Hey everyone i messed up big time im trying to set timing on my 355 sbc and accidentally rounded the harmonic balancer bolt the head how do i go about removing this and replacing it with a new one

 

Cut the head off, pull the balancer then unscrew what's left of the bolt out of the crank.

 

drill it in the center and use an easyout on it would be 1 way

 

weld another nut to the front of the bolt.

 

Ok so i got a rounded out bolt kit says i have to tap the socket over the rounded bolt and it suppose to bite into the head of the bolt should i use a impact gun on it or try to remove it with a regular large breaker bar

 

Try one of those specialty sockets like twist outs.

 

Hi , the original bolt should have had a 5/8" Hex Head... if yours has rounded off the tips of the Hex.... I suggest you try a 15mm metric 1/2" Drive Socket for size. If it wont fit on by hand thats good... if you then use a short... eg say 2 1/2" or 3" long extension bar, fit the 15mm socket to the bar and drive it onto your damaged bolt head using at least a 16 oz Ball Peen Hammer. Be careful doing this that you drive it on inline with the Crankshaft centreline and not crooked... so to speak. If this is successful then get a buddy to lock your Flywheel/Flexiplate with a large screwdriver to prevent the Crank from rotating.... then using a long Powerbar very gently undo the bolt turning it anti-clockwise when viewed from the front. when fitting your new replacement bolt DONT overtorque.... stick to book specs ;-) Best of luck

 

Use the breaker bar. An impact gun can break that socket or prevent it from getting a good 'bite' on the head.