EI digital tachometer

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ghostflyer
Posts: 1390
Joined: Mon Apr 21, 2008 3:06 am

EI digital tachometer

Post by ghostflyer »

Has any body fitted a EI digital tachometer with slick mags . If they have what was the ohms of the resistors used on each p lead.
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n2582d
Posts: 2808
Joined: Mon Apr 29, 2002 4:58 am

Re: EI digital tachometer

Post by n2582d »

EI calls these resistors “isolators”. For what it’s worth, an EI rep writes the following on the Van’s RV forum: “The value of the isolators we include with the R-1 instrument are 79K and 47K ohm. Due to the differences in the mag output, different combinations of isolators are often necessary. I typically recommend starting with the 79K ohm isolator and observe the tach's reading. If it is very jumpy and high, you don't have enough isolation. If it reads 0 at lower power settings and jumpy low, you typically have too much isolation. If you'd like to PM me your address, I'd be happy to ship a package to you at no charge. You would only be responsible for shipping charges.

As I’m sure you’re aware, the instructions for the tach say, “These isolators should not be changed, lengthened or altered in any way. There is another set of isolators in the instrument. These isolators insure safe operation while providing an easy and simple installation free of mechanical cables and pickups. Make sure the mag lead screws are tight and the connectors are not interfering or shorting to any other terminals on the mag switch.
Gary
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ghostflyer
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Joined: Mon Apr 21, 2008 3:06 am

Re: EI digital tachometer

Post by ghostflyer »

Thank you for your offer, I have a number of “isolators” already and presently rebuilding my instrument panel. I was given a number of digital instruments from EI and have fitted all with the exception of the tachometer. I have some trouble removing my venturis . Some one had used some very strong bonding material . The screws were removed but it didn’t want to come off. I was worried I would break off the Venturi and leave the attachment base. I tried all sort of chemicals to soften the bonding material. I ended up separating it with liquid CO2 . This worked .
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