break-up at WOT

hope

hope

Senior Member
i know i saw a discussion before on this subject, but ran it thru SEARCH and didn't come up with anything.
So i'm asking what's the cause of Break-up at WOT.


Thanks: to all the people with the Knowledge.:confused:




HOPE
 
Wide open Throttle?
If so it might indicate a lack of gas or a collapsing spark due to the higher compression
 
Depends on how high WOT is . . . can be a lot of things . . . and different depending on the engine, components, tuning and other specs.

It can be fuel starvation, it can be ignition points that are floating, it can be valves that are floating . . . it can be various other ignition or fuel issues.

So what RPM are we talking about and what are the specs on the engine???
 
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I have experienced problems where a misfire would occur at wide open throttle.
In my case at least it was associated with weak High Tension side of then ignition.
The amount of voltage required to make the spark jump the gap goes up as the compression pressure gets higher in the cylinder. At wider pedal angles the voltage requirements are at their highest.
All the time the spark is trying to find the easiest way to ground. If there is a weakness in the HT side of the ignition the spark will take that route and not fire the plug.
In my experience the problem gets worse until the car becomes undriveable.
Once all has cooled down you can generally make way again until it occurs again.
I'd be looking at distributor cap, leads and rotor arm.
Mart.
 
RPM will have to wait until i get to a trial run again. Did not notice rpm break-up the last time.
 
1931 flamingo said:
No help on the question.


Did you get the brakes fixed???
Paul in CT
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Brakes not fixed yet, i do try different things when i can. But other things come first, like coil getting boiling (burning hot).
I think i finally found the right combination, with a Bosch coil, a trash can condenser and the right resistor.
After a trial run ,coil was only luke warm to touch and NOT burning. And not stalling.

And now on to the brakes and WOT problems. When i can!!!!!!!!!!! i can cope with the problem of movement, but my Brain at 85 is going-going almost gone.:(


Hope
 
I think it is fantastic that you're giving it a solid go at 85 - so more power to yah! If I was anywhere close to you, I'd lend a hand. If the BARN can help in any way, just ask. If you need some personal help, feel free to drop me a PM. Best of luck - you'll be cruising with it soon!
 
May I add that the problems I was describing are not at high revs. It's at wider throttle openings at lower revs. That's when the HT weakness shows up.
 
Had similar problems. Replaced spiral wound ignition wires with solid copper and reset spark plug gap from 0.035 to 0.025". That cured the high rpm breakup, but the lack of static suppression in copper wires completely jammed my radio. So, I went back to a short spiral wound wire only for coil to distributor. That got the radio back and it still revs smoothly to near 5,000 rpm.
 
Now that I am back on track I agree with drolston's experience. That is a symptom of bad plugs, cap, or wires. I was taught that in auto shop class in high school. More compression directly affects ignition.
 
Bored&Stroked said:
I think it is fantastic that you're giving it a solid go at 85 - so more power to yah! If I was anywhere close to you, I'd lend a hand. If the BARN can help in any way, just ask. If you need some personal help, feel free to drop me a PM. Best of luck - you'll be cruising with it soon!
Click to expand...
Thanks for the thought of helping, BUT i think with the help from the BARN i'll eventually conker these gremlins, i've already got a lot of help from the Barn.


Like the Gunny says :Carry-on::D


Hope
 
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