Big Bore Kit -QUESTIONS THAT NEED TO BE ASKED PRIOR TO INSTALLATION
 

All,
I have a 1967-912. I recently bought a big bore kit(BBK) from Stoddard and wanted to know a few basics about installation and other issues from those who have it or have BBK on their cars.[/LIST]Is it possible /feasible to add the BBK and do nothing else?[LIST]what other things would be needed to ensure the BBK puts out power as described?[LIST]What can be damaged if the BBK is installed an dnothing else is done to the car...I heard/read that you need to upgrade the oil coller for example......you can fill in the rest[LIST]Not interested in going the VW motor route or the Polo engine route or street racing theme, etc.....just something simple that can be added on or modified by my mechanic[LIST]forgive my ignorance as I have this and I am debating whether to add it and if so, what are the second and third order of effects of adding this kit that is not mentioned or one does not hear about, appreciate the input in advance!

BTW, I have Duane Spencer book on modification...but I dont have a garage, time or tools to undertake this so anything would have be done by my mechanic
Gordon
1967-912
1969-911E

For a fast street engine with some longevity. Listed are some things to think about:

Balance the rods, crank, and pistons

Polish and port the heads, you do not need to raise the compression with to days gas.

the Cam should be a street cam not larger than a 280 degrees. 290 and larger and street driving will be a little on the rough side in traffic.

An external flow free oil filter will also help in cooling.

The jets, emulsion tubes and etc may need to be changed for the new cam. This can be very critical for the engine to run smooth through the corners and coming out of them.

Don't put oversized tires, 185 should be largest, the larger the tire the more power it needs to get you off the line and push them through the air.

I used an NPR big bore kit on my 1966 912 build.

I sent the heads to Walt at Competition Engineering and had all new valves put in and all of the chambers cc'ed to the same volume.

With the NPRs, I installed Total Seal piston rings - well worth the money!!

I had everything balanced to within a 1/2 gram.

I used a new billet SCAT crank.

New Weber carbs.

Aluminum oil cooler.

I didn't get too crazy as you can see, but the results were impressive.

That engine ran really nice and revved well.

The most important thing, besides making sure everything is clean and in spec, is to balance all the rotating parts.

good luck,
Erik.

The last part is tuning the Carburetors to the engine. You may have to change the jets and etc.