z282slo

I'm switching my 91Z to carb, if I leave the computer hooked up is there any reason I can't use my original small cap distributor? Thanks in advance.

five7kid

iTrader: (14)

The computer will not have enough input to properly control timing. It has been theorized that by using an aftermarket external throttle position sensor, and all other sensor inputs operating, it would work, but I haven't heard of it being successfully demonstrated to date.

Easier to get a vacuum/mechanical advance distributor.

ckeene502

what he said...to me carbs are easier and more fun. i bought an old hei for $10 and put msd parts in it(coil and electronic module) and it really woke up the engine.

z282slo

Thanks guys, now I don't have to feel bad about buying a new dizzy!

yallwatchthis

you may also use your current dist with MSD 6 or 7 series ICM and coil for excellent ignition

five7kid

iTrader: (14)

How would it be advanced with just an MSD attached to it?

91CamaroRS305

iTrader: (2)

Same here, I run a MSD 6A box now, with the spring/weights adv. in the carb setup for my cam, and use an MSD Blaster 2 coil, the modified dust cover on the accel cap and rotor, and have NO problems with the ignition what-so-ever. Plus with the MSD you wont have to worry about the ignition module or capacitor in the dizzy because the MSD box takes car of it all.....easiest way to go IMHO

yallwatchthis

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reference five7kid, your advance would be locked out if you use your current distributor causing a hard to start or wind over strain on your starter, but if you don't run a high torque mini starter you can run a mechanical advance or vacuum advance distributor, either of the two will get the job done. IMHO the mech. advance is the way to go because you can taylor your advance curve to your camshaft's power band, i.e., full advance by 2800 rpm...cam works from 2500-6500, so on and so forth. let me know if you need any more help with this topic

five7kid

iTrader: (14)

I don't need any help with this topic. I need help understanding how you think the system you are proporting would have a snowball's chance of working on the street. If you're talking about a race-only set-up, fine, the computer distributor has enough advance built in to be able to start and provide sufficient WOT total advance to do the job. But, for the street, it would be woefully inadequate for any sort of decent fuel economy, to say nothing of the effect on plug life from constant rich running, etc.

yallwatchthis

I am terribly sorry for the suggestion, the OEM ignition stuff will way out perform MSD's any where. The constant rich issue is a tunable one. nothing further

yallwatchthis

and again I appologize because i am suggesting something to work with a carb as opposed to trying to run all of the comp. electronics.

Apeiron

You're suggesting something that won't work on the street. The MSD won't provide any advance at all.

yallwatchthis

No, if you you will read what I said...you can run mechanical or vacuum advance distributor....mechanical is better b/c..... I am not trying to mislead any one here, and if it seems as though I am then I appologize. I want everyones hotrod to be as pleasing and fun as mine have been for me. The lack of advance in the computer dist is, in fact a problem for the street, thus I suggest MSD with an advance distributor of any sort. Tuneability is in the carb and so is fuel economy. I hope to not have offended or confuse anyone and good luck with your projects.

Apeiron

When you say "you may also use your current dist", it sounds a lot like you're recommending he keep the CCC distributor.

five7kid

iTrader: (14)

For the street, you need mechanical and vacuum advance if you have any concerns about fuel economy. Running mechanical only will require excessive throttle opening at cruise conditions, opening the enrichment (power) circuit, causing poor fuel economy and very likely fouled plugs. This isn't something you can tune out.

I have never seen nor heard of a vacuum advance only distributor. Mechanical only, yes. But not vacuum only. Of course, I haven't seen everything.

MSD 6 or 7 are ignition energy/multiple spark enhancement systems. While they may provide a hotter spark, they don't do anything to advance the ignition timing (although they can provide retard). If all you meant was to add it to the new distributor (assumed to be mechanical/vacuum advance), then as in Apeiron's response, "Never mind." But, if you in fact meant to keep the original CCC distributor, then what we said. On the other hand, this talk about mechanical-only advance should only apply to the track, not to the street (I suffered with 10 mpg back in the 70's with a mechanical-only advance distributor - put together by a successful race engine builder, but not a good idea for a daily driver, which this was).

yallwatchthis

well, clearly I was misunderstood, no hard feelings here, and of course I must clear up that I don't think or even suspect that the ICM will control advance/retard duties. We have retard modules available and advance distributors available to suit near every specific need. Again I am sorry, I should have been more clear in the original post....my mind is drag race oriented more so than that of a street rodder, so at times you will have to remind me that some people drive their third gens on the street.lets go do a burn out!!!LOL yall have fun and good luck