The International Cessna^® 170 Association

I need to change the shaft and coils of my old delco generator, it broke some weeks ago, and i want to know much does the complete gen cost in USA and if mine one, i think the PN is 1101876 is the same than the one in the later 170B, because the guys from the mechshop wants 300 USS just for replacing parts and i have a friend with a grounded 170B. Cant the shaft be done, is it very dificult to an experienced machinist? Hope to get this stuff fixed asap, you couldnt believe how much bad lack im having with this tripo to work in the atlantic coast of my country. My best regards.

The Delco 1101876 is a 12-13 Amp generator. El Reno's catalog shows an outright price of $299, and exchange of $247 (assuming your gen is rebuildable. I suspect that if your shaft failed and allowed the armature to damage the field coils, that may explain the estimated $300 price for replacement. If that is true, then you'll receive very little trade-in value for your failed unit. It may not be worth the cost of shipping it to them.)
Aerotech (in Louisville, Ky) 800/634-0190 told me their exchange price is $177.50 with a $125 "core" charge, meaning that upon their receipt of your failed gen they'll assess the damage and determine how much credit they'll allow for it. I used Aerotech for my recent gen purchase and was extremely pleased with their work and customer service.
Alterfede, it's an expensive phone call for you, so I called them and talked to "Sandy" who suggested you email the manager "Mike" at:
mike@aerotechlou.com for pricing/shipping information.

Let me make a suggestion or two. Make certain you replace the entire generator/tach housing gasket (PN 652072) as a single piece unit. Do NOT cut it or alter it. Make certain you also replace the tachometer drive housing-shaft seal (PN 642714) just above the gen mounting. If you don't you'll likely suffer oil leaks.
Install the new gasket with Permatex gasket sealer (very light film on both sides of gasket.)
Both seals/gaskets can probably be supplied by Aerotech. Be certain to confirm with them that you must remove your gear to re-use on the new generator.

Regarding swapping for a generator from another airplane: The only exact replacement part will be identified on it's data tag with the same part number. Your 1101876 gen is a 12 Amp gen, while other airplanes may have a 1101890 (20 Amp), or 1101879 (25 Amp), or 1101898 (35 Amp). If you change generator part number you MUST also change regulators to obtain maximum amperage and also to avoid burning up your generator. The regulator pn's are: 1118383 or VR-300-12 (12 Amp), 1118736 or VR-300-20 (20 Amp), 1118384 or VR-300-25 (25 Amp), and 1118704 or 1119145 or VR-300-35 (35 Amp).

Another consideration is that in order to use the 35 Amp gen, your crankshaft MUST be a dampened one. Your engine serial number should have a "D" letter within it and/or your crankshaft prop flange must not have a 1/4" hole drilled through it between the prop bushings. The 1/4" hole identifies an UN-dampened crankshaft and must not be used with a 35 Amp generator.

If you must purchase a generator outright with little/no trade-in for your core, then now is the time to consider upgrading to a higher amperage unit. In the U.S. it is illegal, but I don't know about Argentina, ....perhaps an appropriately rated (amperage) automotive regulator could be used which would be very much less expensive. (Here in the U.S. the aircraft regulator is $175 but the virtual twin in the automotive industry is $18-$25. You MUST be certain to use only the correct amperage regulator matching your gen to avoid gen damage. The only substitution is to use a smaller amperage regulator than gen. This would work without damage, but it would also only allow the lower amperage rating of the regulator to be produced. For example, if you presently have a 12 amp regulator, but you install a 25 amp generator, then the maximum amperage that will be produced is 12 Amps. But if you have a 12 Amp gen and use a 25 Amp regulator,...then that regulator will demand the generator produce the full 25 Amps or else! and will burn up the generator.) (Unhappy thought for the day: Is this what happened to your present 12 amp generator? Do you have a larger regulator than 12 Amps?)
Good luck with this, and let me know how your problem works out.

