What's the best way to hook up a cutoff switch ??

[michel schryer]

Here it is,i'm waiting for my kit to arrive to papa on the 2nd of april and it's going to be my first kit car and hopefully i'll love it so much that i'll want to build another one. The electrical side of it is my greatest challenge,don't have experience with electrical though i've been hands on cars before.
Is there somebody out there that has a wiring diagram of your cuttoff switch hook up and wich one did you use. I intend to use a oem starter relay in my circuit with a one wire alternator. I heard stories about some other relays or solenoid failing while the ignition switch was turned off and the engine woudln't shut off. Want to use it as an anti theft as well. I read some guys hook it on the neg. side and some on the pos. side. Can somebody elaborate on that. Can you show me how to hook the switch please.thanks guys.

Michel

[Wayne Maybury]

I have a master cutoff switch mounted on the bulkhead just beside the pasengers seat. It is a marine type cutoff switch that cuts the power from the "+" side of the battery.

MSD has a built in ignition cutoff on many of their boxes like the 6AL. Just follow the directions to wire it up.

Wayne

[michel schryer]

Thanks Wayne,i guess the majority go with the positive side. I won't put Hi-tech ignition box,just the minimun electrical stuff,first build and lack of electrical knowledge.

Michel

[GlynMeek]

Michel...the MSD ignition box is usually wired through the main fuse box, and the positive from the battery 'feeds' this main fuse box anyhow, so putting the master cutoff in between battery and fusebox will disable EVERYTHING (which is what you want!)

Good luck...the wiring was actually the most difficult thing for me to understand in my build!

Glyn

PS there is a thread out there somewhere which explains the differences between putting on the +ve or -ve side. I seem to remember that MOST of us put it on the +ve, but for some reason the 'experts' preferred the -ve...EITHER works.

[wtm442]

Do you know anyone with a Superformance? Is there a dealer nearby? They use a handy shutoff in the trunk with a removable plastic key.

Remove the key and lock the trunk. Nice.

[SPF2245]

Just a simple battery terminal disconnect is what I have on all my cars. This set up allows a few amps to bypass to keep the basic power to the radio/clock ect. But will not allow enough juice to spin the starter. Cheap and easy to install.
http://www.microfiber-products-onlin...adiswandb.html

[GlynMeek]

Most folks just mount the shutoff behind the passenger seat like Wayne (and I!) so you don't even have to open the trunk!

[Wayne Maybury]

Yep, right beside the passenger seat. Completely cuts all power with the turn of a red plastic "key". No one even knows that a switch is there if the key isn't in it.

Wayne

[fastraxsg]

I've used a cutoff switch between the battery and the ground for several years in my roadster. The battery is trunk mounted and a short - wire leads to the cutoff then grounds to the frame. While it isn't mounted anywhere you can turn it off easy, it does work as a theft device just in case. Regardless of which side you mount it, or where you mount it, you can run a thick wire over the top with a 3 amp fuse between the posts on the cutoff switch and it will allow your clock or such to stay on but will blow if someone trys to hotwire your car. This will let you have theft deterant plus your low amp draw. Best is between the seats. Also best to spend the big bucks and buy a quality cutoff switch.
Another method is to splice into the little wire that charges your coil and attach it to a dimmer switch (dedicated solely for this) or other quality switch that can be hidden under a carpet. You know where it is but it isn't visable, and no one would be the wiser as to why it won't start. Assuming you don't forget.....

[jimw427]

Put mine on the positive side, with my one wire alternator wired into my kill switch. Had a problem with it not shutting off the engine after running. Through this forum learned that I had my one wire alternator wired to the wrong side of the cut off, switched it to the battery side of the cut off and worked like a charm.

Jim

[vettestr]

I have used many of the types on the market. Keep in mind that you get what you pay for and look close at the ratings of these devises, don't install a problem while trying to do the right thing with a low quality part. here is a good source for install and info
http://www.timskelton.com/lightning/...y_relocate.htm

If racing the sanctioning body will spec out the minimum quality and location of the on/off control or knob. In general I have used/seen 3 common types with photos below. My comments are intended to be generic not brand specific as are photos, non race general installs.

I have not had good luck at all with the green knob type as they corrode and connection gets funky, you can not clean inside plates (5 to $1o range). The plastic red handle type are often high impedance or have poor contact switching right out of the bubble pac (5 to 10 bucks). The metal body type with brass lugs are more expensive (30 bucks in Jeg's) but are rated and accepted by NHRA and SCCA. Marine or UL ratings on a part ensure what you are getting for your $$.

If this part fails it can be a simple tow bill or an electrical melt down but all possibilities are more BS than buying a quality part and a quality installation. I install on the positive side of the battery because I want to keep everything on a good ground. I also insist on a very small amp value fuse if a bypass wire for radio etc.. is used, say a fast blow 2 amp fuse and lower if possible.

Good info about ratings here http://www.colehersee.com/pdf/master_cat/t_battery.PDF

[michel schryer]

Thanks guys for the replies,I want to use the cutoff switch mostly for safety in case there was a short on the starter relay and the engine doesn't want to stop crancking,don't care about anti -theft,if they want it they'll take it no matter what. The car will hardly leave my sight and sleep in a garage but....
Did anybody bought the flaming river little switch,wonder if i should,don't know which one to choose yet ?

[Wayne Maybury]

The one I have is the one pictured to the far right by Vettestr. It is a black switch with a red plastic removable "key". Marine stores like West Marine carry a couple of different models.

Wayne