Engine Breaking Up

[Vintage914Racer]

Hello all. I am a newby to these forums. I have a questions regarding my 914 race car. For quite some time the engine has been cutting out between 6000 and 7000 rpms (usually around 6300). Usually I can drive through the breaking up eventually, but often it is not worth it because I limit my shifts to 7000 rpms. The car is running a MSD igntion. At my last race at Road America (the Elkhart Lake Vintage Festival) the car started a habit of backfiring once I hit the 6000-7000rpm range. I do not know what to do nor do i know what the problem is and before I bring it in to my mechanic I would like to get some insight.

I have been told that installing a crankfire ignition such as the electromotive unit would solve my problems, in addition to giving me added performance, but before I spend all that money I was wondering if there is anything else I go look into before spending $1000-$1500. I am running a 2.0l engine with weber carbs. Any help would be appreciated.

[chrisreale]

2.0L 4 banger or 2.0L 6? Id say it is fuel delivery, but not positive..??

[John Rogers]

What type of distributor, type of plug wires, type of cap/rotor, using points and how old is the carb rebuild?

[skline]

If it is a 4 banger, the red line is only 5800 and he should not be running it up to 7000. He must be running a 6

[campbellcj]

I would guess ignition like John hinted; check out the points (if any). Or maybe the dizzy advance is sticking somehow, which might explain why it is kind of an intermittent problem.

skline - it is a race car so certainly could be a high-revving four (race motor). If it's a stocker then there is little point revving much over 5K as the power drops like a brick after that and usually the valves will start to float in the high-5's.

[M. Hendrix]

It's got to be a four.

I would open the dizzy cap, and look right there for all the trouble. If you replace everything there, you are in it cheap.. and then you can figure where to go later..

M