TBI adapter drawing

[WEG1192 at aol.com]

In a message dated 6/22/2001 12:34:20 AM Eastern Daylight Time, 
wd0fyf at mpks.net writes:

<< How much interest is there on the list, in these things? I have a son that
 has access CNC plasma cutter. He said it's networked to their computer
 system. You lay your sheet on the cutter and upload the drawing from the CAD
 program and it zips them out. My other son frequents an aircraft surplus
 place that , if memory serves, sells aluminum for $.80US/ pound. How much
 can a half foot square weigh? I'd have to ask if there's 1/4 inch available. 
>>

I need to warn you about the CAD drawing I uploaded. The holes were measured 
by eye with a ruler and are accurate to within probably 1/64" of an inch. If 
you do use the drawing to make a lot of adapters, I suggest you make one 
first and see how well  it fits your manifold before making a lot of them. 
Also, the three holes for the throttle body itself need to be drilled (cut) 
smaller than 5/16" of an inch since they have to be tapped with a 5/16" tap. 
The drill that came with my tap was a size G, and I'm not sure what that size 
is in inches. It's probably some decimal size. What I do is tap the TBI holes 
and put in 5/16" threaded rod and lock them in place with Loctite 271. I 
found that just screwing in 5/16" bolts in the adapter plate eventually 
stripped the soft threads after only a few R&R of the TBI. The steel threaded 
rod holds up much longer. One other thing. To get the threaded rods to stand 
straight up, I use my drill press as a guide. I put the tap in the drill 
press chuck and use my hand to turn the chuck slowly with the belt removed 
for safety. This keeps the tapped hole almost perfectly vertical. I then use 
nyloc 5/16" nuts on the threaded rod to hold down the TBI unit. Oh, one more 
thing. I thought I would just make all the adapters with 2" bores, but the 
5.7L TBIs actually have a smaller rim around the bore, so the 2" bore is too 
big for a good gasket seal on a 5.7L TBI. Bottom line is you have to cut the 
bores to match the TBI bore, 1-11/16" on a 5.7, 5.0 and 4.3. Hope this helps. 
JW
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