greghennings

Hey guys, i'm looking to do away with my vacuum advanced Accel HEI distributor for something that plugs into my Terminator EFI system that will control the timing. I was going to do Holley's Dual Sync distributor that just plugs into the wiring harness, but, i ordered it in December (in stock) and like that it was unavailable, and i've been waiting ever since. After contacting Holley they litterally have no idea when they're getting them in.

So i'm looking to explore some options, Holley does have an adapter to go from the Terminator wiring harness to a GM small cap distributor, but, where and what should i get? Or what anyone else's experiences are?

I already took the time to install an MSD Blaster pack ignition coil as that's what summit racing recommended installing with the Holley Dual Sync distributor. The bad part of the Holley distributor, is i lose the use of my analog tachometer, it would really be nice to keep that but if i can't i can't, i'll just use the tach on the monitor or i can probably buy holley's digital dash some day too.

zwede

You can use any small cap HEI, including parts store rebuilds or even one from a junk yard if you find a nice one.

As for the tach, I take it you have a cable driven tach? You can convert your tach to electric by using a tach from a 75-77 Corvette and keep it looking factory by swapping over the face plate.

BlowAMouse

I use the MSD Pro Bullet with mechanical tach-drive. It has a 2 wire output. I use it with the FAST EFI system on my ride.

any dizzy with either optical or hall-effect sensor will work better than points

good luck

greghennings

My tach is electric, the Holley dual sync doesn't come with a tach out line. I inquired Holley about this and they said the only way to get it is to buy an MDS cdi box, that will give a tach out, I'm not interested in another spending another $250 for that. Holley recommended the MDS distributors as another option, I'm sure their good, but they're even more expensive than Holley's $430 unit. I see Jegs has a unit http://www.jegs.com/i/JEGS-Performance-Products/555/40006/10002/-1. It's only $140, would this be what I could use?

Gale Banks 80'

As some one who is looking to replace my Accel Gen 7 EFI I have been looking at the Holley EFI set ups. And everybody I have talked to has recommended that I use the Holley Duel Sync Distributor. I would start shopping around at different vendors. Somebody must have one on the shelf.

zwede

Yep

dembo

I've got the DUI small cap distributor installed with a GM module for the Terminator timing control. At the Holley forum they really advocate using the Holley dual sync now (no failing modules).
It works ok, but I already had my tach converted to electronic (from a 75) before I went Dakota Digital.

Either way, I was under the impression that the dual sync doesn't work without a MSD box?
Nick

greghennings

As far as I can tell from reading Holley's instructions for the dual sync dizzy is there is nothing about an ignition energy source requirements. I remember emailing someone to figure out what I needed, pretty sure it was summit racing, and they just suggested the MDS blaster pack, simple ignition coil. Which was cheap compared to a CDI box.

The latest I have from Summit is March 31st to ship out. Ofcourse that's a random guess of a day. I did a lot of other work to my Vette this winter and I'd like to test it all but I can't because I have my engine set at 50 degrees btdc like Holley requires their dizzy to be set at and I really don't want to have to redo that.

I looked at other vendors and every one had a wait, there was a guy in eBay that had a few, but my luck it would be a decoy and I would still have to wait for him. Jegs had it on eBay but in the fine print it says might take a while to ship out, despite the listing saying its available.

condor7

I use the Jegs small cap dist with my Terminator. I went to NAPA and got the connector that you would need for one of the terminals. It is exactly the same as a coolant temp sensor pigtail connector. I already had a MSD6AL so am using that as well. Coil is the MSD Blaster SS. Everything works great. I converted my tach to electric a long time ago. Signal to it comes from the CD box. I don't know if you can get a signal just from the coil or not to trigger the tach. The dual sync does require a CD box (according to Holley). Failing module in a GM small cap dist? Kinda rare I think.

Kacyc3

I run the parts store dist. with my cmd950 set up and when I switch it to the HP I will be using a MSD pro billet, if you choose the MSD get a new Delco ICM to go with it as I have read the MSD ones are junk.

pauldana

I run one...
Mallory... it is an HEI locked in distributor,,,
And the reason i picked it, it is HEI... thus looks stock and do not have to put on an external cap out of the 60-70's...

Metalhead140

You don't need the msd box as the sniper has an ignition module built in. I'm using an MSD Pro Billet with my Fitech (effectively the same arrangement), and am using a 6al as i had it already, but have the wiring setup to allow easy bypass of the 6al if needed. It runs fine without the 6al.

greghennings

Well guys finally after just about 3 months of waiting the holley showed up. I was just about ready to order something else and i got lazy one night and didn't the next morning i got an email it was shipping out!

The setup so far has been a little tedious as the 15 minute instructional video doesn't include the fact i needed a firmware update. Even though my terminator ecu was less then a year old. The whole thing took most of my sunday but was it was fun working on my 1976 corvette and hacking on a laptop like a pro .

