Diesel Tacho help

Howdy doody all,

I have a 1991 Perkins TW6.354.4 6cyl - Non Marinized Diesel engine. At the moment she is in the processes of being rebuilt (Parts arrived today)

As you may or may not know, I am building my boat. As such, today I was designing my dash layout with the new sexy gauges I bought off the net.

Now ... I am in a spot of bother as I am not sure how I can hook up my Tacho. The gauge on the back has a switch that you can move to suit the amount of cylinders you have i.e. 4 cyl, 6 cyl, 8 cyl. From my experience working on cars, this switch is designed to tell the gauge how many pings to expect from the ignition coil thus creating a tach reading

Diesels don't have an ignition coil thus rendering this switch in operative in turn giving me no point to record a reading from which leaves me with no Tacho which I don't want.

I thought about fixing magnets to the harmonic balancer and have some sort of electrical thingy to record the magnet passes which effectively tricks the gauge into thinking the ignition coil is pinging at it and records the reading thus giving me a working Tacho.

What I want to know is

1. Has anyone encountered this problem and what did you do
2. Would my way of thinking work with the magnets
3. Has anyone got a better idea

Taking the gauge out of the cluster is not an option nor is putting it in and not hooking it up nor is buying a differently configured gauge.

Any and all help is appreciated.

Cheers
Hendo

iPad Forum Runner

Did you contact Faria direct? They have on line instructions and wiring diagrams too, check those out. Alternator can be the connection if designed with the internal pickup "magnet." The fly wheel or a front mounted dampener works for the pickup also.

sunchaser said:

Did you contact Faria direct? They have on line instructions and wiring diagrams too, check those out. Alternator can be the connection if designed with the internal pickup "magnet." The fly wheel or a front mounted dampener works for the pickup also.

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Yeah they sent me a PDF this morning. I was told about the Dakota DSL-2 that reads off the flywheel. Had anyone used one of these before?

Your tachometer(s) for the 6.354 should be alternator driven..... They will connect to the AC or W pin I believe... The best tachometer for that engine is the Teleflex 8230P heavy duty 3" tachometer for diesel engines. They are a direct replacement for the originals.

Even with a tachometer driven tach...you will have to know the number of poles in the alternator to properly get a starting set point, then calibrate the tach with a manual tachometer or to match an upper or lower station's....

Found this a while back when I was thinking of upgrading my tach.
http://www.aetnaengineering.com/pdf/Perkins.pdf

Good info, Mike. Thanks!

rochepoint said:

Found this a while back when I was thinking of upgrading my tach.
http://www.aetnaengineering.com/pdf/Perkins.pdf

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Thanks Mike!

http://www.aetnaengineering.com

Fixed the link to get to the main site. I need a new sender and I think I will use theirs.

Hi All
Thanks for your replies and provided links and suggestions. I've decided to buy the DSL-2 kit and hook it up that way. I looked into adding another pole to the alternator but not keen on that and I'm deadset against getting a separate gauge for the tach due to the set that I'm fitting so the DSL-2 it is.

Thanks again for everyone's suggestions. I value your input and support.

Cheers again

Hendo

iPad Forum Runner

The "best" way to drive a tach is with a dedicated tach drive.

Second best is an added magnet ot tooth counting pickup.

The problem with an alt driven tach is it is simply a guesstimate at RPM.

Even after its properly calibrated , belt slip will cause the RPM to change as the batts are charged.

Usually a ball park is just fine cruising at 1725 , 1800, or 1900 doesn't make much difference to engine wear or life.

Fuel burn WILL change.

The most important thing a tach will do is help to keep the engine from operating over loaded.

Run at full throttle , pull back 10% or 300RPM , and most marinizations are safe.

The Alt tach ballpark is close enough for this operation.

FF said:

The "best" way to drive a tach is with a dedicated tach drive.

Second best is an added magnet ot tooth counting pickup.

The problem with an alt driven tach is it is simply a guesstimate at RPM.

Even after its properly calibrated , belt slip will cause the RPM to change as the batts are charged.

Usually a ball park is just fine cruising at 1725 , 1800, or 1900 doesn't make much difference to engine wear or life.

Fuel burn WILL change.

The most important thing a tach will do is help to keep the engine from operating over loaded.

Run at full throttle , pull back 10% or 300RPM , and most marinizations are safe.

The Alt tach ballpark is close enough for this operation.

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I can live with Second best in this case :-D

iPad Forum Runner

Hendo78 said:

I can live with Second best in this case :-D

iPad Forum Runner

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Actually, the best way to monitor rotation is a sensor aimed at the rotating body. A hall-effect sensor, sensing gear teeth would be better than a magnetic sensor looking for a flag attached somewhere on the flywheel. But either way what he is doing is fine. It's not like a ultra centrifuge turning 120Krpm, or rocket science.

dhmeissner said:

Actually, the best way to monitor rotation is a sensor aimed at the rotating body. A hall-effect sensor, sensing gear teeth would be better than a magnetic sensor looking for a flag attached somewhere on the flywheel. But either way what he is doing is fine. It's not like a ultra centrifuge turning 120Krpm, or rocket science.

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Well I don't know what mine is other than it counts the teeth on the flywheel via a sensor that relays the info to a box that converts it to a signal that the gauge can accept as a rpm reading. Outside of that I wouldnt have a clue. Just happy I get to keep my cluster and have a working Tacho with some sort of reliability and accuracy ;-)

iPad Forum Runner

What your doing will work just fine.

dhmeissner said:

What your doing will work just fine.

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Phew..... Had me worried for a while there with all the technical mumbo jumbo hahaha. Ya have to speak slowly, use little words and use lots of pictures for me mate! Hahaha :-D

iPad Forum Runner