hey everyone brian here in this installment of summit racing
engine building 101 we're going to cover the house and the
whys of using torque angle for securing connecting rod bolts
let's go through the actual process
all right so at this point uh we've basically torqued down the caps on
seven out of the eight connecting rods these are the pro ls connecting rods and
pistons i've got number eight over here uh
actually number one over here that's number eight
and i want to show you the torquing procedure and i wanna talk about why
we're gonna do it the way we're gonna do it
the the pro ls rods we use arp 2000 rod bolts in those it's a very
nice connecting rod 200,000 psi being 7 16 it's 23 percent thicker
than the factory nine millimeter bolt as a for instance
so it's it's really stout now a lot of people and a lot of you know
folks they just are used to having an old-fashioned torque wrench which is
okay uh you know but the better way to do it is actually
torque angle uh what is torque angle well first thing that it's not is torque
to yield that is a different type type of bolt
torque angle is really just a way of measuring
uh the stretch of a bolt it basically uses the thread pitch
of the bolt itself to calculate the amount of stretch that it's going to
give itself in this case uh the way you do it is you
basically run them down to 30 foot-pounds of torque
that basically seats it there's not a you can tell that there's no stretch
happening really at that point from there we've got a very nice ac
delco torque angle wrench that converts back and forth a couple ways
and i'll show you something pretty cool about this one as well
and then it'll take you back and see why you know doing it this way is better
uh than with a typical uh torque wrench so i'm gonna go ahead and
seat these down just a little bit more we've used the supplied lube with this
on the threads which are up in here and then the underhead of the bolt which is
here that reduces friction and makes for nice
consistent readings put that wrench down pick up our
very nice torque angle gauge and i have it set for 30 foot pounds of torque
initially i'm going to take that back here
make sure i'm seated fully come down
19 22 okay 30 foot pounds of torque on that
one come back do number two
24
30 foot pounds of torque okay again another nice feature just kind of
helps you know when you're sneaking up on it one good solid pull
now at this point we switch up the wrench
and we give it 50 degrees of torque angle
okay this is pretty neat here when you start it
put it back on you're going to want to give yourself a place where you've got a
full 50 degrees of swing without any issues okay here we go
starting our 50 degrees 10 degrees 20
30.
50 foot pounds of torque now if you take a look at that
it also indicates 89 foot pounds of torque
that is the number that the wrench knew was occurring when we hit our full 50
degrees of swing why are we using torque angle
rather than foot-pounds of torque the reason why is bolts when they're new
uh they they stretch a little bit for the first six or so times
that you use them and you kind of just get them pulled into place
uh the problem is is you know these bolts typically like after they're
stretched to be about 82 foot pounds of torque the
problem is from the first time through the sixth
time that you actually hit 82 foot-pounds of torque you're not seeing
the same amount of stretch on the bolt stretch is actually what's important a
fastener is actually a spring and it's clamping
the connecting rod together so with torque angle what you're basically doing
is using the thread pitch of the bolt and you're basically mathematically
going through and figuring out the length that it's going to extend
when you turn that a certain amount of degrees be sure to like
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