This section exists
to help give back to the community by explaining some of the technical
challenges we've faced along with their solutions.
Flexplate and Bolts
Flexplate - the stock flexplate can be used
up to somewhere in the 400-500whp range before the converter
bolts start being near-impossible to keep tight. Our upgrade
SFI flexplate is considerably
stiffer and thicker, making it load the bolts more purely in
shear rather than trying to rock the bolt heads loose. This
helps with keeping the bolts tight. Above about 600-700whp,
it is really difficult to keep the bolts tight with only 4 bolts
and it is a good idea to step up to an 8-bolt system like Precision
Industries offers to go with our flexplate. I do not have any
issues with the 8-bolt joint even on the drag car, which is
well over 800whp. We are planning to release a 7-bolt flexplate
in early 2012, before the racing season begins.
Bolts - in all applications, converter bolts
should be tightened to 50ft-lbs or greater with red loctite.
Re-torque the bolts after the first heat cycle. First gen applications
with the coarse thread (91-92 used M10x1.5) can use 12.9 allen
bolts or any variety of 10.9 bolts in an M10x16mm long. We expect
to have our first run of 2g custom bolts in early 2012 as there
are no available options for a low-head bolt that fits. Until
then, either use OEM bolts which are a little short, or grind
the bolt heads shorter on an M10x16mm. Crankshaft bolts should
be OEM. The 17mm long option from the 1g 5-spd is about the
right length. You can also use OEM ring gear bolts cut to length.
Up to about 500whp, 100ft-lbs with red loctite works fine. Up
to about 700-800whp, 130ft-lbs with red loctite works fine.
Beyond this level, I'm running 150ft-lbs on the drag car with
loctite on the threads and grease under the bolt heads. I cringe
every time I torque the bolts to this as it is way beyond where
an M12 should be taken. All applications should clean the flexplate
and crankshaft surfaces with brake clean during assembly and
then coat them with red loctite to glue them together. The better
fix to this issue at high power will be a 7-bolt crankshaft
pattern with its bigger bolt circle and one more bolt to hold
the joint.
SFI
Flexplate Installation Instructions - includes
a cross-section showing the crankshaft, flexplate, pilot bushing,
and the optional bolt washer plate.
©2011 Kiggly Racing, LLC