(Alterfede, I rec'd your seperate email, and replied only here because I think most subjects have wide interest for others. Many times I receive private emails from 170 owners who likely think they don't wish to "bother" others with what they perceive as a minor and/or personal matters. But the value of a discussion forum is that we all learn from each other. I'd be willing to bet that I learn more from all the other members here than I contribute, (particularly from Flyguy (Ole'Gar) with regard to proper use of the English language, ...and with the possible exception of Joe Harris whom clearly has his mind set about certain matters without regard to fact or science. He lives at a higher lattitude (farther from the equator) than you and I do and he thinks therefore earth's rotation there is a higher speed. )

Goerge, i really apreciate what you (mean you and the other people in this form) do to help me. Thanks for calling those shops, but as i need this stuff as soon as possible i think a local solution will be best, i got to work with the plane!. About the regulator, i think it is the original one, but i say this just looking at it, not sure. The shaft cracked between the seal and the bearing i think, maybe because it is too old, who knows,here in argentina is very rare to find a plane with all the records and the true records too. Ill have to check the regulator i have and tell my friend wich PN is his generator. My plane i think has a long story like many others here, that involves even some corruption of the aviation authority reagrding to the mechshop which did the last annual before i bought the plane, i think we have a bribed IA here, can you believe it was put back into airwothiness with nav lights changed positioon , red in right and green in left, and some more things me and my mech found out and solved in last annual. good thing was the price 18K, hope the engine was done in proper way

It is a long sotry but keeping it short (but i think is has to be very normal in some places ), got to do a long ferry with not many airports in between and without any services. Well this is very messy because he dealed with the shop in buenos aires, but the thing is mine and we both have little money, that is why we need to start doing sightseeing flights asap. And nobody here, altought the economical crisis beats us all in the same way, does any kind of financing, and we DO have to maintain low prices and good services. Letsee what happens now, sorry about my writing, got to practice how to tell things in english and im very new in aviation, 5 years as pilot and 1 year as owner ina third worl d country,and flew very little in the 70, just 30 hours. Saludos

Fede,I don't know if it'd be legal or not,especially if you're doing sight-seeing flights for hire,but you might be able to remove the generator for repair and still keep the airplane in service. Fabricate a blank-off plate to bolt on in place of generator,install oil-tight with gasket. Charge your battery with a battery charger,I think this would be enough for several starts. Recharge between flights as necesary. Use of lights,radio's,beacons,etc will of course run down the battery quicker.
A friend of mine has a 1931 Stinson Detroiter powered by a Lycoming R-680,he needs an electric starter but doesn't want or need a full electrical system. This is what he does.
Good luck with it. Arriba!

Eric

George..... Is a dampened crank needed for a 60 amp alternator
Bob

Well, guys, seems im lucky, i finally got he bucks for the gen, it was hard and fast (it is not what you think ). Thanks again to you all, and to continue with this topic, what are the advantages and disadvantages of the generator to the alternator. Would be this interesting (at least for me)? Saludos

A couple of the differences are that a generator can recharge a dead battery, while an alternator cannot. A generator is affected by RPM - at low engine RPM the lights, etc are using more volts than the generator is supplying, while an alternator is producing the required voltage even at idle.

N1478D wrote:A couple of the differences are that a generator can recharge a dead battery, while an alternator cannot. A generator is affected by RPM - at low engine RPM the lights, etc are using more volts than the generator is supplying, while an alternator is producing the required voltage even at idle.

More accurately,there must be an external power source to excite the alternator before it can start charging a dead battery--ie,a jump from another (charged) battery. An article about this in The 170 Book sez that this can be done using a battery of a different voltage,such as a 6 volt motorcycle battery or even an ELT battery.

Eric

zero.one.victor wrote:

N1478D wrote:A couple of the differences are that a generator can recharge a dead battery, while an alternator cannot. A generator is affected by RPM - at low engine RPM the lights, etc are using more volts than the generator is supplying, while an alternator is producing the required voltage even at idle.

