Anyone know about these? I think this would complement my Holley digital fuel injection system very well. MSD part number 8660. Not listed on Summit or Jegs. I found it on a certain website that FTE software does not like at all, see below.

I was going to post a link, but the FTE software refuses to post the message if I do.

Anyone know where I can get it cheap?

 

A crank trigger will be more accurate than a dizzy mounted trigger for sure. When I convert my engine to FI, I intend to do the entire engine management routine, including crank trigger. Hopefully by the time I can do it, internal combustion will still be legal.

-Scouder

 

Dumb question, maybe not, but why would it be more accurate than a dizzy mounted sensor? Mechanical advance?

 

It would be more accurate because the signal wouldn't have to go through the timing chain, distributor gear, and distributor shaft.

The way I think it works, is you set the crank trigger at 10 BTDC. You tell the engine management computer (Holley Commander 950) that you've got a crank trigger set to 10 BTDC. Then, it adds whatever additional timing you want, and sends a signal to your MSD or other ignition box, which then fires the coil, which sends the spark out through the distributor and finally out to the engine.

In the engine management computer software, I can set a spark advance table based on the MAP sensor and engine RPM. This gives you both what would have been your mechanical and vacuum advance. It also allows you to do additional cool things, like crank up the idle timing so it idles smooth. You can set the timing exactly how the engine likes it. You can even add timing based on engine temperature!

I've currently got a thread in the "Electrical Systems / Wiring" forum about an ignition box I found out in the garage. If I can save money by not having to buy an MSD box I will. Go check it out.

 

Rusty, save your money.While I haven't heard a lot of reports about their crank triggers, there have been sevearl reports about MSD dizzy failures. My guess is the tech for a magnetic pickup on the crank is not that differant from the tech needed to make the mag/pick to go into a distributor. That doesn't seem to be MSD's strong suit. Their ignition control boxes are pretty good though. I have a Jacobs computer on some of my stuff, but I still trigger that with a duraspark dizzy. You could do the same with MSD stuff. A crank trigger seems to me to be solution looking for a problem......and there is no problem. It would seem to be an exspensive way to leave your self vulnerable to problems with mud or snow goofing up the timing when the dizzy already does an excellent job. DF, on lunch @ work

 

That's just the thing. The dizzy doesn't do an excellent job. With the old stock 360 dizzy, the dwell walks around all over the place. I have a Mallory Unilite distributor, but if you sneeze on the ignition module it burns out. I have the old stock distributor in there now. It turns out that connecting the battery (with everything wired up right) burns out the module. And even if there was the perfect distributor, I could never get the timing exactly where I want it.

Not only that, but the Commander 950 can do some other cool things with the spark, like run a knock sensor. It also has idle spark contol, to where it can adjust the spark at idle to better control idle speed. I could also make up an optimized timing map for various fuels, like E85. With a distributor, these are non-options.

They specifically say not to pick up the timing signal from a magnetic distributor like the duraspark in the instructions. They think there will be too much noise on the line that way.

I really dont see what a little mud or snow would do to the thing. It's magnetic; unless I drove through a puddle of iron filings, or something shorted out the wires. Besides, this is a 2wd truck anyway. It has absolutely no business in the mud or snow. The phrase "beached whale" comes to mind.

If I'm driving this thing in mud or snow, either:

a. Take me away from the weed, mushrooms, etc, NOW, or
b. uh, yeah, look back to a.

 

VERY good point. thanks!

 

I've thought of this too. Race car has very wobbly timing. Few degrees here and there at speed. Chain, gears and slop in timing plate in dizzy will all add to the slop.

My damper is chebby pattern, so I would figure I could get the cheapier version(since it's chebby) and make the mount for the pickup(since I'm sure the chebby mount won't work on an FE).

Lock out dizzy, put in total timing and bingo...stable timing. Leave ignition off to start crankin..and hit ignition to start. I helped install one of those timing computers in a buddy's Porche. Worked pretty slick...just don't know if for a race car it's worth the added money(another couple hundred bucks).

 

Just thought of another advantage: I can have the Commander 950 run a rev limiter too!

Edit: I'd really like you guys to go review the thread in the electrical forum. I found this old capacitive discharge ignition system out in the garage, from many years ago. It's a "Knight KG-372". I figured some of the more experienced members might remember it or know what it is.

 

or c. Stop by for a beer, cause you are probably near my house.

-Scouder

 

Not sure about the Holley - but the other EFI (FAST, DFI) systems actually do timing backwards. You set the base reference to something like 50 degrees BTDC, and then the computer pulls timing away to hit your programmed target number.

You need the reference timing point further ahead than the curve ever goes so that the computer has time to "think" and trigger the spark. You set it way ahead because the computer does not anticipate the signal - it reacts to it.

I have a crank trigger on my EFI FE. The crank trigger also helps because the very high base reference timing point will get you into trouble with rotor phasing - the relationship between the tip of the rotor and the distributor cap terminal when spark occurs. A crank trigger seperates the signal and distribution functions - allowing you to optimize them individually.

Barry R.
Survival Motorsports

 

You're right! I went and re-read the manual. You're supposed to set the crank trigger timing to 10 degrees higher than your maximum timing. So I'll probably set mine at about 60 degrees, figuring this thing might like some additional timing at cruise.

Oh, and Barry, can you get these crank triggers? The site I found them on shows $357.70. If I can get one through a board sponsor, that would be preferred!

 

those setup's should only be a simple VRS magnetic pickup, and I'm pretty sure I've seen em' go for like $100 or so. I plan to run one in my motor, w/ a Mallory ignition box cuz I have a few friends w/ MSD's...well 6AL's neways and they are fried after only a year old. Some day I wanna figure out a way to run a waste-spark setup on my FE w/ EFI

 

Well I have been out of the Hardcore Hot tip Ignition set ups for a long time....But with that said..after talking to a couple friends that drag race NMRA ....they all run crank trigger systems, comp. controlled....and the set-ups very as much as the wallet will afford....

But they all say..its "Dead Nuts Timing".... But price for a street Machine.... I'd just use the Davis Unified Distributor and the Infamous Rollmaster timing chain...

I dont want to have my girlfriend sitting on the laptop during cruise ins...Or Drag Night!! LOL..

JMO...

Russ

 

the way I look at a trigger wheel, is that manufactures stopped using dizzys back in the 90's....and started using vrs, and hall effect, and sometimes even LED optic crank position sensors, and I'm sure they did it for a reason, so it wouldn't hurt on an old carb'd big block. and it's not THAT expensive to do. as long as the carb remains at the top, and not some injectors!.....JMO