Need a bit of help getting this thing firing

Ok,
you know for sure that you have good spark. 1/2 " is good so I would think the condenser is fine.

Assuming the spark is occurring at the correct time(you assure us it is), all you need is fuel. Add fuel perhaps 2 table spoons in the carb. Open the throttle a crack and crank it. It will fire if your timing is correct +/- 20*. If it doesn't. :dita:

can you take a photo of one of the old plugs?? May give us some insight of fueling.
 
We're using champion rj12yc plugs. Think of the plug new and color everything below the threads black, then you'll know what they look like. We have to go pick up some new valve cover gaskets before we kick it over. The old ones were not really in re-usable form if you know what I mean.
 
They were matte black when they dried off. They were wet from fuel. I tried to clean them a few days ago with carb cleaner, but it didn't clean them up much. The electrodes weren't worn at all so I imagine the po replaced them but was unable to get the thing started and they just got fouled up with all the starting attempts.

When it had idled a little a few days ago, there was exhaust coming out of the tail pipes so I don't think the exhaust passages are blocked. When rotating the crank, all the lifters on the 2,4,6,8 cyl side seemed to move when they should. For the sake of letting you all know what we do (or don't) I tested compression on the even side cylinders and got 120psi on all of them.
 
Unfortunately, the fuel is less than a week old. We'll try dumping raw fuel down the carb when we put the gaskets back on tomorrow. We've been using starting fluid (spray) before each try or two and giving the throttle arm a little bump to make sure the carb is putting gas into the runners. Are there any critical vaccuum lines that need to be connected? We've got most of them pulled and plugged (except the vaccuum adavance). When it was idling rough a couple days ago, we sprayed carb cleaner on the lines and the engine never surged at all so I don't think any of them are leaking.
 
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Now we are getting somewhere!! Just to verify currently when you crank the engine with the cap & rotor on you can get it to jump a 1/2" gap at a spark plug wire? If so and it still won't start with clean plugs (and a prime shot or starting fluid) it is time to statically time it. Like many things there are different methods of doing such but here is one way to do it on a points type rig.

On the dist body make 2 marks, one directly below the #1 terminal and one directly below the #8 spark plug terminal. Rotate the engine till the timing Mark is between 10 btdc and tdc. Loosen the distributor hold down. Here is where it gets a little tricky to explain over the interwebs but I'll try my best. The rotor should be pointing to the general direction of the Mark you made for #8 or between #8 and #1. Rotate the distributor so that the rotor is pointing between the 2 marks and verify that the points are closed. Establish a 1/2" air gap between the coil wire and ground and connect the b+ jumper to the coil (+) terminal. Now slowly rotate the dist #8 Mark tword the rotor when the points open and a spark occurs stop. Lock the dist down, re-assemble and try starting.

If you can get the 1/2" spark from the coil wire but not at the plug wires then the spark is getting "lost" in the dist, and we need to go down the diagnosis path for that condition.

Don't worry about the vc being off, depending on what wt oil you are using, the ambient temp and general condition of your engine it can take 30 sec or more before oil is present in the rocker shaft and it starts splash around. Setting the vc on the head will limit the oil splatter if you want to run it for while.

If the coil is able to jump the 1/2" gap then the condenser is fine, the main difference between the straight and curved point condensers is the length of the wire. Mismatch them and you will either not be able to connect the wire to the points with the condenser bolted down or you will have ~2" extra wire.
 
Thanks eric, when we got the coil to fire a spark (we didn't test if a plug wire could jump a 1/2" gap...but we could), we actually did have the distributor in the engine. We just used jumper wires from the points to the neg side of coil to tell the coil when to release the voltage from the primary. What we didn't do was what you described when lining up the coil with the cap. I'm thinking we are losing spark around in the dizzy because when using a spark tester, we were getting the usual strong spark along with many smaller sparks on any given plug. I am thinking that means the spark is jumping to multiple different poles instead of just the one closest to the rotor. Maybe the points are staying open too long. Our distributor cam gear has pretty rounded lobes...should they be more distinct points like a bolt head or are they designed to be rounded off more. You can barely see what I mean in the pic of the rotor from before. I'll see if we can get a close up shot of the dizzy cam gear tomorrow.
 
big_b16 said:
What we didn't do was what you described when lining up the coil with the cap. .
Click to expand...

That is called rotor phasing. If you have the correct points cap and rotor installed there is no reason to believe the phasing is off. But (always a but :gringrin: ) lets move to the next item in this post. First

big_b16 said:
I'm thinking we are losing spark around in the dizzy because when using a spark tester, we were getting the usual strong spark along with many smaller sparks on any given plug. I am thinking that means the spark is jumping to multiple different poles instead of just the one closest to the rotor. .
Click to expand...

This can have 2 causes.
1) rotor phasing.

2) carbon tracking. Once you carbon screw up rotor phasing you will/can create small lines of carbon (conductive residue) in the cap that will conduct the spark around the cap from then on. Really only one fix for sure, a new cap. Might change the rotor also.

big_b16 said:
Our distributor cam gear has pretty rounded lobes...should they be more distinct points like a bolt head or are they designed to be rounded off more. You can barely see what I mean in the pic of the rotor from before. I'll see if we can get a close up shot of the dizzy cam gear tomorrow.
Click to expand...


This is normal. The cam lobes should have a rounded tip not a sharp point. As long as the cam is not grooved where the follower rides you should be ok.

