Electronic Ignition Comparisons

[Atrus]

I've decided I would like to take a stab at running an electronic ignition system on my '68 1275. I have the 25D distributor.

I see the pertronix ignitor as well as the Crane Xr-700. I know people have said the ignitor isn't always reliable. What are their experiences with the Crane unit? I'm not concerned with the vehicle looking original, so the external box doesn't bother me a bit.

Is there another system you'd recommend over these two? I am looking to keep my cost down, I'd like to avoid the $300 systems. My thought is that if an ignitor is $85, and the Crane is $50 more but is reliable, the $50 is well spent. So, if there is a better alternative, please post with it!

Thanks guys (and gals), I really appreciate the input I receive on this forum.

Edits:

If the Crane is your recommendation, any clue as to what kit I'd need? Looks to be the 700-0231? If so, Summit has it for $95. Also, reading online, it appears that timing adjustments can be made on this unit. Is that true? I can bolt down the distributor and make adjustments on the control module? If so (and it's reliable), I'm sold on it!

 

[Sarastro]

I'd be interested in hearing about some other people's experience with these, too.

I just bought the Crane XR-700, but haven't installed it yet. I got it instead of the Pertronix, because I have more confidence in the optical sensor of the Crane than the magnetic one of the Pertronix--I can get into details if you want; for present purposes, call it an engineering judgment. (I'm an electrical engineer.) The Crane is designed to work with a variety of distributors, so comes with a whole slew of various pieces that install into the distributor; you, of course, will need only a couple of them, the ones that fit your distributor. Since I haven't installed it yet, I can't comment on any problems in finding a selection of parts that works with my distributor.

One little complication with the Crane--the ignition system must have a ballast resistor. Often, there will be a ballast resistor hidden in the coil; you need to make a resistance measurement of the coil to determine if this is the case. It seems to be the case on my '60 bugeye. If not, you can get a resistor designed for some other car; the ballast resistor has to be about 3-4 ohms, if I remember correctly.

Beyond that, the Crane has an electronics package that must be mounted somewhere near the distributor, but the Pertronix apparently fits entirely in the space where the points had been mounted. So, if you are concerned about keeping the engine compartment looking original, you might want to consider the Pertronix.

As for reasons to do it--if you have a well adjusted engine and a conventional ignition system in good condition, I doubt that you will see much difference in using an electronic ignition. I suspect that the real advantages are (1) reliability, as failure of the conventional ignition is not unlikely, and (2) better performance in situations where tuning might not be perfect--say, if it's running a little rich and the plugs start picking up some carbon fouling.

 

[Atrus]

Thanks Steve. Am I correct in what I had read? Timing adjustments can be made from the Crane control unit as opposed to unbolting the distributor? Also, please feel free to give a layman's explanation of the optic/magnetic analysis. I actually assumed an optic may be a little more sensitive to contamination. Also, what unit did you purchase (model number)?

FYI, I am most definitely not stuck on the car looking stock. I plan some (tasteful) custom mods in the future.

 

[Sarastro]

I didn't notice anything in the Crane's instructions about making timing adjustments from the unit. Theoretically, it might be possible to do this, but I don't know if it's actually done.

My concern with the magnetic pickup centers on the problem of timing of all the cylinders, not just the no. 1. When you adjust timing, you are adjusting just the no. 1 cylinder, and trusting that the distributor is precise enough so that the other three cylinders fire at the right instant, as long as no. 1 is right. That's why the cam in the distributor is so nicely ground--probably to tolerances less than a mil.

Now, my concern with the magnetic pickup is that it's fairly difficult to do sense a magnetic field precisely. You can time the no. 1 OK, but I'm concerned that the others might not be precisely timed. It's easy to do this with an optical sensor, though. The light source is very small and a vane can be made very precisely, so it can fire all cylinders very precisely.

Of course, it's probably true that both work adequately; I can't imagine that the Pertronix would be saleable if it weren't. On the other hand, any optical device is at least theoretically subject to contamination. But, the sensor in the Crane seems pretty well protected, and of course its enclosed in the distributor. After all, conventional points can get contaminated, too, but they're more likely to fail by getting burned or simply worn out than contaminated.

