The International Cessna^® 170 Association

Depending upon the cost of repair of an existing tach, I may be in the market for a new tach. I have ck'd the usual sources (Spruce, Wag, Chief, etc). Wondering if any of you know some other good sources for a Mitchell Tach.? Appears they are selling for $175-$200 & up. Has anyone converted to an electric tach? I was considering doing so, but using one with a dial instead of digital. Thoughts?

Instead of repairing an existing tach, I'd spend the money on having the inst. shop set a new one's hour-meter to agree with my existing one, (or set it to whatever makes sense for the airplane if the existing one failed to do so, i.e., TTAF, or TSMOH.)

Frank-
I am not concerned about originality when it comes to the instrument panel or radios so I converted to the Horizon P1000 digital tach on a field approval. The P1000 is certified on the C-172 with the O-300 engine but they haven't gotten around to adding the C-170 to the AML on their STC yet. I had no trouble getting the field approval after discussing the C-172 applicability with the FAA inspector, there's not really much difference between the two installions.

I like the P1000 because of the large digits, it is a nice looking instrument, it records time, they will set whatever time you want the recorder to start with, lights indicate what RPM range you are in, and it will indicate a mag failure and tell you which one failed. The only problem it's a 3-1/8" instrument but so is the original. I think they are around $500.

The EI tach works just as well but is 2-1/4" instrument. I don't like the lights around the perimeter of the gauge on the EI, it has smaller harder to see digits, and it doesn't indicate a mag failure.

Ditto what Hilltop170 said. I like mine a lot (of course I did pay $480 for it ) and it has already clued me in to a problem on one mag which turned out to be a flakey P-lead. I've always preferred analog to digital instruments including my watches, but in this case I think it's a better instrument. If they made the same thing with a retro looking analog face and incorporated the same features I would have bought that one, but I prefer a more accurate instrument with more features to the older cable drive tach.

Thanks for the suggestions guys! Wondering if anyone has had any experience with the UMA Electronic Recording Tach? Looks like Spruce has them in the $285 - $375 range. I contacted Stahl Instruments up at Northwest Regional Apt (52F)..Ralph has been repairing instruments for many years. He has done some for me in yrs past. He guessed at around $100 to repair if repairable, but said none of the newer mechanical tach's were any good in his opinion. I have about 585 hrs on mine and he said that is better than average based on what he sees in his shop. He couldn't recommend any newly mfg'd mechanical tach. I would go electronic (prefer non digital) and don't really care that it does anything by give rpm's and hours, but I really don't want to spend $400 + .

In my quest to solve the tach situation I have been leaning toward a UMA electric tach that still has a dial indicator. There is a possibility I could have an interferrance problem with my alternator & the tach drive unit that attaches where the old mech. tach cable attaches to the tach drive housing. If this turns out to be the case it was suggested I purchase an "engine right angle drive" such as that shown in Spruce on page 408 p# 10-00814. Would this unit change the rotation of the tach generator or tach cable drive to counter clockwise instead of clockwise? Would hate to put the right angle drive on and have it turn things in the incorrect direction. Haven't found a source for the right angle drive other than Spruce & Chief. If anyone knows of alternate sources I would appreciate having them. Why does something as simple as a tach have to get so complicated and expensive