seen a pre-purchase inspection schecklist for an E36? I found one on the internet for an E30 but no E36..

PorschePlayboy928 · 09-29-03, 06:48 PM

since you are in no hurry, I would pass on this one. Just remember, there are M3s sold every day so just wait and the right one will come around!

LateNightCable · 09-29-03, 06:58 PM

He let you take it out on your own? Thats' cool. I see no reason to pass on a car just because it has been in a small accident, if everything is out in the open about it, which it seems to be, and the repair work has been done by a reputable firm ( find out where it was done ). A knocked up door can't be any worse than bent valves right? The carfax is good. You say that the door was repainted, which suggests it wasn't an accident bad enough to warrant replacing the whole door.

If pre-inspection at the BMW dealer checks out well with no frame damage, go ahead and consider it. Here is a link to a maintenance checklist for the 1999 E36. - www.circlebmw.com/service/main/99e36.htm and an inspection list from a 540i six-speed site, that could very well apply to the 3-Series. www.540i6.com/inspectionchecklist.html