E30 318i woes

So me and a bud are trying to get our little M10 E30 ready to go rallycrossing next weekend. Well, suddenly the car refused to start. I was pretty puzzled and did a bunch of poking around. Finally figured out that when we went to install a strut bar, we had put pressure on the distributor and broken the ignition rotor.

So I went out and grabbed a new one and threw it on. The car starts up now, but runs like absolute crap. I'm new to these old, mechanical distributors. I know ignition timing is advanced or retarded via vacuum on these cars. Apparently there is some timing adjustment in positioning the rotor...

So as I understand it, I need to make sure the engine is at TDC, and then line up the rotor with this mark? Does that sound right?

Should I have just replaced our dizzy cap while I was at it? In honesty, I've never even had to do timing on any of my other cars yet, so Im new to all of this. Thanks in advance!

You'll need to twist the distributor in the housing one way or the other to set timing, the vacuum only helps the advance curve. From memory, what you have there is "right" in that the car should fire.

Go to bimmerforums.com and look in the e21 section, I know there's a really good write up on how to time them (same motor, injection is different). I don't know the e30 section that well, but the e21 section I consider as good as this board. Haven't been on in a long while, so it may have changed, but I doubt it.

You're right, the E21 forum is still a go-to place for skilled advice. People like Layne, TomD, and epmedia can almost always get you sorted.

You shouldn't have to adjust the timing after replacing the rotor. Did the distributor get rotated somehow?

Honestly, I would look for vacuum leaks. These early L-Jetronic/Motronic injection systems were very sensitive to leaks.

If you put enough pressure on it to break the rotor, I'd think the cap is going to be suspect as well. Check it closely for cracks. I would be surprised if distributor got rotated, it should be held down pretty firmly in place.

2002maniac wrote: You shouldn't have to adjust the timing after replacing the rotor. Did the distributor get rotated somehow? Honestly, I would look for vacuum leaks. These early L-Jetronic/Motronic injection systems were very sensitive to leaks.

It might have gotten rotated. I didn't realize that there was ability for adjustment there, so when we were trying to fit the new rotor on, I wouldnt be surprised if we bumped it off by a few degrees or so..

When you drop the dizzy in, the cap will rotate a bit as the gears catch the cam gear, and it should wind up in a relatively decent spot to start the car. You then adjust it one way or the other to get the timing to "spec". You can feel the car running better when you twist it the right way.

If it doesn't smooth out, then proceed to check the L-jet system for vacuum leaks, etc...

It's pretty straight forward, you shouldn't have much trouble.

Thanks OldGray. Just to be sure, when you say "you then adjust it one way or the other", are you talking about rotating the silver wheel with the 4 teeth inside the dizzy (picture above), or are you talking about rotating the actual orange distributor cap itself? Thanks again!

BTW, for anyone reading this thread with similar issues in the future, this thread on Bimmerforums seems helpful:

http://www.bimmerforums.com/forum/showthread.php?965335-How-to-find-1st-cylinder-top-dead-center-%28Distributor-timing%29

Triple check that your plug wires are connected correctly. I've made that mistake before...

In reply to Desmond:

Man, my 320i has been apart too long...

I don't recall how the 4 teeth inside the dizzy move (yes it has been THAT long since I've done anything to it...), but you move the dizzy body in the housing; there's a 10mm bolt to tighten it down so once you've set the timing, you lock it down.

The rotor will stay stationary (since it's on the shaft connecting to the cam gear).

Let me see if I can find some pics to augment the words here....

The collar with the bolt running through locks down the dizzy once the timing is set...

Another picture... same thing really - with the cap on and car running, twist away - I forget which direction is advance and which is retard...

Edit: link to that picture, dist rebuild... dizzy repair link...

This link doesn't seem very useful, but it actually is. Once you're at TDC, drop it in just like it says:

https://www.bmwtechinfo.com/repair/main/027en/index.htm

From there it should fire (which, I think y'all had it running anyway), and then just twist and go.

Edit: dumb link (dumb poster?) - click through to get to electrical, and there's a section on removing the distributor - for installation it says turn the rotor some direction 3.5 cm and drop it in.

AWESOME info OldGray, thanks for taking the time with the photos and everything. Even a blind man could find his way now! I'll let you guys know how it goes.