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Old 01-20-2010, 02:45 AM   #1 (permalink)
Christ
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Join Date: Nov 2008
Location: Troy, Pa.
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Pasta - '96 Volkswagen Passat TDi
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Cylinder deactivation attempt

Ok, well, not exactly.

I bought this '91 Geo Storm with a bad rod knock (assuming it's a rod) that you can hear while cranking the engine, it's so bad.

I've got a few options that I'm considering playing with, since the car is just a toy to me, really. I had thought originally that I was going to put a 3.0 V6 turbo into it, and make it a "fun" car, but I decided otherwise, for now at least.

So the current thought is that in a couple weeks, when I have time to actually go play with it, I'm going to go pull the head off and pull the pan off, and see how bad the damage is.

I don't want to rebuild the engine, and I'm not going to replace it with another stock engine, either, but I was thinking:

Maybe I remove two cylinders, and run it like a parallel twin? Every 360*, I get a power stroke, while the pistons shake the hell out of the car because they're always either up or down, and the counterweights on the missing pistons add to that shaking, because they're in the same locations as the remaining pistons at TDC and BDC... this poses a concern for the engine literally shaking itself apart.

I have two options, though. I can remove #1 and #4, and leave #2 and #3, giving me a power stroke every 360*, but leaving the pistons in sync with each other at all times through the rotation of the crank.

I could also remove #1 and #2, leaving #3 and #4, which are 180* out of phase with each other, canceling out the huge power pulses and associated vibration, but creating it's own funky vibration by having offset power strokes, where the second power stroke occurs at 180* from the first, leaving a full 640* of slack rotation between them, where no power is produced.

There is a less likely option to run #2, #3, and #4 in their original firing order (3,4,2), which provides a power stroke at 180*, 360*, and 640*, but then leaves the remaining 360* of rotation as a slack.

EDIT - This is not really an option, because of the strange balance that would come of it. Maybe if I get bored one day, I'll try it, but I find it highly unlikely that I'll ever bother.

Whatever I do, whichever piston(s) I remove, I will also remove the valves and associated hardware, and leave the cylinder an open bore with no plug.

EDIT - Removing the valves will leave the intake/exhaust open to oil spray, so the valves should/will be left in, and the rockers removed to prevent them from being in contact with the cam. (Thank you, Frank.)


Anyone have any questions, comments, etc?

Looking for some feedback on this, guys.

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Last edited by Christ; 01-20-2010 at 03:25 AM..
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