Alternator / Voltage Regulator

[davids2toys]

Originally Posted by RICK LAKE

davids2toys David I run mine MSD directly to the battery with a fusable link of 40 amps on the + side. I do have a master battery cut off for the car that kills everything but power to my ECU. There have been other threads on here about how much power a 6AL module uses. I am in the 8-12 amp range and the Spike of the system I have not done. If the module draws so little ampage from the electrical system, then why is 12# gauge wiring being used?? I had a problem with high resistance when I first finished the car. You need good grounds with FI systems. I moved the battery to the trunk and main connection was in the trunk. Problem was the motor and trans are isolated with rubber mounts. Yes there is a ground wire on the ERA but FI systems need more. If you do the bolts through the motor mounts and have clean areas of contact this will work OK. I overkill things. I Have 2 grounds to the motor. 1 to the block and one to the head R/S. It is important that the thread holes be clean and no paint on the ground areas. I have a Shelby block and heads of aluminum and it is not the best conductor of juice.
Side note for MSD, I mounted my unit under the glove box with my ECU for the FI system. The R/S foot ducting blows fresh air on both modules to help keep cool. I know that these MSD module gets hot. I had a failure of a new one from working on the car and welding to the frame without unhooking the battery. Good thing it was covered by warranty and fixed for free. I don't know if Pat is right or wrong, I followed the manual for installation, 15 years of racing with same box. Cap and rotor in the distributor, that's a different story, carry spares. Rick L. Ps I also have spare MSD and complete distributor and basic tools to install, just in case. Last note, I solder and climp connectors on my wire ends and use shrink tubing to weather proof sealing. I also use star washers that add bite to a connection and help reduce resistance there. Spraying a connection with grease, paint, undercoating, or sealer, The jury is still out on this. I do use electric dye grease on all my connections. It seals connections and no loss of resistance to that connection. It's a GM fix for years with out side connections under the car or truck. Good luck.

Rick,
I like and believe a little overkill is a good thing...better safe than sorry. I have always sprayed down battery connections with that colored grease, but never the other connections, I think that is a great idea, probably will use dielectric grease though.
As far as the grounds go, I do not have FI or an ECU but I still think the multiple grounds is a good way to go. What I have now is battery to frame in the back. Small black wire from pass head to firewall. 1 " wide braided strap tranny to frame. I would like to run an addition grounding strap engine block to frame and driver head to frame. Maybe even the manifold to frame. Is it OK to run multiple ground straps or wires to the same grounding point on the frame?

Any idea what that rating is for CB on the firewall . Since my POS MSD wire is going there, is that basically acting the same way your fusible link is doing on your set-up?

Planned on soldering and using shrink tube on the splices. Do you think that is necessary on the terminal ends also. I always have heard that a good crimp was sufficient?

Thanks...Dave

[RICK LAKE]

davids2toys Dave,We all have different ways of installing and running our cars. I have been running in the rain. Water comes in under the front windshield gasket and soaks everything in the car. Both my ECU and MSD are getting wet. I have sealed both with RTV around the box seals and at the wires where they go into the modules. I use Packard connectors,(a GM thing, who I work for over the last 30+ years). To date, all connections have remained clean and good contact. Side note, if you get into a problem with checking out curcuits and they have packard connectors, GM recommends replacing them because of causing a weaking connection. We do a drag test to see if the connector is ok, No drag replace, Bending of terminals is a temp fix and doesn't last over the long term. Have to remember that the more amps that go through a connection the more heat is produces and we all know the heat causes metal to bend or weaken.
I wouldn't use a CB for this power curcuit. There shouldn't be a failure of the fusible link unless a major ground out. It will also be stronger on startup spikes on that curcuit. We have used them for 50+ years. I have 2 on my 79 TA that work just fine with 147,000 miles on them in all weather.
Reason for not using CB, Main one is a wire rub through, I have seen this, wire coating rubs through on metal part of car and arcs out to ground. CB blows and resets, wire still grounded. This can go on and on until the CB contact points inside for smoked or burnt off. Alot of wiring damage can be caused. I have seen it and been there once. I learned my lesson.
If you hook your power to the starter soleniod battery side and a ground wire to the heavy ground wire on the block, put wire protective plastic covers on them and ( VERY IMPORTANT ) may sure them are CLAMPED and wiretired to control movement, I see no problem.
Connections, as long and you use good ones, soldered and sealed or shrink tubed, you should never have a problem. Side note, some guys use KUNG FU grip to crush the connectors. You want them tight and soldered. Tightned to a stud or bolt holt but again not overtighten to crack the eyelet.
If you do good basic work, I see no problems.
Other notes Dave don't let the resistance thing run away with you. As long as you are in the .3 ohms and or less you have a good connection. .1 is idea. Doesn't always happen depending on type of wire, wrap of wire and gauge. Lower the better.
As far as MSD for the last 20 years they still gan't get the correct info on where and how to install a MSD box. I was told, no heat area and no vibration. Reason for mounting under glove box. Good freash air and out of harms way. They still have problems with caps and rotors.UGH!!!!.
YOu would have to check with Bob at ERA but I think the ground wire we use to the back of the head is for ground on all the dash lights and relays.
Bottom line, there is a little guy who sits on your shoulder and every once in a while he says, DON'T do that, or That's not RIGHT, you know kind, like the wife or girl friend and GOD is watching this also. Listen and recheck or get a 2nd opinion. I think I have tryed to cover it all for you. You are going in the right direction with the right ideas. Rick L.

