confused need help with 355
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Registered User
Joined: Sep 2001
Posts: 1,268
From: port huron, michigan
confused need help with 355
hey guys,
long story short, my machine shop didnt balence the pistons i gave them for my 355 motor. i'm using stock crank and stock rods from the same motor. basicaly a stock 355 with new pistons!!!!!!
i donno what to do the motor is assembles and i have all the parts, from computer to the serp. belt on this thing!!!!
i dont wanna take it apart again, but if i have to i wanna know now. i'm picking up a stock HMB and flexplate for a auto trans this week.
should i dissassemble it and start over or what?
motor has not been started yet, but its gonna cost me well over 400 to disassemble, balence and re assemble with new gaskets!
not to mention the time line, so much for a M8 run.
long story short, my machine shop didnt balence the pistons i gave them for my 355 motor. i'm using stock crank and stock rods from the same motor. basicaly a stock 355 with new pistons!!!!!!
i donno what to do the motor is assembles and i have all the parts, from computer to the serp. belt on this thing!!!!
i dont wanna take it apart again, but if i have to i wanna know now. i'm picking up a stock HMB and flexplate for a auto trans this week.
should i dissassemble it and start over or what?
motor has not been started yet, but its gonna cost me well over 400 to disassemble, balence and re assemble with new gaskets!
not to mention the time line, so much for a M8 run.
Banned
Joined: Oct 2002
Posts: 6,518
This might not be that big of a deal.
Weight one of the stock pistons and pins, and get the part number of the replacements and call the company and ask for the pin and piston weight (at least the designed weight)
Most aftermarket pistons are the same weight (+/- 1g) and if they are even close your stock piston and pin weight you are good to go.
If the stock stuff was not internally balanced then don't worry about it a new flexplate from GM will work fine here.
This is really something you should have looked into before it was put together, but your not up **** crick yet.
Bret
Weight one of the stock pistons and pins, and get the part number of the replacements and call the company and ask for the pin and piston weight (at least the designed weight)
Most aftermarket pistons are the same weight (+/- 1g) and if they are even close your stock piston and pin weight you are good to go.
If the stock stuff was not internally balanced then don't worry about it a new flexplate from GM will work fine here.
This is really something you should have looked into before it was put together, but your not up **** crick yet.
Bret
Registered User
Joined: Apr 2000
Posts: 948
From: In The Engine Room
It is true that MOST times the aftermarket piston will be +/- 1 gram, but I have seen them be as much as 5 sometimes even 10 if you go to a dish or dome piston for a power adder.
I would call the manufacturer as advised above. Sometimes if you tell the approximate time that you bought the piston they can find the work order and get you an exact weight.
It is is less than say +/- 2 grams per piston, I would worry about it. Anything after that and you really should have the motor torn down and reassembled.
Wouldn't your engne builder assume some responsibility here. Checking bobweight and verifying your rotating assembly has been balanced is kind of important.
Just my .02 Good Luck
After loooking i see you are in michigan. PM me and perhaps I could be of some assistance.
I would call the manufacturer as advised above. Sometimes if you tell the approximate time that you bought the piston they can find the work order and get you an exact weight.
It is is less than say +/- 2 grams per piston, I would worry about it. Anything after that and you really should have the motor torn down and reassembled.
Wouldn't your engne builder assume some responsibility here. Checking bobweight and verifying your rotating assembly has been balanced is kind of important.
Just my .02 Good Luck
After loooking i see you are in michigan. PM me and perhaps I could be of some assistance.
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