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Convert 2 piece main seal to 1

  • Thread starter Thread starter 65FBE2
  • Start date Start date Mar 1, 2010

65FBE2

Member
Mar 8, 2007
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Minnasnowta
Mar 1, 2010
#1
  • Mar 1, 2010
  • #1
Can anyone tell me if you can convert a early 2 piece block to a 1 peice rear main seal? I have 347 in a 71 block with a texas sized leak coming out the rear. I pulled the motor and we can find no reason for the rear main to be leaking. Any help would be appreciated
 

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
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South Jersey
Mar 2, 2010
#2
  • Mar 2, 2010
  • #2
This ain't a small block chevy. Just replace the rear mail seal and be done w/ it. Are you sure it is leaking though? Was the back of the intake leaking or maybe even one of the plugs on the back of the block?
 

BlownFiveLiter

have car, will race....wait, it doesn't run
15 Year Member
Nov 29, 1999
3,133
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108
Chicagoland
Mar 2, 2010
#3
  • Mar 2, 2010
  • #3
65FBE2 said:
Can anyone tell me if you can convert a early 2 piece block to a 1 peice rear main seal? I have 347 in a 71 block with a texas sized leak coming out the rear. I pulled the motor and we can find no reason for the rear main to be leaking. Any help would be appreciated
Click to expand...

Replace your block with a late-model block. That's the only way.
 

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
5,222
3,254
204
South Jersey
Mar 2, 2010
#4
  • Mar 2, 2010
  • #4
The older blocks, pre73, have a higher nickel content and are therefore a lot stronger! Not to mention it is already machined and assembled.
 

65FBE2

Member
Mar 8, 2007
283
0
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Minnasnowta
Mar 2, 2010
#5
  • Mar 2, 2010
  • #5
I dopped the pan and replaced the seal twice. Even shimed it for a tighter fit (recommended by the engine builder for cronic leakers.) I have checked everything including the flywheel bolts and the intake. The block is dry with no sign of leaking behind the bellhousing on the block side. The pan gasket is not leaking. The only place left is the main. And it drips at a rate of about 1 drip every 5 seconds. Could it be the Crank? Is there a differents between a early 2 piece crank and a 1 piece? is there a slinger on the old cranks that does not exist on the new ones?
 
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