Mallory Unilite - retarding advance curve

[type3]

What's a good way to retard the advance curve of a Mallory? Currently running two grey springs. Would two orange springs be the ticket?

This is for a high compression engine on the street. It's fine cruising with no load. It sings over 3k rpm. Just would like to retard the advance when under load.

Mallory curves:
http://documents.holley.com/mallory_ins ... _29014.pdf

[ps2375]

Looks like two pinks.

[Piledriver]

That will slow down your curve, but there is still no load compensation, which appears to be what you are requesting.
Mallory sells setups that have programmable retard, not sure the pressure/vacuum range.

Some programmable ignitions will work, but without that, with a mechanical advance only unit, you just have to set it for WOT and hope the high EGTs at cruise don't cook your heads. There's usually not enough load to be a concern on a bug/Ghia etc, although the CHT can be >50 F higher than with proper low load timing*.
(*based on testing I have personally done with a programmable ignition setup, not "I heard it somewhere")

[type3]

Okay, thanks guys! Will play around with it a bit more.

[type3]

Took 4 degrees out overall (leaving the grey/grey in there for now) and it pulls much better in 3rd!

That takes total advance down from 28 degrees (according to the pulley). Next thing is to check pulley accuracy.

[Piledriver]

Checking the accuracy of the timing wheel is a Very Good Idea...
...But a high compression motor with a tight deck/plenty of squish area will not want or need a lot of total timing.
A motor with a lumpy cam to go with that high compression will probably like a LOT more initial timing.

You may want to limit the advance travel so you get 12-15BTDC at idle and (optimal WOT) timing at 3500.
The Mallory is ~easily adjustable that way.
...a 009 or most std issue VW distributors are even easier, you don't even have to take them apart, just pop off the oval access plug and bend the long "goalposts" in at an angle---they are the stops for the weights. At least one enterprising fellow installed stop setscrews in the goalposts to make it really easy to adjust.
(you usually only need to do it once or a couple iterations)

[type3]

Cool. It was set at (or at least according to the pulley) 14 ~ 28.

So taking it back 4 degrees appears to be set at 10 ~ 24.

It really liked the extra initial for starting. It's not too bad now, just not as good. So hopefully retarding the curve I'll be able to get back there.

It'll go on a rolling road at some point, so at least it's not in destructo mode if I drive it there.

[type3]

It also seemed to run hotter, which I guess might be down to the third gear pulls.

[Piledriver]

It will also run a bit hotter at cruise as well due to retarded timing--- it would probably prefer ~40-50btdc tooling along just off idle at 70mph.
Unfortunately vacuum advance generally doesn't work well with a big cam unless you are using a programmable setup to get it.

Some way of datalogging removes much of the issues with a "butt dyno" for tuning, some WBO2 setups have an RPM input etc, that data can be pasted into various apps to determine acceleration rate and thus HP/Tq.
Some more advanced setups can provide real time instant HP/TQ/fuel economy "gauges".