Fast XR700 E-Ignition Questions

[2LZ]

Yes, I've scoured the web and forums and have run across a good amount of conflicting information from years past, so here I am. I throw myself on the mercy of the Court.
'
Since I've been warned by multiple people recently about how bad today's points sets are, I want to upgrade to the Fast XR700 before I even get it fired for the first time. One of the older threads I ran across says to get the 700-0226. Unfortunately, the 0226 suffix is currently made of Unobtainium from all the major vendors. Has it been discontinued or replaced with an updated unit?

There is the XR700-0231, and it's available, but I've not run across any old threads that specifically state that part number for a Corvair. Does it really matter which one to get???

Also, I've read in a number of places about needing to order a separate mount bracket for the light sensor????

I have discovered that the XR700 will run with the stock coil and ballast resistor (if it's there). If the resistor is NOT there, then I have to install one (or resistor wire) to keep it from overheating??? I'll probably upgrade the coil anyway.

Any and all current information regarding this is greatly appreciated! BTW, it's going into a 1965 140 Corsa.

[caraholic4life]

Here is what the Corvair Ranch installed in my Greenbrier a couple years ago.
3,000 miles later, it still seems to work just fine.

[Spectre]

I am upgrading to the XR700 as well. I found a new one at Summit Racing. It did not have the correct sensor mount for our distributor, but I found that at Lethal Performance and ordered it. I had one of these when they were under the Crane name on a previously owned Corvair and it worked flawlessly. My dad has one when they were Allison branded and it also w=ran great.

[2manyvairs2fix]

To answer your question, the XR-700 with the 0226 suffix is the only one that will work with the GM 6 cylinder. I have called Fasts help line and ordered the correct bracket for a kit I bought used.
I like them because I have been using them for almost 30 years with zero failures.
Try Ebay, they show up occasionally. Also I think Clarks carries them.

[2LZ]

Thanks for the replies guys. Has anyone had experience with this setup????
https://californiacorvairparts.com/elec ... black.html

[66vairguy]

Fast bought the unit from Crane, now some offshore company bought Fast. This was a couple years ago and when I went to their site it was a MESS (then). The Chevy 6 cylinder kit was not listed and you had to buy a couple different generic hardware kits to mount hardware. Not cheap or effective.

At the time Clark's STILL had the kits that fit the Corvair distributor. I'm not sure if they still do, but you can call them.

The XR-700 MUST use the ballast and stock coil. Without a ballast the coil must have a minimum 3 ohms primary resistance. Same as with the Petronix I Ignitor. The XR-3000 is designed to work with low impedance coils without ballast.

A shame the new owners made a mess of it as the XR-700 has a good reputation IF installed properly.

BTW - I NEVER START UP A NEW ENGINE WITH AN ELECTRONIC IGNITION. I use points until everything is sorted. Just one less thing to guess about. Yes today's points are lower quality, but for starting and running a new engine for an hour or two, they work fine IF set up properly.

[2LZ]

Good point. Less to diagnose.

Last night, I ordered a timing light and dwell meter. I haven't had those in my tool box for over three decades. I do mostly motorcycles and I can't remember the last time I took a timing light to one. I think I was 20 the last time I used a dwell meter (I just applied for MediCare).

The rule of thumb was "If the gap spec is 20, set it a little over 18 and the dwell should be dang close". Then set timing by "advance it until it pings when floored, then back it off a little" Then the cam can breathe."
Thanks to the new Corvair in the family, it's all coming back to me.

[Frank DuVal]

BTW - I NEVER START UP A NEW ENGINE WITH AN ELECTRONIC IGNITION. I use points until everything is sorted. Just one less thing to guess about. Yes today's points are lower quality, but for starting and running a new engine for an hour or two, they work fine IF set up properly.

YES!

[dcmarciano]

I'm rewiring a previously installed xr700. Can I put a ballast resistance between the coil and the xr700 (red arrow) instead of before the coil? I figure this will give the xr700 the voltage it wants without reducing spark. Here some of the details of my '68 Monza:
Isky cam 280° duration 450 lift
Original Turbo
Rochester 2CG carb
Snow Methanol injection
Crane XR700 electronic ignition
Blue streak uc-16x ignition coil Measured 1.5 ohm across primary

(Sorry if this is a hijack. Came to start a thread and saw a new xr700 thread was already up)

[Vairone]

Fast bought the unit from Crane, now some offshore company bought Fast.

