pearlpurple

I am getting ready to plastic gauge the mains and rod bearing clearances on my LT1

My Helms manual shows two sets of clearances one is "production" and one is “service”

Not sure what this is? I am assuming production is when the engine was brand new built and service says how much clearance can go but if you look at the numbers below on some clearance production are tighter and some clearances service are tighter so my theory does not make sense.

MAINS
PRODUCTION
#1 0.0008 TO 0.002”
#2, #3, #4 0.0011 TO 0.002”
#5 0.0017 TO 0.0032”
SERVICE
#1 0.001 TO 0.0015”
#2, #3, #4 0.001 TO 0.0025”
#5 0.0025 TO 0.0035”

Anyone know specifically what this is?

Also what main is #1 I am assuming the main at the harmonic balancer??

Thanks

Bigtoyz

iTrader: (2)

This is what I had found for a new/rebuilt motor

Crank Bearing Clearances
#1 0.020 to 0.051 mm (0.0008 to 0.0020")
#2 0.028 to 0.051 mm (0.0011 to 0.0020")
#3 same as #2
#4 same as #2
#5 0.043 to 0.081 mm (0.0017 to 0.0032")


Crank Assembly End Play 0.03 to 0.17 mm (0.001 to 0.007")


Rod Bearing Clearance
0.033 to 0.088 mm (0.0013 to 0.0035")

Rod side clearance 0.16 to 0.35 mm (0.006 to 0.014")

pearlpurple

Thanks.

Why does my Helms manual have "production" and "service" specs?? any idea?