[Gmecm] Bellhousing Design-Iron Duke

[bcroe at juno.com]

My method is a little like others described.  But no 
expensive machines or error prone measuring used. 

I would start with the engine block.  Get a rough metal 
rectangle drilled for one guide pin.  Mark where the 
other guide pin hits and drill the second hole.  Perhaps 
drilling it a hair undersized and filing to fit is most 
accurate.  

Take about 1/2" of 3/8" NC threaded rod and tighten 
on 2 nuts.  Chuck the nuts in a drill press.  Spin this 
and use a file to form an (accurately centered) fairly 
blunt point.  Now back the rod into one of the engine 
threaded holes so that the point barely is above the 
surface.  Put th plate over the guide pins and flat, 
contacting the point.  Tap  the plate one good hit 
right on top of the point.  Use a small bit to make an 
accurate pilot hole, then use gradually increasing 
bits up to 3/8".  

Put the point in another hole, redoing the point as 
required.  Put a fairly long bolt in the first 3/8" hole, so 
that the unthreaded 3/8" dia part of the bolt is in the 
3/8" drilled hole.  

Hold the plate flat and do the next hole, and so on.  
The round portion of the 3/8" bolts should hold things 
in very accurate position.  After the job is complete, 
all the 3/8" holes can be drilled 1/64" over (25/64") 
to provide some tolerance.  But first do the trans 
holes.  

My plan works for the guide pins being the same, 
engine and trans.  Trim the plate as required and 
bolt it between the engine block and trans case.  
Mark the trans holes still needed through the trans 
holes, which are slightly oversized.  Taking your 
pointed rod and putting some tape on it will allow 
a close fit.  Tap it to mark center.  A black marker can 
be pretty close, if you are square when sighting, and 
start with a center punch.  

Bruce Roe

17 Feb 2006  "Burntkat at sc.rr.com" <burntkat at sc.rr.com> writes:
> How would you go about making an adapter-- in 
> other words-- how would you measure the holes
> from center of the shafts with enough accuracy to 
> ensure
> proper alignment of torque converter and flexplate?