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FE Power Forums => FE Technical Forum => Topic started by: bsprowl on February 03, 2025, 01:41:58 PM

Title: Crank turns hard in new short block
Post by: bsprowl on February 03, 2025, 01:41:58 PM
As I said in a the cam card thread, turning the crank takes 35 ft-lbs for break away and 30 or so to turn.  And there is more grim in the cylinders that I like so I pulled the pistons and rods out.  Almost all of the pistons have dirt completely around the outside above the top rings.  THe bearings have a date of 2021 on them so the short block was not assembled before that.  I was told it was done in the 2018 time frame.

THe crank spins easily with only the cam and timing chain installed; 10 inch pounds for break away.

My questions are what is the torque for the rod bolts; they are labeled SCAT 44 ARP 8740.  Also what should I use for lube? They have a light coat of moly on them but it looks dry.

Someone, Blair maybe, told me that these bolts should be upgraded if I was going to do some serious racing.  That is my plan so what should I buy?  Years ago, a bolt change required a resizing of the rod is that still true?



Title: Re: Crank turns hard in new short block
Post by: blykins on February 03, 2025, 02:06:52 PM
The 8740 7/16" bolts torque at 64 lb-ft with ARP lube.  If you change bolts, rods should be measured for size. 

If everything freed up when you pulled the pistons/rods, make sure the rings are gapped correctly, make sure the rod bearings don't hit the radii on the rod journals, and make sure the rods are facing the right way. 
Title: Re: Crank turns hard in new short block
Post by: bsprowl on February 03, 2025, 05:32:40 PM
The radii and and rods orientation seem to be OK.  I'll look again to verify that.

If I have to check the rings I've got a problem.  My vision is really poor with and my hand-eye coordination sucks at best at detailed work as I'm ageing out.  I just watched couple of videos and discovered that they make ring fillers; I did it back in the day with a hand file.  Maybe it won't be that difficult. 

Now I have to determine the gap I need.