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| Lean Burn Computer with HEI conversion Help? https://slantsix.org/forum/viewtopic.php?t=34738 |
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| Author: | BlueBandit [ Tue Apr 07, 2009 9:18 am ] |
| Post subject: | Lean Burn Computer with HEI conversion Help? |
Im new to the site. I have an 84 D-100 with the 225 /6 that is in pretty good shape. I was wondering if the HEI conversion replaces the whole Lean Burn system? |
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| Author: | Reed [ Tue Apr 07, 2009 9:31 am ] |
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The HEI conversion will replace the lean burn ignition system, but will not replace a computer controlled carb. If I remember correctly, Chrysler made some vehicle with computer controlled ignitions but not carbs, and vice versa. If you don't have a computer controlled carb, then an HEI swap is all you need to do. If you do have a computer controlled carb, then you will need to do the HEI swap AND switch to a non-computer controlled carb. On lean burn equipped vehicles the HEI swap is even simpler than usual. Lean burn cars don't have a ballast resistor, so all you need to do is wire the HEI unit into the distributor, run the wire to the (-) coil terminal (and be sure to remove the current lean-burn (-) wire from the (-) coil terminal), run the (+) coil wire to a relay, and power the HEI unit off of the relay. That's it. I recently switched my 84 Chrysler 5th ave from lean burn to HEI and I didn't even wire in the relay. It works, but i have been told that an HEI unit without the relay providing full battery voltage will shorten the life of the HEI module. At some point I am going to wire in a relay. |
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| Author: | BlueBandit [ Tue Apr 07, 2009 9:34 am ] |
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My Carb is the 1945 and the idle stop is all that needs wires to it. |
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| Author: | Reed [ Tue Apr 07, 2009 9:36 am ] |
| Post subject: | |
Quote: My Carb is the 1945 and the idle stop is all that needs wires to it.
If you don't have any other wires going into the fuel bowl or a solenoid anywhere else in the body of the carb, then an HEI swap is all you need. Don't forget to get a new distributor out of a truck or van.
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| Author: | BlueBandit [ Tue Apr 07, 2009 9:38 am ] |
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My stock distributor won't work? |
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| Author: | 66aCUDA [ Tue Apr 07, 2009 9:40 am ] |
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Nope You need a EI dizzy from a non lean burn vehicle. Frank |
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| Author: | BlueBandit [ Tue Apr 07, 2009 9:42 am ] |
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What trucks or vans had those? Sorry I'm still somewhat new to the older mopars. |
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| Author: | 66aCUDA [ Tue Apr 07, 2009 9:46 am ] |
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72-76 for sure cars and trucks. Old Car Parts Northwest is what Dan is reccomending these days. Actually contact Duster Idiot on this board and he can put the right curve into a dizzy and sell it to you. (I have some of his work and its Great). Use the PM function and see if he will help. Frank |
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| Author: | sandy in BC [ Tue Apr 07, 2009 9:49 am ] |
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The hei will work with a lean burn dist....but you would have no advance. You need a pre lean burn dist which has a built in mechanicalvacume advance. |
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| Author: | BlueBandit [ Tue Apr 07, 2009 9:51 am ] |
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What is the curve you're talking about? |
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| Author: | Reed [ Tue Apr 07, 2009 9:54 am ] |
| Post subject: | |
What you need is a slant six distributor for a standard electronic ignition. Not points and not lean-burn. I recommend getting one out of a 73-early 80s truck or van because of the timing advance curve the distributors will be built with. Trucks and vans are heavier than most slant six powered cars, so they will benefit from a different spark advance curve. If you can find one in a junkyard, great. You wil most likely want to completely disassemble, clean, and lubricate any original factory distributor you find. You will also want to make sure that the vacuum advance diaphragm still holds a vacuum. That brings up another point. Your lean-burn carburetor may not have a "ported" vacuum nipple for the distributor vacuum advance. The distributor vacuum advance needs to have no vacuum at idle, but full manifold vacuum as soon as the throttle is opened. You may have to replace your carb to get this feature. Do a search for distributor re-curve on this site to learn more about fine tuning your distributor for your vehicle. UPDATE- In compute controlled vehicles, the timing is controlled by the computer and there is a built in timing advance "map" stored in the computer. Based on different engine variables (RPM, engine temp, air/charge temp, etc...) the computer tells the spark plugs when to fire. In non-compyuter controlled spark systems, the timing of the spark is controlled by the distributor via two systems- the mechanical spark advance system and the vacuum spark advance system. The mechanical system advances the spark linearly based solely on the RPM of the motor. The vacuum advance system advances the spark based on the vacuum signal provied to the vacuum advance pod. Again, do a search and read up on recurving your distributor. |
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| Author: | sandy in BC [ Tue Apr 07, 2009 9:55 am ] |
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As the engine accelerates it needs more ignition advance....when vacume is high more advance gives better fuel mileage. The advance degrees plotted on a graph makes a curve..... The better the curve matches your compression/valve timing curve the more efficient your engine becomes. The cheapest performance tip is an up to date / aprropriate curve. Its not the same towing as racing. |
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| Author: | 66aCUDA [ Tue Apr 07, 2009 9:57 am ] |
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Most dizzys are not set up for the motor to run its best it was set up as a baseline to pass emissions. Most were also REALLY wide tolarances. Depending on YOUR engine and the year, options, etc. a dizzy can be set up to run more to your driving habits ie CURVE. Hope this puts it in easy terms for you. Frank |
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| Author: | BlueBandit [ Tue Apr 07, 2009 10:02 am ] |
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Thanks. It helps a lot. Ive just got to get this thing better gas mileage (better than 13mpg) and ive got to get it to pass emissions and im sick of the lean burn. |
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| Author: | 66aCUDA [ Tue Apr 07, 2009 10:12 am ] |
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Talk to SS Dan about emissions testing he can REALLY set you straight. Frank |
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