To Dave and all others who responded,
Many thanks for the help, I resolved the issue thanks to help mainly from
Paul Hunt and others on the various MG lists.
I found a FAQ on the Mallory and how to set it up correctly. Dwell should be
26deg for the primary set of points with the secondary or trailing set of
points blanked off. Then with the blanking removed the trailing set is
adjusted to provide a combined dwell of 33 degrees. The distributor ships
with 24deg centrifugal advance set inside. Probably not enough for my low
compression factory V8 so I will take the base plate off and adjust it to
the maximum setting which is 28deg. Currently running with 6 deg initial
advance but she doesn't seem to like it - thinks it's too little or
something as she won't come back down to N after a 1/2hr stuck in traffic.
Fans hold the temp, but don't drop it. Sounds like the ignition it too
retarded (10deg makes no difference either) to me but hey.. something to
play with!
Now to the problem, it wasn't in fact due to the Mallory settings, even
though they were not spot on (43deg) and causing rough running. I found that
the engine people in the massive rush/silly deadline I gave them, had
mistakenly installed a ballast resistor inline ahead of the coil - as they
thought firstly my ignition was supplying 12V and that I had a 6V coil.
In fact, the Factory V8 has a length of resistant wire supplying the coil
that drops the voltage to closer to 6V (7.5ish actually). The coil on a
Factory V8 should be 6V, not 12.
So I had a 12V coil (Lucas Sports Coil), receiving only 7V before I even
went for the conversion (explains my earlier engine dying problem IMO). When
the additional external resistor was fitted, the voltage dropped so low, the
coil wasn't getting any chance to energise, hence the misfire.
She runs like an absolute dream now, HUGE difference in performance over the
stock setup. I couldn't be happier! If anyone is thinking about going the
Weber 500, Offenhauser, Mallory route, I can highly recommend RPI
engineering. Great people to deal with.
Before I went for the conversion, I had 220lbs torque at 1900rpm and 143bhp
at 4900. I haven't had the chance to get her on a Rolling Road since (will
report later), but I'd hazard a guess I've gained at _least 40bhp. Not big
numbers for a V8 I know, but as much as I'd dare with a factory car, factory
gearbox, diff etc.
She now smokes the wheels at anything over 4000 WOT and the change up into
2nd at WOT steps the tail out savagely! <VBG> Oops! Really do have to be
careful with it now! <G> Actually the best bit is puttering around town at
1000rpm in third gear, idles so well it's incredible. All I can say is the
Weber combo is sooo much better than even the well set up SU's, virtually
new factory dizzy I had before.
It really makes me wonder why Rover and MG went with the SU's and that
manifold, contractual commitments I guess.
Cheers & thanks for the help list!
Neil
56 AH 100 BN2 / 61A 1600 / 68 CGT / 74 BGT V8
http://www.apphosting.com/mgstuff/
----- Original Message -----
From: David Kernberger <dkern@napanet.net>
To: Neil Cotty <neilc@apphosting.com>
Sent: Friday, February 23, 2001 1:34 AM
Subject: Re: Mallory Dual Point
> 2/22/01
>
> Neil,
>
> Years ago I had a Mallory dual-point distributor and it had the 2
> felt pads you refer to. I think they are just for lubricating the cam,
and
> the rubbing blocks which are inside them. Are they oily or greasy to the
> touch?
>
> Cheers,
>
> Dave Kernberger
>
> ----------------------------------------------------
>
> >Hi all,
> >
> >I have just had a few things done to the Factory V8, Weber 500, Offy,
> >Mallory, new cam & tappets etc. I've run into problems with the Mallory
> >setup. I don't know how to set the points gap and what the dwell should
be.
> >Also any recommendations of what the advance curve should be? and max
> >advance setting? I hear the max advance can be adjusted on this
> >distributor - ? This is a stock 3.5 8.3:1 Rover.
> >
> >Right now, I have severe misfiring under load vacumn connected, and
> >slugglish performance and some misfire when disconnected. Massive advance
> >vacumn connected is apparent. The dyn. timing is set at 7deg vac. disc.
at
> >800rpm. The dwell is showing 43deg. I am guessing that is far to small a
gap
> >but have no idea how to adjust the dizzy as I don't have any booklet to
work
> >with. The car was running fine, for about 12hrs, first thing the next
> >morning this popped up. I think the points gap has slipped but only know
> >Lucas stuff so can't say for sure. There is also something weird, well
looks
> >weird to me <G>, two felt pieces between the points and the cam lobes..?!
> >Should that be there on a Mallory?
> >
> >Can anyone help, or point me to a Website? :) I'm sure this has come up
> >before?
> >
> >Cheers,
> >Neil
///
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