Ignition

[scoutpappa]

I should have the new (take this as correct) carb this week. I have been running through the threads and have a new question. Can the mallory unilite distributor be mated to a 6 box? Does/can the led trigger be utilized as a trigger for this type of ignition system. I think this would add to the reliability factor I am working on if so. If not I have the original distributor with a burnt pertronix module in the garage.

 

[Michael Mayben]

I should have the new (take this as correct) carb this week. I have been running through the threads and have a new question. Can the mallory unilite distributor be mated to a 6 box? Does/can the led trigger be utilized as a trigger for this type of ignition system. I think this would add to the reliability factor I am working on if so. If not I have the original distributor with a burnt pertronix module in the garage.

A big "yes"!

The unilite will trigger any "six" box through the same hookup as for wiring in a breaker point distributor. You will not use the "mag trigger" input on the cd box, so that dual wire pigtail with connector is still left deadhead.

Of course, mallory would like you to use their version of the six series, the hyfire 6a (which is a true digital unit, not that it matters whatsoever!!).

The wiring setup for an msd six series box is virtually identical, again, the "points trigger" wire is used (white wire).

Both installation instructions are posted on their respective websites and specifically call out the unilite distributor in detail.

When using the unilite with either cd box, you will not use that ballast resistor ya spent all that time scruuin' with! That is because with the cd box, the distributor trigger operates the cd box instead of the coil! The cd box will be the interface with the coil, not the distributor...big difference here!!

The unilite module would then simply serve as an "on/off/on" switch for the box and carries hardly any measurable current. And... With the cd box feeding the coil, that opens up several other coil selection "options" though using what you have now is absolutely not a problem at all.

As you have probably read, I use a mallory box on one of my rigs and a msd box on the other. They both are burning the same msd coil, one is switching using a pertronix, the other one still has a breaker points trigger though it will soon get a mag trigger in it's gullet. There is absolutely no difference in performance of either system, I consider one no better than the other.

 

[scoutpappa]

Excellent. So what this opens up is I can get a "6" series box. I can get rid of the "bleeding" type coil (been through 2 in six months). I can source a standard off the shelf "e" coil from anywhere (I think average resistance is .75 ohms on most I checked) and bring the entire system to a capacitive discharge (current technology) system. Does anyone have a used one they want to sell cheap? Saving my pennies for the vintage air system.

 

[scoutpappa]

Also. Doing some real quick reading. These digital boxes seem to have some programming capability (limited type plc). Is it possible to set a at idle advance when the engine is under load (new a/c) most new vehicles have a d/o to the computer that triggers an increase in rpm when the compressor starts. Is it possible to use advance in the same way. Or am I overthinking not thinking. When the compressor cycles that will "load" the motor which will increase the pull in vaccuum?? And advance the motor slightly when at idle. Basically when the compressor cycles and you are at a stop light?

 

[Michael Mayben]

What you describe is not "doable" in that manner.

Yes, there are many "add-ons" for timing control regarding the msd six box, also systems with some of the timing control features integrated.

But trying to "kick" the throttle by advancing (or changing) timing when the compressor is engaged is not the way to do this.

Many vehicles over the years used a "throttle kicker" for just that purpose. Those devices were mandatory for most any carbureted application post 1981 because of emissions regulations.

Most all carburetors used on ihc engines post-1972 used an "anti-diesel" solenoid mounted on the carb, that was energized when the engine was running and curb idle was adjusted against that device. When the ignition switch was cut, the solenoid retracted, thus completely closing the throttle plates which prevented "run-on" which was commonly encountered on those vehicles because of the fuel blends available at that point, along with the really shitty timing specifications required by the emissions regs, both 49-state and cali.

So what can be done is...incorporate a throttle kicker on your carb setup, and wire it through the compressor clutch relay so that when the clutch engages, the curb idle speed will be kicked up to whatever amount you desire.

However...in my opinion, this is not something that is an issue when running a/c on these vehicles. The oem compressor design (the so-called "york" manufactured by cci) has a parasitic of approximately 7hp (yes, I have observed these compressors running on calorimeters). The sanden or seltec/tama compressors we discuss so often have a parasitic of less than one-half the york, and are far more efficient at idle and low engine rpm!

I'm currently running a really thrashy york on our t'all that has been poorboy retrofitted to r-134a to see how long it will last before shelling. And it's been running all summer and fall under ambients not much different than what yawl have in your area. The engine is a fully "built" 392 witha real lumpy cam, the oem emissions carb has been shitcanned and fully dialed in performance carb installed to take advantage of the engine specs. I do not run a throttle kicker on that one, it's a slushbox tranny so I run a curb idle of 750rpm in neutral, with the compressor engaged and tranny in d, curb idle is 700rpm which is my "spec" for this kind of setup.

Simply substituting a sanden or seltec swash plate compressor will do away completely with all the underhood thrashing that is normal regarding the york compressor design, and other than a slight engage/disengage sound from under the hood when the compressor cycles, I don't anticipate idle rpm to be affected at all.

