3.0 SC engine rebuild options
 

I am close to tearing down a ROW '79 SC 3liter engine that I plan to make some modifications too...remove CIS for PMO's...yank factory exhaust for SSI's...bump compression up to closer to 10:1..cams, etc.

I am looking for input from those that have built 3.0's up and what would be the best route to make the max HP for a street driven car. Suggestions for cam grinds (I run dougherty in my 930), piston/cylinder optons, head/valve work greatly appreciated.

I would like to get somewhere close to 300 crank HP (without turbos) but if that's a pipe dream, please chime in.. :D

I would load in a search criteria like "SC horsepower" and search here or in the 911 engine rebuilding forum.

Here is an example http://forums.pelicanparts.com/porsche-911-technical-forum/527974-horsepower-estimate-2.html

Not exactly what you are looking for but a little reading will give you a better flavor.

300hp is pretty darned optimistic. If you are looking for that kind of power, you would probably be best swapping in a 3.6. I love the 3.2SS that I put together for my car, but I doubt that I'm getting much over 250.

300hp = $ cubed + a stressed engine.

The book by Wayne Dempsey "How to Rebuild and Modify Porsche 911 Engines 1966-1989". is great place to start. It is an excellent book.

I will re-read Waynes book and also Bruce Andersons book...I love the talk of historic bolt on kits.. Anyone have a max moritz kit laying around?

From everything i've read, 220-250hp is max with CIS 3L... 300 with carbs is obtainable but very expensive... 3.2 or 3.6 aren't options for this build as we are trying to keep this car #'s matching.

My 3.4 motec turbo motor makes well over 400hp so I'm used to dropping coin...just looking for normally aspirated tips/ideas that won't break the bank...or leave me with a pile of broken oily parts after 3-4 hours running.

I remember talking to Jon F at Engine Builders Supply in the late 1990's and he mentioned that you can take the CIS to a pretty big sized P&C set up (3.4 / 3.5) and retain street manners. I think he mentioned a need for better oil cooling vs stock. This will still be short of a screamer but an option. I don't read much on over 3.2L. Maybe it requires a longer stroke crank?

The Max Moritz P/C's are rare. Perhaps look into the 3.2 Short stroke build with JE pistons and bored/plated 3.2 cylinders.

I built a 3.0 for my 69T and it was a great engine. Pulled very strong and had great throttle response. It was a 78SC engine with the larger port sized heads, web cam regrind to 66 Solex grind, PMO 46's, Euro Carrera centrifugal advance distributor, SSI's, Sport muffler. Pistons and cylinders were stock but notched for valve clearance. Nothing exotic here, just intake, exhaust and cams to let it breathe. I never dynoed the 3.0 but I would estimate between 230-250 crankshaft hp. It was definitely faster and more fun than my stock chipped/cat bypass/M&K 3.2. If you have the access to decent fuel and the budget I would say up the compression or diplacement a little for even more fun.

THanks for chiming in and your build sounds similar to what we want to do with a bit higher compression. Fuel is easy to come by here in Texas as most stations have 93 and there are plenty of options for higher octane race fuels...I believe that building a motor that requires race gas might reduce resale value of the vehicle as a street car??

I suppose 300hp is a bit unrealistic from a 3.0 without major cash or shortened time between rebuilds.

What about spinning one up over 8K rpm...I'd assume that requires aftermarket rods (carillo, pauter) and some ligher alloy hardware on the valve train..

Anyone else been there, done that?

Einer,

I'm just North of you in Montgomery and sail at SSC in a Laser. If you want to see what a 3.0 feels like with a well built engine you are welcome to drive mine. Here's what I did;

'78 3.0 case with Supertec studs
3.0 SC crank polished but stock
3.0 SC rods re-sized and re-bushed by Aaron Burnham
10.5:1 JE pistons
Twin plug heads with new guides and valves, race springs and retainers, stock porting
Aaron Burnham twin plug SC distributor
GE 60 cams
46 Webers

I have 275 / 35 / 17 rear tires and this engine will spin them in second gear. Makes around 275 at the crank. Night and day compared to CIS and stock. No need to spin past 7200...

We need to hookup.! PM me your details and/or lets try to meet at one of the local PCA GTG's..

Everyone who drives this car cannot believe it's a 3.0. It has no idle problems and drives like stock up to 3,000 rpm. Past that it's a different animal. I have run it against 3.2 SS cars and it will run away from them. I don't quite get the "short stroke" thing when the engine is alread way over square (95mm bore, 70.4 mm stroke). Also have a freind with a '74 and 3.6 conversion and it's a dead heat...awesome engine. By the way, I get 20-21 mpg at 70 mph. I get 10-12 while having fun...

Lindy...did you do anything to your gearbox or is it factory R&P and gears? I can appreciate the mpg with the foot in it...my turbo makes it from gas station to gas station when dogged!

I'm going to be building a new 3.5 engine for an Autocross car based on a '78 SC 3.0 as follows;

3.0 case w/ Supertec studs
964 crank
964 rods
964 pump
JE 10.5:1 custom pistons 98 mm
'78 SC heads
GE 60 cams
Twin plug
PMO 50

It's all bolt in; no mods, recipe by William Knight

Looking for 300+ ft lb starting at 2750 out to about 6750. Stay tuned...

Stock box. HP is a direct correlation to fuel consumption; 650 hp requires 1 gallon a fuel every minute!

Small world! I sold Garry/William my old '77 tub on a rotisserie...I talked with William a bit about the engine project.. I need to get back over there and discuss this more.

William drove my car and really likes the engine. We're going to open up the chokes on the Webers (at his recommendation) and hopefully pick up another 10 hp on top. If you're hell bent on staying 3.0 it will be tough to beat this combination. The GT-5 class was won by a car with this same set-up last week at TWS. William will try to tell you to go bigger; ask me how I know...
Garry's long hood 3.8 is a missile; another William Knight combination...

Lindy, Not sure what your schedule is like this Saturday, but a bunch of local PCA guys are meeting at 9:30 at the Cracker Barrel at 518 and 45 South...If you can make it, I'd love to see your car.