New 170B owner

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

Post Reply
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: New 170B owner

Post by Bruce Fenstermacher »

Polarizing cost you nothing. Doesn't hurt anything.

You probably don't have to rewire anything for a 35 amp generator. 35 amps was a option so the aircraft was wired to handle it. But I'd certainly check the wire gauge from the generator to the fuse holder for adequate gauge.

I'm not sure there was a meter larger than 30 amps. Never dug into the detail or thought about it. My 170A has a 35 amp generator and I'd be surprised to find the meter wasn't 30 amps.

If the 20 amp fuse wasn't blown, there was never a call for the regulator to have the generator put out more than 20 amps though it could have.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

This is great info. I am looking at options right now. I did find some heat damage on the 20amp generator fuse. You know how the element gets hot and balls up under the metal caps, and appeared a bit melted although the fuse still had continuity. Not really sure but it may have been pushing the 20amp fuse a bit. will go back to the proper regulator for the output of the gen. Will also look into the 35 amp. Thanks again.
User avatar
n2582d
Posts: 2808
Joined: Mon Apr 29, 2002 4:58 am

Re: New 170B owner

Post by n2582d »

Congratulations on your son getting the tailwheel endorsement!
goodair wrote:... This aircraft is bone stock with the exception of an electric turn and bank, not sure why they did that. ...
Neal, take a look at figure 75 of the IPC. You'll find that the original T&B was electric. Does it happen to say Schwien on the face?

One thought regarding using a 35 amp generator is that it requires a dampened crankshaft according to the TCDS item 306. You probably have that but it would be good to confirm it. Good luck on getting that all sorted out.
Gary
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: New 170B owner

Post by gfeher »

Before converting to a larger-output generator or alternator, I would convert to LED bulbs everywhere and then calculate whether you even need to upgrade. Especially the landing/taxi lights, which by far are the largest draw. I've converted to LED's and in addition to being safer (much less heat) and far more reliable (much longer useful life), they draw significantly less current. I'm guessing that after switching to LED's you will find that you don't really need to upgrade. I've calculated that after conversion to LED's, with everything on (except the starter), using the information in the specifications for each item installed (including the LED's), my plane draws less than 10 A total peak. In any event it's worth doing the calculation before you spend the money on the upgrade.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

I agree, that with some LED bulbs, 20 amps is adequate for a mostly day VFR aircraft of this type. The NAV bulbs have a decent draw, and of course the landing lights pretty much peg the meter and the little 20 amp generator goes cross eyed. These items and probably a set of brushes or at worst an overhauled gen are the easy button for us right now. Thanks again for all the input.
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

OH, and we do have a dampened crank, but I am thinking easy fix this time. I was not aware that the electric TB was stock.....thought that one was vacuum also. Thanks
User avatar
gfeher
Posts: 571
Joined: Fri Sep 26, 2014 9:19 pm

Re: New 170B owner

Post by gfeher »

Forgot to mention. If you do decide do upgrade to a higher-capacity generator or alternator and want a higher capacity ammeter, Steware-Warner made a 60 amp version of the original 30 amp ammeter used in C-170s, as shown in the catalog page that you can download here: http://www.cessna170.org/forums/viewtop ... 47&t=13995. You can usually find a used one, but if not they still make a similar one you can buy new if you check around.
Gene Feher
Argyle (1C3), NY
'52 170B N2315D s/n 20467 C-145-2
Experimental J3 Cub Copy N7GW O-200
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

Completed the trouble shooting routine on our generator and the thing is shot. The regulator and wiring all checks out but nothing out of the generator. We have decided to keep it stock and another generator is on the way. I am going to replace the regulator also as i suspect that the mismatched 50 amp regulator and 20 amp generator did not do the thing any good. We are going all LED and that should improve overall load requirements and keep this thing going for a long time.
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: New 170B owner

Post by Bruce Fenstermacher »

Wish the flashing would have fixed things for you. But at least your not stabbing in the dark, changing parts willy nilly as many "mechanics" do.

I'll be the first to tell you NOT to cut the gasket so you don't have to remove the tach drive housing which the generator gasket goes under. Doing that will likely create a oil leak. Remove the tack drive housing and replace the entire gasket.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
c170b53
Posts: 2527
Joined: Mon Apr 22, 2002 8:01 pm

Re: New 170B owner

Post by c170b53 »

O.k. I ‘m a mechanic and that really hurts :D
Hopefully you also know a local shop that can repair it. I try to support anything local, just to keep things going. When services / part repairs are centralized, the costs go down but sometimes the quality suffers. Good luck with it.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: New 170B owner

Post by Bruce Fenstermacher »

Jim your a mechanic not a "mechanic".
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

I already have the new gasket on order. Thanks for the reminder and I have heard that the short cut can cause long term issues with leaks. I am thinking of doing the tach drive seal at the same time, but its not leaking and the overhaul was done in 2005 so its really not "old". When looking for this airplane I ran across a few that had overhauls done in the seventies and even sixties. I would consider there to be some crispy gaskets!
It is really great to have folks chime in here while we tinker with the plane. I am learning so much. I am also restoring a Waco and there are so few folks interested in the vintage rag stuff these days it is months before someone chimes in on that site with a suggestion or their experience. Soo....if anyone is caring here is a question...:

I replaced everything stock. That is the 20 amp generator as removed. Although the parts manual for this thing called out for a 25 amp generator, it was clearly a 20 amp on the a/c and the fuse for the thing is even labeled "20". Sooo…..I am assuming a 20 amp was offered. I have had numerous issues over the years with these older voltage regulators. I know the one installed here was mismatched but I have experienced them failing from time to time. I actually purchased this: https://www.aircraftspruce.com/catalog/ ... g1200n.php

Sorry, I don't see a link option here....newbie.

