Photo tach SENDERS?

[Genesis]

Anyone have a source for one?

I've got an interesting issue, in that my tach drives (off the vickers pumps) are NOT an integral multiple of the crankshaft speed.

What this means in yeomans terms is that I've got a problem installing the flowscans, and since I have wet flywheel gears, there is no "tooth pickup" possible either.

I also have no good way to get an alternator connection, as they're single terminal altenrators with no external "tach" line.

So - I'm left with trying to cobble something up. I've had no luck thus far finding anyone who sells a photocell pickup. This would seem to be the obvious solution - an IR (or visible LED) photocell pickup that would work with a piece of reflective tape, just as do a handheld phototach.

So - anyone know where I can get such a sender that will work with Floscans (or any other electronic tach - I'm sure there's no difference there in terms of what I need)

Thanks in advance!

 

[Lucky Dog]

Try Aetna Engineering @ 1-800-776-7962

 

[MikeP]

Genesis,

I'm sure you have searched the web thoroughly but this thingie: http://www.techkor.com/industrial/lasertach.htm

sounds like it MIGHT have the potential to perform the task. Per the info, require an additional component and I can't tell if it can send data from the engine room to an instrument on the helm but it sounds to me like a possibility. I am no electronic tech; I'm sure you can quickly determine if it is useful or not.

MikeP

 

[Nonchalant1]

Karl,

What does FlowScan say? You have Detroit Diesel engines that lots of people must have FlowScans for. Is yours different somehow? My Flowscan sender works off the marine gear pump shaft too (8V71TI's). It was made to just hook up as a coupler between the normal tach angle drive (the $400 one) and the tach cable. If the 92 series engines have a different ratio than the 71 series engines, I'd think FlowScan would have a coupler/sender made for that ratio?

Doug Shuman

 

[Genesis]

I can get senders from Xintex that are pass-through (so my Glendinning will still work) but the problem is the RATIO.

Senders don't have a ratio - they just have poles. The ratio has to be in the drive. The problem I've got is that my ratio isn't an integer - apparently it is on most Detroits, but not on mine. You'd think it would be, but you'd be wrong, probably because of exactly where the vickers pump is mounted on these engines (its not on the camshaft PTO - if it was, it'd be 2:1, no problems)

The floscan can deal with any integer from 1 to 256 pulses per revolution.

The drive adapter is 4:1 - that's an integer. The problem is that apparently the ratio off the gear point where the vickers is attached is not - its an odd ratio.

 

[Nonchalant1]

Karl,

I get it about the ratio being a non-integer. I was just wondering how FlowScan hooks up to other engines like yours.

Maybe you can rig a separate drive stub off the blower shaft, a spare PTO drive or some other point? If your PTOs are camshaft driven, they'll be an integer of the crankshaft. I know that the tach drive stub Detroit uses is common to many different engine configurations like busses, big generators, trucks, so maybe they have multiple tach drive options.

Doug

 

[Genesis]

The blower shaft is not integral and depends on what blower gearing you have installed.

The camshaft drives are (obviously). I have one open - the other has the raw water pump on it.

I may have to go this route. I got out my photo/contact tach and it appears the ratio is 1:~1.9 at the tach drive outlet (the tach drive is a 4:1 reduction, so this implies that the drive at the input to the vickers is something on the order of 2.1:1. Getting EXACT is difficult due to idle wobble - there's always just a tiny bit (a couple of RPM) which at idle levels does matter.

Anyway, I may just mark it and live with it - its only about a 5% error - but I know it will annoy me over time. I guess I can see what a tach drive adapter for that other camshaft port will end up costing me.....

 

[NAN-PO 41]

If you have Delco alternators any alternator rebuilder can add an A/C tap to them that you can use to drive the tachs. I replaced my gear driven tachs with Teleflex units and thats what I did to drive them. I got the info direct from Teleflex Cust Svc.
Fred

 

[Genesis]

They're not - they're Neese-Leville alterntors and driven off the blower driveshaft....