or any ignition box really.

i have a 360ci sbc with:
-113 casting aluminum heads with bowl blending
-crane F-278-2 solid lifter cam, .480"/.500" 238*/248* @.050
-a 750 double pumper with the choke horn cut off and some other small deburrings, jetted with the stock jetting and 3.5" powervalve.
-10.2:1 c/r
-hedman longtubes with duals

my ignition system is fairly simple. i'm running NGK plugs, an 8mm accel wire, stock hei coil-in-cap dizzy w/ accel super coil. timing is set at 10* initial, 36ish* total (i still have a stock 305 dampner and timing marker, i know, i need to get a better one) my problem is interesting. if the motor sits at idle for too long, i'll have issues with the plugs fowling. or atleast that's what i think is happening. it seems to pop and bang through the exhaust under load until it "clears it's throat" per-say, then it's fine.

would an msd box, or something along those lines, be beneficial to me at this point? reason i ask is cause it seems that people always say they aren't worth anything, but most every race car i know of has one on it...there isn't any reason my car should run very low 12's or high 11's.

 

Most race cars have them because they run at high RPM or with high cylinder pressures that stock ignitions can't handle, or they want to take advantage of rev-limiters or retarders or other features that the boxes have.

 

ok, yeah, i'd be getting a 6AL with a 6800rpm chip to make sure that i don't over rev, seeing as my shift point is 6500rpms.

 

Some boxes also provide a longer spark duration and/or multiple sparks.

 

They'd like you to think that. An inductive discharge system like the stock ignition has a long spark duration, but also has a long charge time. This makes them great for lighting the cylinder at idle and low speeds, but they don't have time to fully charge at high speeds. Capacitive discharge systems like MSD, etc. have very short charge times, but very short spark durations. They need multiple sparks at idle and low speed to equal the performance of an inductive system. At medium speeds they go back to one spark per revolution anyway.

 

While MSD boxes re nice they will not cure a carb problem or a basic ignitioin problem.
I've never been big on Accel coils. I use a stock GM HEI with a MSD in cap coil. No problem to 6000rpm +++

First

You need to modify your distributor to allow more initial timing at idle. 10deg at idle is not enough for the cam u have.

see this thread on the subject

How much manifold vacuum do you ave at idle?

Why are you using a 305 damper on a 350?

 

i'm using a 305 dampner on my 350 cause it's all i have at the moment, though i'll be picking up an ATI unit in the not-so-distant future.

unfortunately, i have no idea what the manifold vacuum at idle is, i have no gauge...guess i should pick one of those up too.

how will i go about modifying the dizzy? and i suppose without a dampner with more marks on it, i'm not going to know where the timing is, huh....time to drop another $300 or so

will having that much timing be OK with 93 octane, 10.2:1 c/r and aluminum heads?

 

I usually just wind it up until it starts losing power and then grab another gear! lol

 

can you explain to me the relevance of your post so that i can understand what your saying? or are you just posting to post? when you get into the power level that i've broken into, "just winding it up till it looses power and grabbing more gears" just doesn't quite cut it. i'm at the point that i wonder if the msd box would help streetability and possible high rpm power.

 

I have found that putting the MSD "smartbox" on my ignition gave me a smoother idle, easier starts, and *slightly* better gas mileage. (I know, the last reason to install one....) It also improved throttle response in the lower rpm range, allowed my engine to rev a little better (got to higher rpm faster, and ran better at that rpm) but, also made my tach act funny..... I liked it, except for the tach, and that is curable with a filter. (for 35 bucks....)

 

LMAO!!!

 

Get a DUI street/strip distributor....no add on box needed unless you're running some form of FI and need timing retard capabilities.

P.S- these distributors are hand built and custom curved per order for your setup..that way you're not just getting something out of a batch of 500 made in an hour or so lol!

 

where can i get this said dizzy?

 

We've installed multiple MSD boxes over the years on both street cars and race cars. The testing with the street cars after installation netted zero gains as far as performance on the cars that had properly working ignition to begin with.

Main reason you see them on race cars is to open the box for future additions, like 2/3 step for consistant starting line rpm amd R/T's. timing retard boxes to utilize nitrous and or maybe squeeze an extra .01-.02 out on the top end, over revving protection is a BIG reason since it wont let rpms go nuts in the event of driveline failure or missed gear.

