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Anyone setup an MS to run the VR Dist?


naviathan

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What's the highest you would recommend? I tried 90 and even tried adjusting the distributor and it wouldn't crank like it did at -10. I read that only wasted spark systems should be using negative trigger angles. Might that have something to do with why it runs at -10 and why the timing mark jumps occasionally?

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I've tried everything. I had it as far as 130 (yes I know 6 cylinders = 120* 130 would be more like 10*) and it would fire at 120 and 130 but not at 0 or 10. This thing acts like a software problem to me. I pulled apart my third distributor last night and locked it out. This time I didn't remove the mechanical advance I just pulled the upper assembly and tack welded the mechanical slots so it won't move. I also put the screw back in for the vacuum advance and tack welded it to the lower plate to lock out that part. Of course this was after I drained the battery and the jump box again so it'll have to wait until tonight to see if this distributor is any better. At this rate if I can't get this running before the wife's American Idol auditions I'm pulling it and throwing in an MSD box just to get it off the ground. It seems to me that there's way too many things that can throw off the VR circuit in this. Of course I'm sure fresh plugs and wires couldn't hurt. I don't want to buy new ones until I get it at least to start and idle on it's own.

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IT RUNS!!!! WOHOOO!!! I think I'm out of gas now, but hey I got a bit of tuning in for the idle before it died. For anyone having issues getting it started here's what worked for me.

I reset my dizzy and everything to TDC. I filled my advance table with 0s and set my trigger offset to 0. the I pulled the fuses from my injectors power to keep from fouling the plugs as I have been doing quite a bit of. Then I went in increments of 10 until I could see the timing mark. I made it 50 and caught the mark around 40* BTDC. From there I bumped it by 5 to get ti where it was close to lined up. My final offset ended up being 72.5*. Odd, but from the rest of you in the forums that seems normal I guess. Anyhow, I put the fuses back in loaded up a decent advance table and boom! she started right up, not problems. Of course it was really rough. And still is, but it's almost there. I went through a series of datalogging and running the VE Analyzer before I get fairly steady idle. Anyone using the MSA Stage II cam? That thing seems really noisey or maybe I just need to readjust the valves. It's a mild clacking sound. Not what I'd consider super loud, but enough that it raises some concern compared to stock. Well, tomorrow I get some gas in it and start tuning again and I'll take it for a drive. Although the engine bay seemed extremely hot the temps at the gauge were perfectly normal. I think that may be from the header though.

 

Data log attached. I think this is where I ran out of gas.

datalog200708041830.zip

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Funny enough, I am having a few problems with a similar setup. I am trying to run MSnS-e using the e12-80 for an input signal and the vb921 to run the coil. I filled both advance slots with JB and disconnected vacuum advance. After figuring out that my protocar assembled unit was configured for MS2 spark and not Extra spark, I got it running. I think i have a trigger angle of 20ish. It runs pretty good until i try to use dwell control and the timing jumps up to 45ish. It also wants to cut out and backfire around 3500rpm. I put a 1k resistor from the neg on the e12-80 to coil positive, but maybe the module doesnt want to play nice? I will check out my trigger tomorrow, but what dwell setting are you guys using?

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I have my dwell set at 3.0. Don't go any higher than 3.1. I set mine at 3.6 one time and I have the blown VB921 to show for it. Just removing the vacuum advance isn't going to do it. You need to lock the upper plate to the lower plate somehow. I would recommend putting the screw for the advance mechanism back in and JB welding it on the bottom. I did this with my last distributor I locked out only I actually tack welded it. Let us know how it goes.

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What does the vb921 act like when it is blown? Also, what makes it so special, could it be replaced by a transistor with similar ratings? After all that BS with the board settings, and dwell issues, I'm beginning to think maybe I fried it. I filled the slots on the mechanical advance with JB. It felt really solid too...

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Yes but you need to keep the vacuum advance plate from moving as well as the mechanical advance.

The VB921 is the coil driver. It's used in place of the 12-80 ignition module to trigger the coil. You pull the module off and run pin 24 (if you have the DIY harness it's labeled IGN and has a ground shielding and center wire) to the red wire and the ground shielding to the green wire coming off the reluctor coil. That will give you the VR input which you have to have MS jumpered for. Then you run pin 36 (labeled Pin 36 in the harness) to the coil negative. There's no pull up resistor needed for any of this.

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I was using the pullup resistor based on Moby's sketch using two 4pin HEI modules. I guess the 12-80 doesnt behave exactly the same as an HEI, maybe some crude dwell control. Unfortunately, my harness does not have any sheilded wires :(, but I will try hooking directly to the pickup coil...

 

Also, has anyone found a good source for the small size spade connectors used inside the dizzy?

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  • 3 weeks later...

I hate to see this thread die with only a handful of people saying they're running a locked VR distributor, and only one who might be done and hasn't had problems with their setup (X64v). there has to be more.

 

things that should be in this thread but aren't:

-R52, R56 adjustment

-predictor algorithm settings that work (last interval, alpha beta gamma, 1st derivative, etc)

 

also possibly:

-Mask settings

-Pulse tolerances

-Advance offset settings

 

I'm running a locked VR dist, using the VB921 to control the coil with basically stock wiring, but i'm having occasional spark dropout problems. Since the spark timing algorithms use the VR pulses to calculate dwell, ign event, etc, getting a VR distributor to work means more than just getting a good RPM signal i think.

 

or maybe my spark output is hosed and i'm just blaming the input circuit.

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I hate to see this thread die with only a handful of people saying they're running a locked VR distributor, and only one who might be done and hasn't had problems with their setup (X64v). there has to be more.

 

things that should be in this thread but aren't:

-R52, R56 adjustment

-predictor algorithm settings that work (last interval, alpha beta gamma, 1st derivative, etc)

 

also possibly:

-Mask settings

-Pulse tolerances

-Advance offset settings

 

I'm running a locked VR dist, using the VB921 to control the coil with basically stock wiring, but i'm having occasional spark dropout problems. Since the spark timing algorithms use the VR pulses to calculate dwell, ign event, etc, getting a VR distributor to work means more than just getting a good RPM signal i think.

 

or maybe my spark output is hosed and i'm just blaming the input circuit.

 

 

Yeah i've been wondering about adjusting those two pots as well. I have a scope, but not quite sure how to "tune" them.

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Ok I got mine working before I wiped out my cam. R52 and R56 are turned fully counter clockwise as specified in the assembly instructions. Predictive algorithm I have mine set at default alpha beta gamma with no problems. Advance offset (aka trigger offset) on mine ended up being 72.5, but it seems others have some up with different numbers. The rest I'm not real sure as I don't have my MS in front of me to check.

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I've been running with my pots all the way counterclockwise as well, and it seems to work well enough. I had R56 one full turn clockwise and R52 out two full turns clockwise with no noticeable effect. I'll have to play with that more; maybe adjusting it will improve performance at higher RPMs.

 

i want to put my oscope on my VR line while i'm driving to see if my tach drops correspond to noise on the VR line, but i can't power the scope in the car.

 

i've run trigger offsets as low as 28 and as high as 92ish. i really wanted to get to 10 so i could try "trigger rise" for starting options but things got erratic below 28. i figured i'd be able to get to 10 since it is a locked stock dist and my stock dist is set at 12. could be the algorithm gets screwy at such low offsets. at 92 starting was very difficult (3,4,or 5 skipped pulses). 50-70 is happiest, 35-40 is ok.

 

I've played a lot with A-B-G but last interval seems best. maybe i haven't played enough.

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