Malory Unilite dizzy.. anyone fitted one?

[TVR Beaver]

Hi All

Just trying to get the optimum setting from my car and remove the last few bit's of hesitance etc.. It's not bad now but perfection is around the corner!

I've been doing down the road of air flow howere I've just had a conversation on Dizzy's and the failings of the Lucas system... I've been advised to get a Malory Unilite (sale or return) and that will give a much better spark on low RPM and cure all hesitance problems??...

Has anyone any experiance of these distributers at all... and would it indeed address this issue???

Cheers

[neutral 3]

Not had any experience of a Mallory Dizzy on a Griff, however they have a Very good reputation in the States and are the Best Dizzy for lots of cars inc E-Types.
Very impressed with the one that was fitted to my Series 1 E-Type, the standard Lucas one is pretty poor in my opinion.

Would be interested in one for my 98 Griff if they are available ?

[blitzracing]

Dont believe anything year hear about improving the distributor, they all work the same way, and the Lucas system is no worse than any other mechanical system. Infact the Lucas trigger system and ignition amp out perform a "performance" amp sold as an aftermarket goodie in pure HT voltage terms as the RPM rises. (The preformance one does keep the spark burning for longer however.) As for it improving low speed performance, again this would only apply if you where running a ropey old set of points in the first place, that could not produce a decent spark to ignite the mixture, and the Lucas / TVR set up has no such issues. If you want to do the job properly you need a fully mapped ignition system like the Megajolt, that can control the ignition timing acurately, and some significant gains can be made to mpg. BUT at around £400 for the kit, you are a good way cost wise to a fully programmable ECU with ignition control included. Whatever you do, dont waste your money on aftermarket distributors. Dont forget that converasation you had- someone was trying to sell you something, just ask for the before and after rolling road figures and see what happens to the conversation! (And dont fall for comparason to a points based system)

Edited by blitzracing on Wednesday 26th May 13:13

[TVR Beaver]

blitzracing said:

Dont believe anything year hear about improving the distributor, they all work the same way, and the Lucas system is no worse than any other mechanical system. Infact the Lucas trigger system and ignition amp out perform a "performance" amp sold as an aftermarket goodie in pure HT voltage terms as the RPM rises. (The preformance one does keep the spark burning for longer however.) As for it improving low speed performance, again this would only apply if you where running a ropey old set of points in the first place, that could not produce a decent spark to ignite the mixture, and the Lucas / TVR set up has no such issues. If you want to do the job properly you need a fully mapped ignition system like the Megajolt, that can control the ignition timing acurately, and some significant gains can be made to mpg. BUT at around £400 for the kit, you are a good way cost wise to a fully programmable ECU with ignition control included. Whatever you do, dont waste your money on aftermarket distributors. Dont forget that converasation you had- someone was trying to sell you something, just ask for the before and after rolling road figures and see what happens to the conversation! (And dont fall for comparason to a points based system)

Edited by blitzracing on Wednesday 26th May 13:14

That's why I asked... He was saying about the better spark lower down and the fact that Rover had reduced the output instead of addressing the issues... but must say the guy went on a bit so lot's of info / quotes in a 10 min call... didn't take it all in!.....
I'm sure your right however.. fueling and air flow.. with reduced Plenum temps and propper trumpet clearance is the way to go for me... will keep on going!!

[blitzracing]

Its total rubbish about reduced output at low RPM, its the reverse condition where potentual spark energy goes down as the RPM goes up, due simply to the fact the coil has less time to "recharge" between being fired. So you have to work out a ballance in the available time between charge annd discharge. If you let the coil charge for longer, the available voltage to fire the plug is higher, but you have to shorten the spark burn time, so it can start recharging sooner. This is what Lucas do, so you always have enough power to ignite the mixture even at 5000 plus rpm. The aftermarket amp system does the opposite, and provides a longer burn time at the expense of peak voltage as RPM rises, but having said that there is suffcient capacity in the coil either way so misfiring is not a problem at high RPM. At lower RPM, there is nothing between them as there is plently of recharge time, so ignition performance is purely down to the type of coil fitted and HT leads, nothing more.

[TVR Beaver]

Mmmm.. he did want to preach instead of listern to the questions... Do you know the place I'm on about... three letters starting with 'R'...?

[blitzracing]

They talk the talk certainly.....

[wycoller]

TVR Beaver said:

Mmmm.. he did want to preach instead of listern to the questions... Do you know the place I'm on about... three letters starting with 'R'...?

ends in T if same W****r gods gift to TVR,s is how he talks completely concur with Blitz simply put and explained, this **** couldn,t be bothered to answer e mails etc or tell me what cam fitted to car
keep on working with that smoothness issue and send me a fully detailed report LOL

[daxtojeiro]

A distributor usually has a single coil, on the RV8 engine it does anyhow.

A coil takes around 3.5 - 4.0mS to fully saturate (charge) before it can release its full potential, it also takes approx 1.0mS to discharge (create the spark)
So a total of 4.5 - 5mS for each spark.

