Engine breaking up above 4000rpm
 

Car is breaking up around 3000/3500. Absolutely will not rev past 4000. Got a weird knocking (not a death knock very very quiet) on the passenger side. Good oil pressure, everything else is normal. Where do I start?

possibly secondaries going lean? I'd go with a fuel issue.

If you have an electronic ignition module, I'd start there....especially if you're running Pertronix.

MSD 6AL box and summit billet distributor

Check your rockers on that side.
 

Take out the four bolts and gently lift the valve cover off.

Might see something that has slipped off.......

If not, just wiggle each rocker arm to make sure they're adjusted right.

If one of the intake rockers has come loose or just come off, it wouldn't rev....

Good luck!

start with the little gremlins and work up to the bigger ones. If possible by pass the msd box. then the dist. if you have an old hei lying around put that in and see.

Did the rev limiter get bumped or accidentally adjusted?

No the box is messed up. The red light is flickering and it only starts to break up at the 3000 point. If you hold it there long enough it stalls then is hard to restart.

Could very well be RF signal issues. It’s common to see an RF signal problem w MSD boxes if wires are run parallel it will always show up right around 4000k RPM Try shielding the wires w tin foil or cross them at only 90 degree angles

Every High Performance Pontiac V8 engine, Tri-Power, High Output, Ram Air and Super Duty uses points ignition as standard from factory.
Why mess with success?

JMHO

Agree with Kenth.
I never understood why you would want to change from what the Pontiac Engineers designed to work most efficiently for these performance cars 🙄.

While I agree with keep it factory Dave’s car is anything but as originally engineered- look at his build. It may be driven as a daily driver only but is built to the hilt. An HEI would be better in his application.

A power indicator flickering 99% of the time means at that rpm where the issue starts the unit can not pull enough current to sustain its normal function.

You need to double check all the power connections to it, especially if you made any crimp on type connections to get it hooked up and where it’s getting it’s ground from matters also.

All too many folks put electronic stuff on there car to eke out what they think will be the last 5 Hp out of there motor combo, when in fact they are missing 15 to 20 hp in other ways.

Dave - have you checked your rev limiter?

Interesting that you would mention that. Back when the 6AL first came to market, I had one installed in my 455 built by Nichols Engineering. The engine first started not wanting to RPM above 5k, then fell to 4k. I decided to pull the RPM chip and the engine responded as it should. When I sold the car. The RPM chip remained out of the box. I would recommend to David to pull the RPM chip and see how the engine respond

Lack of dwell meters ;)

Plus 3 or 4 for stock points distributors.

Over the past 20 years I've come to hate aftermarket HEI's, and all types of points "conversions". I could put up several hundred pages of stories here where I helped customers correct "carburetor issues" by correcting their DISTRIBUTOR/IGNITION problems.

Points a re simple, reliable, and excellent for performance work. Even better you can put a set of points in your distributor, set the dwell, then remove them and put them in the glove box with a headlamp and screwdriver. Install a second set and go have some fun. If the first set every gives you any issues you will be back up and running in less than ten minutes.......

I'm just a simple person who has kept points and condenser. I'm not computer/electronics savvy to fix electronic ignitions. Now when we start getting junk points and condensers I'll be in trouble.

The "junk" points and condensers are already out there. I recommend to anyone using points to source out some NOS Delco or other USA made points sets at least 20 years old, 30-40 would be better. Probably a good idea to grab a spare VA unit while you're searching for a good points/condenser. They are discontinuing numbers all the time and the prices are going up accordingly......

Dave - did you figure out what the knocking noise is?