BMW 750il Challenge Build

As promised, I'm starting my build for the 750il. I'll be bringing it (with any luck) to the challenge this year. When brand new in 1990, this thing ran 15 second 1/4s, was electronically limited to ONLY 155 MPH, had almost 300 HP, and all of the 12 cylinders functioned.

The story of the car:

1. I found the car on craigslist, running and driving, clean title.
2. I went to look at the car, owned by a cool guy named Bobski (who, BTW, has runs a business selling any and all water-cooled VW parts, and many other VAG parts too). At the time, the heater core was leaking so there was no coolant in the motor. I said I was interested if he could get the core bypassed and prove it runs and doesn't overheat.
3. He called me back a couple days later with good news. I went to go 'take possession' of the car but have it towed home because the brakes need work. Bobski hooked me up with another cool guy named Alex who runs his own tow company. Alex towed me home for a song. I bought the car, budget spent = $1,100.

As the car sits:

Today I got to spend some initial time with the car. Really just noodling with not a lot of purpose. first thing I started looking at was what I thought was the leaking self-leveling rear suspension. Leaving a puddle under the rear passenger tire while the car was running, like this:

So I took the wheel off to look around. Turns out it was a gas line leaking (oooh, moist):

The line was pretty torn up, can't believe it wasn't leaking more:

When I touched the other line (yes this car has two completely independent fuel systems, two pumps, two filters, two ecu's, rails, regs, etc), it immediately starting leaking so I replaced it too.

So, now I've used about 6 inches of fuel line, and had to replace 2 of the 4 hose clamps. Lets say hose is $3 per foot and the HF clamps are 50c each. So, $2.50 spent.

Budget spent now = 1,102.50

Just to make sure... You do not have to include the price of the tow into the budget, if you added that in.

Go man, go!

I next looked into the trunk. Looks like we had a sweet stereo going on back here! Let's start grabbing that crap out.

Wow - quite a clean install even (gah!):

Pulling the wires out and working toward the front of the car, I find that whoever owned this car in the nineties must've gone to Car Toys and said "I'll have one of each, please." The stereo, the alarm, there was also a 'hidden' radar detector. Geesh:

Here is all the crap I pulled out:

I did find something I may be able to sell though! These speakers look to still be in really nice condition. I'll have to test them out to see how they do, but they might be worth something.

Finally, I found some secondhand Dinan chips for this car on ebay. I grabbed them for $100, but I will see if I can use them or not based on budget at the end.

Also, I found $1.15 in change in the car today, so now budget = $1,101.35

Next up, figure out the brakes, and there seems to be a lot of fuel/oil fumes in the exhaust, so I'll have to look at that.

JohnRW1621 wrote: Just to make sure... You do not have to include the price of the tow into the budget, if you added that in. Go man, go!

Thank you! No, I did not include it in my budget for the car. Interestingly, the car was very near O'hare. I got this car towed home for $115 (granted it was a bit of a discount under regular price). I have got stuck before and had to take a cab home from O'hare and spent more than $115. I told the guy next time I need a cab from O'hare I'm calling him for a tow. haha.

Looks like someone changed the wheels to 16" E38 style 5s, which is not that unusual (I did it to my E32), but they even swapped out the spare to match...which is unusual.

nedc wrote: Looks like someone changed the wheels to 16" E38 style 5s, which is not that unusual (I did it to my E32), but they even swapped out the spare to match...which is unusual.

I'll check today, but I thought the spare was a 15 incher just from a casual glance. The lip looked different to me so I assumed. More to come.

just pray it does not need a tune-up, or your challenge budget will go away fast. i almost bought an 89 that needed a tune-up for $1100, then saw how much the bottom of the barrel stuff cost and passed.

patgizz wrote: just pray it does not need a tune-up, or your challenge budget will go away fast. i almost bought an 89 that needed a tune-up for $1100, then saw how much the bottom of the barrel stuff cost and passed.

Yeah, agreed. The m70 stuff is ridonkulous. Fortunately, I think in many cases you can use two sets of m20 stuff with some slight modification, and that might save some real bucks. Especially plug wires.

Italian tune-ups are only slightly more expensive in gas! (but I would like to have reliable brakes first...)

Love this :D

I have a strange attraction to these cars... good luck!

These cars give me wood. Im gonna get one some day. And daily it. Excited to see what comes of your challenge effort.

This was a sleeper challenge car I've wanted to do for a while. Glad you've braved it! Good luck!

