Torque spec for stock rod bolts??

90turbo1

Registered User
hey so I was just wanting to check what is the correct torque spec in Nm for the rod bolts on a 1992 SC.

i have read 42 Nm on one manual and as high as 55 on another.

anyone have a factory service manual?

thanks
 
My Chiltons Master Service Manual says 31-36 ft-lbs or 42.03Nm to 48.81Nm.This manual has work for me for 17 years.
 
i found those same specs on here. and i went in the mid range for the rods and mains and its acting like its too tight. so now i have to take the engine back out and will set it at the lowest setting to torque. now im just wondering if i had it at the lowest possible troque wsould it knock or chew up the berings i just put in?
 
If you torque them to the spec and the motor is hard to turn over by hand (with hand socket and ratchet on crank snout) there is a machining error or a measuring error on the crank, or... The main journals are not aligned.

I would seriously consider rechecking the measurements for your oil clearance if it doesnt turn freely.
 
1990XR7SC said:
i found those same specs on here. and i went in the mid range for the rods and mains and its acting like its too tight. so now i have to take the engine back out and will set it at the lowest setting to torque. now im just wondering if i had it at the lowest possible troque wsould it knock or chew up the berings i just put in?
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Did you use assembly lube when you reassembled every thing?Never turn a crank on dry bearings,it will gal them.
 
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Sorry mine spins over nice and easy.

I was replying to 1990xr7sc's post.

Didnt quote for some reason.
 
Sorry mine spins over nice and easy.

I was replying to 1990xr7sc's post.

Didnt quote for some reason.

It's been one of those off days and I forgot to quote 1990xr7sc's post.Corrected post.Sorry for any confusion.
 
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yes i used assembly lube. and i do plan on rechecking everything again. i mesured everything and it came out to the stock mesurements for the crank. so i ordered stock berings (stock size not .10 under) kept everything in order got the arrows (triangles) pointing to the frount of the motor and the rod caps had nimbers already on them (stock?) so i know i got thoes on correct. so the only thing i tought it could be was it was torqued too tight. But like i said im going to recheck everything.
 
yes i used assembly lube. and i do plan on rechecking everything again. i mesured everything and it came out to the stock mesurements for the crank. so i ordered stock berings (stock size not .10 under) kept everything in order got the arrows (triangles) pointing to the frount of the motor and the rod caps had nimbers already on them (stock?) so i know i got thoes on correct. so the only thing i tought it could be was it was torqued too tight. But like i said im going to recheck everything.

well you cannot actually torque them too tight as to cause that effect.

i am not sure as to the reason for a torque range on the bolts. the rod cap is not going to get any closer together if you torque them to 40 Nm or 50 Nm for example once they seat together thats as close as they will get if you over torque them you run the risk of bolt failure due to over stressing them with the torque of the nut.

if you have a stock crank and stock rod bearing journal diam. then stock bearings should be fine, as long as oil clearance doesnt get too large, or too little. here is a tip for you, I bet your problem lies in the thrust bearing in the center of the block. i was taught this by an old builder that was assisting me in my 302 build earlier last year. when I assembled the motor the crank would not spin easily, I thought of oil clearance and all sorts of scenerios but my math and measurements checked out so it should be easy to turn. (btw... when set up correctly you should be able to turn the crank with no rods attached by hand easily, but not to the point where it will spin.) so after installing main bearings including thrust bearings he taught me to seat the caps but dont torque them then take a rubber mallot and hit the front snout of the crank and then hit the rear of crank this sets the thrust bearing perfectly parallel to the crank and like magic the crank spins freely now. then torque the main caps as normal. I have never had a main failure on any of my motors using this method.
 
To align the main thrust bearing all the main caps need to be seated but loose. Wiggle the crank back and forth with a screwdriver and verify with a dial indicator that you have 0.003" minimum of thrust. You must then wedge a screwdriver between the crank and the web of the block pushing it forward to torque the mains.
 
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