Timing - 440

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morgan
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Re: Timing - 440

Post by morgan »

I just bought one... When I'm done you can have a play :)
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cadboy
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Re: Timing - 440

Post by cadboy »

thanks guys, I think I need one too :thumbright:

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Dave999
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Re: Timing - 440

Post by Dave999 »

very handy for getting the idle right
indicates if the accelerator pump is way too big a squirt

not great for much else but when used with a vacuum gauge as well
or a carb balancer you can see flow increase nicely as you home in on mix that gives a blue flame

multi barrel carbs with 1 or 2 or 4 idle mix screws you need to get em about right by no. of turns in or out first
then tweak each with the gunson on the nearest cylinder

for multi carbs

balance them all up with the gunson and a flow or vaccum gauge up and you avoid having to find a time served "i just do it by ear cos ive been at it since the sixties" kinda dude who knows he can charge anyone who is pulling hair and teeth out with frustration what he bloody well likes :)


oh yeah and

if you have the wrong plugs too hot say or fouled up plugs potentially too cold this task can be never ending

3 sets it took me in differing heat ranges .

NGK 5 standard but not right once i;d chopped a big chunk of head off i think too hot
NGK 6 better i think cooler
NGK 7 cooler still it just runs properly now and the change to them was noticeable by the general reduction in swearing spitting snarling and stropping off for a cup of tea...life is good

dave
David Gray. This year i am mainly In Twickenham, sometimes in Watford, often between the two but only between the hours of 07:00 -09:00 and 17:30-19:00

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morgan
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Re: Timing - 440

Post by morgan »

Right, timing fans.

Vac update.
The good news is that despite various US forums claiming you cant, it turns out you CAN swap the vac can on an MSD.
You need an 'Accel 31034 - for GM point dizzys' - its the same but adjustable (unlike the MSDs).

Got it fitted this morning, got it all screwed down at the mo but will start to introduce vacuum slowly later and see what happens.

Anyway, here is how you do it -

- Dizzy out.
- Remove 'body' top half of dizzy - then you can get to everything.
- Pop the circlip/split-thingy allowing plate to lift.
- Undo the 2 hex nuts.
- Ease the vac-rod out of the plastic housing.

Thats it. I lost about an hour trying to do it without popping the clip, so just go straight there ! :)
So, its on, I can adjust and when I suck on the tube I can make it move easily, with difficulty and lock it down - so the adjust works.
Unless I've missed something I cant see what MSDs problem is and why people dont think it can be changed ?
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Dave999
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Re: Timing - 440

Post by Dave999 »

MSD don't want to admit that their billet dizzy's are just copies of OEM stuff from other brands

i.e its all GM or Ford design, potentially built with a bit more care, the bit you stick in the block is configured for MOPAR.

Dave
David Gray. This year i am mainly In Twickenham, sometimes in Watford, often between the two but only between the hours of 07:00 -09:00 and 17:30-19:00

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MattH
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Re: Timing - 440

Post by MattH »

Colortune :thumbright: :thumbright: :thumbright:

Great little tool. used em for years
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morgan
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Re: Timing - 440

Post by morgan »

Not fired up the colourtune yet. Might have a go tomorrow...
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morgan
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Re: Timing - 440

Post by morgan »

Wow. A year ago. Well, you cant rush these things....

Decided to have a go at getting my idle to be less stinky and smooth out a bit.
Plenty of reading done as well as all the stuff from last year. But my overrun is back (dieseling on shutdown). I mean I can shut it down in D and the natural drag will stop it but its not good. SOmething inside is too hot (carbon? Could possible use a damn good thrashing) and the carb is clearly allowing fuel to go through after ignition is off.

SO - learned that apparently on bigger low-vac cams this can be a problem. Various Holley threads and a solution appears to be adjust secondaries to let some air through. You can then wind back the primaries to cover more of the transfer slot (wot Blue said). So armed with tools, vac guage and a colortune I set to work...

a) Took carb off. Secondaries were indeed at factory setting. Cracked open 3/4 turn, you can see daylight around the edge but crucially not much of the secondary transfer slot. So now she can suck more air.
b) Connected vacuum gauge to manifold. Started car and immediately its breathing better, idle higher. Allowed it to reach op temp. Vac gauge miserably low ~12(unit. Hg?). adjustment of the idle screw managed to increase to 18ish. This is good.
c) Insert colortune ! What a wonderful thing. Color of spark is blueish. Possible white side of blue, but blue. This is good. (see pic).

So now we are looking for roadtest.
Initial reports are that I have not had the overrun (but only tried half a dozen times). The theory of all this is that if the engine can draw air instead of fuel when I shut the thing down it wont diesel on...