Performance wise you can get the same from a properly built HEI unit so you will gain little, but it still costs. I had an HEI worked over and spun balanced to 9K at a cost or $225, so if your just looking for a implistic ignition with no future plans of any add ons a properly built/set-up HEI will provide the same performance at idle/high rpms as a analog/digit box. It all depends on what you want and plan to eventually do with the car. Easier to invest in the goodies now little by little and have the car ready for any future upgrades as opposed to changing everything all at once.

Josh

 

come on IHI, you know me! i got the go-fast bug early last year when my 305 went 13.5's. i wanted a daily driven n/a 305 in the 12's and i got to 13.03 w/o power adders....think i'm gonna stop at 11's with my 350? i don't think so! and this motor is only a go-between till i can get enough cash up for my bbc.

 

LOL, well there was really no need to ask the question then You know exactly where your going and are smart enough to know how to do it properly....I'm thinking a 6AL or Digit 6 is already on order then??

Heck if you've hit pay dirt opt for the newer generation of the digit 7 boxes and then once you start getting nuts in the tq/hp department you can dial in a timing curve to work with the traction control feature allowing the use of radial slicks

I know I just like the simplicity and expandablity of the MSD system no matter if I was racing or not, any future car builds will have them tame or wild...cuz it's cool. Sure beats having to put a sticker across my hood and angle onto my fender LOL!

 

ok then...i'll start looking at the digital series!

ugh...doing this on a $7.20/hr budget is starting to make my head spin

 

This is'nt even the start of it LOL!! What's worse is looking back over 4 yrs of building a car through all the trial and error, costs of racing all the time, etc...and realizing you could have bought the house you live in for cash money and had money left over!!! Wonder now that I'm dont racing for a while if I should refinance my home on a 4yr note LOL!! And my car/racing is miniscule compared to the programs others run with new haulers, stacker trailers, etc...only thing I can brag is it's all been cash money with no credit cards/loans involved, but it takes time no doubt.

 

oh, trust me, i know how easy it is to blow big bucks on rigs and everything else too! pops has a 2004 Coachman Sportcoach and used to tow a 32ft enclosed racecar trailer, but he got rid of that trailer and now is in the market for a stacker tag! if he does get a stacker, i'm going on the road with him!

 

Yes you're only increasing the initial advance at idle. total advance is the same 34-36deg.
You have to limit the travel of the mechnical mechanism.
There is a pin that travels in a slot under the weights. weld up the end of the slot to limit the pins travel.
You can buy a balancer timing tape for under $10 (Mr Gasket) This not a problem that requires a lot of $$$ to fix. If you want to waste $$$$ on shiny red boxes go ahead. but you'll still need to recurve your distributors timing curve to match the new long duration cam.
When you're done the motor will run better and cooler because the spark is occuring at the right time to burn the fuel at idle. The exhaust gas recirculation at idle caused by the cams increased overlap slows the fuel burn rate requireing more initial timing at idle.
You want to dial in as much initial as the starter motor will withstand . The more the marrier. then limit the centrifical travel in the distributor to allow 34-36 deg total at 3000+rpm with the new increased initial timing.
I run mine "locked out" 36 at idle 36 at high rpm.
My car will idle in gear forever without loading up. Throttle response is always crisp. The idle is not over rich because the fuel is being burned before the exhaust valve opens.
the motor runs cool because the fuel is pushing down on the piston, not heating up the cylinder walls from retarded ignition timing.
If you want to temperairly test your motor with the timing locked out just remove the weights and springs and tie wrap the mechanical mechanism fully advanced. Reset the timing at 34-36deg at idle.. reset your carb. (throttle blade alignment) Go for a ride and clean it out and it will idle correctly. Then remove the distributor and modify it as described.
Set it up like this and put the slicks on and you'll probabily pull the front wheels on launch. Try it.

Ultimatly running the distributor timing "locked out" is a little tough on the starter motor but you should be ok with 24-28deg inital timing. 34-36 total and about 15deg vacuum advance at highway cruise. Spend the $$$ ya just saved on not getting a 6AL on a vacuum guage, a timing tape, and a MSD HEI coil and MSD HEI module. now you have a 8000rpm distributor. Don't forget the MSD steel center pin for the distributor cap goes under the coil.
Sell the pretty yellow Accel HEI coil to someone you don't like.
A stock GM center pin (carbon) wil overheat using a high output coil. Send me the $$$ ya got left over..... just kidding. Do you have access to a mig welder?

