Alpina B6 2.8 running issues

E28 technical advice asked and given! Troubleshooting, modifications and more.
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

If you are lucky enough that the bosch sensor is correctly placed, you could theoretically remove the magnet inside of it (3) and have it react the the magic tooth only.
Image

Of course, I am throwing this on the table as a last resort, I could fabricobble something that works scenario.
If the bosch sensor size/format is ok, you would obviously start by sending Schaeffler the measurements.

Image
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Good idea. I just bought one of those viewing films.

Thanks
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

I just read a bit about the mu-metal, and it seems this material is used for magnetic shielding (it is not magnetic itself).
Maybe they welded this material over 1 tooth to turn it into the usual "missing tooth" used for timing; the other teeth being used for speed readout.
If that was the case, you could still try to place a strong magnet (i.e. from a hard drive) close to the teeth and look at their tips through the film.
Galahad
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Re: Alpina B6 2.8 running issues

Post by Galahad »

I would be hesitant to use something as strong as a hard drive magnet, maybe start with a fridge magnet?
I used a mu-metal enclosure at work; it's relatively sensitive and you don't want to have to re-anneal it.
JohnH
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Re: Alpina B6 2.8 running issues

Post by JohnH »

OP does your flywheel have the magic tooth?

How about using a motronic 1.1/1.3 sensor?
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

I did a visual check of the ring gear looking for anything welded to a tooth. After 2 go-arounds, I didn't see evidence.

Mark
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

I don't see a point in throwing sensors at the engine, without knowing where the reference signal is coming from.
According to the ford website, the mu-metal was spot welded in place. Probably like they do with battery tabs:

Image

If that was the case, I bet it just fatigued and flew away. The repair shop then probably threw a sensor at it because nobody knows the AFT system.
If it did break off, maybe the tooth will show as the one with the least wear (if it was fully capped with the shielding).

I figure the remains of the spot welds would be hard to spot down in there. I would look for those on the leading edge of the teeth (the side that doesn't get hit by the starter pinion.

If the magic tooth was found, i would just epoxy some e-bay/amazon shielding metal to it, test it with the viewing film and then crank the engine for a quick test.

As a side note about the sensors: AFT designed the ignition system, and it follows that they would use their own proprietary designed sensor as part of the package. Even if the bosch part did exactly the same thing.
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Not sure how good everybody's German is but here is an article from Auto Zeitung dated 5/84. It talks about the AFT distributorless ignition system sends 1920 different timing signals to the spark plugs.

Oh joy.

MP

https://imgur.com/a/2acrREt
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

That article doesn't say anything useful.
If your AFT system works like the one on the Ford, then you need to find out which tooth should be shielded.
Maybe Alpina in Germany could help. Also, did you get the parts catalog?
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Yes, I got the parts catalog. I was out of town for a bit. I'm going to inspect the ring gear with fine tooth comb tomorrow and post up any findings.

Thanks,

Mark
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

The Ring Gear / Flywheel is indeed an Alpina specific part for the B6 2.8/1. The B6 3.5 uses a BMW flywheel as seen in the longer part number. The flywheel in my car is part #11 22 602...out of the Alpina parts bin. As I mentioned before, I will crawl under the car today to thoroughly check for the mystery tooth.

Mark

Here are pix... https://imgur.com/a/ia93NhI
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Found the magic tooth!

After thoroughly cleaning the flywheel ring gear, I discovered the shielded tooth that sets off the signal for the AFT Crank Position Sensor. It has a tiny piece of gold colored mu-metal micro welded onto it.

I still haven't had any luck finding an AFT sensor or anyone being able to send me a picture of one that I can forward to Scheffler-Engineering (formerly AFT). They've asked for some pictures of the sensor to be able search their NOS parts bins.

Any help would be appreciated.

Mark

pic here... https://imgur.com/a/L6wlabo
JohnH
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Re: Alpina B6 2.8 running issues

Post by JohnH »

You could try putting a oscilloscope on it using the motronic sensor and see if you get a signal. If so you may not need an official AFT part.
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

I'm getting a signal using the Motronic sensor but the engine doesn't like it. Barely runs and shuts itself off after 7 seconds.
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

First thing to check is whether the mu-metal is actually shielding.
Like we said: stick a magnet close to the teeth and look at them through the viewing film. The magic tooth should block the magnetic field.

Check out this video I made; see how the shielded backing plate on this magnet blocks the field:

https://youtu.be/nJFMyWhyx7c
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

P.S.: I just took a closer look at your photo, and that mu-metal tab looks quite beaten up.
From Wiki:
Bending or mechanical shock after annealing may disrupt the material's grain alignment, leading to a drop in the permeability of the affected areas, which can be restored by repeating the hydrogen annealing step.

Just for funsies:
If you don't wanna mess with that tab just yet, you may try sticking a new one on an adjacent tooth. It's only like 3.5 degrees off. If the engine can hold an idle, then maybe the bosch sensor will work with a new tab in the correct spot.
JohnH
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Re: Alpina B6 2.8 running issues

Post by JohnH »

Some disjointed observations.