Fast is not offshore.

The company, Fast, which manufactures the XR-700 is under the umbrella of Edlebrock Group companies. Other companies under this umbrella are Comp Cams, TCI, Russell and Lunati. In 2020 Industrial Opportunity Partners (IOP) purchased Edlebrock.

IOP is not offshore and is headquartered in Evanston, Illinois [https://www.iopfund.com/investments/]

[66vairguy]

I'm rewiring a previously installed xr700. Can I put a ballast resistance between the coil and the xr700 (red arrow) instead of before the coil? I figure this will give the xr700 the voltage it wants without reducing spark. Here some of the details of my '68 Monza:
Isky cam 280° duration 450 lift
Original Turbo
Rochester 2CG carb
Snow Methanol injection
Crane XR700 electronic ignition
Blue streak uc-16x ignition coil Measured 1.5 ohm across primary

Screenshot_20240302-040434.png

(Sorry if this is a hijack. Came to start a thread and saw a new xr700 thread was already up)

NO --- The XR-700 RED wire is to supply power to the box. You do NOT want to limit power with a resistor. The XR-700 originally had a robust power circuit (haven't looked at the circuit in decades) so connecting the RED power wire to the coil "+" lead was O.K. (and easy) but the better method is to connect the RED wire BEFORE the ballast were power comes in from the ignition key. Just a "cleaner" DC voltage source, no voltage spikes.

The Corvair has a "ballast wire" in the harness between the supply voltage from the ignition key and the coil "+" terminal. It may still be there. Except for the 62 turbo engine, Corvairs used a ballast wire like most GM cars of the era.

A lot of aftermarket coils are 1.5 ohm primary. The GM coil was about 1.3 ohm with a 1.8 ohm ballast for a total of about 3.1 ohms. Anything less than 3.0 ohms will "strain" the electronics of the XR-700.

Are you sure there is NO ballast wire. Easy to check, you just need a voltage meter.
Disconnect lead from XR-700 box to coil "-" terminal.
Turn on ignition (DO NOT TRY TO START ENGINE) and measure voltage at coil "+" terminal. It should be about what the battery is (12 - 13 VDC).
MOMENTARILY ground the coil "-" terminal (use a 16 gauge or larger wire) and the voltage should drop to about 5.5 VDC. If voltage changes little, then the ballast is not inline between supply voltage and the coil "+" terminal.

BTW a new engine harness will have the ballast wire. If you buy a ceramic ballast load to wire in make sure it is the GM 1.8 ohm as there were a number of different ohmic values used by Ford and Chrysler. Also note they get HOT so mount on the body and away from other wires. The inline GM ballast wire was so long it barely gets warm IF you use a coil between 1.3 and 1.5 ohm.

Note the when the starter is engage on a normal Corvair (or any Chevy of the era) the starter wire by-passes ballast for a "hotter" start voltage to the coil. This assisted Winter starting. When I help with a Corvair that has worn out engine compartment wiring I tell folks "Just buy a new engine harness as it will be cheaper and will work properly".

[RexJohnson]

'63 Spyders also used the external ballast resistor. I think that the '62 and '3 Spyders used a "hotter" coil and my guess is that a different resistance value was needed with this coil and so it was easier to just use the external resistor. I was probably lees confusing on the assembly line also.

[2LZ]

(Sorry if this is a hijack. Came to start a thread and saw a new xr700 thread was already up)

No worries! Any chatter and knowledge I can collect on this is greatly appreciated!

[dcmarciano]

NO --- The XR-700 RED wire is to supply power to the box. You do NOT want to limit power with a resistor. The XR-700 originally had a robust power circuit (haven't looked at the circuit in decades) so connecting the RED power wire to the coil "+" lead was O.K. (and easy) but the better method is to connect the RED wire BEFORE the ballast were power comes in from the ignition key. Just a "cleaner" DC voltage source, no voltage spikes.

OK, thanks, I will not tap into the power supply wire going into the box. I am still curious why my idea wouldn't work but I'm more interested in getting this car running again. Also, I have a Crane Cams module (it says CARB D-47-2 & 3 Daytona Beach, FL) so I guess this is the older more robust version

The Corvair has a "ballast wire"... in the harness between the supply voltage from the ignition key and the coil "+" terminal. It may still be there. Except for the 62 turbo engine, Corvairs used a ballast wire like most GM cars of the era.

