RE: [alfa] Spica injector problems

["Jeff Greenfield" <alfaguy@xxxxxxxxxxxx>]

Jon -

To answer some of your questions ...

Yes, I have had to heli-coil the injector hole in the intake manifold
before. The good news is it is the same size as a spark plug thread, the bad
news is there is very little room and material in the area to work with. I
don't think you can use any of the solid spark plug inserts, rather you have
to go for the original heli-coil spring type inserts. You also have to cut
it down to something like only three or four coils as the hole is not very
deep.

Don't know if you could do the repair with the manifold on the engine or
not, on the one I had to do the head was off and apart anyway.

As for the injectors, my understanding is that they very seldom fail or
cause problems. This seems to be Wes Ingram's opinion as well as I have
spoken to him about this. I've always been told that you should not take
them apart, and have never tried so you are on your own here.

Yes originally the injectors were matched to the pump. Wes will supply a set
of matched injectors with a rebuilt pump if you ask him to as well.
Generally though, this too will not make much difference. Especially on an
engine with an older well used injection pump.

If you are having trouble with getting the mixture set correctly on the
injection, and everything else is alright (ie all the linkages and reference
gap are set correctly, and there is nothing broken inside the pump such as
the rack return spring), it is possible that the rack in the pump is gummed
up and sticking.

If you feel like spending the time to mess with it, remove the pump from the
engine, remove all the inspection covers, the drain plug from the logic
section and soak it in a tub of kerosene overnight. Put it back in and see
if it works any better.

If not, you are out a gallon or two of kerosene and several hours of your
time. If it does work you've saved yourself the expense of a rebuilt pump.

YMMV,

Jeff

-----Original Message-----
From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of Jon
Pike
Sent: Sunday, May 02, 2004 4:34 AM
To: alfa-digest@domain.elided
Subject: [alfa] Spica injector problems

Hi all..

Well, after getting over my radiator damage problem (shorten and secure
your oil separator hoses!!)  I proceeded on to my next problem..

I have had a few things that lead me to think I might have some
uneveness in my mixture from cylinder to cylinder.  I also seem to have
a bit of trouble adjusting the mixture predictably when it gets as lean
as it's supposed to.

All that led me to wanting to swap two injectors to see if my visual
difference between the deposits moved or stayed the same.  I kinda
doubted it would be the injector,  but hey, it's cheaper than getting
the pump rebuilt. So, I pull out the two,  and think, well, why not open
the questionable one..  which lead to me opening both of the two I
pulled,  which led to me pulling the other two to check, clean with
brake cleaner, etc..  (yes,  sometimes I go too far)

Anyway,  I was hoping that the rubber o-ring seal was not going to have
a problem after being unsealed after 27 years.... and I did notice a
lack of any tension as I put them back together..  I was wondering if
taking them apart was a bad idea.

So, two Murphy strikes follow..  Big one,  as I tighten them back in,
#3 has the sickening lack of tightening up that says "threads
stripped"...  (what is it with me and aluminum threads on this car????)

I had promised the wife a ride that evening,  it was fairly snug,  and
with the fuel hose clamped as it is I didn't think it would go anywhere
for 10 odd miles of driving around town.  So out we go,  but the car was
tough to start..  idled very rough,  but ran better but not great.  Lots
of backfiring.  Were my fears correct about opening the injectors?  My
adventure with my radiator holes was suspect,  but after getting it
soldered up and driving it back home, I didn't notice any unusual
running.. only after my injector massaging.  So I don't think I have
some warped head overheating problems affecting things.

Luckily I have another intake manifold,  and my new mechanic friend has
a box of injectors he's willing to let me try out..

Anyone ever have to Helicoil a injector site on a Spica intake manifold?

Another related question,  I see numbers on the injectors..  and reading
the Spica mantinence manual (from IAP) I see that when one gets a pump
back from the factory, which apparentlly came with a set of injectors,
one "was to match the number of the injector to place" for cylinder.
Does this matter?  I just picked out a group that looked about the same
at the nozzle end.

Jon
77 Spider
Irvine, CA
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