2H/12HT Tachometer (rpm) sensor/sender & gauge info thread

[Eurasiaoverland]

Here is the link to the IMPEX website for the part: New parts search — IMPEX JAPAN - https://en.impex-jp.com/parts/new/search.html?partNo=83180-60040%09

 

[WaifuBeater]

I think all the Japan based part suppliers (Amayama, Megazip, IMPEX) are Russian-origin companies. If you look at baza.drom.ru you see similarities with Amayama's logos etc.

I've had good experience with IMPEX - they are great at price and finding parts, but they are extremely slow. They also have a lot of very bad reviews online, though plenty of these are from people too lazy/stupid to read their T&Cs.

Yeah, I know about baza.drom.ru and use it regularly – they have lots of spare parts from japanese rhd vehicles. That's where I got my tach + sensor combo for about 150$ without shipping Some parts ad rare thingies are extremely cheap compared to what you can find

 

[Eurasiaoverland]

Yeah, I know about baza.drom.ru and use it regularly – they have lots of spare parts from japanese rhd vehicles. That's where I got my tach + sensor combo for about 150$ without shipping Some parts ad rare thingies are extremely cheap compared to what you can find

I have my eye on a couple of parts on Russian websites, the trouble is getting them out of Russia. Are Drom vendors typically happy to ship to Georgia? I had something shipped to Kazakhstan last year, but KZ is in the Eurasian Customs Union, which I believe Georgia is not part of.

 

[WaifuBeater]

I have my eye on a couple of parts on Russian websites, the trouble is getting them out of Russia. Are Drom vendors typically happy to ship to Georgia? I had something shipped to Kazakhstan last year, but KZ is in the Eurasian Customs Union, which I believe Georgia is not part of.

No, Georgia isn't a part of this economic union, which makes some things easier but some more complex. The vendors can technically ship parts via CDEK (cdek.ru) but it's gonna be more expensive because of the fact that it's an international shipping. Making payments is also an issue because of the sanctions, since they accept funds only in rubles within the ru banking system.

For me personally it's faster and cheaper to have the parts shipped within Russia to Vladikavkaz by CDEK and then my acquaintance who lives there drives to Tbilisi and back regularly and brings them to me for a fee.

So, as anything, it can be done but can be a PITA because of the current state of affairs.

 

[WaifuBeater]

Finally got to fitting the sensor (with a while bunch of other vehicle jobs unrelated to this thread).

Pulled out the tranny, removed the bellhousing. I didn't like the original placement of the tach sensor near the exhaust so I found two places where I built up two high spots with TIG and some aluminum filler, and then ground down the surface with a flap disc, finishing the "flatness) with a wide hand file.

Ordered an M20x1.5 tap and an 18.4mm drill with a thin neck from China. Technically it supposed to be 18.5 (thread diameter minus pitch) but I figured the drill is gonna wobble quite a bit when done by hand so I ordered 18.4. If anyone will attempt the same stuff without a drill press or a milling machine (or some other fixture that excludes drill walking) I recommend picking up 18.2mm because the threads I ended up with are quite wobbly (but PTFE tape or a thread locker will fix my issue).

The distance from the bellhousing face to the hole that I picked up is 25mm, although my hole drifted and on the inside it came out 27mm. Stil fine because the center of the flywheel teeth is also 27mm from the block face.

Will get back to posting updates when I figure out the electrical connections and which wire goes where.

 

[WaifuBeater]

Hi, xavsomehj

Not yet unfortunately, no progress except I have all the parts but not the time to do it.

My car came without the tach and, consequently, with no tapped hole in the bellhousing. Found the tach and sensor separately for relatively cheap, about 200$ us. It seems that you either need to drop the tranny or remove the exhaust downpipe to fit the sensor in it's stock place, definitely drop the tranny to make a hole and tap it if it didn't have one.

I'm hoping on getting it done this year. Have another sensor for Isuzu diesels

• ENGINE : 4HK1 6HK1 6WG1
• EXCAVATOR : ZAX200 ZAX240 ZAX270 ZAX290 ZAX330 ZAX370 ZAX450 ZAX470

part number 8973061131.
View attachment 3994336
It measures around 100 Ohm impedance – twice as less than stock but still might work. Although it's similar in length, it's mounted differently – has a rubber o-ring and a hole on the side for a scree to hold it against wherever it's inserted into. Meaning, if it's gonna work, you'll still need to drill a smaller hole and tap it alongside the hole for the sensor itself for the holding screw.

Since the stock mounting place for the sensor is very unfriendly I might just tig-weld another flat on the bellhousing somewhere on the other side, but that's a bit of a different story.

I'll definitely post an extensive update, but I cannot promise on how soon.

Success!

This sensor 8973061131 totally works even though it has a different static resistance. So far tested on idle only, both sensors gave me a ≈700 ±30 rpm just looking at our dash tach. I think it's gonna work in the whole range since it's pretty much a simple sine generator.

I've repinned both the stock and this one with chinese Deutsch DTM clones for compatibility to be able to hot swap them. Also this sensor will fit in our threaded hole but it needs either a small retaining bolt or a custom retainer plate to hold it in place.

Anyway, I think it's pretty much it, I'll keep using stock sensor while keeping this 15$ part as a cheepo replacement that I know just works. If anything new comes up I will post an update.

Cheers guys

 

[WaifuBeater]

Some pics of how I crimped and shrouded both of them

 

[WaifuBeater]

Success!

This sensor 8973061131 totally works even though it has a different static resistance. So far tested on idle only, both sensors gave me a ≈700 ±30 rpm just looking at our dash tach. I think it's gonna work in the whole range since it's pretty much a simple sine generator.

I've repinned both the stock and this one with chinese Deutsch DTM clones for compatibility to be able to hot swap them. Also this sensor will fit in our threaded hole but it needs either a small retaining bolt or a custom retainer plate to hold it in place.

Anyway, I think it's pretty much it, I'll keep using stock sensor while keeping this 15$ part as a cheepo replacement that I know just works. If anything new comes up I will post an update.

Cheers guys

@xavsomehj @KeepCruzin you guys were interested, so tagging you

 

[archerm3]

Quick question since you seem to have a handle on this system and 2H tach info here on mud seems to be less than complete. The original sensor has two wires, do you know what each wire goes to, and does polarity matter? Trying to repair mine with the middle wires missing...I seem to understand that one wire goes to the tach, and maybe the second wire goes to ground? Does the sensor not ground through it's own body?

 

[WaifuBeater]

Quick question since you seem to have a handle on this system and 2H tach info here on mud seems to be less than complete. The original sensor has two wires, do you know what each wire goes to, and does polarity matter? Trying to repair mine with the middle wires missing...I seem to understand that one wire goes to the tach, and maybe the second wire goes to ground? Does the sensor not ground through it's own body?

Polarity doesn't matter.

One lead goes to zero (frame/ground/chassis), one to tach input. But you should use the ground wire in your harness that connects to the frame somewhere around your dash, NOT ground this wire right away against the bellhousing or the frame. Otherwise you might get intermittent EMI problems with your tach and it can start acting weird.

Sensor doesn't ground itself through the body, it's made out of brass because brass is non-magnetic and only because of that.

There is an inductive wire coil inside that has a small magnet in it's center. When the flywheel teeth pass nearby the end of the magnet (behind the brass) the changes in magnetic field are inducing elevtrical current through the coil, which is then can be picked up by the tachometer.

Many modern sensor shells are made from thin stainless steel for the same reason – it's (almost) non-magnetic so this layer would not interfere with the magnet inside.