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1984 6-225 sluggish, low power, timing issues....help
https://slantsix.org/forum/viewtopic.php?t=42340		 Page 2 of 2
Author:  diy_darryl [ Fri Oct 22, 2010 8:10 pm ]
Post subject: 
Reed, You really have me leaning towards this now. As I am able to keep my carb (I think), what is your estimate of the cost for module, distributor and coil? And anything else I am forgetting?

Thanks again for your help!!!!!!

And......do I need to get over the disconnecting of my cat for now to see if that is contributing to the power issue?

While we do not have emission checks here, we do have state inspections, that has me worried.

And by the way.....it seems the EGR valve has already been cut out of the system.......all vacuum lines cut and vacuum source plugged.
Author:  Reed [ Fri Oct 22, 2010 10:35 pm ]
Post subject: 
A good HEI module will run you about $30 from a auto parts store, or about $5 from a junkyard.

You can still find the occasional slant six electronic ignition distributor at a junkyard, but your best bet would be to put a want ad on this site or contact a NOS parts dealer such as Old Car parts northwest. Try to get a distributor for a slant six powered truck like yours. You want a timing advance curve designed for a vehicle with similar gearing and weight as yours. Distributors can run anywhere from free to $200 depending on where you get it.

A clogged catalytic converter will cause lack of power and rough running as well as poor fuel economy. If the catalytic is the original one, I can almost guarantee that it has clogged over the years. If you are worried about passing visual inspection, you can remove it, hollow it out, and weld the shell back in place. You might even be able to find a metal recycler near you that will buy the guts of the catalytic for the precious metals it contains.

I would give yourself a total budget of $100 to purchase a new quality HEI unit, a good condition new or used distributor, a relay, good wiring, good terminals, and all the tools you need to do the conversion.

Go and read the HEI conversion thread and the "How to remove lean burn" article on the articles page. Tomorrow I can post some scans of wiring diagrams from my shop manual.
Author:  Reed [ Sat Oct 23, 2010 8:31 am ]
Post subject: 
As promised, here are some scans. The pictures that have a dotted red line around them can be clicked on to go to a slightly larger version.

First, these are the components of the lean burn system without O2 feedback:

Image

Second, here is the factory procedure on setting the timing:

Image

Image

Looks like I told you wrong about setting the timing- the hose to the spark control computer should be plugged in when you set the timing. Sorry about that.

Third, here are the engine compartment wiring diagrams for a van with electronic spark control but no O2 feedback:

Image

Image

A truck should have identical wiring.

If you are going to remove the lean-burn ignition system, the only component you HAVE to remove/replace is the distributor. All the other components can stay on the engine. In fact, you will want to leave all the sensors on the engine because removing them would cause coolant or vacuum leaks. The wiring can stay in place and just be abandoned. Or, if you want to clean up the wiring under your hood, you can unwrap the wiring loom going to the plugs on the computer and trace the wiring back to the sensors and remove the wiring you don't need.

If I am reading the wiring diagram right, the (+) switched feed to the computer is wire J10D-14RD. You can use this as the (+) feed for the relay for the HEI unit and greatly simplify your wiring when you make the swap. Double check this with a voltmeter before you take my word for it. This is also the (+) feed wire for the coil. If you are careful, you can also use wire J5-18BK/YL as the (-) coil feed from the HEI unit. Both these wires are in one of the plugs or the computer, and, if you are careful, you can use them on the HEI install.

Good luck!
Author:  coconuteater64 [ Sat Oct 23, 2010 12:33 pm ]
Post subject: 
In case you are wondering, I did the Lean Bum conversion to HEI and it sounds daunting but is really simple once you get the gist of it. Took me about an hour and a half. I had the same carb as you and I left it in place for a few weeks until i built my budget back up. Ran like crap but loads better than with the Lean Bum. Once I ditched the carb and bolted on a new one it purred like a kitten!

