wtf is up w/ 100amp alternator fuse

americanjebus

americanjebus

Mr. Evergreen
Mar 30, 2005
1,867
0
0
37
wa.
ok after a day of litteraly mapping every wire and trying to trace every white whire w/ a black line i started pulling out every fuse 1 by 1 to trace my lack of ignition. well what i found was that my 100 amp alt fuse has a hairline mising in it and my wouldnt you know it efi fuse has a hariline thing in it.

my problem: i cant get the damn amp fuse out, is there a trick or do you just pull it out with balls and fingertips of steel.
i already tore apart the top part w/ pliars any ideas????
 
americanjebus

americanjebus

Mr. Evergreen
Mar 30, 2005
1,867
0
0
37
wa.
well for those who glanced at my non starting motor thread this was the fix i blew the fuses to hell and now its running smooth as hell. when i pulled out that fuse i was in awe at the length because ithought it was just like the other fuses that are only like 1 inch long.
 
9

97TSiAWD

In need of more traction
Jul 18, 2006
124
0
0
Michigan
americanjebus said:
OMMG THANK YOU, not much left of the fuse though.
Click to expand...
Had the same thing happen to me. :icon_bigg

Sorry to bring back an old thread, but I really wish I had seen this earlier yesterday when my alternator fuse blew and I proceeded to totally shatter it while trying to take it out. Fortunately I didn't break anything critical and the fuse is only $3.

But seriously, what kind of company bolts down fuses? :dunno:
 
9

97TSiAWD

In need of more traction
Jul 18, 2006
124
0
0
Michigan
jetjock said:
One who understands ampacity and the limitations of spring contacts. And the item in question isn't a fuse. It's a fusible link. There are significant differences between the two.
Click to expand...
Well, I did ask that question jokingly (yes, even with the "but seriously" part in there), but thanks for the clarification. It's not like I doubt Toyota's engineering capabilities. :biglaugh:
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
No problem Jon. Here, I'll bore you with the details:

Spring contacts for fuses (and many other things) are "turned" out. You know, wider where you insert the fuse. This isn't so you can make it easier to install. It's so the narrow part (the part that makes contact with the blade and handles the current) has a small surface area. This increases contact pressure. Think of a woman's high heel and how all the force is concentrated onto a small surface area.

The flip side is the same small surface area means less ampacity ie; it can only handle so much current. You could design a spring contact with enough area and spring pressure to handle 100 amps but it would be much larger, too large to fit in the fuse box. The solution is a bolted contact.

I'll skip the fuse/fusible link differences before you fall asleep ;)
 
9

97TSiAWD

In need of more traction
Jul 18, 2006
124
0
0
Michigan
IJ. said:
LOL kidding I have learnt something for today thanks! :)
Click to expand...
Same here. And it makes sense. Thanks for the info jetjock.

While we're on this educational sidebar, what's the reason for the 14mm hex bolt "caps" that hold the "3rd cylinder head cover" on? Why does there need to be an entry to the cylinder head there? Does it gain access to something I'm not thinking about?

The only somewhat relevant info I could find was another jetjock post in this thread, but he's just mentioning its potential for leaking. :)
http://www.supramania.com/forums/showthread.php?p=95745#post95745
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
The reason they're there is to hold the 3rd cover on ;).

Several (or all, I don't recall) of the hex plugs open into the head oil drain spaces. I haven't a clue as to why Toyota designed it that way. Maybe it has to do with the casting process. So the cover isn't really needed but the plugs have to be there.

The center cover supplies an elastomeric seal for each plug. As stated in the other post I've seen oil that had weeped or misted past the plug threads when the third cover was missing. It was only a bit but was enough to be mistaken for bad valve cover gaskests by the owner.

It's likley this only happens with a plugged PCV system (the engine in question had one) but if you're not going to run the third cover I recommend providing another form of thread seal. You can use an O ring in the reccess that is cut into the top of each plug or a bit of thread sealent. Or at least be sure everything is clean and torqued down. Same if you use the cover but the sealing on it is missing because of polishing or deterioration.

I prefer using the cover myself. Mine is original and in near pristine condition. It's not the heat that deteriorates them. It's oil leaks, usually from bad valve cover gaskets. Call me anal but I don't tolerate even the slightest leaks of any kind on my vehicles.
 
johnathan1

johnathan1

Supra =
Aug 19, 2005
5,056
1
36
36
Downey, California, United States
Why doesn't the TSRM tell you to use silicone on the valve cover gaskets? I listened to them, and had so much oil leaking that my car looked like it was on fire when I pulled up to a light after installing them...replaced them and put silicone, and all was dry again :).
 
You must log in or register to reply here.
Top Bottom