Next up, figure out the brakes, and there seems to be a lot of fuel/oil fumes in the exhaust, so I'll have to look at that.

Straight pipes!

Thanks for the support all!

When I came out the car this morning I was greeted by this image, don't know how it got here or what it is...

Anyway, I got to thinking a bit about the fuel filters yesterday, and thought I should also check the lines on the other side... Well, good thinking:

That lower line is cracked pretty badly, just about to leak I bet. So I fixed it. Another $1.50 in fuel line.

Also, I finished grabbing out all the rest of the sound system. Actually looks like quality stuff. All Rockford Fosgate, mids and tweeters, and dedicated crossovers and enclosures for the rears. I'll be listing it for sale in the classifieds in case anyone wants a great start to a system.

I also did some other rooting around on the car today. Started on the brakes. At the rear passenger wheel, the caliper was stuck, but it was also getting no pressure from the line. Boo. Also, I snapped off the bleeder trying to loosen it. I'm going to look into new calipers all around and possibly a master for safety. No use chancing it on old crappy/rusty parts. The rotors looked fine though, and the pads had plenty of meat (as you would expect if the caliper isn't getting pressure).

Next I took a look at the engine. I had a check engine light, and though the car started and ran well, the idle was a bit rough for a v12. First I pulled the oil cap. No outward crankcase pressure (or maybe even a little vacuum) so that would say PCV system is functional. There was a bit of 'milkshake' though on the bottom of the cap and in the filler neck. Oh no. I ripped the dipstick out, quick as a flash, but it looked great. Hmm. I also checked the coolant. Clear. Weird.

Looking around a bit, the radiator is brand new. Many of the coolant hoses look to have been replaced recently. Hmm.

Well, I wouldn't be surprised if this car had a headgasket issue in the recent past, but I also think that these cars often sit for long periods of time. Maybe there was some condensation in the crankcase that formed and caused the small bit of milkshake? IDK. All I know is it doesn't seem to be showing symptoms of HG issues now. Oh well.

As for the check engine light, I read the code. Driver's side bank only, intake air temp sensor fault. Look at the sensor, OH! ITS UNPLUGGED! Plug it in, clear the code, I have now run the engine through a few start/stop cycles and no check engine light is back. It is also idling MUCH smoother. Wow. Fingers crossed, but if only all check engine lights could be fixed like that.

Budget at the end of today: $1,101.35 + 1.50 in fuel hose = $1,102.85

The milkshake was common in my short mileage driven rx7s. Something something something about cold engines and that it was no big deal. I Do know it wasn't a head gasket in my case.

nedc wrote: Looks like someone changed the wheels to 16" E38 style 5s, which is not that unusual (I did it to my E32), but they even swapped out the spare to match...which is unusual.

I did double check this today and it is a 15 in the trunk. All 4 corners are 16x8s and the spare is 15x7.

How much ate you looking to get out of the crossover mid and pod setup?

Dusterbd13 wrote: How much ate you looking to get out of the crossover mid and pod setup?

I have them up in the classifieds... asking $60 for the whole shebang: Audio Stuff

Well, not a ton of action today, had the brother in law over. I did pull off all 4 wheels to make a list of things I need to buy to fix the brakes.

• all 4 calipers (fronts look ok, but the bleeders all broke off, rusted to the bores)
• one lug bolt - see below
• rotors/pads/lines all look ok, if the lines are cheap I might replace for good measure
• I've been wanting a motive pressure bleeder for a while, and this might be the excuse I need to get it

One of the wheels had a broken lug bolt with the rest of the bolt just hanging out in the threads. Luckily, it wasn't cross threaded or anything so it came out easily with a visegrip.

Also, I started pulling out interior pieces in the backseat area. Found $.76 more in change!

Budget used so far: $1,102.09.

I like it. I'm in to follow the progress!

Awesome

Minor build update: all my new brake calipers have arrived, so I can hopefully get the brakes going soon. A good buddy of mine can help me get brand new brake hoses all round (a big part of his job is fabricating new hydraulic lines), so hopefully this thing will have solid brakes soon. The current hoses look to be in ok shape, but no use in chancing something dumb like that.

I also had an idea, and I think this is the direction I will go: Go Big or Go Home

Nabbed another diff from a junkyard today. It's a 3.65 and seems to be limited slip. The one that came in my car is a 3.15 LSD. 200$.

Good news is this is the same diff case used in lots of other v12 and v8 BMWs, and most have even taller ratios than 3.15. So I may even be able to sell my stock diff to another enthusiast for very little budget hit.