Miss at WOT

[p24-1953]

I changed the points condenser,  coil  and replaced the fuel filter on the truck.  It was running fine but it had been about 5000 miles so I thought while I was busy changing the oil i would do a little preventative maintance.  That was a mistake.   Timing is set to 4btdc, points set at 20.   After this work I have a miss at higher rpms.   The truck now tops out at 40 to 45.  It honestly feels like I hit the rev limiter in a modern car.  You can hear it cutting out. Drop below 40 it purs along fine.  Before this work 55 was not out of the picture.  I rechecked the points and timing. Still had it.  Changed the timing to 0. And set points at 18.  Still there.  Put the old coil back on, old condenser and old fuel filter.  No change still there above 40.

 

This is not like a lack of fuel.  Its not surging it just starts popping and looses power.

 

Any thoughts?

[TodFitch]

On some point sets there is a separate spring piece to provide proper tension. If that was left out or not installed correctly then the points can float at higher RPMs and the ignition will cut out.

[Tooljunkie]

Also check the wire inside distributor, mechanical and vacuum advance are all in at high rpms, points wire could be broken or shorting. Been there. Could be the ground wire too. 

[Merle Coggins]

I agree with what Tod said. I did that same thing once. I didn’t get the points spring locked in correctly. The set I used had a copper strap to make the electrical connection for the points and another spring steel strap that locks in along side to assist in closing the points. I didn’t get the spring locked in correctly so that the only spring tension to close the points came from the copper strap. At RPM’s above around 2000 the points would bounce/float causing the engine to misfire badly. I could barely get the truck above 35 MPH. It took me a little while to figure out my mistake, but once I did, and corrected it, the Ol’ Dodge ran like a top again. 

[p24-1953]

Well it looks like you're right.  Pulled the points and it looks like this metal Spring was not attached firmly to the point so it was slipping loose.  Reinstalled it better and it runs great. Thanks for your help