Install a ground wire from the valve cover bolt to the firewall.
For some reason Third gen cars with HEI's missfire when reved without this ground wire. (engine to firewall)
Check the little wires that connect the magnetic pick up coil to the HEI module in the Distributor. Some times they are intermident ( broken). Some times they are hooked up backwards (poor throttle response) They are delicate and easily damaged.

 

...mark your balancer for 36deg BTDC

 

Correct spark plug gap and electrode length

 

check distributor rotor phasing alignment.
Ya can't buy this stuff in a box.

 

I have my timing locked down at 36 degrees, made my car idle much better and made the engine produce more vacuum at idle. With your cam I would recommend running atleast 16-18 degrees initial timing or lock it down at full advance. Locking down the timing is worth trying to see how your engine reacts to it. I also have a digital 6 plus box, it has a built in start retard function. My starter would start the engine without the start retard but would groan a little if the engine was hot....I never felt real comfortable with it. After installing the digital 6 and turning on the start retard it works great and I'm sure my starter will live a much longer happier life now.

 

so, at this point, the only good the shiney red box will do me is the rev-limiter(shift point is 6500, could be a good thing) and starter retard, which if i go with a full locked out timing, it will benefit me...hmm...guys i still drive this thing on the street everday, it's the only car i got. is locking the timing out at 36* gonna be a good idea for the street? how is it going to act?

also, here's something else to throw into the mix. i haven't touched the timing, but i put my 600 vacuum secondary back on it. it has a 6.5" powervalve up front and the front jets are 62's, can't remember whats out back, been a while since i cracked her open. anyhow, i put this on and the loading up issues at idle went away completely.

 

Ya still need to modify the distributor. I run mine areound onthe street and drive it to the track with the timing locked out. its fine. The motor needs this much timing at idle.
But I'm recomending you run a advance curve instead of locking it out. I recomend you test and see just how much initial timing your motors starter motor will withstand. more is better. Around 24deg should be good.
When you do this even your 600 will idle better.
Your 750 must be leaking fuel. Metering block gasket, Power valve. You'd be suprised at how easily vacuum pulls fuel past the metering block gasket even thou it appears good condition. But once you've modded the distributor for more timing this will allow proper throttle blade alignment relaitive to the idle fuel transfer slots.

 

Once you've done this the vacuum advance amount may be too much. Most are about 20deg at high vacuum.
You'dd want to limit it to 13-15deg at most. you can limit the travel of the vacuum advance rod or buy a Crane adjustable one and use the little limiting lock plate that comes with it.
Your 600 will work fine. I'd try some 65 pri jets and rob the sec metering plate out of an old 750 (#21). then install a light sec diafram spring (yellow) Have you had it out for a test ride yet? How is the power and idle with that Crane cam?
Have you reset the valve lash since break in?

 

You know... MSD makes a nice distributor for street/strip cars... its a Pro Billet dissy, but with a vacuum advance can. It does require a box though.

Why not use that? Thats what I'm going to be using.

 

They also make a billet one that does not require a box.
"Ready to Run"... Uses the same internal MSD HEI module but a Blaster II external coil.
Both distributors also have a nice fully adjustable mechanical advance curve.

 

My main reason for using an MSD box was that it makes it extremely simple to setup a reliable ignition system and a strong spark. I ripped out all of my stock wiring and ECM so mounting a 6AL box and plugging in a distributor is the best way.

MSD 6AL
MSD 8551 dist.
MSD Blaster SS coil.

It doesn't get any easier.

 

I have the crane HI-6s box and I am very happy with it.
It already comes with a set in dials for RPM limiter, and you can get a retard switch as well. It helped with idle, starting, much better response, and I don't have to worry about over revving the motor.
Now, I do run fuel injection, so some of the features might be easier to install, than for, lets say a carburator.

I plan on NOS ing my engine, so thats the primary reason I bought it.


Funny thing is that most of the times these boxes will interfere with you tach signal. So, don't get too upset at the company if that happens.

 

F-BIRD, yes, i have had the car out, actually i have just over 550miles on it with the new crane solid lifter cam. i'm SO happy i went with that thing! it's faster than anything i've ever driven!

yes, valve-lash has been reset since break-in. seems like everything is running very smoothly.

i must admit, if i can get away with the 750 not loading up the plugs and stuff, it's fast as crap! so, i know the motor wants that much carb, but i think that it's time to retire the old 750 and put out some bigger bucks for a new carb. anyone use one of pro-forms carbs? quickfuel is using pro-forms center section to build off of, so i was thinking that maybe they are working together. seems like a pretty decent deal. 500bux for a drag race carb.

tomorrow after church, the dizzy is coming back out and i will be modifying it accordingly. i found where 18* would be on my stock balancer (simple math is so great!) and set it there at idle. the thing runs like a scalded dog off idle and really surpised me, even with the little 600cfm vacuum secondary carb sitting on top. however, i could hear the valves clattering a bit on the interestate if i gave it just a little gas to pass someone or something, so i backed it back down to about 12* initial timing to avoid detonation until i can get the dizzy modded.