[patrickt]

Dave, don't over-think the MSD installation. The specs from MSD say the box pulls 1 amp per 1000 RPM. If you add a 50% safety factor to that the most that box will ever draw, and then only for a brief amount of time, is ten amps. That's it. If you run a 10 gauge wire to extend the leads that come with the box you'll be just fine. The internals of the circuit breaker add a small amount of resistance but, again, that's not going to amount to a significant factor.

Remember, MSD gets to issue one set of instructions, that will have to be interpreted by tens of thousands of people, doing tens of thousands different installations. Everything from mama's Biscayne to borderline-NASCAR revvers. I wouldn't worry about the condensation at all but, if you're obsessing, drill a couple of pin holes in the top (which is the bottom in an upside down installation).

Regarding the circuit breaker versus the fusible link, both have their respective advantages. I run the MSD standard 50 amp circuit breaker, but I have to agree with Rick that a fusible link is probably better, but a breaker is just a little more convenient. The reasoning is that if either one blows then you have a pretty serious problem. Now, if that problem is just transitory, and basically innocent, like a dropped wrench on the starter solenoid, then a circuit breaker is great. It just resets in a couple of seconds and you say "whew, I need to be more careful." With a fusible link you're saying "goddammitt, now I have to cut out and replace that fusible link -- that shoots the day." On the other hand, if you have a persistent serious short, the circuit breaker fires on and off until you can get to your battery cut off switch. The fusible link blows and your ohm meter tells you that the wire is shorted and you have a problem. Plus, circuit breakers weaken over time and pass less current before tripping when exposed to high underhood temperatures. That said, I run an upside down MSD box in the passenger foot well with no drainage holes and I feed it directly off the protected side of the 50 amp master circuit breaker. But, I don't drive in the rain and do no serious racing. Now, if I did heavy duty rain racing, I would have a waterproof box installation and run fusible links at the alternator and at the battery feed. I hope that helps.

[davids2toys]

Rick and Patrick,
Holy crap, I am getting educated big time...my head hurts
I understand everybody has their own way and interpretation of the best way to do things. I consider myself very fortunate to be able to get educated by people who are much smarter in areas I am not so swift in.
So after after researching what a fusible link is, I like that idea. It said to run 4 sizes under the wire to be protected. So if I am using 10 wire, then use 14 ga fusible link wire? Can you put this on the neg wire or just on the positive? Or both? Rick, you said you hooked up your POS with a 40 Amp fusible link. I am only seeing fusible links in wire sizes ex:14 gage...no specific amp rating. Did I miss something here?
My plan at this point is to lengthen the neg wire back to the trunk where the neg off the battery grounds to the frame. I think I will not lengthen the 12 gage POS wire but just connect it to the "unprotected" side of the CB on the firewall or the hot side of the solenoid with the fusible link(16 gage) in between 12 gage POS wire and the connection point. Does this sound OK? I also read no longer than 9' for a fusible link. Is shorter better?

Patrick you are saying you are running an MSD 50A CB? I thought you were using the one on the firewall from ERA( I am presuming it is from ERA). I do not know the rating on this CB.
Nice idea with the pin holes...maybe a #50 drill? 1 hole on each end? I need to think about it a little more because that will let the air in easier including the warm and cold extremes, it might make condensation easier to form. Do you think there are any electronics right next to the cover that I might hit with the drill? I would think not, but I never had one apart. as far as what Rick said about sealing the cover, I know they are dead set against that and the fact that is is not sealed should be an air source for evaporation I would think.
I know you guys know what a drip loop is, we use them all the time in helicopters. So with water coming in as Rick described, a drip loop would be great as the water would drip off the wire before it followed the wire into the box. So I think i will make sure every wire going to the box has a drip loop and I might take a blob of clear RTV and put it at the wire entry points into the box as Rick suggests. Maybe even some duct tape over any unused ports in the box.
I always thought/assumed the wires and box did not get wet in the rain, but I have never checked. I have only been caught in the rain a few times, but as Rick said, it comes in everywhere and for it to follow the wires right into the box seems very possible.

