The diesel Tiny Tach sold here is http://www.tinytach.com/tinytach/diesel.php is superb, They have updated the design and it no longer uses an internal battery, it uses 12V power, and updates much more frequently than previously.

The 6mm transducer is the correct one for our vehicles,

I cant recommend this product highly enough, its superb. If you need a tach for your 240D this is it.


Check out my comming diesel SEC buildup thread for pics of it in action.

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

sorry, so how does it attach? Particularly on a car with no dash tach?

It would be nice for troubleshooting and adjustment... plus the hour meter is good for operating metrics.

JMH

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

the old version was BS, the internal battery lasted <1 year, (prolly due to the hi temps inside the car.) I started out loving it and ended up cursing it.

It has a transducer that connects to one of your injector hardlines and it counts the pulses and displays your rpm.

__________________
Cheers,
Robert

I did not want to buy it untill they updated the refresh rate and its lifespan, now it works great. It connects to any injector hardline, it seems to be very accurate. mine is mounted inside the gauge cluster, where the tach/clock was.

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

So nobody has a pic of their's.....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Wow that looks like a very simple install. Too bad they don't have an analog gauge to match the rest of the car gauges. Either way for $100 it seems like a great addition.

__________________
1974 240D 3.0L 4(M) - 250K -OM617.910 + 300D FW + Rajay turbo power!
1977 6.9 3(A) - 84k

For $100 it would be cheaper, easier and much more stock looking to get all the tach parts from a junkyard car and buy techguy's amp.

Would the 6mm transducer work for my 190D? The injector lines seem smaller than the 240D. Hope its not to dumb of a question.

__________________
Dave

1985 190D 2.2 auto--gone
1975 240D 4-speed--storage
1985 500SEL--daily driver
1985 300TD--bad rust, soon to part out...
1982 300SD--waiting on engine from RD
1984 190E--storage
1996 Dodge 2500 Cummins--daily driver

injector line size should be 6mm, but measure with a caliper for sure,

And Forced, Its not always easier to go with a stock solution, I have an engine from an 85, a bellousing for a 240D, and alot of custom work, The tiny tach is better than a stock solution for me.

Maybe not for you, but you can read your rpm in 10 rpm increments.

With the hour meter feature if i ever have to lend my car I can tell exactly how long the engine was run for

This is the perfect solution for any engine swap situation where you cant get a stock tach solution to work.

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

None of which matters one bit, the stock tach system from a 300SD will install for you just as easily. Your engine already has the crank sensor mount and reference pin on the vibration damper. All you have to do is put in the pickup sensor, amp, tach from an 81-84 300SD, run two wires between the amp and gauge, attach the ground wire and connect the power wire to any switched 12V power source.

Nobody needs that level of accuracy. 50-100rpm accuracy is more than good enough.

There is no situation where the stock tach cannot be added or made to work in a W123 or W126 diesel.

I considered that option, however All the tach amps I had were flaky, I did notice that there are new ones available, however, I decided the tiny tach was a better option for me.

I also have a gps system mounted right on my gauge cluster, so the digital tach was better for me,

to each his own..

Also the 617 can be swapped into other vehicles than the W126 and W123, and w124

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

As can the tach system. MB did a great job not building it into or depending on other systems to operate.

What is the principle of operation of the transducer??

__________________
Dionysius

Every time the injection pump pumps fuel the injection tubes expand a tiny bit. It senses that expansion somewhat like a g@sser tach would sense an electric pulse through a plug wire.

Thank you for this. It is probably a piezo electric transducer then since it senses pressure......

__________________
Dionysius