2004 cts-v piston replacement different weight
03-25-2013, 01:49 AM
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2004 cts-v piston replacement different weight So my 2004 CTS-V #7 piston melted...I pulled it apart and went ahead and ordered a stock piston to learn that the original piston was a pressed fit into the connecting rod and the one I ordered has a full floating wrist pin. So I went ahead and ordered a new connecting rod for a 2004 CTS-V and it came designed to fit with a full floating wrist pin. The only problem is the new designed piston and rod weighs more.
OLD PISTON 606 GRAMS
OLD ROD 619 GRAMS
NEW PISTON 594 GRAMS
NEW ROD 645 GRAMS
NEW PISTON& ROD 1239 GRAMS
OLD PISTON &ROD 1225 GRAMS
Making a difference of 14 grams...will that cause a problem?
OLD PISTON 606 GRAMS
OLD ROD 619 GRAMS
NEW PISTON 594 GRAMS
NEW ROD 645 GRAMS
NEW PISTON& ROD 1239 GRAMS
OLD PISTON &ROD 1225 GRAMS
Making a difference of 14 grams...will that cause a problem?
03-25-2013, 06:26 AM
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Yes it will, anytime you swap out internals it is a good idea to have the whole rotating assembly balanced. If it was a gram or two you might be ok but 14 is a little much and your asking for a bad harmonic imbalance that will put a lot of stress on the crank.
03-25-2013, 08:27 AM
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The LS6 motors had the internals matched. GM weighed the entire pool of parts and matched sets of eight for the LS6 assembly. After it was assembled, every LS6 was fired and run on natural gas and externally balanced at speed. Standard LS1's got all the oddball weighted stuff.
You're not likely to get another set that weighs the same as the originals, and no matter what parts you get they will be the only ones that are out of balance. Will this hurt anything? No. Ideal? No.
Look at it this way...if Denmah can build an LS motor with used internals from several different motors of varying years/mileage, install two different head castings on each side of the motor with used gaskets and torque them with an impact gun and still run 9's I think you're alright.
You're not likely to get another set that weighs the same as the originals, and no matter what parts you get they will be the only ones that are out of balance. Will this hurt anything? No. Ideal? No.
Look at it this way...if Denmah can build an LS motor with used internals from several different motors of varying years/mileage, install two different head castings on each side of the motor with used gaskets and torque them with an impact gun and still run 9's I think you're alright.
03-25-2013, 08:28 AM
#6
I got an original style from advanced autoparts. It was cheap and had the "press" pin not the floater. I say press in quotes because all they do is heat up the rod end very hot then the pin slides in.
If you are not staying with the same piston/rod you might as well re do the entire motor with matching pistons and rods. Hell go forged while you're in there. But by putting a piston and rod in there that is off weight with the others will cause dramatic (while maybe not noticable) harmonics in the rotating mass causing excessive wear on parts like bearings and most likely failure, at some point.
Also, if they do not list one from the V, look for a piston from an 02-04 ZO6 vette.
Please also know that your rod caps are directional, and have to go back on the way it came out! They are the cracking rods caps.
Good luck!
If you are not staying with the same piston/rod you might as well re do the entire motor with matching pistons and rods. Hell go forged while you're in there. But by putting a piston and rod in there that is off weight with the others will cause dramatic (while maybe not noticable) harmonics in the rotating mass causing excessive wear on parts like bearings and most likely failure, at some point.
Also, if they do not list one from the V, look for a piston from an 02-04 ZO6 vette.
Please also know that your rod caps are directional, and have to go back on the way it came out! They are the cracking rods caps.
Good luck!
03-25-2013, 09:19 AM
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The LS6 motors had the internals matched. GM weighed the entire pool of parts and matched sets of eight for the LS6 assembly. After it was assembled, every LS6 was fired and run on natural gas and externally balanced at speed. Standard LS1's got all the oddball weighted stuff.
You're not likely to get another set that weighs the same as the originals, and no matter what parts you get they will be the only ones that are out of balance. Will this hurt anything? No. Ideal? No.
Look at it this way...if Denmah can build an LS motor with used internals from several different motors of varying years/mileage, install two different head castings on each side of the motor with used gaskets and torque them with an impact gun and still run 9's I think you're alright.
You're not likely to get another set that weighs the same as the originals, and no matter what parts you get they will be the only ones that are out of balance. Will this hurt anything? No. Ideal? No.
Look at it this way...if Denmah can build an LS motor with used internals from several different motors of varying years/mileage, install two different head castings on each side of the motor with used gaskets and torque them with an impact gun and still run 9's I think you're alright.
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03-25-2013, 09:36 AM
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If you are worried about it you can have all of the pistons/rods balanced. Just take it them all to someone and have them make them all the same weight. Its usally have all of them matched to the lightest one if I remember correctly.
03-25-2013, 10:16 AM
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Thanks for the advice everyone. I'm on a budget to get this thing back up and running so that would be the reason I'm not going with forged believe me i would if I had the money at the time. I will be getting it balanced. Anyone know about how much it cost for a machine shop to do a balancing job?
03-25-2013, 06:13 PM
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Just get a used one and put it in there you will be fine. If you feel the need have it balanced to the same weight as the old one. I replaced 2 pistons in a 03 Z06 with new GM ones and reused the old rings. It went together perfect and runs perfectly and uses no oil. There are plenty of used LS6 pistons around and I believe 02-04 is what you want. They changed to float in 04.
