Cranckcase for stroke short 66mm...projet 2.5/2.9 block for 2.2T
 

hallo! its new and italian (my write englais its very poor..) I would like to know what the crankcases optimal for 66mm stroke engine. I seek one engine for street/small race (hp 200-250>). What the "popular" solutions?
my idea:
-stroke 66mm (S crankshaft?) (only 66mm.. I like the short stroke))
-heads 2,7 (S ?)
-magnesium case (7R ?) (cilinder spigot bore?)
-Weber or Pmo 40
-connetting rods Carillo
-dual plugs
-max bore for 2.7 heads? (87.5-89-90-92?) (mahle/LN with JE piston?)
-compression ratio min 9.8/1 max 10.5/1
-cams for carbs (solex? ge 60/80?)
-trasmission 901 (reinfosed mid plate)

Thanks to all!!!
danilo italy

Best crankcase would be in this order:

Early aluminum case
7R magnesium case

For cylinders that large, I would not use anything magnesium earlier than 7R. I'd use any head from a 2.2 - 2.7 (they are basically the same) and use ports of at least 36mm, up to 38mm if you plan on using a GE60 cam. My choice would be to use DC40 cams, 10.5:1 pistons for dual plugs. You can get bigger than 2.5L on a short stroke crank, but costs go up significantly above 2.5L. The reason is that you will realistically need to use Nickie cylinders to maintain cylinder skirt strength; Nickies are very stable to 1mm thickness where standard Mahle cylinders are not. If cost were no object, a short stroke 2.7 built with on an aluminum case wit JE pistons and Nickies on DC40 cams would be one FAST and fun motor.

i'm going to build a similar engine for my 68. i'm going to use a mag 7r case with a counterwieghted 66mm crank. i think i will stick with 90mm mahles and 35-36 s port heads. the nice thing about the port sizes is that they are good for a street engine but when the displacement gets smaller they are good for a more race oriented engine and no actual porting is needed. i likely go with a ge60 type cam. not sure what the induction will be or wether to go twin plug or not.

another question:
All crankcases (alu or mag) series 2.0-2.2-2.4-2.7- (3.0 turbo very reinforsed?) its "adeguate" for stroke 66 mm (with heads 2.7) et trans type 901?

..the 2.7 heads accept diameter cilinder over 90 mm?

the chamfer needs to be larger if you use 2.7 heads on a larger die. cylinder (92-93mm). most machine shops can do this when reconditioning the heads. don't skip this - without the chamfer there is a greater chance of detonation at the cylinder/ heat mating surfaces.

Another way to go . I have a set of big port 39/35 911SC 3.0 heads. And you could use a 3.0 Turbo case. 2.8L using 66mm crank. Has bigger valves than 2.5L, would be cheaper than the 2.7 engine Kenik mentioned above.

Email me at KinderSport@gmail.com if you want to talk about the heads.

Yes, 2.8SS is awesome IF you can find a case.

MFI Bosch Mecanical Pump 2.2E to 2.7RS
 

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