ignition timing help

[The4ork]

im not sure where to set my ignition timing. i ran the motor over by hand to find TDC and install some msd timing tape, after install it was within 1 or 2 degrees of the marks on the balancer, so i was happy with that.

but... with the timing light i had my initial timing set at about 12 degrees, and my distributor gives a 24* advance, so that left me with 36* total, and i was afraid to go higher than that.

after much searching i cant figure out how to adjust my comp 9000 mallory unilite distributor. i friggin hate this thing, i cant believe mallory wants $350 or more for these pieces of crap, it came with the car and i would have never bought this worthless thing.

anywho, maybe i just cant figure it out or maybe i just cant find the right instructions (mallory's website blows arse) but i managed to find a timing advance stop tab and bent it in a little bit to stop the advance at less degrees.

the reason being is my engine seems to like to run at idle at around 30 degrees, even more. im guessing this is normal.


with the new stop tab bent i adjusted the timing so that the total timing again was about 36 (this seems like a safe number to me from exp with vw's ) wich left my initial timing at about 28* the engine seems happier like this. but im worried if i have too much timing at low rpms and specifically under light/moderate accelleration at low rpm. and since i have a manual trans i can run lower rpms at my choosing to cruise/save on gas.

just not sure i want to run around like this unless i get some good advice.

right now the engine is as follows

340TA
10.5-11:1 CR
lunati voodoo cam - 262/268 - 220/226 - .475/.494 - 112/108
rpm air gap
road demon 625

as of right now im getting a lean spike on the carb (wideband indication) when i get under light accelleration, im going to call demon tomorrow and see what their remedy is for this because i definately dont want to be lean and have too much timing

any thoughts on how my timing curve should look or proceedures to help me get it right?

[The4ork]

Also I'm running 6a stle box and auto light copper plugs gapped to .060 per reccomendation of a local mopar guy. They seem better than the .35 gap I had them at

[Chryco Psycho]

you are on the right track , you need to limit the advance curve so you can add more timing at idle without over advancing with RPM , more advance at idle will help to a point but the key is to get 36-38* higher up where the engine spends most of the time working . the lean spike is not enough squirter . I think Demon is out of business finally  the quality of their products sunk them .
 I would set the plugs closer to .045 personally .

[The4ork]

no demon is still around and producing new products for 2012. check out their website, their new road demon jr carbs are whatever are interesting looking. not my thing but good to see the BG is still providing competition in the carb business. competition is a GOOD thing.

anywho, ive been in some contact with them. their tech line is pretty helpful, i just wish i got the same tech everytime to cut down the time i have to explain everything.

so it looks like my curve is between 28 initial and 36 total. should i try to up it a few more degrees? 30/38?


i upped the squirter size from a 31 to a 37, think i should still go higher? because at these SLIGHT throttle changes i dont think im 'getting into the squirter circuit' i only think we get into the squirter circuit, or the accel pump circuit when we deliberately mash the pedal down more than a slight amount.

im talking its when i make small corrections in 5 or 10mph increments and doing so by accelerating up to that speed slowly to not waste fuel.

[The4ork]

just got off the phone with the BG tech. he basically said not to tune off the wideband 02, and that it sounds like my engine doesnt like to run stoich (14.7:1 AFR) wich i would agree, anything more than 12 and it starts running like crap. i hope this isnt a mechanical engine problem but assuming its not ill press

his advice was to go with a larger main jet, im running 62/62 in the front and 68/68 in the back, .37 squirters, screws are 3/4 turn out from bottomed out (gives me highest vac and idle speed, and 14-15:1 AFR)

also my throttle plates have 1/8" drill holes in each of the 4 butterflies, dead middle on the idle circuit side.

grrr!


oh yeah one more note, when the engine is HOT and about 190 degrees - it runs very very very smooth compared to around 170 and below. not sure as to why this is? but my lean spike is almost gone, and it just seem smooth all the time. interesting temp taken off intake manifold.

