Juan Lopez

What is the best "recipe" for a 2 liter pure racing engine?

Displacement must remain below 2041cc and fuel requirements are open however, I'd rather consume the least expensive rather than the ultra expensive gas if possible.

I have raced some very powerful 2 liters before but I find myself contemplating building a new one. So far I have identified the following going into the motor:

1. 906 cams
2. Weber 40's
3. 69 Heads, ported flowed, ...
4. Racing springs and titanium retainers/keepers
5. Twin plugs
6. Electromotive

What about...
- pistons? some vote for Cosworths others for JE
- con rods? Carillo, Pauter
- con rod material? titanium or ?
- case? aluminum or magnesium (remember displacement will remain at 2 liters)
- studs? Raceware?
- Oil pump?
- Oil?

One of the old engines I raced had (according to the mechanic) a 14.5 comp. ratio with custom JE's. It had Electromotive and webers and it was VERY fast, our rev limiter was set at 8500 and frankly power was only present from approx 5500 onwards.

Ideas???

Steve Weiner-Rennsport Systems

Hi Juan:

You inquired about a huge subject and asked many good questions that would entail more space & time than this medium can accomodate.

As we build quite a few Vintage race engines in all sizes and 2.0 litres ones are the most popular, I'd make some comments about what you are asking,...

First,....due to the unique but unfavorable design of the 2.0 litre heads, you have no choice but to use race gas. If you want power; if you want torque, you will use race gas and hopefully, twin-ignition. Any compression ratio over 9.8:1 requires 100 octane race gas as a minimum.

Here's a snapshot of what some of our 2.0 and 2.1 litre engines look like:

2.0 "S" Heads with oversize titanium valves, Aase springs, and titanium retainers. Heads are extensively opened up and flowed.

We use 3 different cam profiles depending upon gears, driver skill and tracks. We do not use that old 906 grind anymore. There are much better ones.

Oversize cylinders with custom JE pistons. CR's range from 11:1 to 12.4:1.

Early aluminum case with many mods like boattailing, relieving, and oil pump bypass mods. We also use good mag cases with the same mods and shuffle pinning. Lots of handwork here!

We use Weber or PMO's (where allowed) in 46mm sizes. Suitably configured, of course.

We use either a Bosch distributor converted to RSR spec, or a new Billet distributor that uses a Bosch RSR cap and custom internals. MSD 6AL's and MSD coils with Magnecor wires finish off the ignition. This setup goes a long way toward making these small high-powered engine from being cantankerous.
Crank fired stuff doesn't work as well as it cannot sustain the wide plug gaps necessary for best power and low-speed behavior with race-type compression ratios.

Pauter rods, fully balanced, cross-drilled, knife-edged and micropolished cranks are used.

Factory steel studs are just great here, as are Raceware!

I like the Turbo or 962 oil pumps.

Mobil 1 15w-50.

These make from 200 to 238 HP, depending upon CR, cam profile and heads.

Lots of fun,...

Tim

Juan, Steve basically described my engine, exept mine is a 2.2 so I dont have the issues with the heads, I did open the ports up to 38mm ala the 906. I dont remember if I mentioned in the email I sent you, but I used pauter rods, and had the crank cross drilled and the bearing modified as well.

I am going out on a limb and installing the Haltech ignition.

I do think the 14.5:1 cr is to high