Do you run any type of ignition box,such as an mSD,Jacobs,etc? did it help any? I hooked up a Jacobs box to my 87 Toy truck. I don't seem to notice any smoother running,easier starting,etc.
Do you run an aftermarket ignition box?
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I have a Pertronix ignition module in one of my old Studebakers. I don't believe there is an improvement in performance but I don't have to mess with 2 sets of points that were originally in the distributor. I have a couple of friends that have used the after market systems such as the Jacobs and MSD on later engines and its tough to tell if there is an improvement over the stock ignition system. They might make a difference in racing engines, but I don't think that the cost is worth a very minor gain on the street.
Stock systems have gotten really good. The only thing I want to know is why it took so long. Of course with the lead out, plugs can work well for a long time.
I won't belabor the finer points but spark DURATION is a lot more important than absolute voltage. The good thing about aftermarket "Capacitive Discharge" systems was the high voltage they could create using a stock coil, but while that makes an engine run well at high RPM they didn't produce enough duration to produce low emissions at idle with the lean mixtures
run these days. A fast rise time high voltage pulse is good at firing lead fouled plugs at high RPM but does not improve lean mixture low speed operation. There were CD systems which were fast enough to fire a plug two or three times per cycle, even they didn't produce the right emission outcome.
run these days. A fast rise time high voltage pulse is good at firing lead fouled plugs at high RPM but does not improve lean mixture low speed operation. There were CD systems which were fast enough to fire a plug two or three times per cycle, even they didn't produce the right emission outcome.
I have a Hi-6 Crane(similar to MSD) on my '69 428 Cobra Jet Fairlane, makes a world of difference when cold, not nearly as temperamental... I also have used a MSD on my street/strip '88 5.0 T-Bird and didn't see any real difference vs the factory electronic system...
BTW the Crane is driven by a Pertronix module in the factory distributor, with just the Pertronix conversion, I didn't see any real difference over the points...
BTW the Crane is driven by a Pertronix module in the factory distributor, with just the Pertronix conversion, I didn't see any real difference over the points...
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Originally Posted By: HerrStig
I won't belabor the finer points but spark DURATION is a lot more important than absolute voltage. The good thing about aftermarket "Capacitive Discharge" systems was the high voltage they could create using a stock coil, but while that makes an engine run well at high RPM they didn't produce enough duration to produce low emissions at idle with the lean mixtures
run these days. A fast rise time high voltage pulse is good at firing lead fouled plugs at high RPM but does not improve lean mixture low speed operation. There were CD systems which were fast enough to fire a plug two or three times per cycle, even they didn't produce the right emission outcome.
The MSD (and Crane and probably many others) fire the plug several times (something like 6+ times) below 3,000RPM IIRC. This helps with modified engines, but I can't see it doing anything useful on a stocker. I have an MSD box on my Townie and it didn't make any difference. But the Crane (and formerly MSD) box on my buddy's modified 5.0L (H/C/I) definitely improved cold start manners and low speed attitude.
I won't belabor the finer points but spark DURATION is a lot more important than absolute voltage. The good thing about aftermarket "Capacitive Discharge" systems was the high voltage they could create using a stock coil, but while that makes an engine run well at high RPM they didn't produce enough duration to produce low emissions at idle with the lean mixtures
run these days. A fast rise time high voltage pulse is good at firing lead fouled plugs at high RPM but does not improve lean mixture low speed operation. There were CD systems which were fast enough to fire a plug two or three times per cycle, even they didn't produce the right emission outcome.
The MSD (and Crane and probably many others) fire the plug several times (something like 6+ times) below 3,000RPM IIRC. This helps with modified engines, but I can't see it doing anything useful on a stocker. I have an MSD box on my Townie and it didn't make any difference. But the Crane (and formerly MSD) box on my buddy's modified 5.0L (H/C/I) definitely improved cold start manners and low speed attitude.
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Originally Posted By: jkhawaii
could have sworn the idle was smoother with a MSD, on my dads old 454 powered truck.
The multi-spark does do that in some applications. So I have no doubt that you experienced it.
could have sworn the idle was smoother with a MSD, on my dads old 454 powered truck.
The multi-spark does do that in some applications. So I have no doubt that you experienced it.
We are running the crane spark box on an old PU truck. It has a built up 302 in it.
Great improvement once we learned to tune for it. You can run a huge spark gap and get multiple strikes which really helps a big cammed motor idle better and start better IMO.
I feel there's little to improve on almost any newer car.
Great improvement once we learned to tune for it. You can run a huge spark gap and get multiple strikes which really helps a big cammed motor idle better and start better IMO.
I feel there's little to improve on almost any newer car.
I was thinking about this when posting in the spark plug thread.
Ford actually went to an MSD style multi discharge in 92-93 on EDIS equipped vehicles. It was done to smooth out idle roughness on modulars.
The point is, if your ignition system is working properly in the first place-"Igniting the mixture ontime.....everytime" you will never notice a difference.
On stock engines, not really an improvement. Once you start pushing higher RPMs at higher cylinder pressures a CD system makes sense. Not from a multi spark sense, as it goes to single spark above 3K RPM I think (on 6A series) anyway, but because you get a hot spark and reduced dwell time. Thats your main concern when your VE/cylinder pressures and RPMs get to the upper ranges. Oh, and the rev limiter to keep your driver out of trouble was nice to.
Ford actually went to an MSD style multi discharge in 92-93 on EDIS equipped vehicles. It was done to smooth out idle roughness on modulars.
The point is, if your ignition system is working properly in the first place-"Igniting the mixture ontime.....everytime" you will never notice a difference.
On stock engines, not really an improvement. Once you start pushing higher RPMs at higher cylinder pressures a CD system makes sense. Not from a multi spark sense, as it goes to single spark above 3K RPM I think (on 6A series) anyway, but because you get a hot spark and reduced dwell time. Thats your main concern when your VE/cylinder pressures and RPMs get to the upper ranges. Oh, and the rev limiter to keep your driver out of trouble was nice to.
Hard to beat the stock systems on late model vehicles, but older models can often times benefit from an aftermarket Ignition system. The only vehicle I have using an aftermarket box (an MSD unit) is my 1978 Jeep CJ7 and it makes a difference due to the low voltage of the stock system. I get better idle and response as well as well as better spark plug life w/less fouling.
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New systems re superior to points. Stability and no wear.
A hotter spark is only good if you open the gap a bit to take advantage of it.
A hotter spark is only good if you open the gap a bit to take advantage of it.
It probably depends a lot on the vehicle. I doubt my 2001 Silverado with a coil on each plug would see a difference.
I put the MSD on an '87 Caprice police car with over 150,000 miles on the carbureted 350. It smoothed out the idle and made it a bit more responsive taking off from a stop.
I also had one on a street/strip Pontiac 400. It always fired if there was fuel and battery. I think voltage through the points was reduced, too, so they didn't have to be replaced regularly.
I put the MSD on an '87 Caprice police car with over 150,000 miles on the carbureted 350. It smoothed out the idle and made it a bit more responsive taking off from a stop.
I also had one on a street/strip Pontiac 400. It always fired if there was fuel and battery. I think voltage through the points was reduced, too, so they didn't have to be replaced regularly.
i had an MSD fail.
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Originally Posted By: morris
i had an MSD fail.
Yup, so did I. I like the Crane boxes better.
i had an MSD fail.
Yup, so did I. I like the Crane boxes better.
I ran a Crane cams box on an old Chrysler 2.2. The motor ran smoother, but spark plugs only lasted about 10k miles.
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