My 454 Rebuild

[Spareparts]

Had a short day at work today and got the cap changed. Now has a new AcDelco cap and rotor.
Still showing misfires on #7. More than random but about 1/2 as much and the timing light flashing is looking a lot better.
It was getting up to 38/40 misfires before the meter reset's about every 10/15 seconds then start counting up again.
Now around 15/20 then reset. Better for sure and it feels better also. Drove it about 2 miles.
I also reset the fuel trims so will probably need a few cold starts before everything settles down.
I guess now if this turn out to not be an acceptable improvement Unsure where else to look. Maybe a couple new valve springs on #7? But again no real confidence that would fix anything either.

 

[Spareparts]

Took it for a spin and it does feel better but it is not fixed.
#7 is still misfiring. 5 different caps and rotors and it still has excessive spark at the plug. Tried a different plug wire, no change.
I just refuse to believe it is a cap/rotor problem anymore.
Im pretty sure that only leaves the sensor in the distribution but 3 different distributions and no change and the current one installed was new a few months ago. So im pretty sure distributions can be rules out.
Crank sensor was replaced with new and gap verified but i think with a Standard ignition brand. I would think if it was erratic on #7 at least one other cylinder would be affected just as bad. I even replaced the reluctor when i changed cams.
I don't see how it's possible, but could the plug not be getting a good enough ground through the threads? It's grasping at straws for sure. Im just totally out of ideas on where to look next.

 

[Schurkey]

I don't see how having "extra" sparks on one cylinder is possible, never mind the misfires.

Have you performed a compression test on that cylinder?

Is there a vacuum nipple on the #7 runner?

Spark plug condition?

 

[Spareparts]

Just can't get a good video. The camera does not catch all the sparking. This is idling at 625rpm.

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[Spareparts]

Also, im sure others are doing it also. I have just been concentrating on #7 as it is by far the worst.

 

[L31MaxExpress]

So many pages here, I forget what you have changed and left the same. Have you changed the coil in this adventure? I had one failing in the van years ago and did not even realize it, then we had a Texas freeze and rethaw, suddenly it had a no start. Ended up finding the coil was grounding out on moisture. I sprayed WD40 on the coil and it fired right up. Changed the coil and suddenly it ran smoother, had better throttle response and became apparant just how bad the old coil was. The coils are plastic insulating material over a metal frame. They can arc out internally without you knowing about it yet still fire the plugs.

 

[Spareparts]

Yeah, About two weeks ago i put a new coil on it.

 

[Spareparts]

Looking at the Crankshaft position sensor i see there are two listed.
213-3208
213-4761
Anyone know the difference?

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[Spareparts]

Ordered a crank sensor.
Want to see is a new AcDelco one is better then a Standard ignition brand.

 

[Spareparts]

Got the crank sensor changed last friday and sorry to say there is no good news and it's worse but it's not the crank sensors fault.
After changing the sensor you need to do a crank/ cam reset. Performed successfully but right when the fuel cutoff there was a heavy clunk i could hear and felt.
Engine still runs about the same but it definitely sounds like a piston? is making noise now. The noise is not rod or crank knock, oil pressure is good and has not fallen even 1lb when hot. I have been driving it since this happened and seems to run the same but something is hurt internal.
Just can't believe that after i don't even know how many engines i have rebuilt this one has been a problem since the day i got it back from the machine shop.
I have not decided on what direction to go yet. Something will need to be done though. I need to park it.
I can see 3 options.
1. Buy a good runner engine from a wrecking yard and have it installed. Guessing around $3500
2: Park it and tear it apart until i find what needs to be replaced. Maybe up to $2500 for a garage rebuild with no machine work.
3: Trade it off. Almost not a option. Other than the engine problem it is in excellent shape, No rust, Dents, Interior is decent, Suspension is all good.