Topic: Changing sparkplugs/wires?
in Forum: C3 Engines
So here goes:
I want to change the plugs and wires on our '78, as part of the first steps
we're taking to breathe new life into her. I can already see that this is no
simple task, given the layout of the engine compartment, routing of the
plug wires, etc.
I have an article from Corvette Fever on this very job--and it describes
the need to loosen the shielding, loosen the engine mounts, put a jack
under the engine and raise it slightly in order to be able to run the wires.
Far be it from me to second-guess the experts at that magazine--but is
there any alternative that you guys might know to this approach? It just
seems like a hell of a lot of serious wrenching just to change eight
sparkplugs and their wires.
I don't mind doing 'heavy lifting' (pardon the expression) if that's what it
takes to get a job done--but I'm reluctant to start unbolting the motor
and putting a jack underneath it if somebody's done this a different--
better?--way.
Over to you for any advice/how-to's...
If you don't mind RFI noise or have a more modern electronic radio or ignition system that more effectively eliminates RFI, you can simply route new wires over the valve covers like other models and makes do. I see a lot of Vettes with aftermarket distributors, coils and wires without any shielding at all. Either they don't listen to the radio or have found they don't need the original shielding.
My '79 has a MSD distributor and MSD 8mm wires. I have them running over the valve covers, ( I have headers) and get no ignition noise in my FM, CD player or Xm sat. radio. The reason they run them under the motor mounts is to keep them out of harms way, so they don't come in contact with the exhaust pipes. If memory serves me correct, I took off the old ones with out all that work, and just carefully slipped them under the motor mount. You will have to remove the shielding down below the heads. My old ones didn't pull apart from doing this either.
Dave
The routing depends on if you are having an NCRS inspection or just want new wires that are functional. I routed the new wires as close as practical to how the old ones went except the ones that went throught the engine mounts which I found an alternate routing. Just be careful they are clear of the exhaust manifold and pipes. I cut off the old wires that went through the engine mounts to make removal easier. If you really want them to go through the mounts you may be able to take off the boots and get them to slide through.
For changing the plugs access most from up top and a couple from the underside of the car. It will be obvious which ones when you get there. I also remember needing a 1" extension for one plug which made life easier. Good luck it is not that bad of a job.


my 76 has the current wires routed over the valve covers. i was
going to order moroso blue max wires from ecklers, in their add they
state wires are made for corvettes,my question is will they be for
over or under the valve covers,I imagine under will be much longer
their part to make it that way.
The General didn't really have D-Y-I'ers in mind when he designed the
spark plug/wire system on these sharks, did he?
Well, it doesn't really matter that they're a bear to get to. They're frozen in
place anyway. So another of today's intended projects bit the dust.
The plugs/wires joined the *@* oil filter--that wouldn't come off no
matter what I tried. Including the "Dracula" cure--nailing a screwdriver
through its oily little heart, after having no success at all with a filter
wrench. And a hammer. Make that two hammers--a rubber mallet and a
steel claw hammer.
I'm being reminded just what you get when you get a car that's not only
old--but hasn't been well maintained.
So it's getting hooked up to the back of a tow truck, and off to the Chevy
dealer to have somebody with some serious tools remove the oil filter. Or
what's left of it, anyway. In the depths of my frustration earlier I had
halfheartedly decided to just go ahead and have 'em change the plugs
and wires too.
But I'm not going to. The oil filter may be virtually as good as welded
on--but one way or another, those plugs are comin' out of there with my
hands on the wrench.
At least, that's the plan for now...
good luck to anyone else setting out to change theirs--it is not an easy
undertaking.

Yikes!!
Good luck
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As far as the plug wires go, if you get a set with removeable boots (distributor side) you can run them through the motor mounts. I did this with a set of Accell Super Stock 8mm wires.
As for the oil filter.......I cant believe that the screwdriver did not work. Try a Craftsman Strap Wrench.
Good luck......Anthony