LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently March 29, 2020, 1:58 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
PostPosted: March 19, 2020, 1:48 pm 
Offline
User avatar

Joined: December 4, 2010, 1:53 pm
Posts: 64
Location: Edmonton, Alberta, Canada
Having had the unpleasant experience of being hit from behind in my Miata a few years ago, I looked into getting a switch that shuts off the fuel pump in the event of an accident. I couldn't find anything about it here, but I found lots of info from hot rodders. Seems a lot of them use a common Ford "inertia switch". The photo below is one taken from a 93 Crown Victoria. I used one from a 2004 Lincoln Towne Car which looks identical, and it did not have the heavy bracket around it. Look in the left rear trunk. Apparently they can be found in a Taurus as well. Make sure to install with the red reset button facing up. This switch is supposed to work in the event of a front or rear collision, or from a rollover.
cheers
Doug


Attachments:
20200310_150559-small.jpg
20200310_150559-small.jpg [ 172.86 KiB | Viewed 474 times ]

_________________
book 4AGE build, W58 transmission, Corolla GTS live axle
Top
 Profile  
Reply with quote  
PostPosted: March 19, 2020, 2:05 pm 
Offline
User avatar

Joined: July 17, 2008, 9:11 am
Posts: 5343
Location: West Chicago,IL
Having been rear ended many times in my DD's, frankly, one of the least of my worries about being rear ended in a Locost is shutting down the fuel pump. :ack: Other areas of impact, good idea. Don't forget a rollover check valve in the fuel vent line. I used one from a Jeep of some vintage/model.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE


Top
 Profile  
Reply with quote  
PostPosted: March 19, 2020, 2:25 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6557
It has been brought up many times. Try searching for "inertia". I've been promoting them since about 2008.
Most fords have them from 87-up.
Everything I build has one.
Cheap insurance. :cheers:

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447


Top
 Profile  
Reply with quote  
PostPosted: March 20, 2020, 12:04 pm 
Offline
User avatar

Joined: December 4, 2011, 6:19 pm
Posts: 779
Does anyone have any details on the performance of these Ford switches? How many G's required to activate? Reliability, as in what percentage of the time do they trip if exposed to the correct G load? Is the red button a reset? If so, how many times can one of these switches activate before requiring replacement?

The Emergency Location Transmitter (ELT) in small airplanes is fired by a G switch but they are notoriously known for failure with some people reporting failure rates in the G switch as high as 38% in real world situations. And, that's despite a regulation that the switches must be inspected each year by an approved avionics repair technician.

_________________
Bill H
Winnipeg, MB, Canada


Top
 Profile  
Reply with quote  
PostPosted: March 20, 2020, 1:58 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6557
It is a plated steel ball in a magnetic cup that bridges the ground side of a relay. It should be mounted in a clean dry place out of direct sunlight. The button re-seats the ball if it rolls out of the cup. That is why the orientation is important.

You could remove the screws and bump it with your hand to simulate an impact that should unseat the ball.

Some info on the ELT inertia switch testing: https://ntrs.nasa.gov/archive/nasa/casi ... 010544.pdf

Mazda used an output from the VAF to keep the pump on, so if the engine died, the spring loaded vane returns to its stop, and the pump stops.
GM has used oil pressure so if the engine stops, the pump stops.
I expect newer vehicles will stop the pump based on no trigger input from the engine.

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447


Top
 Profile  
Reply with quote  
PostPosted: March 20, 2020, 2:06 pm 
Offline
Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
Posts: 6027
Location: SoCal
I got mine from a Ford Mustang. Pretty sure it's the same switch in all their cars. The switch is just a ball sitting in a depression at the top of a cone. Enough sideways force in any direction knocks it off its perch and shuts off the pump.

Oh, and wire it so that it's in series with the fuel pump relay coil, so that you aren't running full fuel pump current through it.

_________________
Midlana book: Build this mid-engine Locost!, http://www.midlana.com/
Kimini book: Designing mid-engine cars using FWD drivetrains, http://www.kimini.com/book_info/


Top
 Profile  
Reply with quote  
PostPosted: March 20, 2020, 2:20 pm 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 6557
Inside a couple different types for ford.


Attachments:
90up inertia-switch.jpg
90up inertia-switch.jpg [ 41.39 KiB | Viewed 383 times ]
inertia sw.jpg
inertia sw.jpg [ 81.4 KiB | Viewed 384 times ]

_________________
MV8

https://www.youtube.com/watch?v=Om3C1Ep ... D3E18BB447
Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY