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.

[Tim Walsh]

is it a 2.0 six or 2.0 four? I really don't know much about that problem but what comes to mind is distributor play.

[CamB]

The car is running a MSD igntion.

My wild ass guess is that you are running the MSD rev limiter and that points bounce and/or distributor play is getting it to trigger early. I checked in my BMW by removing the MSD's rev limiting pill and seeing if the car revved properly. Which it sort of did (points etc = bad )

[Vintage914Racer]

I've driven it with the "pill" in and out and it doesn't seem to make a difference. By the way, the engine is a six cylinder.

[Vintage911Racer]

Vintage 914 Racer,

My 911 was doing the same thing. It was my Dizzy. I had enough play in the dizzy to wear it was effecting the points gap and the timing. I had it rebuilt and the problem solved. 8K all day long. Not that I shift it there but in times of need, it will go without hesitation.

It only cost me $65.00 to have it rebuilt.

Well worth it.