Installing Crane XR700's

Yes, It sounds like a very good idea. They need to be mounted at 45 or 135 or 225 or 315 degrees to each other...and it needs to be right, have it done by a machine shop.

 

Birdman, it seems a fine idea.

All timing is done from 1-distributor, but you will still need the second distributor for spark distribution. So, while both pickups will be installed in one distributor, one of the pickups will have to be electrically wired to the second distributor. Since a V-8 fires every 90-crank degrees and the distributors rotate at half the crank speed, the pickups will have to be placed 45 distributor degrees apart or more generally, 45 degrees plus some multiple of 90 degrees apart. This gives possible angle values of 45, 135, 225, or 315 distributor degrees. You will need to use a shutter wheel for a 4-cylinder engine.

 

I know of one person who did this and posted pictures in the old archive. It will be hard to find. It is possible to do and basically eliminates the advance mismatch problems of 2 distributors. Yes, you do need both so that the spark distribution can still take place but the actual firing control will be done by just the one distributor.

 

I am geting ready to do exactly this with the inclusion of two, existing MSD boxes and then installing two hotter coils. My PO, A retired electrical engineer from Raytheon, placed both high speed points in one distributor and installed two MSD boxes. Each msd box fed one coil, which distributed the spark through one distributor per bank.

See my recent post - it is not the best solution but it is what i could come up with to try to bring the car into the 21st century.

After i do the evenings dishes, i will do a search of the old archives.

Any insight at all would be seriously appreciated, since the car is to go onto a flatbed to go back to the seeling dealer to get the smog resolved, (his responsibility) and he offered to upgrade the ignition if i bought the parts, then tackel the rich carbs.

With unprecedented optimism, i remain.
chris

 

Here is one post addressing this issue:

Posted on Tuesday, December 04, 2001 - 8:52 pm:

--------------------------------------------------------------------------------
I finally got my misfire problem solved. As suggested by H.G. the problem was with the points/condenser in the forward bank. I decided to go with crane XR700's because they seem to have a good track record in 308's. After looking at the system and considering a previous message about mounting two pertronix units in one distributor, that is what I decided to do.

The advantages of this approach are; 1) it is much easier because you only have to remove and dismantle one distributor 2) once you get both optical triggers properly aligned in the one distributor, the front and rear banks will always be perfectly synchronized relative to each other. 3) to adjust the timing in the future you only have to play with the one distributor 4) you rely on only one mechanical advance mechanism therefore the advance will always be in-synch in each bank. You do however need two modules and you do rely on the coil, rotor, and cap from the second distributor to send the spark to the right place.

Here is how I did it. Set the engine at 1-4 TDC then removed the rear distributor because it is the easier one to get at. The distributor is taken apart, the small bearing on the spider is pulled and replaced (thank you peter for the SKF part number on your previous post), the advance mechanism is lubed. You then reassemble the distributor by installing the trigger wheel. You then fit the two optical triggers in the distributor so that they are aproximately 45' out of phase (90+45=135 degrees apart from each other). The alignment is not critical at this point because you will fine-tune it when you set the static timing. The nice thing is that there are already two holes in these dual point distributors to pass the wires through. You reassemble the distributor and put it back on the car. You then mount the ignition modules in a convenient place and hook them up, one to the front bank coil and one to the rear bank coil. You then hook up the optical triggers to the modules. The trick here is to keep track of which is which. With the engine at 1-4 TDC you set the optical trigger you are going to use for the rear bank so that it is about to fire as per the crane instruction manual. You then turn the engine to 5-8TDC and do the same thing with the other trigger. The triggers will then be 45' out of synch and will fire each bank at the appropriate time. Reinstall the distributor cap and start the engine. Check the timing for each bank and make sure they are the same. I had to readjust one trigger just slightly to get both banks in perfect synch. Once they are in synch then rotate the distributor to get the timing where you want it(you only have to look at one bank because you know the other will be where it belongs).

I had the car out tonight and it is running well. The only thing I am worried about is that I mounted the modules on the rear fire wall not far from the oil cooler (HOT) but it seems to be hot everywhere in the engine bay.

If anybody can think of any reasons why this approach to installing breakerless ignition might not be a good idea please let me know because I can always switch it over to the usual two distributor technique.

Will keep looking.
chris

 

It sounds fine to me. Very logical and simple. Just set it and forget it. You'll find this one of best mods you have made to your car from an 'ease of maintenence' standpoint.

 

I have this set up with twin Pertronix's units in 1 dist. The pickups are at 45d and you time the motor using 1 dist. You wire the coils like you have 2 dists . The pertronix's system does not use "boxes"so all looks stock. You do need the 2nd dist. set up to to dead 0 . I time the car at 7dbtdc and if you are exact with the pick up at 45d the car is dead on. Works sweet.

 

Always thought the Pertronix system is the "cleanest" looking set up....

 

Birdman,

I have actually used the Pertronix products quite a bit for updating older Hot Rods. http://www.pertronix.com

I really like the Ignitor II which takes the old Ignitor and adds a built in micro processor (like a mini msd box)

I did like the built in rev limiter in the crane though....

-Michael

 

Interesting Michael, so Crane has a system similar to the Pertronix? Will it work with the Marelli distributors?
http://www.cranecams.com/index.php?show=browseParts&lvl=5&prt=1973

 

For those that have used the Pertronix, which model did you buy and what distributor is it listed for? (is there one specifically for a Ferrari or do use one listed for another vehicle but happens to work in a Ferrari?) If you do use one listed for another vehicle, then i would cross refrence that to the one by Crane, if Crane offers something similar then you should be in good shape (if you wanted to use the Crane).

-Michael

 

I had the conversion done around 2 years ago. I sent 1 dist. to this guy , Don King (310) 606-5895 in Ca. Works on Ferrari's for a long time. He mounts 2 Pertronix's units in 1 dist. at 45d apart and brings the leads out through the condensor holes. You hook the neg. wire to the coil and the pos. wire to +12v. No big deal. You could use stock coils or go to Bosch blue or go to pertronix's flam throwers 25K volts. You leave the other dist. set in standard position , he sends a cut a way dist. cap for you to set this up. You then go through a normal dist timing set up (7dbtdc) with the 1 dist. Once you set 1 bank the other one is set because of the pick ups being in one dist. Cost me $500 to have it done and he rebuilds the dist. while doing this. I haven't touched this since I set it up. Slick and clean. No boxes and additional wiring.