Anyway, this is a solid state modern regulator that fits the same footprint/bolt holes and these last forever. It is PMA and STCed for this ENGINE/generator. I have used these before on other vintage a/c and they just go forever. So, my problem is that there is no specific listing in the eligibility for the 170 series for the 20amp. The same year, same engine 172 series is listed. I called Zeftronics and they admitted that it should be approved as its the same installation, they have just overlooked putting the 170 series on the list when they got it all approved....but their gona do it in the new year. Its interesting that their 25 amp unit is listed, as I guess it was a more common installation and made it on the list when they were approving all these units. So the obvious is to just replace it with a 25, but this aircraft apparently had a 20 on it. Anyway, went with the 20.... :?

So....does anyone here have experience with the 20 amp installation with any other regulator than the old stock points vibrating type? Anyone have a 337 with a Zeftronics on it? I am really not overly concerned as the C145-2 is listed and I may be able to get this through without any help, but just wondering if I could get some more ammo here.
User avatar
GAHorn
Posts: 20968
Joined: Fri Apr 12, 2002 8:45 pm

Re: New 170B owner

Post by GAHorn »

While it may seem logical that a 50A regulator calling for more than 20A from a 20A generator should "blow" the 20A fuse...that cannot be counted on. Firstly, the fuse does not protect the generator...it protects the wiring. Secondly, the constant demand of the regulator for the generator to put out more than the gen was designed for ... is not likely accomodated by blast-cooling such as the 35A system is. That little 20A gen did it's best to keep up and it's likely that the battery re-charged before the gen overheated on previous flights (and is why the fuse was only scorched/partialy-melted). But once the element of that fuse was compromised it likely laid down in the glass and continued to allow the passage of current. At any rate, an oversized regulator usually burns-up an undersized generator. You did the right thing to rebuild/replace the generator and install a correctly-rated regulator to match it. You also deserve a "gold star" for replacing that tach-drive seal because simply removing and reinstalling the drive-housing will likley place it in a slightly different location and the tach-drive shaft will ride in a different position on the seal. (I've experienced this and it results in a huge oil leak. In my case a Cessna Authorized Service Center did the work and failed to replace that seal and a cup of oil...at least it seems like it.... ended up on my cockpit floor, having travelled up the tach-dirve-cable and dripping out the tachometer itself and running all down the backside of my instrument panel, contaminating all the switches, placards, etc. Took almost 17 hours of labor cleaning that mess up. The Cessna shop, Ron's at Las Vegas North, refused to own up to their error and tried to blame it on an "automotive" speedo cable instead of the actual, correct part which was existent. Ron even gave the fairy-tale that genuine aircraft tach cables are "wound" in a different direction than auto cables to prevent the oil from travelling up the cable/into the tach. :roll: He deserves some kind of reward for fairy-tales but I warned them I'd never stop telling the story about their work as the result of their failure to make it right. They also cut that gasket ...Twice... before I could convince them to stop it ...in order to stop the leak which the compromised gasket allowed down the engine itself.)
Bruce was right to remind you to "polarize" the gen/reg when you reinstall it.
'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. ;)
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

Thanks very much. I think this will be easy once it all arrives after the holidays. I did find a previous thread addressing my exact situation with the 20 amp Zephtronics voltage regulator. Seems another individual attempted to do the logical and replace the older type with the solid state, but ran into this approval list thing where the 170 is omitted. That was back in 2015. The post does not come to any conclusion and if the individual ever got it approved, he did not come back and update the post. Hopefully someone will chime in and have some good news regarding the regulator. The rest now lies with UPS :D
goodair
Posts: 49
Joined: Wed Jul 25, 2018 5:32 pm

Re: New 170B owner

Post by goodair »

I received the following input from another page on this website regarding this same Zeftronics voltage regulator subject. The question I had was that the list of approved aircraft types didn't show the 170B on their list. The point made is that this regulator was approved as a pma replacement for a particular cessna part number and therefor should be a legal replacement for that particular part number...period. Here is a quote from the other page.
"Folks here is the I way I see it.

Part 0413205-5 is the Cessna regulator called for in the B Model IPC for a 20 amp Delco Generator. 0413205-5 is Delco Remy part 1118736

The Zeftronics G1200N is PMA'd to replace a Delco Remy 1118736.

That is as far as I'd look. There is no STC required. Your replacing a part with a PMA'd replacement part.

I do not see a problem with this, and will proceed.

Thanks again to all.
Post Reply