ARP main stud kit "tunnel boring block"

[legend]

do u have to tunnel bore the block when u fit a ARP main stud kit ?
why is it required to do so
thanks

[ed]

not unless there is some indication of deformation along the tunnel, or if you had to abuse the block getting some old studs out. much like rod ends... if you distort them by driving the old studs out, then they need bore/hone

[legend]

thanks ed jza80
im just replacing the std 4agze factory bolts with some arp studs

[30psi 4agte]

If you stick just the crank in and tension it up and the crank spins freely you will be sweet.

[Sam_Q]

whats tunnel bore mean?

also I still dont get why you need to resize conrod big ends when you change the rod bolts, how could it possible be off-center afterwards?

[The Real Roadrunner]

whats tunnel bore mean?

also I still dont get why you need to resize conrod big ends when you change the rod bolts, how could it possible be off-center afterwards?

read eds post again,
if you DISTORT them WHILE DRIVING THE OLD STUDS OUT they WILL need a bore/hone.

tunnel boring is done to align all main/cam caps so they are straight ie if you have a warped block or had this shoul be done otherwise it may lead to premature wear/lost performance.
if you head warps when you bhg it wont be straight, so what do you think happens to the cam tunnel when youve just taken 20thou off each end of the head, you WILL have a 20thou bend in the cam tunnel also.
same applies if you have cooked a block or its sagged they do the same thing.

hope that helps
linden

[30psi 4agte]

Tunnel bore is where you bolt all the main caps on (to correct tension) without the crank in and run a bore straight through where the crank would be.

This will ensure that all the caps are in shape (round ) and perfectly aligned .

Some fastener like arp studs are sometimes torqued to different tensions and this can distort the cap causing it bind on the crank hence running a bore through to ensure correct Alignment.

Even is your new fasteners are not torqued to different tension it is a MUST to check that the crank still spins freely with the new fasteners if not a line bore is needed .

[30psi 4agte]

Bastard beaten !! .... by seconds.

[The Real Roadrunner]

^^^^
true also.