patrick.net

I sort of spammed-up a thread in the RE section with details of my latest car project, so I figured I would off-load some of that in here. I mean, it is probably more entertaining than the same-old whining & hoping for lower prices in the RBA, but it wasn't my thread.

So, I am in the market for a replacement motor for my vehicle. It is a 1991 318iS that I have been dumping money into since I got it in 2005 for $2000. I had an identical car prior to that (bought in 2000 as my first car) that I wrecked like the 21 year old moron that I was. Messing with that car got me into mechanical engineering, which I got a BSME in in 2007, and it has led me pretty deep into EE & software engineering through side projects with the control system & stuff. It is needless to say that I have a love of the car, and on top of being a source of hobbies & personal development, it is fun as hell to drive.

You just can't find a 2500lb sedan with room for 5 people & a load of climbing gear anymore, that also pulls 30MPG on the highway. Most new economy cars are faster, more fuel efficient and can probably take a corner faster with a good driver, but none of them are real driver's cars. I have rented & driven a ton of these cars, and they all feel like wearing socks in a bathtub. One of my main gripes is this electronic throttle nonsense since it robs you of a great deal of tactile feedback from the motor, and electronic stability control systems that easily override you. The other complaint is over-assisted steering. I used to run the car without power steering at autocross events to enhance the feedback!

OK, anyway, I was driving back from a climbing trip in Joshua Tree last week when part of the timing chain tensioning system let loose. Being that I have driven one of these cars for 12 years, I have built sort of a 6th sense for when things go wrong. Somewhere about 30 miles south of Kettleman City / CA41 I noticed what seemed like a new road noise. I knew it wasn't road noise, but what else was I going to do besides keep driving? I pulled off at CA41 to get gas & maybe a burger, and as I cruised to the gas station, I heard the sound of pistons & valves contacting each other that is so characteristic of this motor when the timing is off. SHIT! This particular motor was badly neglected by its previous owner, and I have had 2 major failures in the timing case in the last few years. I am big on preventive maintenance, but sometimes the remedy is a full rebuild, which I have been putting-off.

Here is what broke this time. Yeah, the stupid sprocket was fine, but the casting it mounts to broke off! Sheesh!

Thread w/ pics: http://www.m42club.coms/showthread.php?t=14748

Honestly, I really haven't been able to trust the motor in the last few years, and was considering other cars at one point. Last year, a little tensioner sprocket's bearings blew out and I spent 40 hours over a 3 day weekend tearing the motor apart & cleaning the hell out of everything in hopes of refreshing it (without pulling the head or dealing with main bearings).
What's wrong with this picture? This was last year's problem.

Thread w/ pics: http://www.m42club.coms/showthread.php?t=13574

I replaced that sprocket ($160 part, OUCH!) & put the motor back together. Well, a couple of months later I was getting some nasty noises from the front of the motor. I suspected a stripped bolt. Yup!

Thread w/ pics: http://www.m42club.coms/showthread.php?t=13720

The bolt head was working its way through the timing case cover lol. After fixing that, the really awful noise was gone. However, I still got this yucky rasping/knocking noise when the motor was fully warmed up & running 3100-3400RPM. I had the case open again to check everything, but nothing was loose or broken. It was a mystery! Well, after [whatever] failed last week, the nasty noise at that RPM was gone, replaced with the sound of a poorly constrained timing chain.
I have had other trouble with the motor, although further in the past. In 2006 the oil pump ate a chunk of timing chain roller. The previous owner hadn't maintained the motor very well, and even though I rebuilt the timing chain assembly, I was an idiot & didn't drop the oil pan to look for pieces! These are generally pretty reliable motors that you can get 300,000 miles from...but that requires pretty active participation in proper maintenance. I guess 220,000 miles isn't too shabby, considering the PO's neglect & how hard I drove it.

Page w/ pics: http://bmw.e30tuner.com/my318is_pic_oilfailure.php

So, I am tired of putting time & money into this 22 year old motor with 220,000 miles. I am NOT tired of the car itself though, and I can't imagine myself in a new car, or some (economical, reliable) boring inexpensive used econobox. I wish I was the type of person that didn't care about what I drove beyond "does it go when I put the key in," but I am not. Well, I have been wanting a fully built version of this motor for 6 years. 205HP, 9000RPM redline, bulletproof construction with all of the weak points redesigned & modified. Now's the time for it haha! Once I get hitched later this year...nope, not going to be able to justify the cost of this built motor. Still, it is cheaper than a new car, and these motors are more reliable than the originals. I expect to pull at least 150,000 miles from it, and that includes race events on top of daily driving.

Who are my fellow grease monkeys in here? Got any fun projects going, or just good home repair adventures?