Welcome Guest [Log In] [Register]
Posted ImageWelcome to the all new Geo Metro Forum. We hope you enjoy your visit.

You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features:

Join our community!




Username:   Password:
Add Reply
Aftermarket tachometer for 3 cylinder?; Want it for testing and timing the engine.
Topic Started: Dec 8 2012, 08:16 PM (9,448 Views)
BMasiak
Member Avatar
Member
[ *  *  * ]
chevystrong90
Oct 27 2013, 04:23 PM
I'm curious is if I go to autozone and purchase a tach that has a switch on it from 4-6-8 cylinder if I put it on the 4 will it read accurately.
I have a tach from HF that has the 4-6-8 setting. At first I set it to 6 cylinders, and multiplied the tach by 2, but now run it on 4, and it's pretty close. It's pretty simple math, when it shows 1000rpm it's at ~1333rpm, 1500 is ~2000 etc.
Offline Profile Quote Post Goto Top
 
PTA2PTB
Member Avatar
I'm totally awesome! I swear.

David95237
Oct 27 2013, 05:02 PM
Now that's in my price range. Know anyone that's bought one? I'd like to get some feedback on how well they work before bustin out $9.98 + shipping for one.
Offline Profile Quote Post Goto Top
 
David95237


I use one for small motor repair. you tell it if its two or four cycle and put the wire around a spark plug wire. But I have used it on a Metro also. For test purposes.
Offline Profile Quote Post Goto Top
 
truckjohn


So... Why would you need a crazy correction factor?
They key off of the spark signal to the #1 cylinder... It fires 1x per 2 revolutions like basically every 4-stroke engine....

There is no correction factor for 3 to 4 cylinders like on the factory gage tach cluster... Those count ALL the sparks to all the cylinders... On a factory gage cluster - you gotta fix the 4/3 thing... but that doesn't apply when you clip the clippy thing to the #1 spark wire...

Thanks
Offline Profile Quote Post Goto Top
 
BMasiak
Member Avatar
Member
[ *  *  * ]
truckjohn
Oct 27 2013, 06:18 PM
So... Why would you need a crazy correction factor?
They key off of the spark signal to the #1 cylinder... It fires 1x per 2 revolutions like basically every 4-stroke engine....

There is no correction factor for 3 to 4 cylinders like on the factory gage tach cluster... Those count ALL the sparks to all the cylinders... On a factory gage cluster - you gotta fix the 4/3 thing... but that doesn't apply when you clip the clippy thing to the #1 spark wire...

Thanks
Most of them do not key off the spark signal to the #1 cylinder. Not unless you get one that has a pickup for the spark plug wire, which doesn't seem to be all that common in the cheaper tachs.
Offline Profile Quote Post Goto Top
 
perfesser
Member Avatar
Elite Member - Former Metro owner

chevystrong90
Oct 27 2013, 04:23 PM
I'm curious is if I go to autozone and purchase a tach that has a switch on it from 4-6-8 cylinder if I put it on the 4 will it read accurately.
It will if you have a 1.3.
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Engine Tech & Diagnostics · Next Topic »
Add Reply