Ignition/Distributor upgrade? Little help...
 

So this year my 406sbc is going to have 480-500 hp this year and Im thinking that I have too upgrade from my Thunderbolt 4. Can you guys recommend what to buy? or point me in the right direction... Im not looking for the best of the best... money is a little tight after upgrading heads pistons etc... I didnt think about this at the time of buying everything else.

Unless you are having problems fouling plugs easily at idle, then the TB 4 should still work fine. You will probably want to use a V6 or V8-HP module though for a faster timing curve.

I use the Davis Unified Ignition distributor/coil they tune it for your motor/ boat. I have not had a lick of trouble out of them...

When we had my motors on the dyno we started with the Thunderbolt ignition and did a couple of pulls and got 661 HP. Then we installed MSD Pro Billet Distributors with their Marine Ignition Boxes and run a few more pulls. We got 698 HP. Thats 37 HP with the only change being the Ignition. We did the same thing with both motors so it's not a fluke. I was totaly impressed.

if you had gotten the timing correct with the TB4 you would have made the same power. there is nothing magic in the MSD.

and please... no nonsense about how the MSD made power... it " made" nothing at all. if your original ignition was garbage and you had replaced it with stock, you would have had the same power.

I will say this about msd.the motors start,ldle,and run better.part are cheap...and yea.u get what you pay for.but they fit my bugget and i have/carry spares

bcfountain,unless you are burning methanol alcohol or nitro,you did not gain 37 hp by switching to msd ignition,if everything else was the same,the thunderbolt4 will make the same hp as the msd will.:party-smiley-004:

Well all I know is what the dyno numbers were. We changed absolutly nothing but the ignition. Exact same timing, jetting, ambient air temp, humidity, water temp., etc. ect. And as bcFountain said they start better, idle smooth, no stalling and just basicly run better than they did with the stock ignition. And the 37 HP came from somewhere, both motors same exact results, if it wasn't due to the ignition where did the extra ponies come from?? :cartman:

Sorry for the multiple posts but what you guys are saying is really baffling me. With a hotter more controlled spark you will get a more complete burn of the fuel. More fuel burned, more horsies. Why would racers or any body for that matter spend money on high doller ignitions if cheap crap stock ones work just as good???? If what all you are saying is true MSD, Accel, Pertronix and all the others would be out of business.

post the dyno sheets!

the merc thunderbolt4 is hardly cheep crap as you put it,i agree that with a captive discharge ignition like the msd 6 box the engine will idle cleaner due to the multiple spark,but that stops at 3000 rpm,then it produces 1 spark per firing cycle,same as the thunderbolt4.unless the engine is high compression or supercharged ,the thunderbolt4 will fire the plug just as good as the msd will,also,please explain to me how the ignition system has anything to do with the amount of fuel that enters the cylinder to make more power.

Ok. I will do that tomorrow.

as far as ignition goes, the motor needs what it needs and no more. if the stock ignition was sufficient for the air/ fuel/ compression ratio you have then MORE ignition buys you nothing at all... and for the record , as far as " stock cheap crap " goes, the factory ignitions in most case is a far better engineering and manufacture exercise than the vast majority of the aftermarket junk. in the "cheap crap" catagory MSD is the world leader. if you are going to run that junk i have only two words of advice...

carry spares

Is there a prefered coil to run with the TB4? And what is the difference between a TB4 and a V8-HP module?
Not to hijack the thread but I'm in the same "boat" as Chris the OP.
Thanks.

the best bang for the buck is a H/P version of the old style HEI, I get the vacume advance block off and the 2 wire ends to make the swap a snap...ran several of them, worked great everything less than $100..

Are you talking about old style automotive HEI

+1...great folks to work with....very high quality simple equipment.

My engine builder has told me he has seen as much as a 40hp gain on the dyno with the MSD HVC II coils. My brother in law has done some work with Ford engineering on some special spark plugs that they gained 30hp from. I am of the theory that a larger, hotter, longer spark creates a bigger, faster, flame front and thus more power. When I was a kid and had a 14:1 go cart race engine running 14,000rpm just spark plugs made a huge difference. When it comes to horsepower, everything matters, no detail is to small to overlook. Remember in the words of Smokey Yunick, "It's easier to find 100 ways to make 1hp than it is to find 1 to make 100hp". As far as the factory stuff goes, you have to evaluate their goals verses your goals. Their CFO wields a bigger stick than ours (sometimes). Their goal is to get it done for the least cost, my goal is to get it done for the most gain. Just do a spec check, the current, dwell, and voltage coming out of a really good ignition system is significantly better than anything factory. Factory motors aren't designed around 10:1 compression running at 6,000rpm either. Just my 2 cents.