When you are prepared to go through a step by step rotor phasing regiment post up after you make sure the advance mechanism under the breaker plate is sound. All you need is a vom (preferably with a tone setting) and a marker to indicate the location of the # 8 plug wire tower of the cap on the dizzy body.

Everybody is trying to help you figure this thing out but I think you need to put all your prior beliefs behind you and follow some ones lead. You will find the problem so be patient
 
Well it finally fired tonight running the hot wire setup. It still isn't timed correctly and I think the gas tank I am running May need cleaned out again but it does run so that is a step in the right direction.

Getting it running smoothly is most definitely the next step, but I also need some help figuring out how to fix the lack of voltage in the ignition wire going to the coil. That is the only reason I was asking for a wiring diagram before to hopefully track down where the wire is shorting. All the wires in the wiring harness containing ignition wire to the coil are black so that makes it difficult to trace where things are going. I am assuming into the connector on the firewall near the brake booster heading in to the ignition, but I am not sure.

Exhaust fumes!!! The smell of progress!!!
 
Congrats guys!!! Glad you stuck with it.

Yeeeha. Don't you luv the smell of sucess.:gringrin:

let us know if we can help more.

I believe that IH has a built in resistance wire to drop the voltage but don't quote me on that. I'll see if I can find a schematic. I'm sure mr mayben does.:winky:
 
Michael mayben posted a diagram of the ignition system for a 79 Scout II in post # 32 of this thread.

Btw --

if the wiring is original, IH usually printed circuit numbers (small) on the wires.

The wiring in my t/a is green - with numbers
 
Thanks Robert , I remembered seeing it but looked and didn't find it. :icon_eek:

wire by16-16 is fed by the resistance wire # 20 or that is fed by the ignition switch. Start at the ig sw and work forward.

Assuming the wiring is stock the resistance wire is usually covered by a woven heat resistant sleeve.

By 16-16 splits at the bhc. And continues to the coil.
 
It looks like one way or another I am going to have to get into the steering column and check out things there and see where that leads.
 
Don't tear into it yet. You can do the checks at the bhc first and chase the wire as far as you can towards the switch. Should have a plug that is easily exposed without taking the colonm apart. Check there next.
 
Good to hear that you got it running what was the final thing you did to get it to go?

As far as the wiring issue don't go taking the steering column apart the ignition switch is at the base of the column and can be accessed under the dash.

The switch is a standard GM unit, but there are 2 different versions one for the fixed and one for the tilt. They plug into the same connector however. Here is a generic GM ign sw diagram, the sii only uses the left half and the terminal in the lower rt "i1" is where the ign power originates.

http://www.chuckschevytruckpages.com/images/ignition.jpg


If you disconnect the plug you will see that it is in the shape of the left half with terminals sol (starter solenoid) bat1 & 2 ign 1 and acc.

Unfortunately I only have the early diagrams so I can't tell you which slot in the bhc it exits the cab through. Hopefully the cir # printing is still be readable at the engine side bhc. It will almost certainly be present at the ign sw connector and the cab side bhc.
 
So we have a cz17 wire going from the starter to the bhc that has continuity. The by16 is going from the coil to the bhc and it looks like either this vehicle didnt have a resistance wire or someone has removed it. By16 also has continuity from the bhc to the coil. So two questions:

1. How should it be rewired to accomodate the ballast resistor and also maintain 12v on start and 9v on run?

And

2. Does this mean there is definitely an issue with the ignition switch?
 
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Please...note that in my post where I provided you the correct wiring diagram for the vehicle originally described, I noted that diagram was not for a sii that May have been originally equipped with a breaker point distributor which requires either a "resistor wire" or a ballast resistor (but not both)! A resistor wire and a ballast resistor are simply two different type devices which accomplish the same end result!

You must decide which ignition system set-up you are going to use on a permanent basis. That will determine "which" wiring system needs to be provided.

If you are going to use a pertronix conversion in the breaker point distributor, then that needs to be accommodated. All you were trying to do when you started this thread was "make it run". The suggestion was to put a points distributor in and "make it run". That takes exactly a single "hot wire" from the battery to the coil positive terminal to "make it run".

If you are ready to progress to the pertronix conversion again...then simply install it and set the air gap. The red wire on the p-tron harness goes to the coil positive terminal, the black wire on the p-tron harness goes to the coil negative terminal.

But...when I suggested that you verify that you have the correct pertronix unit for the breaker point distributor you are trying to use, you never posted the results of that "check". So right now...we don't know what p-tron you have by part number! There are many possibilities!
 
It looks like a zck-1481 for the pertronix. I am thinking this May not even be the right one for this setup because it was purchased when the distributor cap was incorrect among other issues.

Regardless I am going to be perfectly content running points in here but neither will work until the ignition issue is sorted out.
 
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beastud said:
it looks like a zck-1481 for the pertronix. I am thinking this May not even be the right one for this setup because it was purchased when the distributor cap was incorrect among other issues.

Regardless I am going to be perfectly content running points in here but neither will work until the ignition issue is sorted out.
Click to expand...

A pertronix 1481 is correct for a Holley "curved points" distributor. And that is a "pertronix". A p/n 91481 is the number for the same distributor, but in the "pertronix II" version with adaptive dwell feature.

Attached is a .pdf of the "early Scout II cab and engine bay schematics, this is for vehicles equipped with a breaker point distributor and has a clear callout regarding both resistor wires used in the harness, the one for the coil feed, and the one for "field excitation" of the alternator. Do not confuse those two completely separate wire runs.
 

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  • Early SII Cab_Engine Bay Wiring.PDF
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