Car broke down....half mile away

[6bblgt]

Q3-69 (7-8-9 1969) makes the most sense for your Challenger

when your engine was apart did you replaced the timing chain?  if you have not adjusted anything trying to keep it running, at "0" on the balancer is the rotor still pointing at #1?

[kawahonda]

The engine I have apart is a 408 Magnum block. Have yet to touch the internals of this 340...

I think what you're getting at is if this possibly jumped a tooth....let us hope not!

Would be good to have a sanity check though and rotate it to #1 TDC and check rotor position...

[kawahonda]

Here are my findings...

Dashed line on distributor housing references direct center of #1 terminal.

Looks like it's correctly advanced at about the right spot. I will need to advance it slightly more since I backed it off for diagnosis earlier.

As I understand, advanced timing = rotor should be slightly past the post terminal. 0 BTDC degree should be directly pointing at the dashed line.

Looks like we're good here, I think.

[6bblgt]

rotation & Left VS. Right always make my head hurt 
but
with a small block distributor rotating clockwise, isn't that already after #1? or should it be?

[kawahonda]

At TDC of #1, the distributor rotor is pointing after terminal #1 at some degrees...maybe 10-15 degrees or whatever.....that means the spark has already happened when cyl 1 is at TDC. That should be correct and what you would expect from advanced timing....unless you prefer running at 0 BTDC and then would expect it to be "dead on." Most of us run at 12-18 advanced initial, which means the spark will have already happened BEFORE the piston hits TDC. The rotor has "moved on" at that point...helps to think of it that way. You in theory, could use this method to check what your initial is set to, if you had timing tape. The factory timing cover only is -10  0 +10, so you really don't have a lot of resolution.

It's counter-intuitive, but I think it's correct. If I had the initial set at 0 BTDC, I bet it would line up perfectly. If you had retarded timing, it would be opposite...the rotor will be on the right side of the mark, meaning that it still hasn't thrown a spark when cyl 1 has reached TDC. Really bad performance there.

I would expect If the cam jumped a gear due to a loose timing chain then it would be way off...the rotor would be pointing at the next terminal post at that point or even beyond, which it is not. You'd probably hear....ugly mechanical noise which wouldn't be good.

The rotor in theory, should be pointing somewhere after post #1 at cyl #1 TDC when a good initial (advance) timing is set, but certainly not enough to reach the next post or beyond. Luckily, I think we are good!

This doesn't really go into effect when you are dropping a distributor in to the motor though. You simple just point it to where #1 is on the cap, insert it where it matches up perfectly with the cap ( 0 degrees), and probably just give it a nudge rightward, or counter clockwise (facing the engine) to give it some advance. You'd probably be close and she will definitely start and be happy.

This is all arm-chair thinking by a 35 year old by the way, so correct me if I'm wrong.

[blown motor]

@kawahonda What are you using for an ECU? Stock, Rev-N-Nator, MSD?

[Rich G.]

First check for good spark like I said and yes remove the coil wire from the cap. If the spark is good. ( you should even hear it ) you can do the same to the ends of the plug wires when you put the coil wires back in to see if you're getting spark to the plugs. ( could have a cracked cap) . You could do a compression test and that would tell you if the timing jumped. I've never seen that on a Mopar . That was common on Pontiacs with the nylon cam gear.

[Bullitt-]

I'm wondering what the effect of poor wiring connections might have on a standard ignition. As many issues folks seem to have with corroded connections with voltage drops not allowing their electronic controlled cars to start it would make sense a similar issue would effect a points system.  I would suggest checking the voltage to the ballast as well as the coil but even that may not tell the whole story as with no load on it the system will not reveal the amperage available through a broken down wire. 
  One quick & easy test is to put a jumper wire from the positive battery terminal to the + side of the coil thus bypassing all of the cars wiring on that side.. If the problem goes away you know there is a problem in the supply side wiring. If not it's the coil or something to do with the wiring to the distributor given that everything else is up to snuff. 

[Strawdawg]

First check for good spark like I said and yes remove the coil wire from the cap. If the spark is good. ( you should even hear it ) you can do the same to the ends of the plug wires when you put the coil wires back in to see if you're getting spark to the plugs. ( could have a cracked cap) . You could do a compression test and that would tell you if the timing jumped. I've never seen that on a Mopar . That was common on Pontiacs with the nylon cam gear.

This is the first thing to do.  If you have a nice, strong BLUE spark on a steady basis, then it is 99% that the coil and distributor are working properly.  If the spark is not strong and steady as it cranks, then it would seem that either the coil or distributor is bad assuming they are getting the proper voltage

[Chryco Psycho]

I believe he has isolated that as the problem with the timing light being intermittent

[JS29]

 

[kawahonda]

@kawahonda What are you using for an ECU? Stock, Rev-N-Nator, MSD?

70 challenger is pre electronic. Point for now. Eventually pertronix.

[Strawdawg]

I believe he has isolated that as the problem with the timing light being intermittent

yes, I agree.  It seems to suggest a coil problem if a visual inspection of the points show they are not badly pitted. Dwell suggests they are working.  If the spark shows blue as it should, I would assume the condenser is doings it's job.  But that may also rely on the coil working properly.

With erratic spark, I would tend to assume it's not a voltage supply problem to the coil from the key side.

[kawahonda]

As I'm waiting for all these parts to arrive, I could go out there and test the resistance of the coil. As I understand, testing the resistance of a coil is only partially testing the coil, so even if the resistance is all in spec, doesn't mean coil is "fine". The reason I'm thinking about doing it is to see if my OHM meter makes sense, because basically it's saying my wires have 1,150 resistance or whatever, which is way below spec.

[Chryco Psycho]

What type of wires / core type ?