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

[dan67]

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

[kenikh]

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.

[gestalt1]

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.

[dan67]

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?

[dan67]

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

[gestalt1]

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.

[YTNUKLR]

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.

[kenikh]

Originally Posted by YTNUKLR

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.

[dan67]

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