Verifying Ignition Timing: MS2

Discussion pertaining to positive pressure E28s.
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tschultz
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Verifying Ignition Timing: MS2

Post by tschultz »

Hi guys, I am trying to verify my ignition timing and can't really see the the cam/timing mark to be able to verify with a timing light. I know when it aligns the engine is at TDC (0 degrees advance, right?).

I had it set at falling edge 87 degrees as the trigger but wanted to verify it dead nuts... I set my ignition timing to 10 degrees fixed and then try to check it with the light but can't see well enough to know how exactly it is set.

What have you guys used as a pointer or to identify TDC plus/minus the ignition timing? It seems you can easily see the toothed wheel on the alternator side and this woul d be the best place to check it...

Do I set the timing light advance to zero or do I set it to the matching 10 degrees?


Any tips or tricks?

Has anybody used the bellhousing sight glass like on the older m30 cars? I couldn't seem to see the ball when I set timing to 22 degrees. But it is in an obscure place to be able to see with the timing light.
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

I made a pointer from a piece of 1x2 aluminum angle I had. I placed mine on the driver side, front of motor, where it's easy to see. Once you have tdc marked on harmonic balancer at the pointer, set timing light to 10*,set ms at 10*, adjust trigger wizard to match light and ms.
Ju@n
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Re: Verifying Ignition Timing: MS2

Post by Ju@n »

You can actually see it, but only from a very specific angle, a bit towards the alternator... really hard to explain but keep on checking and you'll see a small "cylinder" coming out of the block right above the harmonic balancer
Cannedchowda
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Re: Verifying Ignition Timing: MS2

Post by Cannedchowda »

I'm curious to know this as well, as soon I will be doing the same thing. So if engine is verified at TDC with existing mark. I create a new mark, in a less conspicuous spot on both engine and balancer. Next ,I will be making my own timing tape.
Next, Following these instructions

https://www.diyautotune.com/support/tec ... se-timing/

Will my new TDC mark (balancer) be showing at 10 degrees advanced on my timing tape? Thus being said if it is off, that would be my trigger wizard offset value?

I have never used a timing light, or megasquirt, sometimes the way I drive you'd think I'd haven't used a car yet either.
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

you don't need timing tape, just a tdc mark, then you use an adjustable timing light. Set the timing light to 10* and it should light the tdc mark at the pointer.
I really respect the BMW engineers, but the timing mark at the bellhousing was a screw up.
Cannedchowda
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Re: Verifying Ignition Timing: MS2

Post by Cannedchowda »

Why 10 degrees? Is that factory timing? This pointer you speak of, the mark on the engine block?
tschultz
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Re: Verifying Ignition Timing: MS2

Post by tschultz »

marc79euro645 wrote: I really respect the BMW engineers, but the timing mark at the bellhousing was a screw up.
To be fair, the system wasn't designed to adjust timing. The bell housing sight glass was available for that with mechanical distributors.
Cannedchowda wrote:Why 10 degrees? Is that factory timing? This pointer you speak of, the mark on the engine block?
Because this is the angle generally used for idle. But 10 is somewhat arbitrary also, it could be 15 if you wanted.
The pointer is something you have to make shift.
Cannedchowda
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Re: Verifying Ignition Timing: MS2

Post by Cannedchowda »

My pointer will be merely a dot of white paint. At TDC. One on block, one on balancer. Is ignition timing at TDC 0 degrees? If So, therefore when I set timing light to 10 degrees, balancer mark should be offset 10 degrees when timing light fires?
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

The engine idles at 10*typically +/-, depending on tuner.
When idling the timing light set to 10*, the light will flash showing tdc marks lined up if timing is set right, and should correspond with megasquirt.
If not, change trigger wizard to get light to match megasquirt, or move dizzy if you have old style.
Cannedchowda
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Re: Verifying Ignition Timing: MS2

Post by Cannedchowda »

Perfect thanks for your help. Just for extra clarity, this alm being said, if I set timing light to 0 degrees, TDC mark should be approx 10* off of TDC mark.
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

right!
tschultz
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Re: Verifying Ignition Timing: MS2

Post by tschultz »

Strange when checking timing on my car today, the alignment mark was ~35degrees off tdc. I was set to 10degrees in MS and 10 on my light. and neither was close.

When i adjusted the light to 40-45 the marks started lining up.

My wheel settings are 87 degrees and I know I am within ~3 degrees of where it should be...Any thoughts?
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

Do you have a dizzy w pickup, or 60-2 ?
Trigger wizard was wonky for me. I set mine to 0 and rotated dizz to get them right.
Also I had issues with predictor algorithm. I was getting scatter with 1st derivative, switched to last interval for solid strobe.
tschultz
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Re: Verifying Ignition Timing: MS2

Post by tschultz »

60-2.

Maybe my timing light is messed up?? I am pulling signal off #1 and then set timing light to 10* and MS2 to 10* fixed. The mark is ~30 degrees before alignment of TDC.

I can try setting trigger angle offset to 0 and finding the correct angle while cranking I guess...
marc79euro645
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Re: Verifying Ignition Timing: MS2

Post by marc79euro645 »

It sounds like your doing it right to me. I don't know about 60-2. Please post what you end up with. I have a 60-2 damper to install, but haven't yet. I was thinking of trying it with my early style bracket, and vr pickup, as I have several of them. I'm not sure it would even locate the sensor properly, so I probably just need to get the proper pickup and bracket.
good luck
tschultz
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Re: Verifying Ignition Timing: MS2

Post by tschultz »

I'm set to 87 which would seem to be correct from below.
ianwood wrote: May 25, 2012 1:22 AM OK. I think I might have figured this mystery out. There is indeed 107 degrees between the TDC mark and the sensor. The difference (and all my confusion) has to do with where the O | T mark on the 60-2 is in contrast to the tooth that MS triggers off of. If you rotate the crank so that the O | T mark lines up with the mark on the timing cover, the tooth that MS triggers off of (the first tooth after the gap) is a little over 3 teeth away. At 6 degrees per tooth, that's about 20 degrees. So take 20 degrees away from 107 and you get 87 which happens to be the MS trigger angle for the falling edge (VROUTINV).

So, it comes down to this: at TDC, the sensor is 87 degrees (or 84 for the rising edge) past the tooth that it triggers off of. Ah, I feel better now! From everything I've read on e30tech, it is 84 for the rising edge trigger and 87 for the falling edge trigger.
It is just strange my light does not match up. Car runs fine.. I just wanted to check it to be exact.
euroshark90
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Re: Verifying Ignition Timing: MS2

Post by euroshark90 »

When setting trigger offset, I switch to the fixed timing function instead of use table. I have a wasted spark setup, so having fixed timing dialed in causes it to read wonky due to it firing twice. Set it to 0 degrees, and line up with the mark on the timing cover and balancer with trigger offset.
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