Also got educated on the Packard connections. Looks great if it is part of your job and have all the necessary tooling. If I was building a new Cobra I think I would definitely consider going this route!

Dave

[patrickt]

Originally Posted by davids2toys

Patrick you are saying you are running an MSD 50A CB? I thought you were using the one on the firewall from ERA( I am presuming it is from ERA).

They are one in the same. That ERA furnished master circuit breaker that is on the firewall right next to the starter solenoid is rated at 50 amps.

Now here's another option that you might want to consider. You can replace that ERA furnished 50 amp "auto reset" circuit breaker with one that requires manually resetting. A little button pops out of it when it throws and you have to manually push the button back in -- just like the circuit breakers in your house.

[patrickt]

Here's info on fusible links, their ratings, etc. After I took time to think about it, I'm pretty sure I've never installed one in my life. Certainly not on the Cobra. Weather Pack Fusible Link

[RICK LAKE]

davids2toys Dave short story this time, we covered all the other info.
Fuse links or any power side of a curcuit get a protector, CB, fusable link, fuse, a bubble gum rapper. (Save this for another time)Places to get different size links in kits or wire spools'
Wiring Products 1800-549-0243 kit # FLW 12 GA Kit

White Products 1440-871-0800 service packs, got my stuff here.

Madenterprises 1559-539-7128 FL12 kit

Napa has bubble rapped kits, no 12 gauge kit or larger.

Ground wires don't need fuses because 98% of the time they are grounded and a wire rub through will not change anything to a cucruit. There is a Major catch here, alot of new systems including injectors are using the ground side to turn on and off curcuits and not the power side. Blower motors in some cars have direct power to motor and a series of resistors in a row that have different resistance to control the speed of the motor. Again another story.

Choice is yours. Overkill has worked for me. I have no luck with things so backup plans are also in play. I do like CB in some curcuits, the big old sytle ones from the 80's. The new minies ones are in alot of our new cars. There seams to be a safety built into them if a curcuit blows it more than a couple of times. They will not reset. Some are also smoked after a couple of shorts. I like the K.I.S.S. system, and it's working pretty good. Rick L. class is out, and I have no class. Later

[davids2toys]

Originally Posted by patrickt

They are one in the same. That ERA furnished master circuit breaker that is on the firewall right next to the starter solenoid is rated at 50 amps.

Now here's another option that you might want to consider. You can replace that ERA furnished 50 amp "auto reset" circuit breaker with one that requires manually resetting. A little button pops out of it when it throws and you have to manually push the button back in -- just like the circuit breakers in your house.

Pretty cool item.
This is what I found. They all have plastic mounts. Don't these circuit breakers need to be grounded like the metal mount type 1 auto reset presently on the car?

Manual Reset Circuit Breakers - with Bracket

http://www.ebay.com/itm/171596826353

http://www.wiringproducts.com/50-amp...gle-mount.html

I will still hook up the MSD POS wire with a fusible link as Rick suggested and you agreed. In addition, change out the ERA 50 amp CB with the manual setting type

[RICK LAKE]

davids2toys Dave I don't beleive in 100 years that the MSD 6AL draws ONLY 1 amp for every 1,000 rpms. Why the heavy 12 gauge wire then???
Remember I said overkill, THis fusible link is also like a resistor and you loss ampage going though it. IT's like a funnel you are pouring a fluid through, pour slow and you have no backup, pour fast and the funnel fills. Same applys for electrical curcuits. This is why good connections are so important.
Curcuits are tested with a steady load, not with startup spikes. Your fans on your car my draw 15-18 amps but the startup may be as high as 40-60 amps for a split second. For this second the ampage is way beyond the curcuit limit. The fuses are slow blows and are the safety protectors of the curcuit. This only last for .10 of a second. Over time a fuse or link will weakin from the heat or spike loads. I don't explain theory very good, too many days of missing school.
Any way Yes a 16# link would be ok, just no for me. The link will still blow if a dead short happens. With 12 Gauge on this curcuit I don't believe in having any problems. Other power curuits, yes with running a lighter gauge fuse, depending on the wire of that curcuit. I like to match up gauges.
PS stop finding things on the car. You are 3 hours away, any more problems, I am sending Pat to fix your car.