More accurately,there must be an external power source to excite the alternator before it can start charging a dead battery--ie,a jump from another (charged) battery. An article about this in The 170 Book sez that this can be done using a battery of a different voltage,such as a 6 volt motorcycle battery or even an ELT battery.

Eric

Accurate, or not accurate - if I am out camping in a remote location and the battery goes down, there is an advantage to having an airplane with a generator. Even if an excited motorcyclist does not happen to motor by the campsite, the airplane can be started by hand propping, and with the dead battery, the generator will function.

There are more differences than these, and a lot of people have chosen to upgrade their planes to have an alternator.

Also, don't forget that if your battery is completely dead, you must find power to jump across the battery solenoid thus closing the circuit to the battery so that it can be charged.

Well I'm frustrated! I got home on Wed, on Fri afternoon the local shop went to work on finding out why I had no Electrical. Generator had a one bad brush and wire off the other. Rolled er out the door at closing, started right up, but not charging. We'll look at it after the weekend.
Mon afternoon - regulator checked out, bridged (battery to generator?) something to excite something. Anyway generator voltage isn't putting out enough. What I see is - Everything is good until I turn on lights or something, then amp meter drops neg further each time. They're thinking generator not good, so after Christmas eve / day. Thurs we'll pull the generator and take it to someone in Clarksville ( wait for him to fix it ) thurs or Fri? Then the weekend and I fly back to Alaska (work) Mon morning. actually more like
And I banged the tail feathers into the maintenance shop door when pushing it in this last time. Easy fix, but still can't wait to get a new paint job so I can bang it in to everything!

Don't know if it applies to your plane. but awhile back I had a intermittant gen and traced it to the master switch contacts being a little corroded and not allowing the field circuit to complete. The master switch is a two part switch ( or two in one ) and the brass contacts get a dark coating on them and low voltage doesn't get through.

I lost my generator output over the Blueridge Mtns at night a couple of months ago. New generator and solid state regulator. Problems was the panel fuse to the regulator. When I took it out, it looked like a relic from the dark ages. All burned up and cruddy looking, and the end cap appeared to be almost welded into the fuse holder cap. A new fuse has restored normal operation for the last couple of months, but I do wonder what it was that caused the original fuse to become so damaged?

Yes, my generator fuse was distorted also. Looked like a big brown S, but still working.
TODAY (Fri) evening found out the armature is shot in my 35 amp generator. It just so happened that there is a matching 35 amp generator from a late 50's 172 laying on the floor at the maint shop. They upgraded to an Alternator last summer. We called the owner and he said we could put the generator & new regulator on my plane and if it works, give him $175 and if not, take it off and try something else. Does this sound like a descent deal My mech is ready to jump on it in the am (sat).

What is the cost of switching to the Alternator? Should I change?
The generator has always worked just fine for me, but I'm wondering if it will keep up with the load now, GPS, Transponder, Radio, Pulsing wing tip strobes, beacons, old strobe, landing lights, Sony CD Stereo.
I mean, what made this fellar change to an Alternator?

For $175 you can get a completely overhlauled gen from Aerotech (in Louicville, Ky) complete with a warranty. And just because your gen quit doesn't mean your regulator needs replacing too. I think that some mechs are so ignorant of electricity that their attitude is to replace everything....needed or not. What a waste of money.
The only reason to "upgrade" from a gen to an alt is to get more amps (if needed, ...rarely necessary), save a few pounds of weight (3-5 lbs) but hardly worth it unless there are other compelling reasons, ...or if you are consistently experiencing discharged battery due to long waits in line for takeoffs at night at idle power settings (usually only at large airports, and even then only if departing IFR with low ceilings should it become a problem. It's a simple matter to just increase RPM to 1200 or so for a while or switch the landing lights off while waiting in line. I'd first question what I'm doing that sort of operation in a single engine airplane to begin with, before I'd consider the expense of an alternator conversion.) There are a lot of other items I'd rather spend $700 on before I'd just arbitrarily throw away a reliable and rugged generator system and switch to a more fragile alternator.