msd ignition
 

I'm thinking about changing out my bosch ign. for the msd talked about in 101 projects. Although my 82 runs fine, the fuel mileage could be better. Since I can't drive slow I figured this multispark system might help. My question is, how do i adjust the spark plug gap for optimum performance to comply with 101 projects.

Hi:

Having installed a LOT of MSD's in my time, I honestly cannot tell you that the fuel economy grew appreciably better, but the starting and drivability certainly did,...:) :)

Of course, plug gaps must be opened up to take advantage of what the MSD's are capable of. Buy a sprak plug gapping tool at your auto parts store and its very easy to do. Be aware that some plugs come pre-gapped and should NOT be changed so I use either Bosch or NGK copper plugs and sometimes Bosch Silvers.

Hi Steve, what do you recommend the gap to be?

Naturally aspirated motors running MSD or Crane CDI's can run between 0.040-0.045+" plug gaps. This is less for forced induction motors running non-standard boost.

You may even be able to run a larger plug gap than 0.045", so adjust gap and drive to ensure you're not misfiring under heavy load. Find the sweet spot and leave it there ;)

I've read a bit about this topic and haven't commited yet. A lot of guys say it only helps at lower rpms (under 3K). In my case I spend at least 40 miles during my commute at 60mph :(
Couple questions:
Given the above commute should the car should run "smoother"?
And improve on Mpg?

I put a MSD in my 83SC myself and I love the results. I run a .06 plug gap. I initially installed mine b/c of a problem called "bucking" that my car was having that was a very very scary deal and if you have had it you will know what I mean. The bucking in my case was being cased by a rev limiter that was starting to fail. Since I put the MSD system in is starts much better in cold and especially in wet where I was starting to have trouble with the Bosch. Plus I would swear it revs to red line faster than before. It idles much much better. Best part is for a tight wad like me is that I installed it myself, almost paid for the entire MSD system with the money I made from selling my Bosch 6 pin bax (the bucking was not being caused by teh Bosch box but by the rev limiter up in my dash). By having my neighbor make me an aluminum bracket I was able to mount the new MSD box in the same spot as the old unit also even thought the old one is smaller if you make the bracket right you can fit it there and even still use the same mounting holes. Good luck and it is a mod that is worth it IMO.

I had an MSD 6AL in my BMW race car for about 1 1/2 years, that's maybe 11 races, and it failed. Needless to say, I wasn't impressed.

Well I think we can all agree that a purpose build race enviornemnt is far different that a daily driver enviornment/part time track or DE kind of enviorment Dave. Plus, I know people who race and they swear by MSD so your experience may be more of a one-off nature than the norm. I would bet that the issue was with 3 letters but that the 3 letters where BMW rather than MSD.

Well, the unit was properly mounted, isolated, inside the cockpit of the car, i.e. not exposed to extreme heat of the engine compartment and ran fine for 11 races. That's a total of about 14 running hours, including a few practice days. I seriously doubt there is anything different about a BMW 2002's 12VDC compared to a 911's 12VDC. The stock ignition has performed fine in my '02 since, as I sure it had for the 26 years it ran BEFORE it became a race car. I just look at the MSD's performance and look at the original Bosch CD in my 29 year old SC and scratch my head. I guess I just got a bad one.:(

Could be that you did get a bad one. It happens a lot in electrical components. Did you contact MSD to see if they were willing to do anything for you? You know I am playing with you about the BMW remarks. I think they are a great red-headed step-child for Porsche. I hope the PanAmerica takes a lot of business away from the step-child too. Why Porsche didn't make a sedan before they made a SUV I WILL NEVER KNOW...

I dont think you are going to see much of an improvement in a 911SC unless you have modified the engine. I swear by the MSD6AL on Amercan muscle cars. You can feel a big difference at the higher RPM's, it gets better gas mileage and it has its own rev limiter. I put one on my SC about a year ago to see if there was any advantage and couldnt feel any. I did not dyno or check the gas mileage.
If your stock Bosch is not working it is a fine replacement, but I wouldnt do it as a performance enhancement.

No, I never went back to MSD about it. It was outside their warranty and it was in a race car; I figured they'd give me a hard time and just wrote it off. Ironically, the main reason I got it was to improve the longevity, reduce maintenance on the distributor points because I was concerned about the reliabilty of Pertronics. I knew that with the MSD the points were just basically an on-off switch carrying very little current and the points would probably last forever.

I'm not a huge BMW fan either. I love racing the '02 because there are several in my class where I race and ITB usually has a big field, and it doesn't cost much to run a season, relatively. The '02 has been pretty reliable considering.

I don't own one but from with the data compiled on this list the Bosch CDI seems to be a good design, reliable and easy to repair. I am not sure what the advantage to an MSD unit would be.

I think early S man has the complete service manual in a thread.

DaveE -- BTW, what sort of gap were you running on the plugs prior to the MSD failing?

One advatage to the MSD system is that it is a helluva lot cheaper than the OEM Bosch unit. A new Bosch unit is like $1400 from the manufactuer. I found rehabbed ones and used ones ranged from $300-$450. I think I spent $175 on my MSD set up with the Tach sending unit. So you have 21st Century technology that costs 8 times less than 20th Century technology I would call that a HUGE advantage unless you have money you are just looking to try to clog your septic system up with.

I don't see too much 21st century technology in either, they look similar. If I were going to date them I would say 70s early 80s.

MSD reverse engineer

6 pin CDI

So do you see enough difference in the Bosch unit that would compel you to send 8 times the amount of money on it?

"I don't see too much 21st century technology in either, they look similar"

Rick is correct. The MSD has no proven advantage with the multiple sparks
below 3000 RPMs with the major disadvantage of less reliability the result
of more components.

Read here under Ignition Systems for more info:

www.systemsc.com/technical.htm

"8 times the amount of money on it?"

Do what????

No one does this! Pelican sells rebuilts as do others.

The 'real' price of used, working Bosch units is typicaly $100. That makes Bosch LESS expensive, rather than more.

I heard from a very experienced Porsche guy that some 911's respond well to the MSD system, and some do not. Some 911's run more poorly with MSD than Bosch. And.....overall it has been my observation that MSD and Permatune both have a WAY WAY higher failure rate than Bosch. Yeah, we've heard of Bosch units failing. But it's rare. Everybody has a Permatune or MSD failure story.

I think Warren and Glenn both chuckle at guys who think they are "upgrading" to MSD.