Mallory Dual Point owners

corazon

corazon

Well-Known Member
This is directed at anyone running a mallory dual point on their V8, or indeed knows more about them than I.
I'm having a little trouble fitting mine.
It rotates into place dropping down and engaging with the gear.
However it doesn't appear to be fully seated, by almost half an inch. The O ring only just goes in to the hole, and there is half an inch showing before the larger diameter part of the shaft. This looks like it really should be flush with the manifold as per my lucas..
So i've measured against my original lucas 35D8, and the mallory is taller by that half inch.
What's the score here, do i need some kind of washer/spacer?
The model is 27 series vac advance.
Thanks in advance, i'm feeling a little retarded :LOL:
Jim
 
There's usually only one reason for that. Have you checked that the base of the distributor shaft has the same tongue as the one you took out? Early engines have the tongue on the distributor, later engines have it on the drive (or was that the other way round?), with a cooresponding slot on the other component. If you try and fit a distributor with a tongue to a drive also with a tongue then the distributor will stand proud by 2 X the height of the tongue, which sounds about right for what you are describing.

There are a few solutions if this is what the problem turns out to be. You could swap the oil pump gears for the other type. Or you could find that the distributor drive is detachable with a scroll pin and you can fit the other type of coupling there. (this varies between different Mallorys).

What are you planning to do about points wear with the Mallory? A very good solution is to fit an ignition amplifier so that the points only carry switching current and the amp provides the working current for the coil.

Chris
 
Ignition amp was the plan, perhaps even favourable over a pertronix conversion
It is definitely the correct gear, looks identical to the lucas one.
It feels like the gears are meshing correctly, and go as far as they can.
It just the shaft on the mallory is slightly longer, and therefore the larger diameter "ring" of the shaft doesn't mate with the manifold if that makes sense :?:
Doesn't look right at all :?
 
huh. Just been out to check my Mallory, it sits like this



looks like no gap between anything :?

Sounds a bit odd if it does slot in as you say - presumably it goes in and 'feels' OK apart from the tallness..

is it definitely for the same age engine? Perhaps a spacer plate would sort it out if it does turn out to be right..
 

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Thanks for that pic, i thought i was going mad!
Yes that 'collar' for want of a better word is not flush with the block.
It does clamp down easily, but would there be oil pressure :?

I have read on other forums about one quick click of the key and the distributor dropping further and fully seating itself, but i'm a little reluctant to lose my timing on something that only might work
Plus it's definitely taller overall.
The guy i bought it from originally bought it from RPI and has just sat unused in its box for years- there's even a note form RPI inside the box.
 
Hi Jim

I'm not talking about the gear - that will indeed be identical. Below the gear and at the base of the shaft there will either be a tongue projecting out of the shaft or a slot visible in the base of the shaft. This tongue or slot engages with the opposite on the top of the oil pump. Hence why you've come across this suggestion of turning the engine and everything slotting together.

So has the base of the Lucas distributor you've removed got the same base as the Mallory (whether slot or tongue)? If it has, then the issue is getting the tongue / slot drive arrangement to engage in the top of the oil pump gears. If all else fails, remove the cover from the oil pump so that you can manually rotate the gears from underneath until they engage with the distributor shaft.

Essentially, the cam drives the distributor shaft via the skew gear. The shaft also projects down below the cam and the distributor shaft thus drives the oil pump via the tongue and slot arrangement. So for the oil pump the sequence is that the cam drives the distributor and the distributor then drives the oil pump.

If it does turn out that you have two tongues or two slots with the new arrngement, then simply change the oil pump gears for the type to suit the new distributor.

Hope that's clear

Chris
 
Ok thanks for that Chris,
Yes everything is identical to the lucas, recessed tongue on the distributor.
I guess the mating parts are just sitting on one another then, hence the gap
I will have to have another play tomorrow, i've only just thawed and don't fancy going back out now :)
Jim
 
Hi, I have had this 'hiccup' with lucas distributors, the dist and cam skew gears are
engaging but the oil pump tongue and slot are not. All you have to do is pull the dist
out again and tweak the pump shaft round a bit and try again till it drops in.

Colin
 
Didn't have long today but it's all in perfectly now thanks.
Long handled screwdriver did the trick. Just a minor tweak, and everything dropped into place.
Now to set everything up!
ps Has anyone else running one made use of the adjustable mechanical advance? It's adjustable from 0 to 28 degrees.
What would be preferable for the stock 3.5 cam engine?
Jim
 
Chris,
Regarding the ignition amp, i was planning on going with the £10 kit from maplin.
However once i've soldered the whole lot and mounted in a suitable aluminium box etc i will have spent more time and money on it, making it not such a cheap option.
At this stage i'm thinking;
Just run on the dual points with my old lucas coil until they need replacing.
Then replace with an ignitor II (using my flamethrower coil) costing around £80, or £100 with flamethrower II coil.
OR spend similar money now on something like this which i could just plug and play and use with my existing flamethrower coil
http://www.ebay.co.uk/itm/Mallory-N...r_Truck_Parts_Accessories&hash=item53eb1bc242

Probably can't afford to do the latter after recent expenditure on the car, but if it's an investment...
Do those ignition boxes work with electronic modules too?
Jim
 
I actually have the RPi equivalent of that Mallory one fitted to Lucky. It happened as a bit of an accident, but now I've got it I'm extremely pleased with the result. It's working on the original ballasted system without problem. It leaves the distributor unmolested to do what distributors do best, the points don't wear and the electronics are mounted to a stonking heat sink away from the oil and vibration environment of the engine. So, yes, I'm now a fan of this method of going electronic over that of trying to stuff everything inside the dizzy.

