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This article is now being maintained on HowTune.com: Installing Plugs, Wires, Cap, and Rotor on a GMC Syclone or Typhoon

The biggest pain in the ass on these trucks.. The ignition. We've been handed a wonderful distributor design. It wears down quickly, while our trucks demand perfect operation from it. If your truck is knocking, its time to think about wires, cap/rotar, and plugs. Its nearly pointless to do just one, as its possible to damage another part in the process.

You have several choices when it comes to parts, these are proven, and used by many sy ty owners. These are not the only available on the market, just the most likely to work well in our application.

Cap & Rotar:

Conrad (red) available at autozone (regular s-15 part, they have syclone in computer as well)
Accel (gold)
Napa (black)
GM (black)

Wires:

Accel Extreme 9000
ATR Black Beauties
KB Red Hots
Holly Annihilator
Magnacore 10mm

Plugs:

ACDelco CR42TS ONLY!!!!!!!!!!

Coil:

GM (stock unit has proved to be the most reliable, aftermarkets may cause problems)

Changing Wires/Plugs/Cap&Rotar

Relatively simple, however it can take some time.The ONLY way to get to the plug is through the fender wells. Some people use the flap on the lower side of the fender well, some remove the wheel, and the fenderwell to get easy access to the plugs. I remove the wheels, because I figure I'm already down here, I might as well clean the beast up and inspect everything else while I'm digging around.

So, here we go:

Step 1: Jack up the front of the truck, placing it on Jack stands. Remove each wheel and remove the fender wells.
You should have a great view of the engine now that the fender wells are out. There are, of course, 6 cylinders, 3 plugs/wires on each side.

Here's a little diagram to keep things straight.

Rear
6
5
4
3
2
1
front

The cylinders are numbered from side to side of the motor so that # 1 is in the front on the drivers side, #2 is on the passenger side in the front and so on. The driver's side of the block has #1, #3, and #5 while the passanger side has #2, #4, and #6.

I usually start be removing one wire at a time so that I know where they connected to the distributor. But I finally decided it might be easier to do a little diagram.

conrad cap numbered

This is an Autozone Conrad cap that I numbered before installing. It makes it much easier to understand where your wires are going. The center "crossed out zero" is the Coil wire and the numbers correspond with the cylinder number they belong to.

Now that we have this information we can pretty much just remove the entire ignition setup without worrying about screwing things up.

Step 2: Pull the wires out, you may have to clip some zip ties or wire looms to free the wires.
Step 3:Remove the plugs using a 5/8 wobble ended spark plug socket. You'll know why you need the wobble ended socket when you try to remove #3.
While your here it's a good idea to Read the plugs in order to help diagnose problems.

Step 4: Reinstall your new CR42TS plugs to keep things from flying into your precious cylinders.
Gap the plugs at the stock setting (it is on one of the emission stickers under the hood) at .35.
You can use Anti-Sieze on the threads of the plugs to make them easy to remove next time.

Step 5: Remove the distributor Cap and Rotar.
The cap has 2 screws, one on either side. I have to scoot up and lay on the motor in order to reach it. (watch not to push on the fan shroud)
After it's unscrewed, just pull it strait out and discard.
The rotar can be a little difficult to remove, especially the stock unit. I had to use a large prying screw driver to break the rotar inorder to get it off the first time. Yank upward as hard as you can, and if that doesn't work, begin trying to pry or break it off

stock rotar pryed off
used conrad rotardistributor without cap/rotar

Step 6: Replace the new rotar (it only goes on in one direction, see the little tab inside the rotar) by pushing it on as hard as you can until it is seated all the way down.
Step 7: Replace the new cap over the distributor and screw down tightly. Again, there is only one way for it to go on, and it should not wiggle at all when installed.

Step 8: Next route the new wires in.

Typically there are different angled wire boots in each of the cylinders:
#1: straight boot
#2: 90 boot
#3 90 boot
#4 90 boot
#5 90 boot
#6 45 boot

Place the boot on the distributor cap, and run the wire down towards the plug, keeping it as far away from heat and moving parts as possible. The manifolds or down pipe can melt right through the wires. Some people use wire heat shielding, which is a fantastic idea to keep your wires lasting longer.
Hook the other end to the spark plug after putting dielectric grease into the boot.
Then, trace back the wire and zip tie it into the wire looms or wherever you find necessary, just keep in mind not to zip tie it without slack to parts that do not torque over with the engine.

After everything is back in and secured, remove everything you have sitting in the engine bay and start her up.
It should start just like it normally does, if it seems to have a harder time idling then before, something is not correct. Double check the wire connections on the distributor and plugs.You may have a bad plug or maybe the rotar didn't sit all the way down or the cap isn't seated correctly.



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