So you want to go with a Coil On Plug setup? Don't want to pay $400 or more? This tech article will show you how to build your setup for less than $100.
Parts needed:
1. Four coils off of a 1999-2002 Dodge Intrepid 2.7L or 3.5L (can also be from other cars, but I used the ones from the 2.7L) $10 a piece from the junkyard.
2. If you get your coils from the junkyard also cut off the pigtails for the wiring harness. Free w/coils.
3. You need a plate of metal to mount them to the valve cover. So, go to your hardware store and look for small pieces of steel or aluminum probably 12"x24". I went with mild steel, really wanted diamond plate but couldn't justify the price. $4.99 for the steel.
4. Pick up 8 bolts and 8 nuts and 8 washers that will hold the coils to the plate. I always use S.S. hex cap bolts for my projects. $5
All that for about $50. Your coils may need new boots on them you can replace those really cheap. Just go to your auto parts store and look up the vehicle you got them from.
You can also just get the coils from the parts store. But it will be more expensive and you wont get the pigtails with them.
HOW TO:
1. The first part is to fab up your mounting plate. The steel I used cut easily with tin snips. I outlined the shape I needed with the stock spark plug well cover. Then just cut it out.
2. Now you need to cut out the holes for the coils. I used a piece of metal that I had cut for a template to draw out the square hole. Go and measure half the distance from the top to the bottom of the plate and draw a line all the way across the plate with a sharpie. Next, go out and measure the distance to the center of each spark plug well. Draw a line perpendicular to the one line you already drew at each one of those measurements. Take your square template about 1"x 1.5" and draw around the template. Note that the boot on the coil is a little offset it is not in the center of the coil. So, when you use your template move it closer to the right . Cut out your holes with a dremel and use the reinforced cutting wheels.
3. Mount your coils. I just used bolts and nuts for mine. make sure you get the bolts short enough so they won't hit the valve cover when you put the plate on.
4. Wiring. This is by far the hardest part. I will try to illustrate it well. The pigtails that I used had two wires, green and white. The green wire is the top wire in the pigtail and the white wire is the bottom. Coils 1 and 4 will be linked together and coils 2 and 3 will be linked together. To do this, take the green wire from coil 4 and solder it to the white wire of coil 1 . Then take the green wire from coil 3 and solder it to the white wire of coil 2. The green wires from coil two and coil 1 will be soldered together to get 12volt power from the ignition harness. I had an old stock coil around and pulled the harness off of it so I could use the plug. That way all I had to do was plug it into the stock harness. The colors on the stock harness are Black w/White stripe, Red, and White. Take the black wire from the harness and connect it to the two green wires from coils 1 and 2. Then take the red wire and solder it to the white wire from coil 4. And the last wire should be the white one, solder it to the white wire from coil 3. There it is all wired up. Now, you can used heat shrink to cover the wires or just use some electrical tape.
5. The next problem you will have is with the boots that go on the spark plugs. You need to trim them at the top so that you will be able to mount the plate onto the valve cover. Trim them like shown in the picture then shorten the spring to match.
Edit: I am going to be upgrading the plate that holds the coils here in a little bit. The plate I used for this install was purely the cheapest metal I could find just so I could mock it up. It is very flimsy and works but clearly isn't the best.
When looking for a plate to use be sure you get the correct one for the coils you have. The 2.7L coils have the screw holes in the 12 and 6 O'clock positions. The 3.5L coils are in the 3 and 6 O'clock positions.
Stay tuned for better pictures!!
Parts needed:
1. Four coils off of a 1999-2002 Dodge Intrepid 2.7L or 3.5L (can also be from other cars, but I used the ones from the 2.7L) $10 a piece from the junkyard.
2. If you get your coils from the junkyard also cut off the pigtails for the wiring harness. Free w/coils.
3. You need a plate of metal to mount them to the valve cover. So, go to your hardware store and look for small pieces of steel or aluminum probably 12"x24". I went with mild steel, really wanted diamond plate but couldn't justify the price. $4.99 for the steel.
4. Pick up 8 bolts and 8 nuts and 8 washers that will hold the coils to the plate. I always use S.S. hex cap bolts for my projects. $5
All that for about $50. Your coils may need new boots on them you can replace those really cheap. Just go to your auto parts store and look up the vehicle you got them from.
You can also just get the coils from the parts store. But it will be more expensive and you wont get the pigtails with them.
HOW TO:
1. The first part is to fab up your mounting plate. The steel I used cut easily with tin snips. I outlined the shape I needed with the stock spark plug well cover. Then just cut it out.
2. Now you need to cut out the holes for the coils. I used a piece of metal that I had cut for a template to draw out the square hole. Go and measure half the distance from the top to the bottom of the plate and draw a line all the way across the plate with a sharpie. Next, go out and measure the distance to the center of each spark plug well. Draw a line perpendicular to the one line you already drew at each one of those measurements. Take your square template about 1"x 1.5" and draw around the template. Note that the boot on the coil is a little offset it is not in the center of the coil. So, when you use your template move it closer to the right . Cut out your holes with a dremel and use the reinforced cutting wheels.
3. Mount your coils. I just used bolts and nuts for mine. make sure you get the bolts short enough so they won't hit the valve cover when you put the plate on.
4. Wiring. This is by far the hardest part. I will try to illustrate it well. The pigtails that I used had two wires, green and white. The green wire is the top wire in the pigtail and the white wire is the bottom. Coils 1 and 4 will be linked together and coils 2 and 3 will be linked together. To do this, take the green wire from coil 4 and solder it to the white wire of coil 1 . Then take the green wire from coil 3 and solder it to the white wire of coil 2. The green wires from coil two and coil 1 will be soldered together to get 12volt power from the ignition harness. I had an old stock coil around and pulled the harness off of it so I could use the plug. That way all I had to do was plug it into the stock harness. The colors on the stock harness are Black w/White stripe, Red, and White. Take the black wire from the harness and connect it to the two green wires from coils 1 and 2. Then take the red wire and solder it to the white wire from coil 4. And the last wire should be the white one, solder it to the white wire from coil 3. There it is all wired up. Now, you can used heat shrink to cover the wires or just use some electrical tape.
5. The next problem you will have is with the boots that go on the spark plugs. You need to trim them at the top so that you will be able to mount the plate onto the valve cover. Trim them like shown in the picture then shorten the spring to match.
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Edit: I am going to be upgrading the plate that holds the coils here in a little bit. The plate I used for this install was purely the cheapest metal I could find just so I could mock it up. It is very flimsy and works but clearly isn't the best.
When looking for a plate to use be sure you get the correct one for the coils you have. The 2.7L coils have the screw holes in the 12 and 6 O'clock positions. The 3.5L coils are in the 3 and 6 O'clock positions.
Stay tuned for better pictures!!
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