New motor ideas, 2.0 liter rebuild (or bigger) Options

[realred914]

2.0 liter four is apart, needs work. would like some performance upgrade while it is being gone thru. thinking of a displacemnt increase. would like ot be able to run the D-Jet still.

what are the piston size options? draw backs of any (are cylinder walls too thin on any of thge big bore sets? is case machinging required? etc..

what are best brands?


also ideas on valve sizes and cam selection would be appreciated.


looking for a modest perfromance boost, but still able to retain the D-jet system
already have the ealry 2.0 liter exhaust system.

let me know what you all have done, and what is available.

thanks

[Bleyseng]

I have heard of a 103x71 motor working with Djet and I was going to build one myself to see "IF" it would work with a Raby cam. Tuning is the big issue but I can do that. (IMG:style_emoticons/default/biggrin.gif)
I think a 98x71 motor would work fine with a Raby cam and valve sizes of 42x36 or 38. Larger intake valves start blocking the intake charge and slowing down the velocity so avoid the impulse to go to bigger unless you go carbs. 98mm would have to be nikkies unless you can find a set of old birals. People use the 96mm cylinders because its cost effective to use old 94mm ones as they are excellent cylinders and can be bored out cheaply. New pistons are made to fit for your application forged or cast.

This is why the 2056 motor is soo nice for 914. Using the basic engine combo, changing a few parts to improve it and using the Djet to get about 115-120hp. This is with SSI HE's and a Bursch exhaust system, heat and hp.


Back to the 103x71 combo limits which looks like the limit of the intake system. The plenum and runners run out of air at 2.3L it seems. But this is theory and I think it still will work with tuning. Larger stroke isn't an option IMHO. I think this combo would be in the 150 hp range and rev nicely to 5500rpms before running out of air. It would have to use a CFR header for exhaust, forget heat!