Weak Spark, All New Components

[Studdley]

Hello, I'm new to this forum and I signed up because I'm tired of going to get my battery charged at autozone for cranking my 351c for seemingly hours on end.

I did a top end rebuild on my Cleveland and put on new wires and i get intermittent and weak spark. The distributor and coil are less than 6 months old and the plugs and wires are less than a week old. When I crank, it sputters then absolutely zero bite, when I pull the plugs they are all carbon fouled, when i put the new ones in, I laid one up against the block and got a fairly weak spark if any at all, please help, I'm thinking I over torqued the rocker arms and they dont allow the valves to close all the way, bit the thing started about 2 weeks ago in colder temperature, I'm getting super frustrated, please help!!!!!

 

[libram]

well that's a lot of things at once. Lets try and get clear so individuals with specific knowledge can tackle each issue.

1 Battery keeps dying?

2 Starting issue? or is this just straight up caused by the battery

3 Carbon fouling the plugs, is this like every single plug, every single time you run it? Like crank it and run it 5 mins and the plugs are all shot?

4. How are you defining weak spark...... just visual?

 

[Vinnie]

5: points or electronic ignition? (does the coil match?)

 

[Studdley]

well that's a lot of things at once. Lets try and get clear so individuals with specific knowledge can tackle each issue.

1 Battery keeps dying?

2 Starting issue? or is this just straight up caused by the battery

3 Carbon fouling the plugs, is this like every single plug, every single time you run it? Like crank it and run it 5 mins and the plugs are all shot?

4. How are you defining weak spark...... just visual?

The battery dies from me cranking it for so long, I've tried multiple batteries

Carbon fouled from the engine sputtering and not starting, it does not run

Visual and from the fact that the engine rarely even "pops" when cranking

 

[Studdley]

5: points or electronic ignition? (does the coil match?)

Points and it has started and run well with this setup

 

[turtle5353]

Has it ran since you did the top end rebuild??

you may have the timing WAY off....180 out.

 

[delawarebill]

i don't know how u do your valves on a 351C motor. but my 302 i turned ea cyl to TDC and torqued down, maybe u need to revisit the adjustments. now u didnt say when u replaced the plugs how it fired up. did it start up with more/less no problem and then later u had the carbon problem come up again??? carb rebuild time maybe ???

and since u are using points ck the voltage at the coil from ign sw. u have a resistor wire that may be going bad/fraied and not getting correct current. that voltage is like 8V. and u can do a TEMPORALLY bypass of coil and put a full 12v to it and see what that does... don't run it long for the ign sys don't really like full 12v.

 

[Studdley]

i don't know how u do your valves on a 351C motor. but my 302 i turned ea cyl to TDC and torqued down, maybe u need to revisit the adjustments. now u didnt say when u replaced the plugs how it fired up. did it start up with more/less no problem and then later u had the carbon problem come up again??? carb rebuild time maybe ???

and since u are using points ck the voltage at the coil from ign sw. u have a resistor wire that may be going bad/fraied and not getting correct current. that voltage is like 8V. and u can do a TEMPORALLY bypass of coil and put a full 12v to it and see what that does... don't run it long for the ign sys don't really like full 12v.

I kinda half assed bolting the rocker arms down and didn't rotate the engine, but it ran with the top end rebuild, I tried hooking a full 12v and it didn't we to have much of an improvement, the car does shale and vibrate a good bit when it did run, do you think something could have gone loose?

 

[Studdley]

Has it ran since you did the top end rebuild??

you may have the timing WAY off....180 out.

It has run, and I pull the number 1 plug, put my finger over the hole and feel for the compression stroke, and when I take my finger off the rotor is pointing straight at the number 1 cylinder, could a vacuum Leak completely stop my car from even sputtering

 

[Studdley]

i don't know how u do your valves on a 351C motor. but my 302 i turned ea cyl to TDC and torqued down, maybe u need to revisit the adjustments. now u didnt say when u replaced the plugs how it fired up. did it start up with more/less no problem and then later u had the carbon problem come up again??? carb rebuild time maybe ???

and since u are using points ck the voltage at the coil from ign sw. u have a resistor wire that may be going bad/fraied and not getting correct current. that voltage is like 8V. and u can do a TEMPORALLY bypass of coil and put a full 12v to it and see what that does... don't run it long for the ign sys don't really like full 12v.

I'm sure the carb could use a rebuild, but starter fluid doesn't do the trick either

 

[delawarebill]

lets just ck off some boxs... clean the points, and do the valve adj again and to spec's. with the plugs out and dizzy cap off turn engine by hand and ck the TDC to #1 cyl and the rotor button. oh and don't assume the new plugs are gapped correctly out of the box. hopefully it fires up and u can ck the dwell too.. ford's are a pain to adj the dwell but u might want to try. on chebby motors i always tune by dwell with points.

 

[73pony]

lets just ck off some boxs... clean the points, and do the valve adj again and to spec's. with the plugs out and dizzy cap off turn engine by hand and ck the TDC to #1 cyl and the rotor button.  oh and don't assume the new plugs are gapped correctly out of the box. hopefully it fires up and u can ck the dwell too.. ford's are a pain to adj the dwell but u might want to try. on chebby motors i always tune by dwell with points.

+1 on these steps. Also, just because a coil is new that doesn't mean it is good. Just a heads up since you indicated weak spark. I've seen plenty of coils bad out of the box.

 

[mustang7173]

Studdley,

Check your timing. Sounds like a 180 degree off in alignment. Recommend to get TDC tool to dial it in.

 

[c9zx]

Are you sure the + and - wire are not reversed on the coil? Just something to check. Chuck

 

[Don C]

A bad condenser can cause problems.

Is the breaker plate grounded to the distributor body with the small bare copper braided wire?

Is the coil case well grounded through the bracket? No paint in the way?

 

[SVO2SCJ]

Welcome and thank you for returning with "the info you need" for internet diagnosis.

Cranking LONGER isn't going to "fix" problems you have. If it won't start with starting fluid - says ALOT as to lack of spark/timing issues. SHAKING also would be associated with an out of time/wrong order for secondary spark!

You also need to CLARIFY what you mean by "tighten rockers HALF ASSED" As well as WHAT you have pedestal/stud and if the motor is hydraulic or solid lifters!

1) Where are you . Profile says EAST and Midwest. I ask because there are many in any area that can in 20 Mins time a motor. (and of travel to other areas to buy cars and parts a lot)

2) Step back and reconfirm your work. Start with the firing order and timing. As suggested, confirm you have distributor installed on TDC of intake stroke and go from there once running.

YOu can do this if you read, take your time and show/ask questions.

Mark

 

[OzCoupe72]

As others have noted you need to get back to basics and check your valve/ignition timing first, check points and if the coil wired properly

I would also add to do a compression test then let the forum know what your findings are

 

[Nuts]

Hi studdley I had a weak spark problem on a 351 4v Cleveland some years ago and found it to be a dead condenser hope this helps

 

[Studdley]

lets just ck off some boxs... clean the points, and do the valve adj again and to spec's. with the plugs out and dizzy cap off turn engine by hand and ck the TDC to #1 cyl and the rotor button.  oh and don't assume the new plugs are gapped correctly out of the box. hopefully it fires up and u can ck the dwell too.. ford's are a pain to adj the dwell but u might want to try. on chebby motors i always tune by dwell with points.

+1 on these steps. Also, just because a coil is new that doesn't mean it is good. Just a heads up since you indicated weak spark. I've seen plenty of coils bad out of the box.

How many ohms should a coil have