e30 cab project

[roguetoaster]

You are on the right track, chase those items down and narrow the list of potentials.

[theroundcow]

if my ECU doesn't not receive power, what functions should be operable/inoperable? it is my understanding that a blown fusible link would only prevent the fuel system from functioning, not the windows/dash.

[bmwman91]

Correct, a blown fusible link only affects the fuel injection system (fuel pump, ECU, all the things it controls). However, I think that only the 318iS has it since it is part of the wiring for the trunk-mounted battery. If the convertible was converted to that setup, then you would have one.

I am still betting that it is some combination of a bad ignition switch and whatever nonsense happened with the alarm system.

[theroundcow]

hey everybody, solid update incoming : got the car started. new key + ignition didnt fit right, the steering wheel lock assembly fell apart, and then the ignition switch itself kept giving weird outputs. replaced the switch and it started! I still need to figure out if i can reassembly the steering wheel lock assembly or if i have to replace it *cry*. every single fuel line had been previously replaced with low pressure line + NOT fuel clamps, ended up replacing all of it. so it started! ran poorly then coughed and died. i taped up the various hoses that create vacuum leaks just to see if it made any improvement (are those male/male plastic nipples that connect all these hoses really from the manufacturer? or is this some sort of botch job?). I also cleaned off the crank position sensor with brake clean and the car ran MUCH better, smooth throttle inputs (even though the cable to throttle bottle connection isnt perfect). but then after running for a bit i heard a strange rattling begin to emerge and noticed some movement from the valve cover, turned it off. several of the valve cover bolts were loose and then i found they did not all match. off came the valve cover to reveal that nearly all of the female valve cover threads had been helicoiled, some not well (crooked). As i realized the job just got much larger, i called it quits for the day. ive also got a clutch master+slave on the way as the transmission seems to have the clutch frozen engaged, car rolls in neutral even with transmission in gear. i think after ALL this...it will drive.

*i also wasted a bunch of liquimoly oil and deserve a scolding*

[roguetoaster]

Research the mess under the intake for the vacuum system.

Bummer about the VC bolts, but whatever you do, replace the bolt grommets as the old ones often collapse to the point where they prevent actual clamping due to the bolt design.

[bmwman91]

*i also wasted a bunch of liquimoly oil and deserve a scolding*

Forgot to put the drain plug back before refilling?


Otherwise, good work getting it running. It's always amazing how terrible the "maintenance" that some people do is. Now you get to fix their work!

[theroundcow]

Forgot to put the drain plug back before refilling?


Otherwise, good work getting it running. It's always amazing how terrible the "maintenance" that some people do is. Now you get to fix their work!

*tail 110% tucked* yup exactly, forgot drain plug. hopefully if i experience enough shame itll be the last time i ever do something like that. Fortunately, there is some emotional attachment and respect for this car and its previous owner, so when i encountered the valve cover helicoils i just chuckled and held my glass up in their honor (may have contributed to forgetting drain plug). Cheers to everyone who takes the time to contribute to this thread, I appreciate each and every one of you.

[bmwman91]

Ha, well don't let the shame get to you I also did an M42 VC helicoil fix back when I was in my early 20's, and a few of them were not quite straight either! Forgetting the oil drain plug has not happened (yet?), but I know a ton of people who have done it.

[theroundcow]

well see if it keeps me up at night :) Pretty tempted to install studs into the head and use flange nuts similar to how the m20 does, im sure i could approximate the clamping force required for an adequate seal. has anyone ever seen something like this done?

[theroundcow]

ha just found your old posts regarding the stud conversion idea. im reading that there are two different materials = two different thermal expansion rates and there is concern over this. now that its 2020, has anyone experienced symptoms of fatigue failure in their studs or threads? studs or not, one of those helicoils is in there pretty crooked....i got replacement helicoils today + m6x1 tap to try and clean up anything that might be salvageable. still pondering the stud idea.

[bmwman91]

Ha, well I would say that basically every M42 I have ever seen in the last 20 years has had somewhere between 2 and (all) VC bolt holes stripped. I would wager that it is mainly from people over-torquing the shoulder bolts. BMW's design intent was neat and all, using shoulder bolts and rubber grommets to try to maintain compression on the gasket while leaving room for the CTE mismatch between the steel fasteners and aluminum VC, but it probably caused more problems than it solved.

Studs are an interesting idea, but you would still need to be mindful of the CTE mismatch and re-use the rubber grommets. Really, these things to NOT need to be tightened any more than is needed to get the shoulder to bottom out, and if you are worried about them working loose use some thread locker. The torque spec in the factory manual service procedure is 10Nm (89 in-lb). Well, that is the spec for basically all of the M6/G8.8 fasteners on the engine, and it is NOT a lot. I have basically always gone "by feel" with the timing cover bolts and whatnot, although with the current engine I started using a torque wrench, and I would guess that I probably tighten M6's to closer to 120 in-lbs when going by feel, which is apparently way too much!

Personally, I dislike studs in just about all cases because aluminum parts sliding on the get scuffed and make metal particulates. Repairing a botched helicoil job is a pain in the ass, I would imagine. I have never tried to remove one, but it looks like a chore. You could probably get the bad ones out, re-drill and use some Time-Serts that have a large enough OD to allow you to bore out the crooked holes.

[theroundcow]

thanks for the replies man, really appreciate it. I got a good chuckle out of your comments regarding bmw's 'neat' design. haha funny you mention time-serts, currently at work there is a discussion about repairing aluminum threads with either helicoils, keyserts, threadserts, timeserts...theres another one im not thinking of. Ill probably be investigating into which one would allow for the largest OD drill out to maintain the original thread spec. ive got a clutch master+slave on the way, hoping that job doesnt reveal further issues....

[bmwman91]

From what I have seen on the internet, the "which thread repair product is best" topic is up there with politics and religion. In non-structural applications, anything is fine if installed properly in my opinion.

[Robert Fisher]

I think Keenserts are much larger diameter than others. Never used them myself.