[Diy_efi] OT - cap/rotor clearance correction - 0.045 thou

Bill Shaw b.shaw
Tue Oct 18 03:54:14 UTC 2005


Hi,

I'm not getting anywhere on the f-list,  so I thought I'd ask here.  Please
indulge my off topicness :-)   I'm just finishing up a major service in a
1980 Ferrari 308i.  It's K-jet injection with lambda and dual Marelli
Digiplex ignitions.  (kinda of makes it e-fi,  doesn't it?)

pic at http://b.shaw.home.comcast.net/308eng4.jpg  (and eng, eng2, and eng3
if you're interested)

All's gone well until I started it.  The new rotors seem to be a bit too
long,  one gouged a cap a bit:
http://b.shaw.home.comcast.net/ferrari/308cap.jpg

and the other hit enough to break off:
http://b.shaw.home.comcast.net/ferrari/308rotor.jpg

As you can see in the next pic,  the new rotor (on the bottom) is quite a
bit longer than the old one (on the top):
http://b.shaw.home.comcast.net/ferrari/308rotor2.jpg

When I clayed the cap/rotor combination (after the fact) I found the old
rotor had about 0.035" clearance to the terminal with the old cap,  and
about 0.045" (oops!) with the new cap.  The new rotor scraped the terminal
in both caps.  

The f-parts suppliers haven't offer much help beyond a refund (which was
nice).  Parts sources for this car are so scarce that it leaves me
re-working some very expensive new parts to make it function.

So after all that,  my question for the group is.... What is a 'reasonable'
rotor-to-terminal clearance?  I can make it anything I want,  since I now
have 0 or less clearance.  Left to my own devices I'd shoot for 25 thou.  Is
that a reasonable target?

Bill
'84 928s 5 sp. Vortech/749
'84 Mondial cab (for sale)
'80 308i (still in surgery)
'94 z28 LT1/A4 (mean green snow eating machine)





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