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tach for aircraft power

J

Jason Allen

Well-known member
I am building an new instrument panel. Where can i find a mechanical tach? I have seen the ones that Classic offer, but am looking for some variety. Also what kind of luck have you had with electric tach's on aircraft power can it be done?

Thanks,
jason
 
There are tachs that you can buy that will run off a pulse generator or tachs that are alternator driven. You see in marine applications tachs that are driven off pulse type senders so they can be sent to separate tachometers. Stewart Warner, ISSPRO, Clark Brothers Instrument, VDO all make tachs that will work for that application. The electric tachs are all settable for the drive ratio for the tach drive of the engine. Heavy duty diesel parts places can usually get what you need easily enough.

Good luck.
 
I am running a tach from a mack truck on my 0540, been running it for 20 plus years
 
The pulse generator screws on the tach drive. You have to buy a diesel tach but it will work as long as there is a tach drive on the engine.
 
lgower":fxfwcni9 said:
I am running a tach from a mack truck on my 0540, been running it for 20 plus years
Click to expand...
Mack still offers a tachometer that runs 0~3,000 that also records Hours. Tach & cable from any of the older modles will work just fine. (I worked two years in parts at a Mack Dealership)
Mine was slavaged from the instrument panle of a 70's era Military truck...tach, cable and all.
 
what does an aircraft tach turn, 1.5, 1to 1 or what. I know something might be different, I tried to go digital and could not find a sender to work?
 
mwood7800":1ijagcv6 said:
what does an aircraft tach turn, 1.5, 1to 1 or what. I know something might be different, I tried to go digital and could not find a sender to work?
Click to expand...
I assume the ratio is 1:1
If Stewart Warner doesn't make it, it proabably doesn't exsist.
 
Aircraft tachs run a .5:1 ratio. I have a pulse generator that screws right onto the tach cable fitting on the motor that puts out 8 pulses per revolution and have a VDO marine tach set for 4 pulses per revolution. I went electric for a cleaner setup and have heard the hour meter is more accurate.

Larry
 
if you know of any big truck junk yards ' you can find mechanical tach's there for a few bucks ....check out olld macks i picked up 3 for 15 dollers in ocala, had to remove my self took all of 15 minits to pull all 3 out of old tractors .... all worked..as for hour meters those tachs count rev.s x100
 
Looks like the thread was started by someone looking to install an electric tach.
The same tach generator used on HD Diesel engines and industrial applications should work perfect for AC engines with mag. ignition.

Cable & mechanical tach is still a viable way to go, but it might not be the way some want in their boat, especially in tight places. Ironically I was looking at a '61 Ford F600 in the junkyard yesterday and it had a spanky new VDO tach mounted on the front grill (Front PTO water pump control) and under the hood was this 4"x4"x 6" box marked "Steward Warner Tachometer Control unit"
All the electric tachs I ever used just applied a ground, 12V and a lead from the hi-tension (-) side of the coil. Pulse Generators are real simple, again from something like a Mack Truck might just be the ticket, especially if you're running a six cyl. engine. 8)

If you go to a dealership, look for the "Old-guy" in the parts Dept. tell him what you're trying to do, and chances are he'll be able to help. :wink:
 
you can also get them that run off an alternator signal. If you don't have the proper alternator it's pretty easy to go inside the alternator and wire to get the signal. 8)
 
COLD":2pzcyfx3 said:
you can also get them that run off an alternator signal. If you don't have the proper alternator it's pretty easy to go inside the alternator and wire to get the signal. 8)
Click to expand...
YEP, forgot about that...it's actually a better choice than a signal generator and your alternator might already have the lead for it! (of course there could be some math problems to solve in calibrating the tach due to drive/driven raitos) Some applications also had mechanical tach drives on the rear of the alternator.
 
I think SW might be the only one other than aircraft dealers that still has a mechanical .5 to 1 tach aviable. I have not seen any electric senders with that ratio.
 
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