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Author
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Topic: Early and Late SBF Crankshafts
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Jim B
Journeyman Posts: 19
From: Chicago
Registered: Feb 2003
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posted 03-04-2004 10:38 PM
   
I know that early cranks and blocks used a 2 piece rear main seal. I think it was a rope type and the later crank & blocks use a one piece neoprene seal. What I want to know is how the cranks differ between the two types of seals and how the blocks changed also.And also is there any modification that can be done to the crank or block to use a late model seal in an early block with a late model crank. Thanks in advance. Jim B. Chicago, IL
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Jim B
Journeyman Posts: 19
From: Chicago
Registered: Feb 2003
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posted 03-05-2004 12:43 PM
BTTT
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SteveLaRiviere
Administrator Posts: 43152
From: Saco, Maine
Registered: May 99
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posted 03-05-2004 12:47 PM
While the early crankshafts came with the rope seals, most people remove the pin from the main cap and use the two piece neoprene seal which works great when installed properly.------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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alanq64
Gearhead Posts: 174
From: missouri
Registered: Feb 2004
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posted 03-05-2004 01:31 PM
You don't happen to have pictures or a link that would show this procedure do you?------------------
68 coupe
302 w/C4
PS & AC
*update*
I'm getting the parts together for a T5 swap.
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SteveLaRiviere
Administrator Posts: 43152
From: Saco, Maine
Registered: May 99
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posted 03-05-2004 01:38 PM
No, but it's pretty straightforward.Take the main cap and grip the seal retaining pin with a small pair of vice grips, and it pulls right out. Then you just install the two halves of the seal, making sure the li of the seal points toward the center of the engine, and installing it so one end of the seal protrudes from the block by 1/4" and put a dab of silicone at each end. ------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
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posted 03-05-2004 01:38 PM
The pin can be knocked out with a simple drift punch, or ground down with a Dremel tool, or even a rat tail file.
Neoprene two piece replacement rear main seals have been offered for SBF engines since the 70's.  ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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n2oMike
Gearhead Posts: 2419
From: Spencer, WV
Registered: Jan 2001
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posted 03-05-2004 01:40 PM
quote:
Originally posted by Jim B:
What I want to know is how the cranks differ between the two types of seals and how the blocks changed also.And also is there any modification that can be done to the crank or block to use a late model seal in an early block with a late model crank.
The early crank has a raised lip, or 'ring' just to the inside of the sealing surface. I suppose this is to keep the oil splash off the seal. The later cranks do NOT have this. An early crank can be used in a later block as long as this lip is removed and an early balance (28oz-in) flywheel and dampner are used. As far as using a LATE style crank in an early block goes... You'll need the later (50oz-in) flywheel and harmonic dampner. The only part I'm still unsure about is the lack of a lip on the later crank. I'm not sure if that would cause possible rear main oil leaks when used in early blocks. Do all those aftermarket stroker cranks have this lip? If they don't, and people are successfully using them in early blocks, I don't suppose it's a concern. Maybe some people with experience with them will chime in.... As far as the seal itself is concerned, a late model (one piece) seal cannot be used in an early block. It would take a ton of machining. However, neoprene (rubber) seals ARE available for use in the older blocks. Just like Steve and Alex said, knock out the retaining pin in the cap before installation. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 [This message has been edited by n2oMike (edited 03-05-2004).] [This message has been edited by n2oMike (edited 03-05-2004).]
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Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
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posted 03-05-2004 02:17 PM
Mike and others, the replacement neoprene seals have an oil grove that faces the crank case side. That grove gets oil fed to force a tight seal around the crank surface.
A slinger is no longer needed with the new style seal.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
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