At 6000RPM theres only 10mS to fire 4 cylinders, so that means firing the coil every 2.5mS

So you can see theres not enough time to fully charge the coil at higher rpm, in fact, as the rpm increases above 3000rpm the charge becomes less and less. This is the same on any distributor setup that uses a single coil.


With wasted spark you only need to fire the same coil once every 10mS at 6000RPM, so you have loads of time to charge the coil, you only start to lose charge time at around 12000rpm on a V8

Phil

[TVR Beaver]

But does the Malory address this?.. Don't think so??

[daxtojeiro]

TVR Beaver said:

But does the Malory address this?.. Don't think so??

No distributor with one coil can address this, its simply a fact of life and why OEMs went over to wasted spark twenty odd years ago,
Phil

Edited by daxtojeiro on Thursday 27th May 20:01

[blitzracing]

I bench tested the Lucas system, and the peak spark voltage drops off quite sharply above 5000 rpm, but what effectly happens is the coil neither fully charges or discharges fully in the available time, so you end up with a coil thats partly charged, then partly discharging, so the peak voltage does not drop so far to the point it cant jump the tiny spark gap. Typically a spark from an HT coil could jump say 2 cm in dry air with a full charge at say 27kv. You do need to consider the fact that you have resistive plug leads, and an extra gap at the rotor tip plus the plug is in combustion chamber full of compressed air and fuel (a pretty good insulator), but the total HT available is way in excess of whats needed just to fire the plug even as the RPM rises. The design of the trigger rotor and pickup and amp control the charge and discharge periods, but its quite apparent that the electronic Lucas system is up to the job of igniting the mixture as required all the way to 6000 plus rpm. More to the point, I cant see how the Mallory would do any better given the laws of physics. Timing it acurately however- thats another matter, where a mapped system would be of great benefit. (Dont get me wrong here- Id love to fit a mappped system over the Lucas just to improve the economy!)

[blitzracing]

I bench tested the Lucas system, and the peak spark voltage drops off quite sharply above 5000 rpm, but what effectly happens is the coil neither fully charges or discharges fully in the available time, so you end up with a coil thats partly charged, then partly discharging, so the peak voltage does not drop so far to the point it cant jump the tiny spark gap. Typically a spark from an HT coil could jump say 2 cm in dry air with a full charge at say 27kv. You do need to consider the fact that you have resistive plug leads, and an extra gap at the rotor tip plus the plug is in combustion chamber full of compressed air and fuel (a pretty good insulator), but the total HT available is way in excess of whats needed just to fire the plug even as the RPM rises. The design of the trigger rotor and pickup and amp control the charge and discharge periods, but its quite apparent that the electronic Lucas system is up to the job of igniting the mixture as required all the way to 6000 plus rpm. More to the point, I cant see how the Mallory would do any better given the laws of physics. Timing it acurately however- thats another matter, where a mapped system would be of great benefit. (Dont get me wrong here- Id love to fit a mappped system over the Lucas just to improve the economy!)

[rev-erend]

There was someone one here recently who had bought a unilite and
as the std lucas unit was shagged it sounded like a good idea but
the problem was no one could tell him what poundage springs the
advance/retard springs should be to match that of the original set-up.

My advice at the time was that I believed TVR power was able to remanufacturer
the original. The car drove like a dog aparently and I cannot remember if the guy
got the issue sorted.

[rev-erend]

I found this thread :

http://www.pistonheads.co.uk/gassing/topic.asp?h=0... Distributor with Coil over exhausts :-(

You could ask him how it runs ..

[TVR Beaver]

Mmmm.. love some of the comments also... 'selling half the shop' etc, guess we talked to the same guy!!;)
No.. think I'm okay with the existing.. it appears to be working spot on following a number of tests this weekend

Not sure how long that coil will last though! boiling oil.. just what you need!!

[wycoller]

blitzracing said:

I bench tested the Lucas system, and the peak spark voltage drops off quite sharply above 5000 rpm, but what effectly happens is the coil neither fully charges or discharges fully in the available time, so you end up with a coil thats partly charged, then partly discharging, so the peak voltage does not drop so far to the point it cant jump the tiny spark gap. Typically a spark from an HT coil could jump say 2 cm in dry air with a full charge at say 27kv. You do need to consider the fact that you have resistive plug leads, and an extra gap at the rotor tip plus the plug is in combustion chamber full of compressed air and fuel (a pretty good insulator), but the total HT available is way in excess of whats needed just to fire the plug even as the RPM rises. The design of the trigger rotor and pickup and amp control the charge and discharge periods, but its quite apparent that the electronic Lucas system is up to the job of igniting the mixture as required all the way to 6000 plus rpm. More to the point, I cant see how the Mallory would do any better given the laws of physics. Timing it acurately however- thats another matter, where a mapped system would be of great benefit. (Dont get me wrong here- Id love to fit a mappped system over the Lucas just to improve the economy!)

all to do with hysteresis affect on ya BH curve