I could bore you to tears with the why/fors of using an MSD *set-up* but will just generalize.

Carbs need to run rich to force a flat Porsche engine to run properly.
Throw in a hotter cam & it gets worse....particularly on the idle circuit(below 3500ish rpm)

With the proper MSD (or its ilk) set-up.....which includes a hot coil, fat wires, and wide gapped plugs.....will "burn throgh" this rich mixture.

The distributor is your problem. I would recomend talking to Mr. Raby for his recommendtion (I doubt that is a 009) cause I don't know shit about T-4s.

On my past 4 cyl cars, I used the MSD Igntion, MSD Coil & MSB Billit Dizzy. It worked well as a system and eliminated all the flat spots

T.C.

OK, but why did it? Were yours a HP engine? Bob

On our 1.8 F-Prod engine we ran with a MSD 6-AL and also tried the comparable Mallory with our mallory dist. After we fell out of a race at Barber (while leading) when the mallory box crapped out I rigged up a back-up ignition system that used just a coil and no MSD box. We could switch it on the fly so next time the box crapped out (as they are prone to do from time to time in race cars) we could at least keep racing.

When Jake and I dynoed the car the first time with the two systems in place (which included the new 6-AL) we switched on the fly and the MSD box showed 0% more torque from 5000-8000rpms. That's Zero torque increase. The two graphs lay right over each other. And this was on his chassis dyno that has repeatability within 1%. We were so surprised by this that we did multiple runs and tried different timing for the two systems and the results were the same.

I removed the box and sold it. Less crap to fail and less wt to carry.

At the '05 runoffs the Finch FP car (winner that year) had a 009 with tiger-stripe points! Jake and I saw it with our own eyes.

I'm not saying the msd boxes don't have their place, but our testing on our 4cyl race car at our revs (with 12.7:1CR) showed it was no help at all.
That's my .02 worth.

That would require the long version.

OK another short one. Crack open your carb's butterflies & look down one hole. That 6ish inches you see above the intake valve is all a carb gets to make the mixture correct for that hole throughout the whole rev range. Carbs can't do it. A big, hot, multi spark compensates.

Re Raby: I read his stuff

Multiple discharge Spark units aid in firing a wet or large droplet fuel charge at low to mid RPM range. Not needed in alot of applications when good fuel atomization is part of the equation and spark charge is hot and fat. But Carbs tend to be hard to balance across the range. Often they end up fat with fuel in the low to mid range with hi lift short duration carb cams. This is fine if you can keep the plugs firing until you get the engine up in the balance zone. That's where MSD plays a roll. I think...

On our 1.8 F-Prod engine we ran with a MSD 6-AL and also tried the comparable Mallory with our mallory dist. After we fell out of a race at Barber (while leading) when the mallory box crapped out I rigged up a back-up ignition system that used just a coil and no MSD box. We could switch it on the fly so next time the box crapped out (as they are prone to do from time to time in race cars) we could at least keep racing.

When Jake and I dynoed the car the first time with the two systems in place (which included the new 6-AL) we switched on the fly and the MSD box showed 0% more torque from 5000-8000rpms. That's Zero torque increase. The two graphs lay right over each other. And this was on his chassis dyno that has repeatability within 1%. We were so surprised by this that we did multiple runs and tried different timing for the two systems and the results were the same.

I removed the box and sold it. Less crap to fail and less wt to carry.

At the '05 runoffs the Finch FP car (winner that year) had a 009 with tiger-stripe points! Jake and I saw it with our own eyes.
Not looking for more HP, just want spark that will better allow us to set up carbs across the driving range, and not foul plugs. Bob
I'm not saying the msd boxes don't have their place, but our testing on our 4cyl race car at our revs (with 12.7:1CR) showed it was no help at all.
That's my .02 worth.

Raby stuff, where do I find it? Bob

The biggest reason I run them is for the soft rev limiter function...

That being said you will never foul a plug and a carb'ed car starts much easier. I run the Mallory 6AL so I can just dial in the rev limit without having to buy pills (like the MSD) and I've never had one fail.

We stopped selling ignition components 3-4 years ago retail. We of course still install them on turnkey engines. Selling ignition components retail is like asking for customer relations nightmares.

Capacitive Discharge Ignitions have a place with these engines, however until you reach 12:1 CR the benefits are not as great. With CR in the 13-14 range I have had to use them, because with CR increases the load on the ignition system also greatly increases.

A CDI system will allow more spark plug gap to be ran and will generally equate to smother performance at lower RPM. Note that "MSD" only allows for multiple spark discharge at below 3K RPM.

Typically a quality CDI unit will give 4HP and 6 lb/ft of torque in a 150HP 2270cc Engine. When applied to my 175HP 2270cc Performer we can see up to double those figures across the board.

The higher the CR and better the chamber filling the more benefit you will see from more intense ignition.

I have a HP 2L carb 44 IDF 914 that runs great above 3K, Porsche mach of some 30 yrs says I have a very solid rebuilt engine with a hotter then stock cam, the exhaust sys in too big past the collecter but header is a damn fine unit. He also says the exhaust sys has nearly no back pressure and wants to size it down from 2inch to 1 5/8 or 1 3/4, and I need to dump the TOO damn loud cherry bomb muffler. The porsche guy builds racing engines for the local Indy market, has his own dyno and flow bench, grinds his own cams, and seems to know his stuff as he only works on Porsche's. After talking to him yesterday, he thinks I also need a hotter/better eng sys, like a MSD, rather then stock 009 sys. Gents........... Your thoughts??? Questions?? Bob

In my direct fire mode I can get the MSD to work much higher than 3000rpm since it is only firing one plug each. The MSD is ultimately limited to internal capacitor time constants; The time it takes to charge and discharge. At the cylinder triggers increase with rpm, the MSD cannot charge and discharge the capacitor as multiples and reverts to single spark.

But to be honest I (personal opinion being expressed here) am very leary of them (and all electronics) on a race car. I do everything I can to keep the electronics simple and to a minimum, use high quality parts (if it comes in a white box it goes into the trash with the white box ((Cole-Hersee makes excellent switches of all kinds and Hella makes a great, high quality master kill switch)) ) 3m terminals with the right crimping tools, shrink wrap and strain relief all leads, regular applications of silicone spray and say many prayers to whomever is listening up there before each race.