I looked for it (20 W/R/B according to '68 wiring diagram) but maybe it's wrapped inside the engine compartment harness so I couldn't find it. I expected to see it coming from a two spade plug but all I see are 20 yellow plugged into 20 yellow and 12 purplish-black plugged into 12 purplish-more_blackish. Oxidation + black spray job + slight green color blindness makes confident identification challenging for me. I did find the broken end of the 20 yellow wire near the distributor and it looks like it shorted at some point. I also found the 20 yellow wire near the starter to be toast and disconnected. The previous owner ran 12V directly to the + of the coil from the IGN Fused 10A spade terminal on the face of the fuse box. That wire frayed under the rear seat which was the source of my current problems.

A lot of aftermarket coils are 1.5 ohm primary. The GM coil was about 1.3 ohm with a 1.8 ohm ballast for a total of about 3.1 ohms. Anything less than 3.0 ohms will "strain" the electronics of the XR-700.

I found a ballast (no markings on it) bolted to the bottom of the engine compartment but it was not hooked up. I measure 1.5 ohms across the terminals of this ballast.

Are you sure there is NO ballast wire. Easy to check, you just need a voltage meter.
Disconnect lead from XR-700 box to coil "-" terminal.
Turn on ignition (DO NOT TRY TO START ENGINE) and measure voltage at coil "+" terminal. It should be about what the battery is (12 - 13 VDC).
MOMENTARILY ground the coil "-" terminal (use a 16 gauge or larger wire) and the voltage should drop to about 5.5 VDC. If voltage changes little, then the ballast is not inline between supply voltage and the coil "+" terminal.

I found the unused yellow wire. It looks to have had a short at some point (melting near the coil end) and broken/brittle at the starter end. I could cut a few inches from each end but I don't really trust the condition of the yellow wire.
I found this by testing the wire with the + coil disconnected and measuring V in Run and Start positions. I hope I didn't damage anything by this but with no power to coil or module I don't see how a few cranks would hurt much.

BTW a new engine harness will have the ballast wire. If you buy a ceramic ballast load to wire in make sure it is the GM 1.8 ohm as there were a number of different ohmic values used by Ford and Chrysler. Also note they get HOT so mount on the body and away from other wires. The inline GM ballast wire was so long it barely gets warm IF you use a coil between 1.3 and 1.5 ohm.

Note the when the starter is engage on a normal Corvair (or any Chevy of the era) the starter wire by-passes ballast for a "hotter" start voltage to the coil. This assisted Winter starting. When I help with a Corvair that has worn out engine compartment wiring I tell folks "Just buy a new engine harness as it will be cheaper and will work properly".

I know you are right about this but also it's been nearly a year since I've been able to start this car and I really want to get it running (I'll blame David Freiburger for endorsing this mentality). I've spent much of that time getting all the gauges and warning lights working again and all that would be for naught.
I may change my mind on that but for now my plan is to recapitulate the 20 Y – resistance wire by running a new yellow wire from the starter (same post) to the the 1.5 ohm ballast and then to the + coil post. I’ll run a second 20 awg wire from the start post directly to the + coil post. I’ll probably remove the ring terminal from the xr700 red power line and tie it where 12V is entering the ballast (based on your above recommendation).
I really appreciate you always giving me good advice, 66vairguy!
Please let me know if you (or anyone) sees problems with what I’ve laid out.
Also, can I get an award for annoyingly long posts?

[RexJohnson]

On a '68 the ballast wire should meet up with the yellow wire at the coil negative terminal. On the '65 and '6 the ballast wire ran from the body to engine connecter towards the left back up light and then turned around and hooked up with the yellow wire at the 2 pin starter connecter. In '67 and latter the resistor wire went to the coil. Maybe when the wire looped around if the 2 wires ran side by side it could get too hot and cause problems? It sounds like you might need a new harness?

[66vairguy]

On a '68 the ballast wire should meet up with the yellow wire at the coil negative terminal. On the '65 and '6 the ballast wire ran from the body to engine connecter towards the left back up light and then turned around and hooked up with the yellow wire at the 2 pin starter connecter. In '67 and latter the resistor wire went to the coil. Maybe when the wire looped around if the 2 wires ran side by side it could get too hot and cause problems? It sounds like you might need a new harness?

Rex is correct. The 68-69 shop manual diagram is INCORRECT. Keep in mind folks swap different year harnesses so you never know what you will find. The ballast always supplies power if the key is "ON". The YELLOW wire only supplies power when the starter is engaged.