I can think of two things to check.
1. What type of distributor are you using? There is a small wire
inside the points type distributor that can break after years of
flexing. Often it looks OK externally but the strands may be broken
inside the insulation. If the strands are in contact with each other
the car will run fine. As they lose contact, you lose spark. Use a
test light or ohm meter and pull & tug on the small wires to see if
there is a problem. I don't know nuttin about the 'pointless'
distributors.
1a When you experience power loss, check to see if your coil is hot
(ie too warm to put your hand on for more than a few seconds). I have
experienced coils going bad that work OK if they are cool but quit
when they get hot (and then work again when they cool off...)
B. How is your fuel pump functioning? There is a set of points inside
the original SU pump. As they wear & arc, the pump can function
intermittently. Since your float bowls will hold a small quantity of
fuel, you might not notice the pump running erratically. On occasion,
however, perhaps the pump does not 'restart' and you are running out
of fuel. The SU pumps will often start working again (for a while) if
they are jarred. I remember trying to get my MGA home with a dodgy
fuel pump by aiming for bumps in the road when I'd feel the car lose
power. If that didn't work I'd get out, reach under the right side and
whack the pump until I heard it start clicking again.
Eric
----- Original Message -----
> Date: Thu, 26 Jun 2003 20:42:33 -0400
> From: Tab Julius <tab@penworks.com>
> Subject: Intermittent power loss
>
> My '78 B has an engine rebuilt to have dual carbs, high performance
engine,
> etc... (iow, it's not stock). I use it as a daily driver, and yet I
> occasionally get this intermittent power loss.... I can be going 80
(oops,
> sorry - I meant the speed limit, 65), and without any warning, on
any kind
> of day (temperature & humidity wise), at any incline (flat, uphill,
> downhill), at any operating point (right after starting, after
driving for
> 1 hour), at any fuel position (full tank, empty, new gas, etc.)
I'll get
> this sudden loss of power, and speed drops down to 40, giving it
more gas
> doesn't necessarily do anything, engine will start to have power and
then
> falter, feel ragged, etc.
>
> After about 5 to 10 minutes or so it'll clear up and then be fine
(back to
> full power).
>
> It's too infrequent to test reliably. Two days might go by and then
it'll
> happen again.
>
> My guess is something in the fuel delivery is getting clogged, and
> eventually it frees itself. Any idea where to look?
>
> I've never tried some of the carb cleaners like GumOut. Should I
bother,
> or should I do it by hand? Obviously there are places I can't get
to, and
> I don't have a ton of equipment (i.e.: no compressor).
>
> Any ideas welcome...
>
> Thanks
>
> - - Tab
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