Need some electrical help with my ‘68 Plymouth Valiant 100

Okay, Dana did a great job of explaining and illustrating a number of things, so I am going to just make a couple of comments, without directly addressing or quoting any questions or statements:

That broken intake manifold bolt is bad.
It's a big effin' problem.
It's not insurmountable, but will create gluteal pain for a while.
Possible courses of action:

• Drill a very precise small hole right in the center of the broken-off screw (it's a screw, not a bolt, as it threads into a solid object, and not a nut), then use a screw extractor to turn the broken part out.
This will only work if the part of the screw that is in the hole is not tight or rusted-in.
There are also neat extractors that you attach to a drill, they drill their own hole, then they twist the screw out.
This almost never works.

• Remove intake manifold. There is a tiny chance that the screw is broken off below the manifold, but above the head. If so, then remove with Vise-Grips.
This is also unlikely to be the case.

• With manifold off, drill a precisely-centered and precisely-straight hole almost but not quite as large as the screw itself. Sometimes when there's very little left, you can back it out with an extractor.
But probably not.

• Remove the head as well (this entails removing the exhaust manifold) and bring it to a machine shop, where it can be set up on a mill, aligned precisely, drilled out, and then fitted with a HeliCoil or a TimeSert to replace the drilled-out threads.
(You can try this at home, on the car, if you're brave, but if you screw it up, you may need to buy a new head).

Was the car really cheap? This could be why.



I am not certain from what you wrote how much you understand about fuses.

First, to start at the most basic, you do understand that they come in different values, right, and that you need to put the right ones in the right places to protect the right circuits?

Second, the current flows in one metal end and out the other, and the fuse itself doesn't care which.

Third, one edge of each fuse is the "hot" side, which is supplying the power, and the other edge is the side to which the power is being sent.

Fourth, you described jumping a bunch of wires around to make things work –
You know that if you put too much load on a particular fused circuit, the fuse will blow (that's why they're there), right? And you also know that if you put that load before the fuse, the wires will melt and the car may go on fire, right?

Just clean the little snappers that hold the fuses very carefully and thoroughly with a little wire brush, with the battery disconnected, then clean them with some decent contact cleaner, such as Caig DeOxIt, then test the continuity through each fuse, out of the car, with a continuity tester or ohmmeter, or with a test light, which you can make with a small instrument panel lightbulb (don't want to blow any fuses) and a bit of wire, or which you can buy.

I strongly, and I emphasize strongly, do not recommend jumping wires around your fusebox.

Good luck!

And Happy Thanksgiving!


– Eric

edited slightly for style after I woke up more.