You shouldn't be too concerned about environmental issues. Mine smogged better after the HEI and Holley carb swap without catalytic converters than it did in stock form! If you are subject to smog checks in your area, just put on a new catalytic converter and get rid of everything else smog related. Chances are, the tech checking your vehicle is younger than the vehicle itself!
Author:  diy_darryl [ Sat Oct 23, 2010 7:45 pm ]
Post subject: 
Thanks Reed, those diagrams are awesome, going to have to locate a proper service manual. The cost is way less than I had anticipated.

Thanks to all others who posted also, glad I found this site!
Author:  66aCUDA [ Sun Oct 24, 2010 6:43 am ]
Post subject: 
Reed is spot on on the info. I have done this conversion twice. HEI and Mopar both and the HEI IS better. Use the computer Hot as Reed says and its a snap. I just left my computer in place on my 87. On my 82 I removed it from the air cleaner and patched the hole. I you want to remove your computer check to see that you are still charging as some models the computer seems to control this.
Frank
Author:  Dizzydean [ Sun Oct 24, 2010 10:55 am ]
Post subject: 
Just a thought I had similar issues with my pick up and it turned out that a V8 rear end swap had been done.
Author:  Scnoleman [ Tue Jun 26, 2018 10:58 am ]
Post subject:  Re:
Quote:
Reed is spot on on the info. I have done this conversion twice. HEI and Mopar both and the HEI IS better. Use the computer Hot as Reed says and its a snap. I just left my computer in place on my 87. On my 82 I removed it from the air cleaner and patched the hole. I you want to remove your computer check to see that you are still charging as some models the computer seems to control this.
Frank
Jumping in on an old post.... when you say use the computers wire, do you mean keep the computer and harness hooked up and use the wire (in this case where it connects to the coil per that diagram, in the proper places....basically providing us with the hot and (-) leads the hei conversion needs? Been reading and reading,. Trying to soak up the info and tips for doing this on my 87 ram. Any recommendations on the distributor model or type you used for your truck, as Reed mentioned using a truck version. Thank you
Author:  Reed [ Tue Jun 26, 2018 12:43 pm ]
Post subject:  Re: 1984 6-225 sluggish, low power, timing issues....help
RE: Distributor. The only diffeence between a truck distributor and a passenger car distributor are the mechanical and vacuum timing advance curve. A passenger car distributor will work, but the timing advance curves will not likely be optimized for a truck. However, if the issue is just getting the swap done and the vehicle running, timing advance curves can be fine tuned later. I do recommend taking any distributor you get apart, throughly cleaning and lubricating it, and making sure the bearings are in good shape.

RE: the hot wire for the computer. You can leave the computer hooked up, but the only wire you want to tap into is the big fat black wire that provides the 12v + signal to the computer. You do not want to use the - wire fromthe computer to the coil because then the coil will be controlled by the lean burn computer and won't work with the HEI. You can remove the lean burn computer but tap into the + feed wire in the harness for the computer. If you want to be clever, you can gut the computer housing and leave it in place and hide the HEI module inside the old computer housing and use the factory wiring to the HEI module.

If you are converting a lean burn vehicle, the absolute simplest way to wire in the HEI module is to hooke the HEI module + and - leads to the + and - terminals on the coil and then hook the HEI unit to the leads on the distributor. That is it. Done. It is beneficial to use a relay to provide full battery power to the HEI module, however.
Author:  Scnoleman [ Tue Jun 26, 2018 2:16 pm ]
Post subject:  Re: 1984 6-225 sluggish, low power, timing issues....help
Tap the black wire before the computer (drivers side) or can I tap it where it comes across on harness on passenger side where it goes off to the alternator etc. Thanks for the handholding.

Then that black wire leade will go to (coil +) and then wire as you stated above but with the replacement distributor?
Author:  Reed [ Tue Jun 26, 2018 2:52 pm ]
Post subject:  Re: 1984 6-225 sluggish, low power, timing issues....help
That is one way to do it, yes.
Author:  Scnoleman [ Tue Jun 26, 2018 3:27 pm ]
Post subject:  Re: 1984 6-225 sluggish, low power, timing issues....help
Quote:
That is one way to do it, yes.
Excellent! Thank you kindly.
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