 

[Dave Russell]

[ QUOTE ]

I just bought the Crane XR-700, but haven't installed it yet. I got it instead of the Pertronix, because I have more confidence in the optical sensor of the Crane than the magnetic one of the Pertronix--I can get into details if you want; for present purposes, call it an engineering judgment.


[/ QUOTE ]
A different take on the subject,
The Pertronix uses rotating magnets & a Hall-Effect sensor. It is NOT a magnetic pickup or a variable reluctor. The air gap is about .085" but can vary over a wide range with no problems. This setup is very insensitive to gap changes, is totally insensitive to vertical position variations, & not subject to optical shutter contamination.

The optical trigger system is sensitive to all of these problems & as you say, comes with a whole slew of pieces to sort through to get it right.

Pertronix will work easily with any internally ballasted coil of about 2.6 ohms to 3.2 ohms. The typical non ballasted coil has a resistance of around 1.5 ohms, with an external ballast of around 1.5 ohms.
I guess there is "something" for everybody.
D /ubbthreads/images/graemlins/savewave.gif

 

[GreenHornet]

I went with the Crane and got mine from Summitt also. Forget the part number though. Paid about $110. for it about a year ago. No trouble at all putting it together. Just followed the instructions. Had to do nothing with timing adjustments it took right off. Best money I spent by far.

 

[justaguy]

I have used the XR-700 conversion in several of my cars and a boat. I have never had a lick of trouble with it. "Set it and forget it"... Much easier starting than with conventional points. As for timing the engine with the control box??? NOPE... still done the same as points... If you seal the entry point for the under cap optical unit as instructed there is an extremely small chance of any contamination of the optical trigger. I have never had it happen to me. I would recommend the Crane unit... Just my opinion... /ubbthreads/images/graemlins/yesnod.gif

 

[Baz]

[ QUOTE ]
Paid about $110. for it about a year ago.

[/ QUOTE ]

Is that the price for the entire distributor?

 

[GreenHornet]

[ QUOTE ]
[ QUOTE ]
Paid about $110. for it about a year ago.

[/ QUOTE ]

Is that the price for the entire distributor?

[/ QUOTE ]
Everthing that goes under the cap. It fits under the stock cap and uses the original distributor. Just the trgger and optics. It has a box with the brain that you can mount outta sight if you like, to make it look stock.

 

[Atrus]

hmmm, that's a bummer. I was searching around and thought I had read that timing could be done off the unit. That'd be a darn nice feature.

So, nobody seems to have trouble with the Crane unit? The Pertronix seems to be a "when it goes" not an "if it goes". I just want something that's reliable as possible, and both are under $100, so that's worth it to me.

 

[Baz]

[ QUOTE ]
It has a box with the brain that you can mount outta sight if you like,

[/ QUOTE ]
At least there's one in my car then.

So what you're saying (to a novice who is considering an ignition 'upgrade') is that there is a chunk of stuff that goes under the cap, an external processor and (get) a new coil and then I'm golden?
BTW Thanks Atrus for bringing this up, it's on my to do list too.

 

[Atrus]

Glad everyone is interested. I figured I'd get a lot of flack for not keeping the original points system. What can I say, I am 25. This is my first carb'd car. I like electronic ignition and EFI, just less hassle (in my opinion) once it's up and running ;-)


And Baz, yes, from what I understand, the pertronix all fits under the cap. The Crane has bits to go under the cap (it's a universal system, so extra brackets, etc that won't be needed), plus there's the actual control module that has to be mounted somewhere. The Pertronix you can't see other than a few extra wires. The Crane has more extra wires and a control module to mount. And, so far Summit seems to be the cheapest.

 

[dklawson]

I have run both Pertronix and Crane over the years. The reliability issues with Pertronix are more often than not... the result of operator error.

The Pertronix will burn out if you operate it with a low resistance coil (too much current flows through it). The Pertronix will burn out if you turn on the ignition and leave it on for 5+ minutes without starting the engine. It will also perform strangely and fail early if you connect it to a power supply less than 12V. As was mentioned above, the Pertronix is a Hall Effect device similar to the Bosch units VW has been running for more than two decades. It's a proven technology, there are just a couple of caveats as mentioned earlier.