We'll be doing this compressor conversion using an ihon mount in the early spring and will have a complete write-up here on the forum.

 

[scoutpappa]

I knew the "factory' compressors were hogs, I think I have read up to 10hp loss somewhere. I was basing the need from what I have observed on newer vehicles, but had to ask the question as I have never observed a system on a Scout to accomodate this. As with anything you say though I'll take it as gospel. I'll be installing a full vintage air system (compressor back to fan unit in cab) so I will not be trying to scavenge/integrate any old componants. This way I don't need to add any systems to any new systems I'm adding. I do believe in the keep it simple stupid way of doing things. So I have looked at 6a boxes on ebay/etc. Is there anything I should look for? Nothing on the site but I haven't called Jeff yet to see about aquiring a decent used unit.

 

[Michael Mayben]

I knew the "factory' compressors were hogs, I think I have read up to 10hp loss somewhere. I was basing the need from what I have observed on newer vehicles, but had to ask the question as I have never observed a system on a Scout to accomodate this. As with anything you say though I'll take it as gospel. I'll be installing a full vintage air system (compressor back to fan unit in cab) so I will not be trying to scavenge/integrate any old componants. This way I don't need to add any systems to any new systems I'm adding. I do believe in the keep it simple stupid way of doing things. So I have looked at 6a boxes on ebay/etc. Is there anything I should look for? Nothing on the site but I haven't called Jeff yet to see about aquiring a decent used unit.

The latest six series msd boxes going forward are a digital technology with a slightly more compact case overall. And new design wiring harness connector. The smokeblow sez they are bit hotter units but in regards to use on any IH engine, that is a moot point.

I would venture that in the future , the analog six series (for msd) will fade away and the digital stuff will be the basis for the add-on hardware.

The "rev limiter" version is likewise a total waste for any IH application!

For the a/c system, if you don't have one already, ya need to score an oem-type alternator/compressor mount. With those, the alternator hangs below the mount and the york compressor sits on top. But...ya ain't gonna use a york! Ihon has designed and produced a very nice "adapter mount" that interfaces either the sanden or the seltec/tama compressor and is much nicer than anything else on the market for doing this. It also properly aligns the compressor pulley gauge line.

In the past, there was one source for a so-called "dedicated" mount for an sv or I-4 engine, but I don't think they have ever made the needed changes in their tooling to correct that mount. The problem is it simply does not properly align the belt gauge line and also allows interference between the clutch pulley and top radiator hose as well as belt interference. I tried to help them in correcting their issues back in 2003 and 2004, but they were not receptive to my suggestions so screw 'em! It's easier to scratch build a mount than try and make their mount fit correctly.

 

[scoutpappa]

the latest six series msd boxes going forward are a digital technology with a slightly more compact case overall. And new design wiring harness connector. The smokeblow sez they are bit hotter units but in regards to use on any IH engine, that is a moot point.

I would venture that in the future , the analog six series (for msd) will fade away and the digital stuff will be the basis for the add-on hardware.

The "rev limiter" version is likewise a total waste for any IH application!

For the a/c system, if you don't have one already, ya need to score an oem-type alternator/compressor mount. With those, the alternator hangs below the mount and the york compressor sits on top. But...ya ain't gonna use a york! Ihon has designed and produced a very nice "adapter mount" that interfaces either the sanden or the seltec/tama compressor and is much nicer than anything else on the market for doing this. It also properly aligns the compressor pulley gauge line.

In the past, there was one source for a so-called "dedicated" mount for an sv or I-4 engine, but I don't think they have ever made the needed changes in their tooling to correct that mount. The problem is it simply does not properly align the belt gauge line and also allows interference between the clutch pulley and top radiator hose as well as belt interference. I tried to help them in correcting their issues back in 2003 and 2004, but they were not receptive to my suggestions so screw 'em! It's easier to scratch build a mount than try and make their mount fit correctly.

The mallory version of the 6a (digital) seems much more cost effective than the msd unit so that is where I think I will be looking. I posted in the parts wanted to see if someone has a used working unit they want to get rid of and we'll see. It's not critical but it has made it to the list for reliability reasons. This Scout had a/c and the only parts that are missing are the fan rail in the cab and the compressor itself. The compressor mount is still installed with the alternator hanging from it. Now I actually have the fan rail in la and I actually have a compressor in my other Scout with the pulley but I think that if I install a vintage air unit I'll be happier in the long run with performance and economy. Also as I understand it Jeff has two mounts being manufactured right now for this application (one stationary and one adjustable) so I will definately be ordering the adjustable model when I get ready for the vintage air system. I have read alot in the hvac forum but I'm not real confident that I could get the existing system working. All the componants have obviously been in a non-functional state for a long time and I don't have a reclaimer or anything else for that matter to test/hold vaccuum and all the things I would need to work on before I even consider introducing refridgerent. As well as trying to convert to 134a and getting all the correct fittings installed on hoses for a retro-fit of the system. I guess I know just enough to be dangerous but not nearly enough to feel confident I could get the system operational from what I have now.