THE BIG problem, this freaking MSD 8207 ignition coil! I can't get any dang spark out of it. Last sunday i was trying it out, and the thing blew up, literally S$$$ the bed. So summit replaced it no problem, and i got the new one. I installed it tonight, went to use my timing light, wouldn't work, i said what the heck. Pulled a plug and cranked it, nothing. took the main lead off the distributor and put a plug in it and turned it on, nothing. Yes i chassis ground the plug while i test it.

MSD recommends using a ballast resistor in line of the positive lead if your not going to use a CD box, so i bought one of those too and that makes things worse. Instead of getting 12V to the ignition coil you get like 3 and then the thing gets hot. I tried running an 8 awg wire to the negative post just to see and that didn't work. I tested the coil for ohms, and it specs out, .4 primary and 4.4k secondary. I even ohmed my spark plug wires and tried my old plug wires (i bought new MSD 8.5mm wires) and still nothing. Its like my chassis isn't grounded but geses it has to be i've got one line right to the frame and another to the starter and everything else on the car works.

I don't understand how something so simple is kicking my a$$ right now!

greghennings

On another note cause this is driving me mad, o pulled the msd coil out and Jerry-rigged some wires and a spark plug and hooked the thing to my tractor battery and it does light my spark plug. I thought it should deliver a constant spark but evidently it doesn't? It would only light up my spark plug when I touched the wire to the battery. Of course I had my leather gloves on, it was still skechy.

So now I wonder if it's not getting through the distributor cap? I pulled it off, and I can't see anything out of place, the cap only fits one way. Time for bed, I'll probably figure it out around 2 am like everything else...

condor7

Wow, Hope you get this figured out. I am planning on converting over to the dual sync and I want to go DIS. Think I have most of it, parts wise, figured out. Looking for some sort of coil over the valve cover bracket for the ls coils, without drilling into my valve covers. Have perimeter bolt valve covers. Lots of different brackets for the ls coils but all require drilling into the valve cover. Anyone got some insight on this?
Please keep us posted on your issue. I have not purchased the distributor yet and now you have me a little concerned. If I mess this up after spending more $$ on this car my wife will throw a pillow in the garage. Hope it is something simple.

greghennings

So far my plan now is to get a cdi box like a msd 6al or summit makes their own and it'd $100 cheaper with good reviews. What I didn't realize is a cdi box outputs 450-550v to the ignition coil, where right now I'm trying to feed it with 12v. So I'm hoping this is the solution.

zwede

When power is connected to the coil the primary windings build up a magnetic field. When power is interrupted the field collapses and that generates a voltage in the secondary coil. As the secondary side has about 70-100 times the windings of the primary coil, the secondary voltage is tens of thousands of volts.

tl;dr: A spark is only created when power is disconnected from the primary side of the coil.

zwede

Not as big of deal as it sounds. When you interrupt power the voltage spikes. In a 12V coil the momentary voltage when ground is interrupted spikes to 200V. With a typical 100:1 ratio of an ignition coil that generates up to 20kV at the plug.

CDI bumps the 200V to 400-500V, so about 40-50kV at the plug, but there is a downside to that, namely that although the spark is intense it is short. So short that it often fails to ignite a lean mixture. This is why CDI generates multiple sparks at low rpm.

CDI is a good choice for high rpm engines as they charge the coil faster. Also good for engines with high cylinder pressures (forced induction, nitrous or high compression) as the spark is more likely to jump the gap due to the higher voltage.

greghennings

I'm getting this all now. So here's the trick, in the Terminator manual the wiring diagram for a GM small cap shows a pink wire going into the distributor, and leaving as a white wire (points trigger) to the "-" of ignition coil. Problem is with the Holley dual sync distributor there is no input/output leads. So whether I use the coil as a stand alone or with an cdi box, how do I trigger the ignition coil?

i wish they would make a wiring schematic for their dual sync dizzy, theres nothing about ignition or any kind of wiring.

zwede

The Terminator ECU does not have a built-in coil driver, so you need to either use an ignition (HEI) module or CDI.

You have the dual sync distributor. This only provides input signals to the ECU, it has no ignition module to drive a coil so you will need a CDI box to drive the coil.

The CDI will be triggered by the white "points output" wire. This wire sends a pulse each time the coil should fire, which is then amplified by the CDI and fires the coil.

Be sure to adjust the distributor and configure the ECU as shown here:



Btw, I have the Summit CDI you mentioned earlier and like it. It's well made and I've had no issues with it.

I have the Holley HP EFI. I'm basically doing the same thing you are for the ignition except I run a crank trigger and cam sync. But the only difference is both of those signals are coming from your dual sync distributor. Everything else is the same.