multi-spark discharge (msd) systems

[mdec]

for a 2.8L SU / Mallory Unilite combo. Is this a worthwhile upgrade ? ...some say 'driveability' improves, others less enthusiastic. Have orig 260Z alternator (50A I think) will this need upgrading as well ?. Any special coil requirement ? - Thanks.

[gnosez]

I've had an MSD box and a Pertonix set-up on my L28 for over 10 yrs with no issues at all. My spark plugs have the same profile after 5 or 10,000 miles. I have it wired so it can be switched back just in case the MSD box goes and have experienced the difference just to see what it was like.

In normal driving I couldn't feel a thing but in hard driving (up to the 90% of the rev limit in each gear) it has a smooth feel and a sense of a bit more power. Worth the money? Good question. I bought this set-up 10 yrs ago so that money is long gone.

My engine is far from stock and has a GM one wire 105 amp alternator.

Where are you in MA?

[30 Ounce]

I use the MSD triggered by the stock magnetic pickup in my 3.0 liter 260. I would skip te Mallory dist. Mine runs great.

[Lazeum]

I had a L28, DCOE, Mallory Unilite dist. + Mallory Hyfire 6AL box.

Last year, the 6AL box fried, most likely due to inappropriate primary coil resistance (1.6Ohm instead of 0.6Ohm).

So I've ditched the box and run the car with only the Unilite. Guess what: No change at all in car behavior I could feel & mileage.

I was in advanced break-in (600mi after rebuild) mode so I did not go above 5000rpm, maybe above I could have felt something but based on my experience, the box is not necessary.

Since then, I've moved to Distributorless ignition with megajolt ecu + EDIS. I have yet to try it on roads with no salt - winter is long

Edited February 2, 2013 by Lazeum

[Mike W]

gnosez,

Quick question for you.

I'm about to do the 1 wire GM alternator upgrade. I know about the mod that needs to be done to the lower bracket and that will not be an issue.

Any other words of wisdom about the upgrade? It seems really simple and eliminates the need for the OEM voltage regulator and associated wiring.

Would appeciate any other guidance that would keep me out of trouble.

Thanks in advance.

Mike.

[zKars]

Ive done this mod, and if I'm assuming you mean the "chop the lower block bracket to 1.7inch long" mod, the only thing I did poorly the first time was not checking that the cut off face was exactly 90deg to both the mounting face AND the thru hole. Left the alternator a bit crooked. Stuck it on my mill to face it flat and square, but a file and a square does the same thing.

Then there was the hunt for the just-right belt, and a bit of 'adjustment' of the upper bracket, but I'm totally happy with the prospect of having an alt that I can replace anywhere anytime if need be.

Edited February 2, 2013 by zKars

[Mike W]

zKars,

Thanks for the feedback I will keep a close eye out when I am cutting the bracket. I have a pretty good band saw that I think will do the job.

On the electrical hookup, is it really as simple as just connecting the charging wire to + Bat? I know that I will also need to remove or at least disable the OEM voltage regulator, but just trying to confirm that the electrical connection is reallty that somple.

Thanks for your help.

Mike.

[SteveJ]

One word about upgrading the alternator with the 260Z to an internally regulated alternator. (Okay, it's really a few sentences...) If you want to keep your electric fuel pump you'll need to get an oil pressure switch or install a diode between the alternator and the battery. I would have to do some research to tell you what wire.

One of the electric pump relays is energized straight off the alternatore (before the voltage regulator). The other relay is energized off of the starter circuit. The voltage regulator keeps the battery from draining back toward the alternator and fuel pump relay coil. Going to an internally regulated alternator will allow the battery to energize the fuel pump relay coil even with the car off.

[Mike W]

SteveJ,

Thanks for the tip on the 260. Fortunately my electric fuel pump system is wired from scratch. The original relays have been disabled and in fact removed from the car. The only part of the original OEM system that I use is the wire that runs from the fuse box area back to the pump itself. Everything else, including a separate relay and an inertia switch is new.

Mike.

[gnosez]

Mike W - sorry for the delay (on a plane and then over to the hotel).

Since you don't have to worry about the fuel pump that's taken care of, the bracket for the lower bolt has been covered, you will need to make up a different top bracket (I made mine longer) and it will be hit or miss on the belt itself until you get one that works for your set-up. Changing the pulley diameter helps.

I went over to a local auto electrical shop and they can make any one-wire GM style alternator you want in whatever amperage. They also carried different covers including chrome. Their prices were cheaper than MSA and others. I like to try and shop local since I have a 40 yr old car and I will need help for some other problem in the future.

BTW, my lower bracket was bought 10yrs ago as a custom replacement (no cutting) but I'm can't recall the name of the seller.