haven't i seen recently an advertisement for a product that allows you to mix-n-match tachs & engines? did i dream this? a bud here at work has spotted a factory tach for his truck that he can buy. but the factory (chevrolet) only put tachs in 8 cylinder trucks and his truck has a 6 cylinder engine. if i were at home i could look through my mags and maybe find it, but here at work i don't have those resources. darren thanks you for any/all information you provide.
depends on what signal you have to work with, square wave, analog, pulse? what is he putting it in? There are conversion boxes, used to put a skyline 6 in a 240, retaining the tach. they are for analog signals.
chevy pickup v8 tach into a 6 cyl chevy pickup of the same year (more or less; same mid-to-late 70's body style)
i seen a website some time ago when i was lookin for info on settin up a tach in my late model f-250. . . anyhow, the guy scratch built a sensor/brain box to convert a v-8 tach to liner 6. . . used a plug wire pickup from an old timing light... worked pretty well from what i remember. i'll do some diggin on the laptop and see what i kin find
To do 6 cyl tach to 8 you added a 15,000 ohm, 1/2 watt resistor to the sensing wire. I'd guess you take that much out to go the other way. Hopefully there is a resistor you can access in the back.
What year is the truck? I converted Vega tachs (all were 4 cyl) to V8 operation by changing the capacitor on the back of the tach. The capacitor is what changes the "timing" for the different number of cyl. Is your friend running an HEI? They would be the ones needing a different style adapter.
running truck w/ 6 cyl. is a '76. the gauge cluster he can buy is of the same generation, but unknown year.
His truck is probably using an HEI. The only knowledge I have of using an old tach on an HEI is when I posted on another forum about using a '66 Corvair Corsa tach on my '66 Corvair with a 4.3 and HEI. A fellow poster wrote that I would need to run a converter circuit in order for the tach to work. I don't have the car running yet so I have not tested his circuit. I think your friend should hook up the tach and see if it works at all. If it just wiggles the needle without showing any RPM he would need this additional circuit. If it shows RPM but at the wrong value he would only need to change the value of the capacitor as I wrote in my previous post.
hey, folks. this subject again... darren finally bought a dash with the gauge package from a V-8 truck and is going to put it into his truck that has a 6-cylinder engine. so we're looking again for the "magic box" that i saw advertised somewhere in one of the rod magazines. anyone know what i'm talking about or where you get them?
I swear one of these days we're gonna have a google tech http://www.dragonaero.com/TachChangerPage.htm
thanx squirrel. actually i did google; and got about 6,000 items to look through. after i looked at the first ten or so entries i concluded that everything i was coming up with was how to run an old tach after you replace your distributer with an hei. thanx again. a hunnert and fifty clams sounds higher than i remembered. are there any alternatives out there?
yeah, I noticed it was a bit pricy. have you guys seen this? http://www.stovebolt.com/techtips/tach/index.html
were you a hboa person, or bob gumm's site????? just wondering because years ago i remember tons of tech articals on this
Atch- Is your friend just trying to use the 8 cyl tach on an 6 cyl? If that is what he is trying to do all he has to do is change a capacitor on the 8 cyl tach. Should cost about $3 if he buys the most expensive capacitor he can find! Capacitors are available at Radio Shack for less than that. Even if he has to buy a soldering iron will cost less than $125.
it seems that on www.inliners.com site their was a tach. tech article. that site focuses on all 6 cyl. engines. or try www.stovebolt.com good luck
A little late to the party here on this subject, but I actually make a little converter box that allows you to use a 4, 6, or 8 cylinder tach with a 4, 6 or 8 cylinder engine. Bob --- [email protected]
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