ignition systems

alright guys, so my motor has been pissing me off ever since i had it smogged. the people reduced the size of my fuel jet because my motor was blowing raw fuel..according to the smog dyno. it was originally jetted for kentucky.. with humidity making the air so dense a big fuel jet was used. since the jet was reduced my truck feels like its starving for fuel. i came up on a crane ignition and proformance coil. aside from that i dont really know where to go with it. any info on these ignition systems. can i run it with a stock distributor? my vacuume advance has been plugged off because of the cam. will a proformance distributor do anything more than what the stock one does? the crane box what exactly does it do? just limit the rpm? i would like to put the bigger fuel jet back in and upgrade the ignition so it will burn all the fuel the motor is fed but i dont know if what i have is all i need... any light on this topic would be greatly appreciated.

p.s. i can get pictures if what i got incase your wondering. the box is a hi-6 cran box and a fireball coil.

oh and lc told me that the distributor needs to have the vacuume advance but the guy that did the timing and stuff said that because of the cam, the dist. doesnt start to advance until the motor is already at redline... by the time the advancing starts, the motor just physically cant go any further. so he capped them off. which is the 'right way'?

well glad to see im not the only one having motor problems.. lol
i think my ignition took a shit

I have that ignition on my 88 , w/ a pro street 22re from LC, it is a multi spark ignition, so has rpms increase it will fire more than once per stroke. I have the stock distributor, & works great. I do not have a vacuum advance , but you should keep that functional.
Call LC for advice!! What ever they tell you is what to do!!

I have that ignition on my 88 , w/ a pro street 22re from LC, it is a multi spark ignition, so has rpms increase it will fire more than once per stroke. I have the stock distributor, & works great. I do not have a vacuum advance , but you should keep that functional. The cam as nothing to do with ignition timing,only valve duration!
Call LC for advice!! What ever they tell you is what to do!!

haha, yeah my truck runs like butt right now. thanks california smog regulations.

thanks for the info! i spoke with lc about what i should do about the vacuum advance and he recomended to just pull out the plugs and run it to see what it does. put it back in then run it again and make the decision based off of its performance.

it was explained to me, as the motor climbs in rpm, the vacuume advance builds pressure and the vacuum advances the timing. because of the cam shaft being bigger than stock the duration of the intake and exhaust stroke is slightly longer... reducing the rpm rate. (which there was a noticable difference. i can get like 70 out of 3rd gear where as before i only got like 60) because of that it, the motor starts to build its vacuum at a higher rpm then it did before. so by the time the vacuum is high enough to advance the motor, the rpms are already at redline. this is a learing experience for me as ive never messed with performance ignitions, timing curves, and stuff before. im relying on other peoples knowledge of this. the guy that told me this is a big block guy so i dont know if those motors work differently then these as far as the advancing and stuff goes.

as for the ignition system i would like to get it wired up this weekend. lc was telling me about this coil they have that smog legal...it utilizes the stock ignitor as he called it...not quite sure what that is but their proformace coil mounts on top of the stock ignitor. lc said its just the thing below the coil that sends the signal to fire. the coil i have is just one unit, it replaces the stock on...so im assuming the one i have isnt smog legal. which is fine if all i gotta do is just swap it out for smog.

sorry for the book, but if someone could explain how the vacuum advance works it would be greatly apreiciated... after this is all said and done, i think im gonna make the trip to havasu city and have lc tune my motor accordingly.

[quote="holcombe347"][quote="truck action"]

sorry for the book, but if someone could explain how the vacuum advance works it would be greatly apreiciated...


It can get pretty confusing on all the stuff regarding ignition timing, advance rates ect. you could fill books with all the info.
Basically you have 2 advance units in your distributor, mechanical advance and vacuum advance, they work together and work work independently.
Later units don't have the mechanical advance, its computer controlled but we won't go there.
Mechanical advance is the pair of weights and springs inside the distributor, as the dist, spins the weights are thrown outward by centrifical force, and controlled as to the amount and speed they can move by the spring pressure thats holding them.

In therory when the engine is running the timing would be perfect at "0" degrees or TDC, as the piston is moving up the cylinder compressing the air fuel mix, just at the point the piston hits TDC or "0" degrees and starts to move back down thats when the fuel mix should explode to drive the piston back down, but take into account the speed things are moving and the time it takes to fire the plug, ignite the fuel mix, have it explode and expand thats why the initial timing is set a few degrees before TDC so hopefully they can all happen at the right time.

The faster the engine spins the more advanced the timing has to be so it can fire the fuel mix at the correct time just when the piston is breaking over and starting back down, too early (advanced) and detonation, the explosion is trying to stop the piston, too late (retarded)and the piston is already traveling down and the blast doesn't have as much force. Thats where the mechanical and vac advance is doing its job, the faster the engine spins the more the weights move the more the timing is advanced.

The vacuum advance varies a bit during light throttle as the manifold vacuum goes up and down, but under full throttle the manifold vacuum is nothing so the vacuum advance on the dist does nothing.
Now at hiway speed cruising along at 60mph, the engine is say turning 2500 rpm, the mechanical advance inside the distributor is not fully advanced because of the springs holding back the weights, so the vac advance steps in because you have a good strong manifold vacuum so it advances the timing to give better power and fuel economy.

Bottom line, if you have a vac advance use it, old rule of thumb, advance until it pings then back it down a few degrees for best performance, but take into acount that rule is for best performance and hard to deal with for a daily driver that see's varied driving conditions, grades of fuel, ect.

Sorry its not a great explanation but I tried.

thanks nook! i had the basic knowledge of it but never really understood what the vacuume advance did. my buddy that did the timing and stuff in the toyota (which recommended to get an ignition) mentioned something about pulling the distributor out and tweeking with the springs and weights to get the truck to begin advancing at a lower rpm versus when it begins to advance at a higher rpm. last time we messed with it, he had this gun that measured in degrees, the advance at what rpm so he was able to give me all the numbers but i have since forgot them. basically what it came down to was when the motor began to advance, the rpms were getting close to redline. so with my cam shaft being bigger than stock, does it effect the timing advance? or is it just in my head. and by playing with the springs and weights can it be used to compansate for initial and advanced timing?

With the cam change you would want to run the initial timing up a few degrees, probably somewhere around 10, if you encounter some pinging or kick back when trying to start the engine back it down some.
The stock distributor is a little lazy, meaning the mechanical advance doesn't hit full advance until the rpm's are probably in the upper 3000 rpm area. Using a lighter spring to allow the weights to advance quicker will help some with power, each engine will react differently so its not a gaurantee of great gains, NWOR used to sell an advance spring for the Toyota distributors, doen't know if they still do or not.
Your bigger camshaft doesn't physically effect the timing advance, the timing advance is regulated by engine rpm and to some amount by the vacuum advance.
The weights and springs inside the distributor can't compensate for the initial timing or advanced timing, they only control when the timing advance
starts , how much it advances, and when it reaches its limit and stops advancing.
I added a link to some info you might useful,


Good luck and happy tunin!!