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Machine shop Balancing Crankshaft

Practical Engine Building

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2003 Evo 8 4g63.

What's up guys,

Assembling my first 4g63. I recently bought my 94mm crank brand new and needed to clarify on balancing it.

Would the crank alone need to be balanced? OR Would it be best to provide the engine dampener and clutch setup along W/ crank to provide the best balance ? Thanks in advance.

Talk to the people doing the balancing. Normally I'd expect everything from the front pulley to the pressure plate to be required, including the pistons and rods to be used.

I had my rotating assembly balanced on my 4G63, the machine shop requested pistons set ,rods, crankshaft, clutch kit and front pulley.

if your question is about what components you need to send in to get balanced you will be looking all reciprocating mass. stuff that cycle up and down and rotate. so conrods engine bearings and crankshaft and with this engine the balance shaft as well. it all works together. the HPA practical engine building has a video on this. i dont usually balance cranks as on small power builds it doesnt make thaaat big a difference in what i do (below 400hp). just rod and piston balance for me usually is fine.

you would want to send all reciprocating mass in. this because the crankshafts has primary and secondary forces. the crank has those wedges and they do more than just offset the conrod journal. long story short the crank counter weight also counteracts the kinetic energy of the piston and rod as it reaches tdc and starts heading down. then you also have the torque created from when cyl 1 2 3 and 4 fire from the center of mass of the engine creating a rocking motion. so if you change one thing it all changes.

so what you will end up with is if you balance everything your crank will be a little off balance on its own to account for the kinetic energy of the pistons and things. you see this on motorcycle cranks sometimes. this is also why you balance your rods and pistons separately. so that the y axis weight is the same and the z axis weight is the same so when you combine them they are all equal. then the crank gets balanced off that then balance shafts.

in summery if its bolted to the crank by a chain gear or bearing it has an effect.

the effect is very small though. if you are making under 400hp i wouldn't be too worried about it. balancing the pistons and rods is most cases is all you need. If you are a serious racer the yes it matters. if its your daily street car, no it doenst matter.

also do a balance shaft delete on the 4G series engines.

im currently working on a 4G64 block and pistons with a 4G63 head and crank. it destrokes the engine and im needing to make custom rods and valve spring upgrades but such configurations can rev up to 10k iv seen guys pull 12 000rpm. its mental.

so to summarize: send in pistons, rods, rings, gudjing pin, piston circlips, conrod, conrod bearing and crankshaft and remove the balance shaft with a delete kit. just make sure you get the delete kit that has a replacement weight for the balance shaft otherwise you strain your oilpump

there are people here who might disagree with me on this and there are people on here that do know far more about 4g63T engine than i do but this is how i do it and it works. is it overkill?? yes, but things are right or they are not right, there is no in between for me.

hope this helps and i didnt confuse you more

You don't need to balance a 4 cylinder crankshaft that's horizontally opposed. They are already balanced to themselves. Just weight balance the rods and pistons to eachother.

Hi John, yes you do need to balance them it is just as important because the crank itself can be a way off with itself and the counterbalance weight to piston rod weight and also front damper and flywheel with clutch assembly, its all maths and physics

Regards Ross

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