Will report back...
:salute:
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Blue
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Re: Timing - 440

Post by Blue »

The factory solution to stop six pack cars running on was to fit a solenoid under the idle screw. When you turned off the ignition the solenoid would retract to totally close the throttle blades.
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morgan
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Re: Timing - 440

Post by morgan »

Huh ! Never seen that. One way of doing it instead of tuning it out - thump it shut !
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Blue
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Re: Timing - 440

Post by Blue »

Yes that's it. When I was setting up Jem's six pack it didn't have the solenoid and I modified the outboards to get a bit of idle air. Never had a problem with in running on it just the rest of it I never totally got on top of. These cars definitely do run better if they have a run up a fast road occasionally.
"Jesus died for somebody's sins but not mine"

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morgan
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Re: Timing - 440

Post by morgan »

Well, Been out. No hesitations or flat spot (good). No overrun at all even after a fast run (good). Still smells. (not good) - but given that I know the timing is good, the spark is blue, it runs good I think that might just be silly cams overlap smelly. :dontknow:
Either way, I am happier now and car seems it too. Just got the more-power-than-traction issue now hahaha
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Dave999
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Re: Timing - 440

Post by Dave999 »

excellent news, glad you found the joy of colour tune...simple thing in a crap bubble pack that almost ensures you loose all the little bits in the box the first time you tip it over rummaging for the BFH. but if you look after it and don't go driving at 5000 rpm with it in it will last forever

carb cleaner for the glass once every 10 years. allowed me to set up a 2bbl with 2 idle mix screws on a I 6 to get no.1 and no.6 nearly looking like no.3 and 4 one screw in a bit and 1 screw out

with a high static CR and loopy cam are you sure it needs 34 all in.... you have an efficient motor with high CR, meaning it will not necessarily need the help that a standard motor would to increase rpm under load, be interesting to see what it does with no advance in the dizzy. i.e set it to 15 initial on an ELB fixed advance dizzy and try it


i now run mine at 28 15 initial 28 total 28- 34 just adds noise.. no pinging it just doesn't sound right.

to achieve this i used a degree wheel the the centre bored so it went over the top of the rotor stub and sat on the body of the dizzy

i clamped the dizzy drive in a soft jaws vice

remember 2 degrees timing is equal to 1 degree in the dizzy

make a coat hanger pointer that reaches the edge of your degree disc

bend it so it fits down the centre of the dizzy rotor mount
bend it out through the little cut out to the edge of the degree disk
then with a set of mole grips and a copper shim to stop them biting the dissy rotor mount twist the top of the dizzy so it swings out the weights and record how far it goes on the degree disc
record where it stops.
make a adjustments to get it limited to what you want. in my case i pressed and soldered on bits of brass model makers tube

i aimed for 6 degrees but it worked out about 6.5 which is 13 degrees advance at the balancer. 15 initial + 13 via dissy = 28 total

you can experiment by removing the springs and replacing them with elongated washers that you have mangled with your mole grips/vice.
if weights can't swing=== no advance in the distributor. try vacuum advance then as well
David Gray. This year i am mainly In Twickenham, sometimes in Watford, often between the two but only between the hours of 07:00 -09:00 and 17:30-19:00

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morgan
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Re: Timing - 440

Post by morgan »

28 all in ? Now thats a new one - everything I have read points at 34 (few swear by 36 - but I guess it fuel related).
My dizzy can have the curve changed and the advance restricted. Currently I am on the 'stock' curve (as I dont know whether I should be aiming to advance faster or slower with my setup so stuck at stock) but the the narrowest advance range.

18 degrees is the narrowest the dizzy allows with the biggest bush. So with 34 all in thats 16 initial.

Going less than 34 all in would push my initial way back. I mean it'll start and run OK with 10.
Just for fun I might knock it back and see what it does for the smelly idle. If anything.

Generally I am pretty happy with it now - it runs nice and seems healthier on spark. Just the smell. (which could be cam overlap I understand - in which case 'live with it')
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Pete
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Re: Timing - 440

Post by Pete »

On the Dyno (with a Hemi - which has different - and better - flame propagation than a Wedge) we set the full advance at 32 degrees and detected a very slight knock and I backed the timing off to 30 degrees.

If you have a pretty basic engine with low compression, low overlap, etc and good fuel, and a convertor with sufficient stall levels - the basic ignition system will be fine.

What you are now discovering is that a "basic" Ignition system has limitations, and in reality you need a better system that you can "Map" to meet all your needs.

For the best result, you need a system where for any given rpm you can add in or take out ignition timing.

This costs money, so at this point you may have to decide what is "good enough".....
Pete Wiseman; Cambridge.

Mopar by the grace of God

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