MSD ignition conversion on my '88 5th Ave

[MoparKidD-4]

I just got all the parts to convert my 5th Avenue over to "conventional" ignition with an MSD box (used free from friend), Blaster 2 coil, and factory electronic distributor (used free from my '70 Duster). I am also planning to do a 4-bbl swap with a ThermoQuad I rebuilt but that's a bit farther out time-wise. Is it possible to change the ignition system over now but retain the ESC for the stock feedback carburetor so it doesn't run rich or will the factory system not work because it's no longer hooked up to the distributor or any ignition components to get signals from?

 

[AJ/FormS]

uh, IDK I thought
ESC was Electronic Stability Control

 

[MoparKidD-4]

uh, IDK I thought
ESC was Electronic Stability Control

LOL "Electronic Spark Control System," I'd rather not call it Lean Burn because it has nothing to do with Burning Lean although that's what everyone calls it anyway.

 

[AJ/FormS]

My name is AJ
Every body knows my name
If people reference AJ everybody knows who is being talked about.

Anyway, does your carb have that big ugly cylindrical thing hanging off the front of it, with the wires going into it? If no then hack away. Altho if the current system is working, it's hard to imagine you improving it any.
If you do have that ugliness, IDK, I never owned one to hack.
Maybe Bud will be along shortly or Kris. Those guys know stuff.

 

[rcmaniac791]

Just my .02 cents, so bear with me

IMO, an MSD box on an fmj body (especially if it's mostly stock) won't really do much performance-wise. If the stock system isn't giving you any driveability issues, I personally wouldn't mess with it until you do the 4bbl upgrade.

as far as keeping the computer working with the MSD, don't quote me on it, but I'm pretty sure the whole system has to be in tact to work properly. Like AJ said, Bud and Kris will know.

 

[MoparKidD-4]

Just my .02 cents, so bear with me

IMO, an MSD box on an fmj body (especially if it's mostly stock) won't really do much performance-wise. If the stock system isn't giving you any driveability issues, I personally wouldn't mess with it until you do the 4bbl upgrade.

as far as keeping the computer working with the MSD, don't quote me on it, but I'm pretty sure the whole system has to be in tact to work properly. Like AJ said, Bud and Kris will know.

I'm not really looking for performance from the hotter spark alone, more from having an idea of where the timing curve is at and being able to adjust it myself. The distributor I'm swapping in already has the centrifugal advance plate modified and different springs installed for more of a "performance" curve. The car already has homemade dual side exhaust coming off the stock manifolds btw, and I also have an 8 1/4" rear swap with 3.07 gears in the works.

I could wait until the 4-bbl swap but I figure since I have all the parts for the ignition it would be easier to install it first and get it sorted out, in case there are any issues it would be easier to narrow them down to carb vs. ignition.

 

[kkritsilas]

Do you have a vacuum port for the distributor on your 2BBL carb? To get full benefit from the older style ignition (pre-Lean Burn. pre-ESC), vacuum advance is highly recommended.

 

[Rustyroger]

I'm not really looking for performance from the hotter spark alone, more from having an idea of where the timing curve is at and being able to adjust it myself.

You won't get any performance gain from a "hotter" spark unless what you have won't fire the fuel air mixture properly, most modern engines will manage perfectly well with what they left the factory with. You don't need a sledgehammer to crack a walnut. If you have modified the engine for high performance that is another matter. Late model engines with big plug gaps and strict emissions requirements as well as very long intervals between scheduled replacement mostly have a coil per plug or a coil for two plugs and a spark that would throw you through a wall.

Roger.

 

[BudW]

My ’86 5th Ave with Lean Burn/ESC has been going for 6+ years now with a non-computer controlled carburetor on it. The computer is still sending its signals to the carburetor (which is sitting on a bench in my garage) and overall, it has been doing a great job with spark control (not so much with fuel control).
Just too lazy to remove the rest of it.

Now to answer your question, there is a chance you can get it work the other way around – but I doubt it will work the same way I did. ESC (Lean Burn) needs the RPM signal to do its job as well as to know that engine is running. The only way to do that is to split off the signal coming from distributor and have signal go to both MSD as well to ESC computer.
Generally speaking, splitting the signal like that might work - but most likely won’t work or work very well.

I recommend finding a Carter BBD (or Holley 2286) and replace it at same time – so problem is solved, for good.
Also computer controlled carburetor's generally do not have the port needed for vacuum advance.
BudW

 

[MoparKidD-4]

Ah screw it I'll just wait for the 4-bbl swap... at least i can test the ignition system on my workbench, this old MSD box I got for free wasn't working for the friend who gave it to me but the wiring was definitely not right.

 

[AJ/FormS]

I'm not really looking for performance from the hotter spark alone, more from having an idea of where the timing curve is at and being able to adjust it myself. The distributor I'm swapping in already has the centrifugal advance plate modified and different springs installed for more of a "performance" curve. The car already has homemade dual side exhaust coming off the stock manifolds btw, and I also have an 8 1/4" rear swap with 3.07 gears in the works.