[The4ork]

here is a picture of my distributor guts. as  you can see there doesnt appear to be a whole lot of adjustments here. just the two springs. which just moves the curve around, and doesnt help with total timing adjustments.

so you can see the tab on the floor removed from the distributor, and gets inserted in the large open are of the distributor to the left side next to the spring perch. and is screwed in at the screw hole. this is the stop tab that i bent to allow less movement of the whole mechanism. basically cut movement by a little more than half, wich took the 24 degrees of adjustment to about 8 degrees of adjustment.  does that make sense?

[The4ork]

contacted lunati whom gave me the cam choice i went with, and they said its because of the compression and cam combo that it wants so much timing. he said the intake valves will open and close so fast with that cam making the motor think its got even higher compression than what it really has, and high compression likes high timing and he said hes had a number of people call with high timing concerns and everyone says the motor runs drives and starts just fine like that and he tells them to keep giving the motor what the motor wants
just keep a more vigilant eye than normal on the detonation

[MEK-Dangerfield]

As for the squirter, size 31 was the stock one for your carb size. You might have needed a 33, or 35, but going 37 or more is just too big of a shot. On my Proform, you can see the squirter begin to shoot gas down the primaries pretty much as soon as you start to pull back on the throttle when you are under the hood. Maybe you can find another person to push down on the gas pedal with the engine off, and you can look down the carb throat with a flashlight to see whats happening.

[Chryco Psycho]

even the slightest movement of the throttle should produce a squirt , I have had to weld the the slots to limit the advance so your dist is easier to modifiy by just bending the tab , if it works well at 8* curve leave it there . the BG / Demon may be very different from the proform in the way is pulls in fuel so if using a larger squirter works stay with it .
 Most people using a wideband O2 tune in the mid to high 12 range , it will be too lean in the 14 range , EFI can be tuned more accurately .

[The4ork]

yeah i tried a few different cams, i think im using the blue cam right now, with the adjuster on the cam arm taught and it squirts pretty much instantly.

its a little rich when mashing the gas, as to say 'rev up' at a stop light, but its doable.

i also went out about 1/3 turn on my idle mixture screws, all 4 - this seems to fatten my cruise circuit up as well. now im cruising around 12.9-13.5 range - or low 13's

it still seems to peg to about 14-15 sometimes when making throttle adjustments in cruise.

also thats a good point, these engines really dont like to be 1 lambda, they like to be about .8 or 12-13 range, and im mid 10's at WOT. normally on a fuel injected engine your 14-15 all the time sometimes higher at cruise, and about 12.5:1 at WOT (12:1 with boost)
and since these carbd engines like to be about 2 points lower then im guessing a 10:1 wot is perfect, but i'll expirament in raising it up to 12:1 and see if it likes it. ill prably need to do this when i get it on a dyno this summer.

so far. im gving it a B- in terms of drivability right now. it smells kinda rich (one exh runner leaks at the gasket, maybe replacing it will help some) so my wife doesnt like to ride in it if it makes her stink, and its got a small hesitation sometimes when its not fully warmed up. and i cant get my idle low enough it seems to hang around 1200rpm with the butterflies all the way closed, so i think i have my holes in the butterflies a little bit too big. doh.

[Chryco Psycho]

you can close the holes by squishing some solder into them & reaming them out smaller ,
the advance spring may be too light , I ran into a situation where an engine would idle at 1200 or 500 but not in between , over 500 rpm the advance would kick in & raise the rpm

[The4ork]

wonder if i can find some heavier springs? im about ready to just lock it out at around 36 and call it a day LOL if not for the high idle i probably would.

i have a street avenger 670, im going to see if i can use the base plate from that on my demon. if all the holes and such line up i dont see why not? then i can expirament to see if i can get it to idle with the transfer slots squared and the timing set much higher than i was trying originally.

maybe ill just try the 670?