Chris
 
corazon wrote,...
Has anyone else running one made use of the adjustable mechanical advance? It's adjustable from 0 to 28 degrees.
What would be preferable for the stock 3.5 cam engine?
Click to expand...

Hi Jim,

The 3.5 litre engine typically requires a maximum of 36 degrees of total mechanical advance. Some of the factory set P6B engines ran with as little as 30 others more. If you set your initial timing to 6 degrees BTDC @ 600rpm then you'll have 34 degrees of total mechanical advance. You can run more or less initial timing and experiement with how the engine performs. The total mechanical advance will come in quicker than the factory Lucas distributors which were set extremely conservatively, so your engine should in theory perform substantially better in terms of acceleration.

If your engine pings then you'll either need to reduce the initial timing or see if you can replace the advance springs within the distributor for stiffer ones, or just be more conservative in how you drive and use less throttle if she starts to ping.

Ron.
 
Ok initial set up with the mallory has been great.
However i'm having some idling issues.
Unfortunately I think it's pointing to the cam timing, ie the new distributor showing up the cam wear..
What do you think?
I can make it idle as low as 450 ish rpm but it is happiest around 750/800.
So today setting it at around 800, the throttle response is generally very smooth throughout the range.
After revving though the idle then wanders, lower almost to stalling then higher than 800 and wont settle down.
There is a clear miss too.

On a test run yesterday, the timing wasn't quite right but i had terribly erratic throttle response- couldn't get above 2000 revs and consequently couldn't get into 2nd gear. As soon as i got near 2000 rpm the revs completely dropped and bounced up and down in a crazy manner :?
I don't think it's my dashpot oil as i changed it beforehand yesterday- a mix of 3in1 and 20/50 as either one seems too thin or thick in this cold weather.
I may try some ATF today anyway.

Throttle linkage sticking? Fuel starvation?
It's definitely running too rich, i think it had to compensate for the worn distributor previously.
Could flooding be causing these symptoms? ie when i put my foot down ..

What am i overlooking here?
Jim
 
Hi Jim

Well first off there's little point doing anything until you have the decent set of plug leads (I hope they are Magnecor) you were talking about earlier. That is very likely to cure the misfire. Make sure when you install them that you use lots of lead seperators to keep the leads from touching anywhere.

Next off the symptoms you describe sound much more like weak mixture rather than rich. The hunting in particular is completely typical of running too weak.

So if you are confident that you have the static ignition timing set at a sensible value I think it will be time to get you up to speed on how to tune carburrettors. Over to you first, what sort of experience have you had of doing this before? And what level of understanding do you have of how the SU carb works? Also we need to know what model carbs you have - HS6's or HIF6's? The HS type have a cylindrical "can" mounted to the front of the carb, which is the fuel reservoir for the carb - so that's where your fuel pipes would go into the carb. HIF type have eveythithing in one unit. Also do you have a mechanical fuel pump or electric? If you can answer those we'll talk you through how to set everything up. (Don't bother trying to follow the manual on this!)

Chris
 
Yes the magnecors are about to be ordered :D Can i order the sd1 set or is the coil lead wrong?
I have HIf6 carbs which i was planning on rebuilding after sorting the ignition-something i've not done before.
Coupled with the freer flowing air filter/richer needle route.
I have a basic understanding of the carbs, and there appears to be a minor air leak which i haven't located exactly yet.
I have read some of your posts on tuning, very detailed and easy to follow.
A friend has offered to give me his old colortune tester which he has no use for now when it comes to that.

Electric fuel pump was fitted before i owned the car, is there a simple way to check the pressure? I had the fuel line off before the fuel filter to check it was pumping. Came out pretty fast, but that's hardly a good measure is it..
 
It's just dawned on me.
If the mixture I made from 3in1 and 20/50 naturally separates that would result in the piston moving slowly through the thicker oil and then suddenly quickly through the 3in1 :shock:
I will definitely try with some ATF tomorrow
Jim
 
Hi Jim,

If you lift off the distributor cap and turn the rotor, is there much in the way of free play before you feel spring tension? If you turn it as far as it can go and release, does it spring back to the start? Can you feel any lateral movement? With the aid of the timing light, when you increase the engine revs, do the timing marks wander back and forth?

How much initial timing did you set it to? Does the engine ping when you accelerate? What SU needles are you running?

Ron.

P.S Thicker oil in the dashpots enrichens the acceleration mixture more so compared to thinner oil as the piston will rise more slowly.
 
Hi Ron,
No play in the distributor at all, it's brand new and really very solid and sturdily built.
I don't have a timing light currently, i have set it by ear- but i'm trying to get hold of one.
No pinging, really throaty healthy sounding when revving until the described behavior.
I will need to check what the needles are tomorrow, have been on the car since i've had it, which was all standard in that respect.
Another thought i just had was I didn't fully drain the tank of all the ancient (brown) fuel. I guess i could be getting small quantities of bad fuel between the good.
Jim
 
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