LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Timing set install question

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Old Aug 17, 2017 | 10:00 AM
  #1  
Muncie4sp's Avatar
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From: atx
Timing set install question

Just want to be sure I have this right before is slap the rest together

1996 lt1 motor. heads/intake off. Just a simple H/C swap.

#1 piston all the way up
cam dowel pin @ 9
cam gear dot @ 12
crank gear dot @ 12

Is that correct for TDC #1?
Old Aug 17, 2017 | 11:49 AM
  #2  
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Re: Timing set install question

no

# 1 @ TDC
cam dowel at 3 oclock
Top gear dot at 6
Bottom gear @12
Old Aug 17, 2017 | 01:38 PM
  #3  
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Re: Timing set install question

#1 is up
ill spin the cam so the dowel is at 3
cam gear will be at 6
crank will remain the same at 12
Old Aug 17, 2017 | 07:10 PM
  #4  
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Re: Timing set install question

Shoebox has an illustrated cam install guide:

4th Gen LT1 F-body Cam Install

http://shbox.com/ci/sprockets.jpg

http://shbox.com/1/cam_timing_ani.gif

Old Aug 17, 2017 | 08:14 PM
  #5  
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Re: Timing set install question

Originally Posted by Muncie4sp
Just want to be sure I have this right before is slap the rest together

1996 lt1 motor. heads/intake off. Just a simple H/C swap.

#1 piston all the way up
cam dowel pin @ 9
cam gear dot @ 12
crank gear dot @ 12

Is that correct for TDC #1?
Yes, that is correct for #1 TDC

Originally Posted by Chimera96
no

# 1 @ TDC
cam dowel at 3 oclock
Top gear dot at 6
Bottom gear @12
This is #6 TDC.
Old Aug 18, 2017 | 07:44 AM
  #6  
Muncie4sp's Avatar
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Re: Timing set install question

just goes to show if you think long you think wrong.

Thanks
Old Aug 18, 2017 | 11:11 AM
  #7  
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Re: Timing set install question

Originally Posted by Chimera96
no

# 1 @ TDC
cam dowel at 3 oclock
Top gear dot at 6
Bottom gear @12
Originally Posted by shoebox
Yes, that is correct for #1 TDC



This is #6 TDC.
....I followed the procedure in "How to Rebuild LT1/LT4 by Mike Mavrigian" when I assembled my short block. Both #1 and # 6 pistons are "up".....when I installed the top end and proceeded to lash valves I then rotated motor so both I & E valves on #1 were closed and started on #1 cyl for the valve lash

apologies for assuming #1 was TDC following the procedure in the book...as it was #6

I think the author advised doing it that way so it is easier to see the dots top gear being at 6 and bottom gear being at 12 to see alignment better vs having both gear dots at 12 position....
Attached Thumbnails Timing set install question-lt1-timing-cam-dowel-6-tdc.jpg  
Old Aug 18, 2017 | 07:39 PM
  #8  
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Re: Timing set install question

Yeah, dots together are easier to visualize and is the most common way to set the gears. If you were doing a traditional, old school SBC, dots together would be #1 TDC (at least I think I remember it being that way ) .
Old Aug 19, 2017 | 11:37 AM
  #9  
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Re: Timing set install question

Originally Posted by shoebox
Yeah, dots together are easier to visualize and is the most common way to set the gears. If you were doing a traditional, old school SBC, dots together would be #1 TDC (at least I think I remember it being that way ) .
Yeah,that had me scratching my head when I rebuilt the LT1 and work out which cylinder the opti was pointing to.




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