After having my 170A no longer show a charge on the ammeter, I followed the trouble shooting steps in the 170 electrical manual that George wrote. Thank you for doing that, George. I have found that I need a new regulator.
I’ve read a number of threads on here and will likely go with the Zeftronics regulator, however I’m not sure the size of my generator so I can order the correct regulator. I have a ‘51 A model. It seems to not have too many updates over the years, but the bad regulator looked pretty new (although not mentioned in the logbooks). The decal on the panel for the generator fuse says 15A, but I did read in one of the threads that some 170’s had 20A generator’s with the 15A decal.
What is the best way to figure out which generator I have? I didn’t see a part number on it, but I admit it was getting late and I still had the cowling in which limited visibility.
Thanks, Doug
Here are some pictures of my regulator just for fun.
The only way to know the size of your generator is by part number. The panel overlay stencil did not change, but the generator did. So it is likely you have a larger generator.
But if I were you, before you buy a regulator, run a ground wire from the base of the regulator directly to the engine. I prefer a ground point near or directly on the generator. Your pictured regulator is only grounded with the bolts at the bottom to the firewall. This has proven not to be the best most positive grounding method. You could temporarily attach a ground with jumpers for testing purposes.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce,
I did run a ground to the engine from the case of the regulator per the instructions in the electrical manual and it still did not charge. See picture showing my method and let me know if I did it correctly.
I’ll have to go see if I can find the part number on my generator. Do you know where on the generator it is located? Do you think I’ll need to remove the cowling?
The gen data tag is a small oval tag rivetted to the gen case similar to where it is on your starter. (They are both made by Delco-Remy.)
You can jumper that ground wire from the small screw on the side of the reg (exactly as you did) and to the mounting bolt of the reg. Or you can run it to the eng as Bruce suoggested, either way.
Try RE-POLARIZING IT AGAIN now that you’ve grounded it.
Have you checked for continuity of the gen field across the master switch? (Run a jumper from the gen FLD terminal to the reg FLD terminal after polarizing to see if that will activate matters. If so, then the contacts or wire thru your master switch is failed.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I’ll try your check to see if it is the master switch. I did see that at the end of your troubleshooting instructions in the electrical manual, but in the second or third step I ran a jumper from the regulator field terminal to ground and the generator did show a charge. The instructions then said it is a faulty regulator. Because of that and running out of time I didn’t go any further.
I polarized again and still no charge. I jumpered between the generator field and the regulator field terminals and still no charge. I believe that means a new regulator is in my future...
Generators: Pretty reliable proven design and easy to service. If you run down the battery somewhere by leaving the master on, you can hand prop it and the generator will produce a charge. (That’s not the easiest procedure on the battery or conducive to long battery life but you can get home and the radio and lights work.)
Alternators: Much lighter weight, more efficient electrical production at lower rpms. Requires some current from the battery initially to excite the field to be able to generate current. If your battery is totally dead, you may be able to hand prop it but you won’t get the alternator producing current until you can introduce some voltage into the system.
David, your temporary grounding of the regulator looks good.
Do George's test of the master switch. If it has failed, your regulator won't work.
If in fact you find the regulator to be your issue, swapping for a alternator is a bigger project then fixing what you have. On the other hand 12A is a bit on the small side depending on what equipment is installed and how your fly your airplane. Somewhat easier would be to replace your 12A gen and regulator with a 20, 25 or 35A gen and regulator.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
If you do swap out your 12A for a higher Amp gen/reg setup, don’t forget to check/upgrade your Armature lead (wire) gauge and C.B./fuse accordingly.
A “D” in your engine serial is indicative of a dampered crankshaft ( early, undampered cranks have a 1/4” hole in the prop flange between bolt holes and are extremely rare these days.)
Note: edited for error correction
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
Well, for now I’m going to stick with the 12A generator since I found a Zeftronics regulator on EBay for a good price.
I do think an upgrade will be in the future, but I’ll time it with other electrical changes (I’ve got a long wish list )
I definitely understand the need for the correct wire gage if I upgrade, but what is the requirement for the dampened crankshaft for? Is that required with an alternator or just the 35A generator? I’ve got a C145-2.
Thanks for everyone’s help! I’m learning a lot. Hopefully I can help other 170 owners in the future like you guys do.
The increased drive-load of a 35A generator creates vibratory interactions with the crankshaft that an undampered crank cannot reliably withstand.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
gahorn wrote:The increased drive-load of a 35A generator creates vibratory interactions with the crankshaft that an undampered crank cannot reliably withstand.
gahorn wrote:... Make certain you also have a dampened crankshaft, indicated by ... the absence of an extra 1/4" drilled hole between prop bolt holes in the prop flange.)
gahorn wrote:... a 1/4” hole in your crankshaft prop-flange are indicative of a dampered crankshaft (and undampered cranks are extremely rare these days.)
According to the overhaul manual you got it right the first time; "Early production C-145 crankshafts had no counterweights and were identified by a 1/4 in. diameter hole drilled between propeller bolt bushings through the propeller flange." According to Karl, you were also right with your most recent statement:
lowNslow wrote:[... there are many C145 cranks around WITH the quarter inch hole AND dampers. The only way to tell for sure is to remove one of rear cylinders and look inside.
I was able to see the counterweight looking through the oil filler neck with my low budget Vividia VA-400 boroscope.
