coil pulling for compression test

I stayed up tonight to work and plan to get up early to get stuff done so I can run out and do that compression test tomorrow. I've been studying on it, and I think I have it figured out except for one question. In various posts, you say you "pull the coil" before you run the test. (I guess so the electricity doesn't spark over to the unhooked spark plug wires?) I am not sure WHICH part of the coil or its wires to undo -- the part that goes to the distributor? The part coming in from the generator direction? The part going out toward the spark plugs? The whole shebang? :-) Here is a diagram from the I&T FO4. The coil is #16 (it says). Can someone please use this picture to explain to me which thing I should undo? I presume I take the wire off, sort of like I did with the spark plugs? Thanks in advance!! --Dawn

OK, wait a bit . . . give my heartbeat a minute to slow down to something less than about 325 . . . breathe, breathe.

You guys aren't kidding about totally redoing this, are you? I'd better have coffee this morning instead of tea.

I'd better put chocolate in it.

You can do it Dawn! The radiator comes off with two bolts on the bottom, then just start loosening the head bolts. Mine was surprisingly easy, I was expecting the bolts to be frozen in there and then have to pry off the head, but it just lifted right off. You will get a good view of some of the insides of Arther.

Good Luck!
Scott

Take lots of pictures, I worked on Bingo late last night and this morning I already forgot where some things go.

Just my experience,do it right or do it over..

Hope you got the coffee brewin, :)

Tim

You first got to fix what ever is knocking.

Probably going to involve overhauling the engine and if you do that you are going to have good compression and still won't need to be taking a compression test.

This is called getting the cart before the horse.

Zane

In reading about compression tests, I learned that if I do a dry test and then compare the results to a wet test I should be able to tell whether my problem is primarily in a piston or pistons, or in a valve or valves. That sounds like a good diagnostic thing to do. BUT, on the other hand (as I was thinking this through), then I was wondering what the results will mean in terms of what I do.

For instance, if two pistons side-by-side show loss of compression that can apparently mean there could be a crack in the head between them. Or I could find out one piston has a problem and the others are fine. Or that there is no piston or ring problem, but something going on with the valves, etc. And it made me think about the balance between "if it's working, don't fool with it" and "as long as things are off, might as well refurbish them." So I've been reading those parts of my books, too, chewing it over. Because obviously ANY of those problems is (I think?) going to require that I take off the head.

On the one hand, I don't want to mess up anything that's working well. Given that I'm such a novice, I figure the chances of my doing that are high and that I should only fool with things that are broken or messed up. On the other hand, I know as a bottom-line "gimme" that I'm going to have to split Arthur. His clutch is rusted into non-functionality. There's no question about that at all. There's even a real good chance I'm going to have to fix rust damage or stuckness on the shift forks and so on. He simply sat out in the rain and snow way too long, and there's no boot on his shift lever.

So if I have to split him anyway, and if I have to undo things enough to fix a valve, or to redo one piston, or to remove and repair one connecting rod bearing . . . then it seems like it would make sense to do the whole job "while I'm in there." But that takes me right back to the "if it works, don't fool with it" thing and my just-learning status.

I'd like to know what I'm getting into, regardless, simply because the closest thing I've ever done to this kind of work is my research, and this methodical approach is what I know. When I put my work on Arthur in that context, then I feel more confident. But as I look ahead, I realize that the "flow chart" of my potential future actions depends on variables I'm just unsure of. So although I feel like I want to know these test results, I'm also aware that I don't know exactly how I want to act on the results.

How do YOU see the balance between "while you're in there, fix it" versus "if it works, don't fool with it", especially in a situation like mine where the person is a novice? I'd really appreciate your advice on that. (And anyone else's too!!!!)

Dawn

Should I still do the compression test? Naw, don't answer that. I'm obsessive about data. LOL I know I have to do it, out of curiosity if nothing else! LOL again.

Thanks, David!!!

Dawn

I know that you will post the results. I am anxious to see them.

One thing I don't quite understand is this: "you do know that your ignition coil is a seperate switch controled electrical circuit than yer BIG THUMB starter switch by the tranny shifter, don't you?" (from Dell). I know what the big thumb-controlled starter switch is, but I'm not sure about the "separate electrical circuit" of the electrical coil part. Do you mean that the starter on the floor by my feet just activates the starter motor, which then kicks on the engine -- but that the coil and everything past that is then activated by the generator once the engine is running? -- that the current does not flow from the starter button on the floor by my feet all the way through to the coil "by itself"? I mean, I think that's how it IS, but I don't know if that's what you're referring to. And I'm not sure, if that's what you mean, where the switch would be for that circuit ("separate switch-controlled circuit" part of the statement).

Just trying to make sure I understand everything you guys have explained. Sorry to be so slow on the uptake... But THANK YOU all again, guys! --Dawn

Heres the deal, most modern cars, to crank the engine for a compression test, you use yer steering wheel ignition key. Wannna guess what else gitts turned on when yer crankin' for compression test? That is why they're telling you to pull yer ignition coil wire. So you don't accidently sparkle sumptin. You could remove eather the nipple outta the top of the roundcan ignition coil ...or... remove the coil nipple outta the middle of the 5-nipple distributor cap.

But really you don't haffta remove the distributor coil wire for your 8N ...because... are you ready for this? You don't turn-on yer seperate ignition switch just to crank yer 8N's engine. Simple, eh?..... .....Dell

However, if the setup were different, and the coil would be sparking, rather than just pulling the high-tension wire off, and letting the sparks fly, possibly leaving "carbon tracks" on the coil's "lead out" tower, it is far better to pull the coil wire out of the distributor cap, and then ground it, so the high voltage spark is shorted to ground, rather than finding it's own path, and possibly doing damage to the coil.

Often, it is possible to pull the coil wire from the distributor, and tuck the free end into the coil bracket, shorting it to ground.

I'm married! Why would I want to go to bed???

Have a good 'un!

No dog. I guess I'll have to go to the CATHOUSE.