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Discussion Starter #1
distributorless ignition?

Hey, was curious if anyone has tried to put a distributorless ignition system in a GT? Was kinda thinking about doing it, but looking at it a little more I'm thinking I'll just put in a nice electronic ignition system. Just curious if anyone had done it before.
 

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Yes. Any engines that will be run past 7000 RPM will benifit from it. But it will be expensive and not worth it for anything less. ...about $700 + some machine shop work if you don't have the capability). If you're going racing, email me off line and I'll give you more info.
 

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Compufire ignition to be tested

Well, I ordered a Compufire DIS-IX 'distributorless' ignition today, I'll keep the group informed as to how it works once I install it. It replaces the OEM cap and rotor with a trigger mechanism (however the distributor is still retained), and has a dual coil pack to distribute the spark to the cylinders. This should at least theoreticaly eliminate the typical spark-scatter Opels have at higher rpms. Ignition timing is set the normal way, and I'll have to swap the wires around to suit the Opel's firing order (the VW it's designed for has a different sequence). Supposedly good for 60,000 volts, and with two coils there's more time for saturation and for cooling. We'll see.....

Bob
 

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Discussion Starter #4
You ever try a distributorless with like an MSD ignition? I'm thinking of going with an MSD DIS-2 ignition, finding a good 4cyl coil pack, and fitting a crank angle sensor on the front pully for my whole setup.

Looking forward to hear how your test goes.
 

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Price tends to be the issue there. I've done the Electromotive TEC-2 on two vehicles (non Opel, and not my own), and it required quite a bit of work to get the crank sensor correct. Air gap was .030", and prone to damage from road debris and even from harmonics of the crankshaft.

The MSD would cost quite a bit more than the Compufire....it's currently $175 on special. Not that the MSD/ TEC-2 type stuff doesn't have its place, but since this will be used on my ITB car, it doesn't make sense to invest a $600 ignition on a $2000 car with a junkyard engine. On a high buck turbo engine with extreme cylinder pressures, or a high rpm NA engine it makes perfect sense. I surely wouldn't bother with that good of an ignition on anything under 150 hp, it's a waste of money and unnecessary for proper operation. Like putting titanium valves in an engine that doesn't get revved above 6000 rpms, why bother? The best bang for the buck I've found for Opel ignitions has been the Crane XR-3000. We'll see how the Compufire compares in value.

Bob
 

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Got the Compufire in today. Looks like I need a tach adapter to figure the pulses out...the tach won't work otherwise. Also might need a harness extension, as I believe the stock cabling is too short for proper permanent mounting. Either way, it will be installed this weekend, and results will be posted!

Bob
 

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Damn, damn, damn, damn....

Damn! Well, after reading the instructions and doing a trial fit onto a spare distributor, I now realize this will be more involved than originally anticipated. The phasing of the Opel rotor relative to the 'lobes' on the distributor shaft is different than the VW that the Compufire was designed for. It's probably off by about 20 degrees or so. So even if the rotor and cylinder are lined up, the firing occurs at a different time. Looks like I'm gonna have to customize the trigger rotor, or steal some parts from a VW distributor and fit them to the Opel. The never-ending saga of modifying Opels goes on......

Bob
'It's either easier than envisioned, or harder than you can imagine, but either way, nothing goes as planned!'
 

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Well, I *think* I have the whole distributor phasing/firing order thing all worked out with the Compufire. Not only is the phasing different from a VW, and the firing order, but also the location of #1 cylinder on the distributor! I hope it works, we'll find out tomorrow. As it is, had I just installed the unit 'as is', #1 cylinder would have fired about 30 degrees too soon, then #4 would have fired, then 3, then 2.....all out of phase. Would've sounded interesting I'm sure.
 

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Success is sweet....

Damn, I'm psyched right now! I figured the new firing pattern for the Compufire last night, and this morning dug into the car I was using as a test-bed for the new ignition. I tore off the XR-700, and aligned cyl #1 for firing. Then, I had to turn the distributor so that #3 on the distributor was firing when #1 was @ TDC (because of the VW's phasing being different). Fitted the Compufire unit onto the distributor, then ran the #1 wire from the coil pack (actually #3 for the Opel) to #1 cylinder, then the #4 wire from the coil pack (next in line on the VW's firing order) to cylinder #3 (this is #4 on the Opel's distributor). Next the #3 wire from the coil pack was run to cylinder #4 (#2 on the Opel distributor), and finally #2 wire from the coil pack was run to cylinder #2 (this is #1 on the Opel distributor). I checked to be sure the timing was close to TDC, and turned the key. It fired immediately! I timed the engine to 10 degrees BTDC (normal for this particular engine) and voila! Throttle response is awesome, way better than the XR-700's, and better even than the previous ignition consisting of an XR-700 trigger, Jacobs computer, and Jacobs Ultra-coil. And NO distributor cap or rotor to wear, and NO chance of arcing, ozone build-up, or cross-firing! In fact, the distributor can now be completely sealed with silicone from the environment, no breather holes needed. And all for $175 on sale. Just gotta get the tach adapter wire now (didn't need the harness extension wire BTW). Sweeeeeet!

