I know some of you are a gold mine of info, while some prefer to keep secret. but can anyone here tell me where I can find all the dimensional specs. on mercedes connecting rods for their late model v6 and v8 engines?

I just cant find anyone who has this info available. Other than actually purchasing individual parts.

My idea is to find a rod that will give the little 3.2 motor, say another 1.5 - 2mm stroke. so what do you guys know, ay?

 

Maxwell, changing connecting rods will not change the stroke. That's a function of the crankshaft. You can use shorter con-rods if you want to lower compression a bit. Longer con-rods wouldn't be recommended as this is an "interference" engine, meaning that if things aren't just right the pistons and valves will make contact, which I hear is quite bad for the engine.

 

If you lengthen the connecting rod the piston will travel further in the bore, but most likely will need to adjust the wrist pin location on the piston so it doesn't collide with the valves.

It's like a cheater stroker kit, minus the crankshaft. pretty cool and much cheaper. I'll have to calculate the displacement increase.

 

If you lengthen the rod then move the wrist pin up in the piston you are still doing nothing for the stroke, as mentioned above the crank is what determines the stroke. The only way you can stroke a motor without buying a crank is to take it to a machine shop and they can weld material to the back side of the crank were the connecting rod bearings go then they take the same amount off the front side making it have a longer stroke. I don't think this method is used much anymore because of the variety of companies making aftermarket cranks.

 

Sorry, I wasn't thinking clearly there, maybe over thinking things. Was doing a little reading and the only thing I could gain from the longer rod length would be maybe more torque on the upper end of the rpm band. Otherwise going shorter would achieve the opposite, by making more, or the same amount of torque but much earlier in the rpm band.

My mistake.