It does sound like valve float to me also but I believe another vac leak could be the cause too. Check the vac can with one of those vac/brake bleeder tools to make sure it not leaking by the diafragm.
WOW! Well, well well. After years of aggravaition etc. with my motor problems I am happy to report that my most recent "breaking up" issue has been solved. It's almost too hard to explain but the bottom line is that I had my hood tach wired wrong and beleive it or not this was causing the breaking up.
My hood tach has been wired the same way since we bought the car 7 years ago. However, it did not seem to present a problem until recently when I finally felt comfortable pushing the car towards it's red line. I thought the problem had something to do with the Pertronix II unit. So yesterday I removed the conversion unit and installed a stock set of points. Afterwards I took the car for a run and still had the same issue. However, during this removal process I noticed the threads on the negative teminal of the coil were stripped.
So, I bought a new coil today and before I changed it, I noticed the hood tach was no longer working. Now this tach has always worked everytime I have started the car for the last 7 years. Now all of a sudden it doesn't work.
Hmmm. So now I am assuming it was the "bad" coil. Drove to the store to buy a new one and realized the car did not break up at high revs. So, I lay into the ole girl and sure enough, NO breaking up at all and running like a mother!
Come home with the new coil and look at the tach situation and realize both bulbs had blown. Again, this tach has always worked and the same bulbs have been in there for all the years I've owned the car. So now I pull out the wiring diagram and realize the tach is wired completely wrong. I had the tach wire correct (going to the - terminal on the coil. However, the other two wires I had going directly to a bolt on the firewall as a ground. I have no idea who this worked all these years but it did. The lights worked, the tach worked and no issues.
What I can't understand is how for the last 7 years the tach lit up and worked fine. Now all of a sudden it blows the bulbs, quits working and the car runs perfectly. All in all, none of this makes sense to me, however, everything now works and the car is running AWESOME!!!!!!!
I have now rewired everything with the tach, coil & starter etc. Now I can get this blue printed M21 insalled along with the new Hurst shifter!
Never got into it? Hell, that's the problem. Valves were hanging up because of gunk. If you were to look back at the days when I gave technical advice, one of the first remidies was wring the dogchit out of it a few times.
But that's why I quit giving advice. If no one bothers to take it, why give out high quality advice?
I would also like to thank everyone for their help along the way as well. I truly appreciate all the ideas/suggestions etc. I am sure I will have more questions as soon as I move on to my next project...
Good to hear you are 'out of the woods' and fully enjoying your car. One thing is for certain, after going through all those 'trials and tribulations' you surely do appreciate it more. Wait until you get that new four speed trans installed. A new trans is another great improvement that you will notice!
Yes indeed. I can not wait for the new tranny and shifter. I am already planning my next step after that (interior work). All new front and rear door panels, the new am/fm radio and rear window defogger! I've been stalled out so to speak from moving forward with engine problems for so long now that it seems nice to start moving forward again!
Amervo, revving the snot out of something rarely "cures" anything besides pent-up frustration and can very likely cause damage if the timing or jetting is faulty or there are mechanical issues. A systematic approach to solving the problem usually gets results (not always but mostly) and is much easier on the engine.
Reading the thread from the beginning to see what clues are given helps. Paying attention to the facts that are presented helps too. And when the problem is solved and the reason is given (thank you for telling us, a lot of times we're left wondering!), maybe it should be appreciated instead of questioned.