Spark Plug Wire Routing

[ltmark]

This is about my fifth posting as I almost have my wife's '85 back on the road after a lot of fixing things that I have put off for a while while my wife has been going through Chemo. I'm down to new plug wires (MSD), but as I have always had problems with in the past, I never am able to figure out which length goes to which plug. I always end up with one or two that are obviously in the wrong spot because they have too much slack and just don't look right!

Is there any way to get them right the first time? I know which ones wrap around the distributor, but that actually contributes to my problem!

 

[LT4man]

I would take them off one at a time. Use a tape measure to measure the length. Have the new wires spread out from the shortest to the longest. Start to replace them. Do not push the boot all the way onto the spark plug. That way, if you want to switch one, you do not have to worry about ripping the boot.

Hope this helps!

Don't forget to push them all on the spark plugs when you are finished! :L

SAVE THE

 

[eddie20875]

have changed the wires on my 90 and with premade ones they were too long for almost all the plugs (msd). you can get the wires that you can make the exact length you want. all you have to do is crimp a connection on one side of it.

 

[vette007]

I replaced the wires and plugs on my 90 vette just 2 weeks ago. I am glad that I went with a custom set of wires. I laid them out and went from longest to shortess.

 

[Vettefan87]

I have done wires on my car with both sets (pre made and non). For mine it seemed the pre made ones the long one was WAY to long, and the short one was barely long enough to make it. Now the ones I put the end on went much better I could route all of them away from the headers and out of the way.

 

[David-F]

1985 - 1991 "Y" (L98) Plug Wires
#1 - 44" (90deg. boot)
#2 - 44" (90deg. boot)
#3 - 40" (90deg. boot)
#4 - 32" (90deg. boot)
#5 - 26" (90deg. boot)
#6 - 26" (sraight boot)
#7 - 26" (90deg. boot)
#8 - 26" (90deg. boot)

David Fulcher

 

[joshwilson3]

1985 - 1991 "Y" (L98) Plug Wires
#1 - 44" (90deg. boot)
#2 - 44" (90deg. boot)
#3 - 40" (90deg. boot)
#4 - 32" (90deg. boot)
#5 - 26" (90deg. boot)
#6 - 26" (sraight boot)
#7 - 26" (90deg. boot)
#8 - 26" (90deg. boot)

David Fulcher

Old thread. But was wondering if these are the OEM lengths?

As those lengths matched up with some AC Delco plug wires I got. But they are way too long. The Taylor Spiro Pro wires I pulled off had a nice fit. The longest wire in the Taylor set was 40".

 

[TedC]

On my 1989 I replaced with AC Delcos, they were +/- 1" to stock. Used Bosch wires on my 1988, they were +/- 1" to stock. The FSM outlines the proper wire routing under ignition section with a special note that wires #2 and #3 must be routed around the front of the distributor.

 

[joshwilson3]

On my 1989 I replaced with AC Delcos, they were +/- 1" to stock. Used Bosch wires on my 1988, they were +/- 1" to stock. The FSM outlines the proper wire routing under ignition section with a special note that wires #2 and #3 must be routed around the front of the distributor.

The Taylor Spiro Pro wires must be a custom fit. As they fit real good. And the longest wire was 39". After I routed the AC Delco wires, I was trying to figure out what to do with all the extra slack. But then I had a problem with getting the wires to click onto the plugs. Did you have any problems with that? I've never before had a problem getting a wire to click on a plug.

But I returned them and ordered some Belden wires from Napa. They are the same length as AC Delco. So, I guess I'll have to figure out what to do with the extra slack to make sure they aren't touching anything.

 

[vetteoz]

And if your dist is not in the factory location # 1 plug to front ; it throws the whole lot out and none fit correctly

 

[G Winter]

When I put wires on my 90 I took them all off as a unit. Put them on a piece of cardboard and labeled where everything was and the lengths. Then matched up each wire and replaced. Then install each side as a group.

Glenn

 

[TedC]

I've had problems with non stock wires snapping into place. The AC Delco wires fit with no issues on either the AC Delco stock cap, or an Accel cap (I just replaced my cap and rotor with an Accel). They fit with no issue on the stock plugs and rapidfires. Watch the wire thickness, so that you can reuse the same retainers. The HEI ignition used by GM requires that the wires are routed properly as outline in the FSM.

 

[joshwilson3]

I've had problems with non stock wires snapping into place. The AC Delco wires fit with no issues on either the AC Delco stock cap, or an Accel cap (I just replaced my cap and rotor with an Accel). They fit with no issue on the stock plugs and rapidfires. Watch the wire thickness, so that you can reuse the same retainers. The HEI ignition used by GM requires that the wires are routed properly as outline in the FSM.

I've got a pic from an 87 book showing the routing.

Maybe they have switched suppliers since. I think part of the problem is the plug boot for the spark plug was really long. So that made it harder to push the plug wire on all the way. But even then, some of them wouldn't click. Even with a plug in one hand and the wire in the other.