Anyone got a Perkins 4108 to hand - electronic rev counter retrofit

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nimbusgb

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I want to make up a chopper disk to drive an electronic rev counter. Basically a circle of 3mm mild steel plate with slots cut into it to drive an inductive sensor. ( if anyone else wants one I'll be happy to get them cut at the same time )

I'm looking for the OD of the crankshaft pulley, the overall diameter of the bolt head in the centre of the pulley and the diameter circle proscribed by the 3 threaded fan mounting holes , Pitch Centre Diameter is think is the technical term.

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Hi, I am also interested in fitting a CANbus/NMEA2000 interface to my boat engines - 2 venerable Detroit Diesel 453n's. Some more info on your installation would be much appreciated.

Regards

Hugh
 
Re: Anyone got a Perkins 4108 to hand - electronic rev counter retrofi

Yes, I've got one to hand, in the garage & just taken off the measurements that you've asked for.

Crank pulley: 146mm dia
Centre Bolt: 38.5mm from across the flats of the bolt
PCD of the three holes: 44mm
cross check on the pcd: the distance between centres of the 3 holes is 77mm so if you set out an equilateral triangle with the corners 77mm from each other, you can check the PCD

let me know how your instrumentation project goes as I may be interested to do the same with my engine.
 
Re: Anyone got a Perkins 4108 to hand - electronic rev counter retrofi

You are a scholar and a gentleman.( Even got the measurements in units I understand /forums/images/graemlins/laugh.gif ) Thank you! Will update as soon as project is done ( March is next trip to boat I hope )
 
Would it be easier to integrate signal from an optical rev counter ?

I have no RPM gauge for my 4-107 and I'm thinking to rig an optical job in front of crank-pulley with reflective strips on the pulley.

Model shops do hand RPM meters for about 20 quid ... and others, some of the classier models have connector leads to feed gauges.
 
A hall effect transducer costs £18 from RS. sensor . It's an industrial unit, fully sealed, optical units tend to get dirty and signal discrimination deteriorates. Revs are integrated with oil pressure, water temperature ( fresh and sea ) Exhaust temperature, Alternator output voltage , engine hours and engine room temperature all on one display. The same signals can be fed to the e-series for back up and a second display could be fitted at reasonable cost at the chart table.

You could use the output from one of these hall effect transducers to drive a simple counter/timer circuit from maplin if you didn't want to go to the expense of CanBus instrumentation. You could also use the same chopper disk for an optical sensor.
 
Interesting ... as some twit removed the gear connection to fit the original cable Rev counter to my engine, so have been looking at ways round that.
Will have to see about your alternative. I only need simple revs ...
 
Don't know the circuitry involved with your index disk, but if it's just a signal squarer and then a calibratable counter, why not use the raw AC signal from the alternator like Volvo ?(and others).
 
[ QUOTE ]
Don't know the circuitry involved with your index disk, but if it's just a signal squarer and then a calibratable counter, why not use the raw AC signal from the alternator like Volvo ?(and others).

[/ QUOTE ]

Are you referring to the 'W' terminal ? It's a long time since I had alternator off and I mean to check for that. On Ebay there are a number of 'W' terminal tachos and it would be good if it can be done.

I've just today ordered this :

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&Item=220326141422&Category=40004

as I would need to calibrate / check any system anyway that is finally fitted.

After reading this thread and the sensor that nimbus is illustrating. There are various ways to do this. Even a paddle wheel speed log would do it - as it has magnets for pulsing. But then you'd need to convert displayed numbers to rpm from knots ! So I've been looking for magnetic pick-ups that are not slotted teeth type as in the thread. Seems there are some - but then it needs interpreting the pulses developed.
Back to 'W' terminal !!

In fact a standard type like that would sit nicely with the analogue fuel gauge I fitted.

Before closing this reply - does anyone have a complete cable / gauge set-up for a Perkins 4-107 ?
 
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