Damn, I gotta take a cold shower now.....

Bob
 

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Recomendation?

On the Bob's 1-10 scale of things to do to one's Opel, where would you put this, Bob? By the time you buy a new coil, points eliminator, cap, rotor, wires and such $200 isn't really much more expensive. Is the extra $ worth it? I lean torwards "yes" myself, and will be ordering one shortly, but would the average Opeler gain much?
 

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Tough call, it depends on the state of tune of the existing engine I'd think. For a stock engine, it's probably overkill, unless you like the 'wow' factor...it looks pretty neat under the hood, and it's nice eliminating the cap and rotor.

Once I figured the firing order out, it was VERY easy to install. Press the supplied trigger over the distributor shaft, snap on the sensor unit over the top of the distributor, screw the coil pack to the inner fender (this is also the ground), plug the harness from the coil pack into the distributor sensor, run a 12V key-on wire to the coil pack (don't use the stock resistor wire), and attach the spark plug wires. Literally 15 minutes to install. I give it an 'A' for installation simplicity.

For a reasonably modified engine, I feel it's a way better deal than the Pertronix, MSD, Crane, etc. I have yet to try it out on a 'crazy' engine with a lot of rpm potential, but theoretically it should be better. I took a few photos of the unit in the car, and a few others of the 'mess' I removed, consisting of the old XR-700 and trigger, rotor, cap, wires, Jacob's, and Jacob's Ultra coil. The amount of wiring alone that is avoided is worth using the Compufire! I'll post them once I can download them into my computer.

Bob
 

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This is the 'spaghetti' I removed from the car, consisting of the cap, rotor, plug wires, Crane XR-700 pickup, Jacobs computerized ignition, and Jacobs Ultra coil. TOO many wires....
 

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Here's the replacement for the distributor cap. There's a 'rotor' with metal inserts for the electonic pickup under that 'cap', and then the cap lines up with the slot in the distributor, and the standard spring clips retain the new 'cap'. It's all primary-voltage stuff, here, so no chance of cross-firing.
 

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Here's the coil-pack, consisting of two coils with two terminals each. They're batch-fired, so there are two sets of sparks going at any given time, but wasted-spark ignition is fairly common these days. It costs a lot more to get into the 'one spark per revolution' type of ignition. The coil case must be attached to sheet metal so it's grounded, and vertical orientation with appropriate air-space is essential to prevent the coils from overheating. It's all in the instructions.....

Note there's one red wire feeding the unit (12 volt positive, key-activated), and a plug-in harness for the distributor sensor, and another harness for the tachometer adapter. The adapter is needed to correct the signal received from two coils, and lets the tachometer 'see' only one coil so it reads correctly. I'm gonna order one next week.
 

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And lastly, here's an overview of the entire installation. The wires worked out fine ironically, even though they're made for a VW Beetle. I just used wire-ties to re-route them neatly. As you can see, there's a lot less crap under the hood compared to the old ignition system. And today I got to do a bit more testing with the car. Yesterday I only fired it and revved it up a bit (nice throttle response), but today I got to beat the hell out of the car, and it performs beautifully. I can recommend it wholeheartedly for those people running modified engines, it really does the job of a $500 ignition, but has a lot less parts to potentially break. Can't wait to get it out on the track.

Bob
 

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Compufire

Where did you Order your Compufire DIS-IX?
-civin
 

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I ordered mine from www.doghouserepair.com , and received it in two days. It's on sale right now for $175, I think they normally sell it for $185, and the list price is $249. Don't forget to order the tachometer adapter too! Don't bother telling them what kind of car you have, they sell parts for VW's only!

Bob
 

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vac Advance

I noticed in the above pitures it looks like you do not have a vac adv, on your distributor. Am I wrong? If I change to a Compufire Ignition does my VAc ADV go away?
-thanks for your help
 

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The vacuum advance unit has been removed, and the breaker plate riveted. I do not use them on modified engines, they don't perform well for my needs. This distributor also has a modified advance, it is restricted to 25 degrees of mechanical advance (10 degrees baseline + 25 degrees advance = 35 degrees total advance).

However, with a standard engine and camshaft, the vacuum advance unit should remain operative. I do not know if the Compufire unit will accomodate the vacuum advance, but I see absolutely no reason why not. There is no internal trigger mechanism like an XR-700 or Pertronix, only a trigger rotor, and the electronic pickup is in the 'cover', not on the breaker plate. So it shouldn't be a clearance issue.

Bob
 
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