I can't believe that I'm doing one page on my site about
locating dowels. What the heck are they and why do we need them
or even care about them. What I learned from my friends on the
Triumph and 6-Pack Mail Lists are that locating dowels are
precision ground to ensure "perfect" alignment of critical
components. Specifically, in my case, the transmission to the
engine. Some people say to just use an appropriate sized bolt
and you'll be fine but, for example, a 3/8" bolt is made to
"acceptable" tolerances. They're not made to align things, they're
made to hold things together. And there's a big differences in
those two needs. The shoulder on a 3/8" bolt is made to a rather
wide + or - variance when compared to a locating dowel. So where
do you have locating dowels on a TR6?
Well, as I was assembling bits and
pieces I was surprised at how many I found and how many were
missing! The ones I'm addressing are critical in the alignment
of the transmission to the engine and it all starts at the rear
of the engine.......obviously :-)
two align the back plate to the block
one sets the flywheel to the crank shaft
Once you get the back plate
aligned to the engine block and the flywheel to the crank, it's
time to add the pressure plate......yup.....more locating dowels.
This time there's 3 of them
|And with the Pressure Plate on
Seeing as I'm doing the Toyota 5
speed conversion it was important to save the dowels that came
with the 5 speed. These were located between the tranny body and
the bell housing.
Here's two different
views of the Toyota tranny dowels: with & without
the bell housing.
And then there's the "BIG
ONE".............the dowels that mate the bell housing to the
back plate. If your car is like mine, these two dowels are long
gone..........having been replaced by plain old 3/8" bolts.
However, they are easily replaced by going to
ordering part# 98381A624.
are back plate to engine block dowels & yellow arrows
are bell housing to back plate
So there you have all the locating
dowels that are required to ensure perfect alignment from the
engine block to the transmission. If you're missing any of these
DO NOT replace them with a bolt of the appropriate size. Get a
dowel that is precision machined for this purpose.