There is nothing wrong with the Crane/Alison units. If the dizzy is in fair condition it will operate properly with a Crane, just like a Pertronix. However, the Crane units I'm familiar with require a heat sink and from personal experience I can tell you they should not get wet. Though they are sealed/potted, over time water can get in them. Mount it in a dry location if you choose Crane and don't get it wet when/if you wash the engine.

The last option in the under $100 category is the Hitachi distributor conversion. There are links on the web about this but succinctly it involves sourcing a Hitachi dizzy from a 1.6L early 1980s Nissan Pulsar or Sentra. You recondition it and transfer the Lucas drive dog to the shaft. It wires up the same as the Pertronix.

The following rant is on terminology. There are normal/standard coils and ballast coils. Standard coils are often referred to as internally ballasted. This is misleading. There is no extra internal resistor, they are just wound differently. A ballast coil uses an external ballast resistor and is wired in a manner that allows it to operate on higher voltage during cranking and lower voltage after the engine starts. As Dave said a standard coil will measure around 2.8-3.2 ohms across its low tension terminals (wires removed) while a ballast coil will measure closer to 1.5 ohms.

 

[msoylemez]

Hi, I am replacing the OEM bugeye coil with the Crane PS40 and I'm also upgrading to electronic ignition using the Crane XR-700. I just checked my PS40 coil resistance, and it measured 1.6.

To confirm, do I need to use the ballast resistor that came with the new PS40 coil?

 

[dklawson]

You should always refer to the documentation that came with the ignition module you purchased. Following those instructions will keep your warranty valid. Without seeing those instructions however, I suspect that with a coil resistance of 1.6 ohms you must use the ballast resistor. After all... Crane didn't bundle it with your new coil just for fun. For the Crane to work properly I also suspect they'll tell you to find a point other than on the coil to get the 12V supply to power the module.

 

[SilentUnicorn]

https://www.cranecams.com/pdf/90001700c.pdf

generic crane instructions

mark

 

[Sarastro]

[ QUOTE ]
The Pertronix uses rotating magnets & a Hall-Effect sensor.

[/ QUOTE ]

Is it really a rotating magnet? That would worry me quite a bit. Do you know what the shape of the magnet is? I'd be interested to know how they create a precisely timed change in the magnetic field.

Usually, similar things in other types of equipment use a Hall-effect sensor biased by a stationary magnet and a rotating steel wheel. The wheel has notches in it. The change in magnetic field through the sensor, when a notch passes by, is sensed by the Hall-effect sensor. This is much more precise than a rotating magnet could be, but still not as precise as a vane and light source, I think.

 

[Sarastro]

[ QUOTE ]
...the ballast resistor has to be about 3-4 ohms, if I remember correctly.

[/ QUOTE ]

Sorry, my error: it's the coil resistance that should be in this range if you want to avoid the ballast. If it's lower, you do need a ballast resistor. The resistance of the ballast resistor is 1.4-1.9 ohms. You want a total resistance, coil plus ballast resistor, in the 3-4 ohm range.

 

[sparkydave]

[ QUOTE ]
[ QUOTE ]
The Pertronix uses rotating magnets & a Hall-Effect sensor.

[/ QUOTE ]

Is it really a rotating magnet? That would worry me quite a bit. Do you know what the shape of the magnet is? I'd be interested to know how they create a precisely timed change in the magnetic field.

Usually, similar things in other types of equipment use a Hall-effect sensor biased by a stationary magnet and a rotating steel wheel. The wheel has notches in it. The change in magnetic field through the sensor, when a notch passes by, is sensed by the Hall-effect sensor. This is much more precise than a rotating magnet could be, but still not as precise as a vane and light source, I think.

[/ QUOTE ]

Steve, the Pertronix has a plastic collar that mounts on the distributor shaft, and the "magnets" are small cylindrical pins set in the plastic collar. Not sure if it's Hall effect or not, since the pins don't seem to be magnetic. I've been using the Pertronix for about 4 years now, and haven't had a bit of trouble. I think as long as you don't leave the ignition on for long periods with the engine off you should be fine. I went with it because they had one specifically for the 45DE4 distributor, and it fit neatly inside without having to mount some amplifier box somewhere.

 

[sparkydave]

Correction, I guess it is Hall effect. Pertronix says it is.