Hall effect sensors are also digital sensors and return a DC 0V and +V off and on signal, the Motronic sensor is analogue and returns an AC variable voltage signal depending upon engine rpm. Maybe -2v to +2V at idle and -12V to +12V at max rpm.

Hall effect (digital) sensors use 3 wires +12V battery, and earth/ground and a return signal wire.

If the AFT ignition control unit is expecting a digital signal, then one of the wires should show 12V with the ignition Key On and Engine Off (aka KOEO).

I think your engine has a non motronic flywheel. It has a TDC (OT) mark and a BTDC timing ball. You would expect the gearbox bell housing to have a small cutout on the top for a timing light. You have a motronic bell housing that has two holes for the motronic M1.0 timing sensors. It seems strange to me that Alpina would have fitted it so is it possible that the previous owner fitted it when they tried to use the motronic sensor? If they did then its unlikely that any sensor supplied by AFT would fit anyway.

Most modern cars use a hall effect sensor. Maybe you could find one that would fit with a bit of fiddling.
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

I have three wires running to the sensor out of the AFT smart box. AT KOEO I measure 5V on two of the three wires.

I've also been busy looking for this AFT sensor and may have sourced one in Germany. I'm waiting on confirmation and pictures. I will keep everyone posted.

Thanks,

Mark
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Found that elusive AFT Crank Position Sensor!

After looking on Ebaylokal.de (basically Ebay's version of Craigslist in Germany), I reached out to a guy who was selling some Alpina B6 stuff. I shot him a note if he happened to have some AFT ignition items, specifically the sensor. After some searching in his parts stash, he found one and it looks to be in excellent condition. He had purchased it for a project that never came to fruition.

I'll keep everyone posted once I get it in my hands and installed.

Thanks,

Mark

https://imgur.com/a/qWTZdNj
JohnH
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Re: Alpina B6 2.8 running issues

Post by JohnH »

Thats great news! Looks like it will fit the motronic bellhousing as well.
Federico
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Re: Alpina B6 2.8 running issues

Post by Federico »

Any news about the Alpina?
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Hello everybody,

Thanks for checking in. I'm currently in a holding pattern. The car still didn't run right even with the correct crank position sensor. I contacted AFT in Germany and they offered to check out the sensor and the control unit. I sent everything over a few weeks ago and am waiting to hear back. If they check out fine, then it's got to be the flywheel with the mu-metal that's defective. I've got a line on one in Germany that's been refurbished but am waiting to hear back from AFT.

That's the latest. I will post up news soon.

Thanks,

Mark
blammogarage
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Re: Alpina B6 2.8 running issues

Post by blammogarage »

Update

Hi all. I'm still trying to get this 1985 Alpina B6 2.8 running. I've sourced a good crank sensor, had the Alpina AFT smartbox checked by a company in Germany and repaired! but I'm still experiencing the same issues of the car not wanting to run properly...hardly at all. Now I'm thinking that it's the Mu-Metal on the ring gear. It's been partially removed by wear and tear now is pretty much all gone due to my attempts of gluing new pieces of Mu-Metal (that I've purchased on Ebay) onto the tooth. My attempts have been futile. So now I'm convinced that I just need a new flywheel/ring gear with the factory Mu-Metal micro-welded in place.

Here is a picture of my tooth before I started to fiddle with it (gluing and using epoxy new pieces onto it).

That's it for now.

Mark

https://imgur.com/KqSLdpt
JohnTickford
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Re: Alpina B6 2.8 running issues

Post by JohnTickford »

Hi Mark

Just come across this thread I have the same AFT unit in my Tickford Capri with the same flywheel set up. I have two spare AFT units that i need testing one from a Tickford Capri and one from a Ford RS1600i. Same units just different mapping. How are you getting on with you problem? I see you found the web site (A400mod.com) with the Tickford Capri info you can see some of the owners have spent some time on these units .Some of our cars now have swopped the AFT units out but I am keeping mine original as long as possible. (I have had the car from new in 1985) I also have a spare sensor but I see you did eventually source one. Can you tell me who in Germany you had your AFT unit checked out and repaired. (I am in Spain so Germany is practically next door) We did have a place in the UK but he retired this year and I am having problems finding another source. Good Luck
Last edited by JohnTickford on Jun 21, 2021 8:08 AM, edited 1 time in total.
blammogarage
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Location: columbus, OH

Re: Alpina B6 2.8 running issues

Post by blammogarage »

Hi. His name is Andreas. Below is his email address. Drop him a line and he should be able to check over your ignition system. Best of luck. I'm still tinkering with mine, although there is a guy in Russia who has a system that he's working on. I may give it a try once he has it refined. What are some of the other Ford owners swapping their systems out for? I'm curious.

Thanks,

Mark

andreas-nithammer@online.de
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