IDEALLY, i'd buy one of the kits from msd that includes plug wires, billet dizzy, msd 6al box and a blaster 2 coil, but they want $550 for it. guys, i ain't got that kinda money layin' around for car parts. infact, i ain't got that much money layin' around period! i still need to get a set of street tires for this thing! i'm runnin' around on my frickin' ET Street Radials right now!

 

Glad to hear you're happy with that Crane cam so far. I thought it would be a good choice for you to go solid. Thats a sweet street cam. Also very N2O friendly
I just scooped a Proform center section my self and have a 700DP to use for parts. You may want to look into Proforms Billet metering blocks as they are fully tweekable with screwin air bleeds, emulsion jets and idle feed restriction.
Could really dial in that 750 so its not so fat at idle.

 

I did find that the addition of the msd 6AL on mine cleaned the idle up and fixed the plug loading issue quite a bit. As said earlier it also allows for add ons. I run a two step to allow for launch rpm and redline rpm. I have read a number of posts re: people having problems with their digital boxes. A search might turn up something. No complaints with my 6AL but I did have one crap on me when the car sat over the winter. Car never even tried to fire in the spring. New box, fired right up.

 

yeah, that's what i'm sayin'! they make a whole carb with billet throttle blade plate and metering blocks and all now! for just $500!

 

Summit had a pretty good sale on MSD stuff not long ago. Maybe check to see if its still on?

 

hey matt give me a call tomarrow and i think i can hook you up on the balancer and can set you timing. i have a timeing light that we can ck your total timing, and let me look at it alittle and see what i can come up with. u might need a subjective opinion on it. and i have a vacumm gauge we can see the vac. is at. shoot you just need to stop buy and we can work it ove if you have time tomarrow. i miss messing with the carb stuff. give me a call bro i will do what i can

 

got a full day tomorrow and tuesday, you available wednesday? i never got to the dizzy today. i slept for like 4 hours this afternoon.

 

well wedsday it would have to be after 3pm you know the sleep thing. lol but yeah weds is cool

 

What are we looking for in the cut out dist. cap sketch where the rotor is marked to check alignment? What position to mark ?

 

I had the same problem a few years back with my Carbed engine, like the plugs just kept fouling out, orignally i had Boush pulgs, they fouled in a couple of days, then i went to Accel racing plugs they fouled out in a couple of hours, then i went to advance auto and picked up some Autolite plugs($1.28 a piece) and never had a bit of trouble since. i would take the NGKs and toss them in the trash and put in autolites

 

i hate to say it matt but the issues that you are having is the same reason why i went to a fuel injection engine. the carb and timing thing gets to be pain. I know how you feel bro, i was in your shoes with the vega i had, it was a low 12 second car if i could have gotten the issues with it right, well atleast it could have been. i just got so darn frustrated with the whole carb and timing issuse, and like u have seen it gets real expensive once you get into the 12's. well i am here to help out as much as i can, let me know what i can do to help you out. and i will look for the 8 inch balancer

 

Lock the advance out on the distrobutor

 

it's a street car, i'm not going to do this. thanks for the input though.

i got the timing squared around now. it's got 18* initial and 36* total and pulls very well now with NO vacuum advance. took that off and hooked it up to my HVAC system, makes the vents operable again.

i was lookin' at the bottom of my 750 and the primary throttle blades were too far open, exposing too much of the slot that meters fuel in part throttle cruising type of driving so the carb thought i was at part throttle all the time at idle allowing more fuel to go in during idle than should have been. i've got the throttle blades back closed to the proper setting and new gaskets throughout. i will be putting the carb back on the car tomorrow morning before i go racing. (that is, if the rain quits)

i had trouble with autolites blowing out at idle before, so i don't think it's the plugs.

i put a brand new replacement balancer on the car yesterday and went ahead and figured the math out for where the timing marks would be at for 18* and 36*, then marked them.

 

cool glad to hear it bud

 

you sure you don't want to come racin' today man?

 

i would but have drill. have to work tonight. darn it let me know how she does