Re: Injector size, homemade plugs

[jonathan coates <alfa@domain.elided>]

In message , JJK1204@domain.elided writes
> I just converted my 75 spider from SPICA to Webers so I too had to find a 
>"plug" for the injector holes.
> 
> I tried everywhere - specialty nut & bolt shops, automotive repair shops = 
>nothing.  The bolt store measured the injector for me and I think it was 14 
>mm by 1.25 thread pitch - pretty fine threads for such a large bolt.  Still 
>they were unable to help me.
> 
> I showed it to a guy at one of my favorite autoparts stores and he 
>immediately said "looks like the same thread as a spark plug" - I'll be 
>dammed he was right.  So I made some plugs out of some old Bosch Platinum 
>plugs - the following may not work with other types - I don't know.  Nice 
>thing about spark plugs is that they seal like the injectors.
> 
> 1. Put the plug in a bench vise and cut off the threaded part with a hacksaw 
>(about 1/2" long) - cut metal all the way around.  Smooth out/level with 
>bench grinder.
> 2. Break out ceramic insert/center with plug in bench vise.

> 3. Tap the center hole with 8 mm x 1.25 tap - should be just enough meat for 
>tap to grip.

How did you hold it? Threads in the vice/vise?
> 4. Got some nice looking 8 x 1.25 allen head bolts - cut them off to fit
> 5. Screw and JB weld allen head bolt into tapped spark plug
> 6. Let JB weld cure overnight - don't get any on plug threads.
> 7. Thread plug into manifold and tighten with allen wrench
> Worked great and looks real professional - took about 15 minutes a piece to 
>make - well the first one took a little longer than 15 minutes.
I dont need this advise personally as we in UKland get the purer Alfa,
ie no SPICA. However if somebody does mess up the threads in the old
spark plug and then screw them into the inlet manifold (right?) which is
aluminium(right?), they WILL bugger up the female thread, not
good(right?).
- -- 
jonathan coates

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End of alfa-digest V7 #860
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