Topica Loopframe_Guzzi Archive


Subject: RE: Generator replacement

Author: murp-@aol.com

Date: Mar 8, 2001, 4:51 PM

Post ID: 1705784960


Hunter,
Thanks again for your comments. I have compared the Eldo cam with a
T-3 cam, and it looks to me as if the 'thread pitch' (I'm not sure if
this is the correct term for the pitch of a worm gear) on the worm gear
on the Eldo cam is about one half of the pitch on the T-3 cam. I may be
wrong, but this leads me to believe that the Eldo distributor is driven
at half the speed of the T-3 distributor.
I think that the Eldo distributor fires each cylinder on the
compression stroke only, but the T-3 distributor fires each cylinder on
the exhaust stroke as well as the compression stroke (the Eldo
distributor runs at 1/4 engine speed, and the T-3 distributor runs at
1/2 engine speed).
Does this sound right?
Brian


Hunter Jones wrote:
 Hi Brian

I think the difference between the Eldo cam and the later cam may be the
size of the distributor drive gears, not the ratio. Both distributors
run
at half engine speed. The Eldo distributor has one set of points and two
lobes on the shaft whereas the later dual point setup has two sets of
breakers and only one lobe on the shaft. The distributor has to run the
same speed as the cam in order to fire properly in either engine.
I think the culprit is (if memory serves) that the gear size on the eldo
cam is smaller than the later bikes. The Eldo distributor may not be
capable of mating up at all with the newer cam unless the single point
distributor can accept the gear from a dual point distributor. If you
have
the two cams out of the engine to compare I would be interested to know
how
the distributor drive gears are different.
I think that for the sake of maximum performance I would make a blanking
plug for the distributor hole and get a crank ignition. :-)
My two cents.


Hunter



At 12:51 AM 3/8/2001 -0800, you wrote:
 The reason I want to go with a non-standard setup is because in my
Eldo restoration I am installing 1000 cc cylinders and a B-10 cam. This
cam was designed for the Tonti-frame bikes, and so the worm gear at the
end of the cam drives the distributor at twice the speed of an Eldo cam.

This means that I will have to go with a dual-point distributor setup
(which also means that I can use an electronic ignition system), but the

problem with that is that the distributor body will not clear the stock
generator. Because of this, I am looking for a setup which is smaller so

that I can mount the dual-point distributor. I would prefer an
alternator over a generator for the reasons already stated, but a
generator would be fine as long as it clears the distributor.
That said, I would very much like to see how that VW generator was
made to work.
Thanks,
Brian
'74 Eldo
'78 T3



Tom Bowes wrote:
 
Todd M. Nordwig wrote:
 What would be the advantage of an alternator
on a loopframe vs the generator? The advantages
in general?

Todd

Well, Todd, there are many advantages to having an alternator rather
than a generator in nearly any vehicle application, not just for
loopframes. The advantages would be, in no particular order:

1) Rated output at lower RPM's than a comparable generator.

2) No commutator to wear out.

3) Reduced brush wear due to the fact that on a generator the armature
(rotor) output is carried by the brushes. On an alternator the brushes
ride on slip rings and carry the field current, which is much lower.

4) Modern alternators usually have the voltage regulator built in.

5) Higher amperage output from a similar package size.

6) Less "hash" and electrical noise.

All that having been said, there is one HUGE disadvantage in trying to
graft an alternator to a loopframe. It is nearly impossible to find one
that will directly bolt in place of the generator. Therefore,
installation of an alternator will probably adversely affect the looks
of what is becoming a "classic" bike.

Tom

'70 Ambassador
'82 V50-III
Shelby Township, Michigan

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