help-just broke down and car won't start!

Roundel Tech Talk

Who keeps their Roundels? Maybe a month or two ago there was a letter describing the exact situation. I was thinking coil or Pertonix when the same problem happened to me however, Mike Miller says it it the wires that connect to the coil. I am away from home traveling but maybe someone else can find it. If not I will post again on Friday when I am home. Seemed like a very simple and inepensive fix. Unplug the wires from the coil, snip off the old spades, bare new wire, crimp on the new spades and reattach....
 
I'd start with loose distributor. This is what happened to me. Went thru a tune up and didn't adequately tighten the distributor. Vibrated out of time and back into. Finally fell far enough out it blew the muffler....exactly like yours.

Guessing you may have a new distributor but otherwise a worn distributor, gear mesh issues (worn) either on the dizzy or the cam. Rotor also. Not fully seated. Worn / loose for some reason. Etc

Just don't see where a coil could impact out of sequence combustion large enough to blow out a muffler. I suppose the Petronix but even if dwell changed the basic timing would not be sufficiently effected to cause a big event miss fire.

If someone else on the site has had a massive misfire sufficient to blow a muffler which was finally attributed to coil, points or wiring I will be surprised.

But hey... been surprised before!
 
you could have a new distributor, rotor, coil and Pertronix BUT (if I understand correctlt) it the wire that connects through the spade to the coil is corroded or worn to the point where only one or two threads of wire connect. .. The weakest link
 
I will check all wires but would like to see this article Stan's referring to, and put it in here for the record for the next person who get's the gremlin

Stan said:
you could have a new distributor, rotor, coil and Pertronix BUT (if I understand correctlt) it the wire that connects through the spade to the coil is corroded or worn to the point where only one or two threads of wire connect. .. The weakest link
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Dyno... increased plug gap clearance... backfire....rich fouled plug symptom caused by larger gap...
 
Update

I cluster bombed the problem with a new plug wire set from Kingsborne, it's a work of art and I did the 8mm size option:

http://www.kingsbornewires.com/product.sc?productId=9&categoryId=2

New Bosch 1.8 ohm ballast resistor for my red coil since it was long overdue.

New Pertronix.

Cleaned all contacts.

Reason for the cluster bomb approach: didn't want to replace one thing at a time and drive around till it dies/blows out my exhaust stranding me again somewhere in no man's land.

My plugs are gapped at .030 so I think they are ok. The issue of not restarting for a while I think eliminates the gap and the timing as causes, we'll see.

Rear exhaust can welded back together and the seam plugged with JB Weld until I can get a new stock one.

Drove today for 2 hours in various speeds/conditions/coffee shop stops and knock on wood, no issues.
 
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The gap is based on the capabilities of the coil/ignition system. If you haven't changed the coil, don't change the gap. YOUR orig. problem is the petronix .
 
Still looking for anyone who has had Petronix or coil / wire issue significant enough to blow out out muffler?
 
Lotuss7 said:
Still looking for anyone who has had Petronix or coil / wire issue significant enough to blow out out muffler?
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When spark is lost, the fuel don't stop . Exhaust then has raw fuel in it, then ignites, and bang there goes the weakest part of the exhaust .
 
Steve,

Running a vacuum advance distributer still?

Triples need more advance at idle but still all in timing must remain the same. That means a mechanical advance distributer. No getting around it.

Throw in an MSD that will increase spark duration for some measure of insurance. That's what you're dyno sheet and history was saying. Dial in more timing up top and you're going to loose it down low. It was timing just not the direct kind.

At differing rpms, individual intake runners have no vacuum causing a retarded condition. Because of mechanical valve overlap, retarded condition under part load caused by little or no vacuum advance, cam profile, fuel not being burned.................. well, you know how that story ended.

Don't tune an engine on a dyno for max anything on a street car. Set it up to run on the street and the rpm you use the most.

Opening up the plugs just retarded the timing more surely as though you twisted the distributer.

Don't be tempted by the dark side unless you got a spare motor built up.
 
All valid points and I iwll investigate, but why then did I not have spark for an hour or so on the side of the road both times?


61porsche said:
Steve,

Running a vacuum advance distributer still?

Triples need more advance at idle but still all in timing must remain the same. That means a mechanical advance distributer. No getting around it.

Throw in an MSD that will increase spark duration for some measure of insurance. That's what you're dyno sheet and history was saying. Dial in more timing up top and you're going to loose it down low. It was timing just not the direct kind.

At differing rpms, individual intake runners have no vacuum causing a retarded condition. Because of mechanical valve overlap, retarded condition under part load caused by little or no vacuum advance, cam profile, fuel not being burned.................. well, you know how that story ended.

Don't tune an engine on a dyno for max anything on a street car. Set it up to run on the street and the rpm you use the most.

Opening up the plugs just retarded the timing more surely as though you twisted the distributer.

Don't be tempted by the dark side unless you got a spare motor built up.
Click to expand...
 
Temporary fouled plugs caused by excess fuel( rich) caused by incorrect timing ( late or retarded)? Hot engine, manifolds, perculation? Basically the engine got flooded same as if you choked it too much.

Watch those upshifts and keep the rpms up.
 
I was getting no spark from the plug insulator to the valve cover nut when I tested it on the side of the road.

To answer your distributor question my Weber DCOM's have both ported and manifold vacuum ports. I am running manifold vacuum advance for higher advance at idle, and all in at 30, maybe I will bump it back up to 32 but at 34 it pings.

The way the engine cut out all of a sudden and went bang seemed electrical to me but time will tell I suppose.

Thanks for your input everyone.


61porsche said:
Temporary fouled plugs caused by excess fuel( rich) caused by incorrect timing ( late or retarded)? Hot engine, manifolds, perculation? Basically the engine got flooded same as if you choked it too much.

Watch those upshifts and keep the rpms up.
Click to expand...
 
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