never said anything about h/p numbers......starts,idles/runs smoother.msd:eekdrop:

sorry,it was likefastboats that said he gained 37 hp with the msd ignition,i am still waiting for him to post his back to back dyno sheets.i thought he was speaking for you.

and for the record,both of my supercharged boats run msd ignition,so i am not one of the msd haters,but on a basically stock n/a engine,it is just not going to do any good.

i believe you are mistaken,my 2012 honda accord is 10 to 1 compression,and redlines above 6000 rpm on 87 octane fuel,and this is pretty normal in todays world.

I have to disagree with you guys, regarding the "MSD" VS. "thunderbolt" stuff.

The stock thunderbolt ignition is a very good and reliable ignition. However, it is not in the same league as a aftermarket high performance capacitive discharge system.

The reason for multiple sparks below 3300RPM from a CD ignition is for a reason. The CD ignition, by design, provides a very short duration, high output spark, when compared to a stock inductive ignition's, long duration, weaker spark. So, what engineers at crane, msd, etc, have done is made the CD boxes so that they fire multiple sparks at low rpm. At high RPM, the multiple sparks simply aren't needed. Theoretically, some say you can run a tad more ignition lead with a CD ignition, since the spark duration is shorter.

While stock ignitions have their place, and do well for what they are, are limited. There IS a difference between a 450HP N/A 5000RPM engine, and a 700, 800, 900hp, and so on, forced induction, 6000+rpm engine, when it comes to ignition requirements. When you get into radical cam profiles, superchargers, big carburetors, boost, low vacuum signals at low speeds, the stock ignitions start lacking. I've seen it plenty of times, where engines like this, run soooooo much better simply by locking the timing out. The OE were so scared of detonation, they had some modules/springs, that wouldn't allow full ignition advance to 5000RPM!! I believe the 525SC was one of them.

Without getting into dwell, coil saturation, primary and secondary voltages, and all kinds of tech talk, in certain scenerios, I can see where a high output CD ignition, will lay the smack down on a stock setup. Some write off aftermarket ignitions as being "snake oil" and will be content bolting in a HEI from a 1975 Caprice classic, and feel good about it, and bolting in a higher output coil. I wonder why the Crane, MSD, Daytona sensors, and other high performance igntions, have a 10 gauge direct battery feed with capacitors and what not, to store energy and provide the secondary side with ample voltage. And the stock ignition has a single 16 or 18 gauge wire coming from the ignition switch 20 ft away.

In my opinion, "Likefastboats", you did good by replacing the stock T-IV ignition on your supercharged engines with a CD ignition system. I'd like to see the dyno sheet. My gut tells me your HP gains were in the upper rpm band.

Do I think every engine needs a super duper ignition, no. Most of the time stock is fine. But do I think high performance aftermarket ignitions are "junk" or "worthless snake oil"? Absolutley not!

I agree. Todays coil on plug, and overall ignition systems are waaaayyy better and more advanced than the stuff of yesterday.

I used to hear all the time about guy's bragging on how great their stock GM HEI ignition is/was. Were they great for 1975 when they first were introduced to replace points style ignitions? Yes. But they don't really hold a candle to whats available nowadays.

I wonder why mercury racing used a Standard Thunderbolt ign on everything up to the 800SC. But on the 900SC/1000sc, they used a CD style ignition. 800SC max RPM=4600-5000. 900SC/1000sc max RPM=5800-6000 hmm. Considering they probably had a slew of thunderbolt setups laying around, why the change to a CD box?

Yes ThisIsLivin you are right on the money.

And for the record I never said anything about an ignition system "introducing" more fuel. What I said is with higher voltage and a better flame you will burn more of the fuel that is in the cylinder instead of blowing unburnt fuel out of the exhaust. More fuel burned, bigger explosion, more power. It's not rocket sceince. I'm not new to this thing of making horsepower. I have been building race motors since I was 18 years old, I'm now 54. I sure wish I could post my dyno sheets today while this thread is still hot but my wife tells me they are in our boating file at my lake house. This thread started out as a simple question as to what ingition is good. I thought I would help posting my recent expierince on the dyno. I never expected it to turn into a pissing match over stock and aftermarket ignitions.