I could wait until the 4-bbl swap but I figure since I have all the parts for the ignition it would be easier to install it first and get it sorted out, in case there are any issues it would be easier to narrow them down to carb vs. ignition.

Since you got the MSD for free, yeah you might as well use it, but is way overkill.
Don't get carried away with the timing in that thing, or you will get into detonation pretty quick. The factory ELB computer did a pretty good job on the timing end of things. So much so that 5ths,up here, regularly get 25 mpgs on the hiway. That is 20mpgUS.
The new rear gears will be a tremendous improvement to 2.2s; almost 40% better. Your car will feel like it just got a turbo.
I would encourage you to get that installed first.
The 4 bbl will do nothing for you with those 2.2s, until over 40 mph, and it won't amount to much.
Whereas the gears will improve performance everywhere. With the new gears, the 4bbl will start to pull at around 30 mph.That is also a very nice improvement. Keep in mind that even on a hotrod engine, the secondaries only add about 8 to10% power. On a 300 hp engine this is 30hp. On your teener it might make 15hp difference and it won't make that until maybe 4500 or 56 mph in first with 2.21s.

 

[BudW]

Gotta get rid of the 2.2 rear gears before even considering a 4-bbl.

A 2.9 or 3.2 will wake the car up and then a 4-bbl could be of use.

3.5’s and a 4-bbl and you will feel like a rocket was strapped onto the car. You might start having rear tire wear issues as well as a face stuck with an ear to ear grin.


With 2.2’s, not even a supercharger or nitrous would make a dent in your ¼ mile time – - - - until you change those gears out.

Until then, a 2-bbl and single exhaust will work fine.
BudW

 

[Dr Lebaron]

If you ever desire a 4bbl, better find some linkage.
Tough to come by these days.

 

[BudW]

I’ve been recommending Lokar cable setups to people, than to locate a complete linkage setup (plus cable will be cheaper, and little chance of incorrect linkage parts).

Cable setups (new)
http://www.manciniracing.com/retobotokica.html
https://www.summitracing.com/parts/lok-kd-2904ht

Linkage setup (new)
http://www.aandatrans.com/Products/318340360-One-4-Barrel-Carb-3-Piece-Kickdown-Linkage__34014B3P.aspx

Note: I would be cautious on purchasing a 273/318/340/340 4-bbl linkage setup used – because I have seen TO MANY friends purchase the incorrect set or incorrect parts of a set (non-usable sets).

In most cases, a 318 FMJ car will need a 3 piece linkage set (like one pictured in above link). Every once in a while, a person can use a 1 piece linkage set – but most cases, it hits the firewall.

Any small block 3 piece kit for a 4-bbl, should work.

I can look at a used linkage set and can give you a thumbs up (or down), but in most cases, just get a 904/998/999/500 cable set and all of those problems will go away.
BudW

 

[MiradaMegacab]

I'm not really looking for performance from the hotter spark alone, more from having an idea of where the timing curve is at and being able to adjust it myself.

X2 I agree with this.............

 

[MiradaMegacab]

With 2.2’s, not even a supercharger or nitrous would make a dent in your ¼ mile time – - - - until you change those gears out.

You sure about that?

 

[SirRalliart]

I’ve been recommending Lokar cable setups to people, than to locate a complete linkage setup (plus cable will be cheaper, and little chance of incorrect linkage parts).

Cable setups (new)
http://www.manciniracing.com/retobotokica.html
https://www.summitracing.com/parts/lok-kd-2904ht


BudW

I just installed the Lokar cable on my Kit Car. An excellent addition. I can open the back barrels all the way now!

I also did the Lokar trans kick-down cable, but that caused a comedy of problems. I thought I overspun a tail piece bolt and stripped it, but miraculously it tightened up without leaking without the Lokar bracket. Then I still had a massive leak, which was coming from the gas line that was used in place of the metal trans cooler lines. So luckily, I had a set of SS trans lines from Inline Tube, so I installed them. It turned out to be a all-day job, but the car is better for it. I still have not hooked up the kick-down cable.

 

[BudW]

You sure about that?

Fairly sure – but not tested to confirm.
If you supply either a Nitrous or a blower, I can go find out – to confirm my theses?

It might be fun just finding out.
BudW

 

[BudW]

On the Lokar cables, there is a 904 (998/999/500) version and a 727 (518) version.

Had a friend get the incorrect one. It works but not an exact fit.


Same goes for the kickdown linkage.
There is a difference on 727 vs. 904/998/999 versions – because of the torque converter is larger, the 727 linkage is wider at that spot. The linkage works either way, but is not a direct fit (some rod bending is required or linkage will bind).

I don’t know the Lokar part numbers but I do remember 727 (or 904) is in the part number, somewhere.
BudW

 

[AJ/FormS]

because of the torque converter is larger,

I didn't understand this at first, so, just to clarify, the torque convertor HOUSING is deeper , putting the VB levers a little further to the rear of the car. Is that right?