Hi there. Advice please team./.....to change to an MSD setup (on a 350) recommendations on distributor, coil and ignition. (and what's the deal with some msd that can run with or without the ignition module???
looking for part numbers as well please.


Cheers, Mark]

 

Some info on your engine will help greatly on what to recommend for an ignition set up. Just a driver or are you seeing a bunch of track time?

 

Hi fair call....daily driver stock 350 injected 76 olds in a Caddy Seville TH400, standard torque converter. what Im trying to do is assemble parts to change out and get the old smogger going better without going to a blower (which is what a couple of mates are suggesting is a the best to go)........A4 manifold, q'jet, something like a w31 cam, #5 or #7 heads with 2/1.6 valve change (or #6 if I can get some), block huggers....

 

For what your doing a plain old GM/ aftermarket HEI would be simple and work fine.

 

cheers Eric, I did wonder if the hei that's on there already would be ok. would you stay with factory (GM) hei cap, rotor, coil etc or change?

 

Bet it would work, stock cap, coil and rotor are fine.

 

 

The cap is interchangeable but the distributor is not, the coil is also different because of the reverse rotation.

 

Why would the coil be different?

Stock HEI's are fine but you might want to swap in a performance module to give it a little boost.

 

Here is an article, scroll to the bottom:

http://www.chevelles.com/techref/ftecref5.html

From what I understand, having a mismatched coil and pickup leads to really hard starting and backfiring. Its based on polarity due to distributor rotation.

 

Interesting, we have a mystery

 

I bought one of those 50 dollar eBay special hei distributor for my cutlass. When I received it I took it apart just because and noticed it had both the Chevy coil (red/yellow) and the normal Chevy pick up coil and it runs just fine in my car. I figured it would run like **** have all the wrong parts in it but it works just fine.

 

Yep, I think it works fine if the parts are matched; it's when they are not matched that issues arise.

 

MSD distributor and coil and a 6AL ignition for the rev limiter feature, you will never have another issue with ignition other than plugs and wires. you should also run about .060 gap to get full advantage of the multiple spark and some good wires 8mm or better. toss all that other stuff in your ebay, swap meet or scrap pile

 

Mrhotrod, curious how having a .060 gap is the best way to utilize the multiple sparks. And exactly how does that work?

 

fair question, MSD as it's name implies is a Multiple spark CD type ignition, I believe at this time all CD types are multi spark now but regardless they have much more power available.so you can open the plug gaps up without causing damage to ignition parts. opening the gap takes more power to jump the gap thus creating heat in the ignition ect. but since this type of ignition is designed as it is it can easily handle the bigger gap so that gives you a much larger and hotter spark to ignite the fuel. btw works great on older worn engines that like to foul plugs .. at least until you can fix that problem. most newer cars run at least .050 to .80 gaps for the same reason.

 

I have actually mixed n matched coil and pick up without problems. While not ideal they ran Ok.

 

Actually I was being sarcastic, I know exactly how they work. And your facts are little skewed, sorry.
It's not an automatic that you'll get more power or efficiency with a wider gap. In fact in some cases less is more.
All multiple spark systems stop the multispark process at about 3000rpm, all of them.
And you can't compare multispark CD systems to the newer Inductive systems in LS's, Hemi's and such. Although both are measured in millijoules across the gap, they're two different ways of delivering spark. Plus combustion chamber swirl, plug location and such will effect the burn rates of the fuel inside, not just the spark gap.

Thanks.


P.S. Christian, you are correct. The different styles of coils are mainly due to the module used, not the rotation of the distributor. That's right from Mallory.

 

yes, I knew you were trying to be cute but in fact most of what you say is true to some degree. it would take way more typing than I am going to do to explain all the differences. but as far as using an MSD which is what we or I was talking about a Bigger gap is indeed better you can ask MSD about that. my comment about the newer cars was to point out they are using bigger gaps. why do you suppose that would be? all your mumbo about swirl and plug location has nothing to do with what I was saying. yes that does have an effect as does your foot on the pedal and everything in between pretty much. The multi spark decreases as RPM increases true and the multi spark mainly helps at lower RPM and at start up so why do you not like that ? CD and Inductive are in no way similar other than they use a bigger gap.

 

For some reason you're hell bent on this larger gap stuff. Do a dyno test and compare Hp and bsfc of different gap settings and get back to us. I've done it a few times with no appreciable difference on the Olds' I've done it on. Let us know what you find out.
Quit believing the everyday guys who answer the phone. Go check it out for yourself. Do some real world tests.
And there are lots of things that go into opening plug gaps, whether you choose to believe it or not.
Thank you.

 

no not so much really , I do think a larger gap will help with this particular engine along with the properly set-up MSD .060 may be a bit large he may end up at .040 to .050 working best but that is something you need to determine on any engine you build. I have and still use this same set-up and I run a .040 gap on my engines but they are not built for street driving there is a difference. I was basing what I said on the fact that this is a street engine so lower RPM operation will be the norm here.