Lost another alternator.

[Terry Posten]

/ubbthreads/images/graemlins/frown.gif

1st trip was 10 blocks and all was good.

2nd trip was to the Post Office to ship 2 ECUs. By the return trip (maybe 10 miles), volts are pulsing 13.3 to 13.5 and at idle, 13. Headlights on, no fan. Must be bad.

I'll take it for another trip later but not holding out too much hope.

I think I will hit harbor freight to get a few fender protectors before I do it again.

At least it is an easy job.

 

[turbowop]

That sucks, Terry. /ubbthreads/images/graemlins/frown.gif

James, Your link doesn't take me directly to what I think you were trying to show me? I was looking at this EvoM thread and figured I'd use the same stuff or something similar.

 

[CarRacer]

Yeah, that BMW site blows. That's exactly what I was thinking, it seems like a great application for that stuff. It's really thin too, so it shouldn't make for any clearance issues either.

 

[Terry Posten]

OK, drove her tonight. Good voltage until the car is hot, then is around mid 13's. I think a heat shield is needed. Without a heat vent in the hood, it holds a ton more heat now.

Last night, my ECU was learning the idle after having the battery out for the alt swap. It was only idling around 500 revs and would stall out and I feel that is why I saw 12's last night.

I readjusted the BISS and she now idles at 1000 hot, 1300 cold, and the revs stay 200 revs higher until a full stop. Just like it should (for my Keydiver chip).

I guess I need to break out my fab skills (God help me /ubbthreads/images/graemlins/crazy.gif).

 

[turbowop]

I think just a simple plate separating the O2 housing from the alternator would help as long as it was thermal coated or had that heat reflective tape on it. That's all I'm planning to build. I want to make sure it still gets airflow as well.

FWIW, on a hot day, my car has always showed mid 13's voltage on the logger when fully warmed up. A multimeter directly on the battery showed higher voltages. The last alternator was like that from the start, then poof, it went bad suddenly.

 

[Hertz]

There is a direct correlation between underhood temperatures and alternator voltage. ( I think toybreaker posted the chart once )

Terry, you're in the middle of summer, in traffic, with a non-vented hood now.

 

[Terry Posten]

I am thinking about a very basic heat shield that mounts to the back bolt of the PS unit and the bottom pivot bolt of the alt. I could coat the one side with reflective tape.

Should fit ANY 4G63 car with the PS pump and alt in stock location. Should also be cheap and easy to remove for servicing.

Any body interested?

 

[Barnes]

You don't even need the reflective tape. Sure it will help, but just the plate alone should make a world of difference.

 

[toybreaker]

I've made a couple of different shields over the years.

The problem with using sheetmetal is that while it may block direct heat, it will get warm, and when heatsoaked, it will begin radiate heat itself, giving dimishing returns.

While heatreflective tapes and the like can mitigate that to some extent, I've found using the cat heat shield stuff works the best, (at least for me.) The good multi-layer foil stuff from under a bmw/mercedes/audi makes for really good material to cut, bend, and shape into a viable heatshield. The back side of the material is hardly even warm to the touch, while the front side will hit 500* and more.

I've got my sh*t all torn down, but I'll see if I can get some pics up of my previous set-up, and maybe you guys can see a way to improve things. It's not the prettiest thing, but it sure worked well! I used my last n.o.s. brush set/regulator in that alternator, and it was still going strong 75,000 miles later. It also didn't suffer from hot voltage sag near as much as an unshielded unit would have.

I've been thinking the next version will have a little shield protecting the p.s. pump as well.

Any, and all, suggestions would be welcome, as I'm thinking of doing an alternator how-to. Mitigating the effects of adverse heat on the regulator is one thing I'd like to address.

tia /ubbthreads/images/graemlins/smile.gif

 

[turbowop]

Quoting BarnesMobile:
You don't even need the reflective tape. Sure it will help, but just the plate alone should make a world of difference.



As Toybreaker mentioned though, as soon as said plate heats up on a long drive, it'll be the same as being next to the O2 housing again. It would be ideal to have a factory style heat shield around my tubular O2 housing and wastegate, but that's not possible.

 

[Barnes]

Quoting Turbowop:
As Toybreaker mentioned though, as soon as said plate heats up on a long drive, it'll be the same as being next to the O2 housing again.



Actually it won't. Yes, the heat shield will get hot. Yes, it will radiate it's own heat. No, it will not get as hot as the O2 housing and thus will not radiate nearly as much heat. At minimum the heat shield should reduce radiative heat transfer from the o2 housing by half. I don't want to go Dialcaliper style on everyone, but that's just the way the equations work out.

 

[turbowop]

Okay, I don't want to argue against your ME degree. Wouldn't the reflective stuff help even moar though?

 

[toybreaker]

I'm open to any and all suggestions, myself, and I gaurandamntee you know more about the subject than I do, Jon. /ubbthreads/images/graemlins/smile.gif

Thing is, I've been bodging this kind of stuff on my own equipment for ages.

I tried sheetmetal heat shielding back in the day, and I learned a lot from it. I learned that there's a reason the o.e. manufacturers used the foil insulated stuff.

From a simple noise/vibration/harshness standpoint, they win because they are a laminate, and the different layers have different excitable frequencies, so they hardly ever buzz/rattle/sing.

But the main reason I really like them is the temp drop from one side to the other.

It's flat unbelievable what a 1/8" foil laminate can do.

From the yards, the stuff is cheap/free, and it so formable it's silly.

If there's enough interest, I could take some pics of what I have, and of the material I'm using, and maybe we could come up with a better solution that anyone could replicate themselves, cheap like.

Might make for a cool how~to for the archives... /ubbthreads/images/graemlins/cool.gif

Speaking for myself, I'd rather spend the time/money now, and not have to deal with charging system problems out on the road.

 

[Barnes]

Quoting turbowop:
Okay, I don't want to argue against your ME degree. Wouldn't the reflective stuff help even moar though?



Yes it would. If you want it to be really slick, make it 2-ply. I.E., two pieces of metal with a few millimeters between them. However I'm pretty much convinced that a single piece would probably be plenty.

 

[Barnes]

Toybreaker - Yes, the laminate stuff is this shizzle. If you make a heat shield with two outer metal layers, and an inner insulating layer, they will work way better than a single sheet of metal. I'm just trying to point out that a single sheet of metal will drop the heat transfer from the O2 housing. That's it. I'm not making a statement about it being the best heat shield, just want it can do.

 

[toybreaker]

I'm just a cheap bastard at heart, and if I can get the goodies, cheap like, I'm happy. /ubbthreads/images/graemlins/smile.gif

 

[Barnes]

Probably the simplest way to build a very effective shield would be to build it as a one layer piece. Then attach a second shield on top of the original using small offsets.

 

[Brianawd]

I think the shield is a good idea to keep some of the heat off the alternator in stop and go driving. I have been planing on building one for my car along with some brake ducking to direct air right to the alternator when driving. This way its getting fresh out side air right to the alternator. I was thinking something like this

click

 

[mistaVR4]

Thanks for the link Brian. That Raceflex looks to be some great stuff!

 

[turbowop]

That's the stuff I want to use for ducting. I wanted to find something locally, but it looks like I'll have to order it. I don't think Home Depot is going to have anything that specific.

I also want to say, I really hate issues like this. Most failures on our cars can be prevented via maintenance. Unfortunately, the alternator is one of those items that can just fail whenever. It's a little unnerving on long trips when the weather is hot. Nothing like being on the side of the road miles away from any services or possibly in an area without cell service. /ubbthreads/images/graemlins/uhh.gif