So well said!!!! You my friend are ABSOLUTLEY CORRECT! And yes my HP gains are in the upper RPM band. I'm only running 5 pounds of boost and at 5300 rpm with the stock ingition HP started falling off. With the MSD's HP kept going up all the way to 5800.

:thankyouthankyou:

ok boys and girls,let me clarify,i thought that likesfastboats was speaking for the op,i now see that is not the case but he somewhat hijacked the thread talking about his engines,that he failed to mention are supercharged so,will the op benefit from the addition of a msd ignition on his basically stock n/a engine,imo the answer is no,will likesfastboats supercharged engines benefit from the msd ignition,absolutely,as the boost goes up so does the difficulty to ignite the fuel in the cylinder,now the hotter spark can fire the plug and start the combustion cycle.if i did not believe the msd is necessary with the supercharged engine,i would not have them in my supercharged boats.i cant make it any more clear than that.now if anyone wants to tell me i am wrong,im all ears and always like to learn,so lets have the facts,just the facts please.:thankyouthankyou:

I was getting worried. I thought next time I came by the shop I was gonna see a pair of ford duraspark igntions on your 1200's! Or maybe some HEI's with a set of magstar wires. :lolhit:

maybe i will try a points dist from a 58 chevy as my 588s only have 8.5 compression ratio:lolhit::lolhit::party-smiley-004:

you'll be fine as long as you run those coil's Joe B has and some projected tip plugs. :lolhit:

Ok I think we might be getting close to all being on the same page. I didn't mean to hijack the thread just want to tell of my reacent expierience with MSD's. "The thread's question was about ingition upgrades" And sorry I didn't mention my motors are blown, yes I agree that makes a big difference. I know the increases I saw are probably not typical or the norm. That's why I said I was "amazed" in my first post. Also I agree a NA motor will not see these gains from an MSD upgrade. Never the less I am a fan of MSD and do believe any engine would see some benefit from an upgraded ignition. Eaiser starts, smoother idle, better throttle responce and possibly a pony or two due to a more complete fuel burn. Sorry I got every one so rilled up. I didn't mean to turn the thread into one like the ever so popular SRW or Dually threads. The weekend is here so lets all go churn up some water and pollute the atmosphere a little more!!! :lolhit:

I was told a long time ago, there are many things you can go overboard with and ruin a engine's performance. Cylinder head size, camshaft size, carburetor size, etc. One thing you cant overdue is having a quality ignition system

You are right. I know from expierience that all of the parts have to work together and compliment each other. That's where a lot of guys go wrong. Just upgrading one part ie: cam, carb, heads, etc. sometime will set you backwards instead of helping. But you really can't go wrong with a well timed hot spark.

When do spark plugs become an issue, what I mean is when making changes to the rest of the ignition system does a change in plugs become necessary? If so, how? Not trying to hijack as they are part of the system too. Randy

by the way what do you tow with drw or srw,lol,just kidding,its all good and just a misunderstanding,in the original post the op said he was short on cash because he just spent a lot of money on engine parts,i can totally relate and thats why i suggested that he stick with the thunderbolt 4 setup,why spend money on something you dont need,espically when money is tight.if he was running any type of power adder i would have suggested that he bite the bullet and upgrade his ignition,so at the end of the day,you and i might be on a different paragraph,but we are on the same page.
:thankyouthankyou:

I tow with a dually, but we don't want to get that thread started again!!! LOL As far as the op goes you are right, for his setup the cost of going MSD is not necessary. I to understand about tight budgets. I know I've throw a lot more money at my boat than I really should have. But then this go fast boat thing is a very serious disease that most of us here on OSO can relate to. I know all of us wish we could get shot in the azz with gold nugets!!

most of the aftermarket distributors have roller bearings instead of sleeve bearings. old guy that tought me always ran 8 guage wire from block ground to cylinder head(s), told me made 6volt ignition more reliable, simple/cheap so always did it. well several years back turbo mag for rice burners does dyno test, good for 5hp back to back testing. i normally go up in ignition primary wire size also.

I have tried an MSD coil with a TB4. No change in performance and the MSD dies after 2 years.

The TB4 uses a module to control the timing advance curve. The V8-HP module has about the best curve for a performance engine. It has 20* of advance all in by 3000rpms.

hey.. wait a minute... what do you mean by posting a factual statement that contradicts all the mythology ,voodoo and bullsht . it has NO place in this discussion. careful . you can get banned for that sort of thing.