Acceleration On Rebuilt Motor
 

I have been slowly breaking in my 911SC motor and now that I have reved it up to 5000 rpm the acceleration is not a quick prior to the rebuild. Any advice?

Hey..
I suspect you have not set the timing right...? ( 5 deg. BTDC)
If not, check the ignition on each cylinder, cam timing, and so on...

Thanks, Would using Bosch platinum cause a problem?

Sorry, never heard of it, so I don't know...

Bosch Platinums are typically too "hot" for old air-cooled Porsche flat-sixes. This can cause detonation due to the heat retained in the cylinder head. Detonation/misfiring can cause poor acceleration.

On the other side, too "cold" of a plug can cause plug fouling, which will cause poor running all over the rev range but can clear up when pushing it hard. It would re-appear at idle.

If your engine idles smoothly but is down on power, maybe it is detonation from too hot a plug? The cold ambient temperature would lead to leaner air/fuel ratios...

Flieger,
I beg to differ. Bosch platinum plugs can be had in a wide variety of heat ranges. Often the platinum type plug is not required but this alone will not change the heat range of the plug.

My car came from the factory with Bosch platinum plugs and that is what I currently run.

Before you suggest that a plug is "too hot" you would have to know the designation on the plug. If it was a WR9DP0, I might agree with you, assuming a stock engine of course.

Transformer,
What is the designation of your Bosch platinum plugs?

Thanks,
Mark

How about this..what do your plugs look like?

Do you have access to/can you borrow an AFR and check you mixtures?

firing order..............

How many miles on the build? Mine was a little slow for a bunch then seemed to kick in around 500 miles... I suspect the rings seated at that point and I'm now getting decent compression. Perhaps your rings have not seated yet?

-Michael

where in ny are you located?