LT1-LT4 Modifications 1993-97 Gen II Small Block V8

rod bolts spec

Thread Tools
 
Search this Thread
 
Old 07-08-2007, 10:20 AM
  #1  
TECH Resident
Thread Starter
iTrader: (25)
 
Ari G's Avatar
 
Join Date: Jul 2005
Location: Houston
Posts: 818
Likes: 0
Received 0 Likes on 0 Posts

Question rod bolts spec

what is the correct Tq spec for the rod bolts?
Old 07-08-2007, 04:49 PM
  #2  
TECH Resident
Thread Starter
iTrader: (25)
 
Ari G's Avatar
 
Join Date: Jul 2005
Location: Houston
Posts: 818
Likes: 0
Received 0 Likes on 0 Posts

Default

I have heard 4 diffrent specs
Old 07-08-2007, 04:54 PM
  #3  
Launching!
iTrader: (1)
 
Imnotfast's Avatar
 
Join Date: Jan 2006
Location: In a box next to walmart
Posts: 259
Likes: 0
Received 0 Likes on 0 Posts
Default

what kind of rod bolts?
Old 07-08-2007, 04:57 PM
  #4  
TECH Resident
Thread Starter
iTrader: (25)
 
Ari G's Avatar
 
Join Date: Jul 2005
Location: Houston
Posts: 818
Likes: 0
Received 0 Likes on 0 Posts

Default

stockers
Old 07-08-2007, 06:25 PM
  #5  
12 Second Club
iTrader: (129)
 
fergymoto's Avatar
 
Join Date: Aug 2005
Location: Rock Hill, SC
Posts: 2,810
Likes: 0
Received 2 Likes on 2 Posts

Default

45ft lbs.
Old 07-08-2007, 08:41 PM
  #6  
TECH Resident
Thread Starter
iTrader: (25)
 
Ari G's Avatar
 
Join Date: Jul 2005
Location: Houston
Posts: 818
Likes: 0
Received 0 Likes on 0 Posts

Default

from what source did you get them?
Old 07-08-2007, 09:10 PM
  #7  
12 Second Club
iTrader: (129)
 
fergymoto's Avatar
 
Join Date: Aug 2005
Location: Rock Hill, SC
Posts: 2,810
Likes: 0
Received 2 Likes on 2 Posts

Default

It's the spec for all GM 3/8" rod bolts whether it be a small or big block. Look anywhere you want.
Old 07-08-2007, 09:40 PM
  #8  
Launching!
iTrader: (1)
 
Imnotfast's Avatar
 
Join Date: Jan 2006
Location: In a box next to walmart
Posts: 259
Likes: 0
Received 0 Likes on 0 Posts
Default

Dont know how to link a PDF but scanned from the 1995 service manual its
27 Nm (20 FtLbs) plus 55deg.
Old 07-08-2007, 09:42 PM
  #9  
On The Tree
iTrader: (2)
 
WYD-01's Avatar
 
Join Date: Jul 2006
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts

Default

20 ft lbs plus 55 degrees
GM service tech via Service Info
Old 07-08-2007, 10:29 PM
  #10  
12 Second Club
iTrader: (129)
 
fergymoto's Avatar
 
Join Date: Aug 2005
Location: Rock Hill, SC
Posts: 2,810
Likes: 0
Received 2 Likes on 2 Posts

Default

Don't follow that horse ****. The average Joe is not going to nail 55* on every rod bolt every time, he's gonna say 55*? All you end up with is **** all over the place and problems on your hands.

If you clean your new bearings up (wipe with acetone), install them in the rod and rod cap, torque them to 45ft lbs, and measure them with a bore gauge then you will have something accurate to calculate your clearances on once you measure the rod journals on your crank. In this case I wouldn't follow the service manual.
Old 07-09-2007, 04:08 PM
  #11  
TECH Resident
Thread Starter
iTrader: (25)
 
Ari G's Avatar
 
Join Date: Jul 2005
Location: Houston
Posts: 818
Likes: 0
Received 0 Likes on 0 Posts

Default

I have used the 45ft/lbs and they are too tight,i used the 20 ft/lbs + 55° but and where dead on 0.0025 with plastigauge

I didin´t have a angle finder so i found that 55° is about 37 ft/lbs,thanks
Old 07-09-2007, 07:21 PM
  #12  
TECH Enthusiast
 
lethal93ta's Avatar
 
Join Date: Sep 2003
Location: bethel PA
Posts: 501
Likes: 0
Received 0 Likes on 0 Posts
Default

plastigauge isnt worth jack, we torque the rods to 45 at the shop and check them with a bore gauge, if there out of spec or round they get rebuilt. did you have the rods rebuilt? did you have new rod bolts installed? a lot of that plays into factor, 45 is what most engine builders go by, my 93 service manual says that as well, if they were resized you need to know from your machinest what he used to size them and set them to that so there not out of round, if you didnt get them rebuilt or put new bolts in there, your nuts, the rod bolts are one of the weak links in the motor. and in that case you need to go by what ever rod bolt spec that manufacture tells you every rod I ever did was 45 tho.

if your only going to 37 lbs maybe your oil clearance isnt right and thats why its to tight! thats the reason you use a dial bore and a micrometer to set oil clearance.

Last edited by lethal93ta; 07-09-2007 at 08:19 PM.
Old 07-09-2007, 07:58 PM
  #13  
12 Second Club
iTrader: (129)
 
fergymoto's Avatar
 
Join Date: Aug 2005
Location: Rock Hill, SC
Posts: 2,810
Likes: 0
Received 2 Likes on 2 Posts

Default

Thank you.




All times are GMT -5. The time now is 06:36 AM.