April 12, 2013 at 1:27 am #84135April 12, 2013 at 2:02 am #98347
Can your A&P make you a replacement? Mine had said he could – even make it using copper instead of aluminum.April 12, 2013 at 9:22 am #98349
That was my next solution, I am away from home and took the old one out. I wanted to find a replacement so a local mechanic can install it. I am at KPMP so I am going over to Schmidt’s later today and see what they tell me. I would like them to do the work but I don’t know if they would travel. I’ll let you know what they say. I did notice that it was aluminum, from the looks of the tape that was wrapped around it, it had been in there a long time! I noticed from your tag line that you have an N model also, they are really a great plane!
C310-NApril 12, 2013 at 11:59 am #98350
Most of the battery cables on these planes are original. The aluminum is fatiguing continuously, meaning greater resistance and thus worse starter performance and more strain on the system. On my Aztec, when they got pulled to be replaced with copper they looked like they had caught fire at some point.
On our 310 my mechanic said he thought just replacing the ends and cutting the last few inches would be sufficient to improve the right side, but I haven’t seen a huge improvement from it. Mainly I’ve noticed I need to keep the left engine above 1000 RPM to have the alternator helping out.
The N is a great plane. I think that unless one needs the extra cabin or nose baggage space afforded by the Q and R, it’s one of the best options. Handles sportingly, wing lockers, and large rear door. It’s worked very well for us. Glad you’re enjoying yours, too. 🙂April 12, 2013 at 12:37 pm #98351
All that wiring looks bad, I would like to replace all of it, I probably should have done that at the engine overhaul!
Thanks – Barry
N4140QApril 14, 2013 at 6:35 pm #98374
I talked to my A&P and he pointed me to a company called Bogert (http://home.bogertgroup.com/) that makes battery cable kits. I found out the starter cable is basically part of the battery kit. It seems that changing from aluminum to copper requires a 337, Bogert sends that with the kit. I need to call them because they don’t list a kit for a 310, they only go up to 210’s. Aircraftspruce, SkyGeek and others that sell battery cable kits all seem to resell Bogert kits. Interestingly Aircraftspruce sells them cheaper than buying them direct. I will post what I find when I call them.
I would be interested in hearing any other comments on the requirement for the 337, kits are about $300 per engine but it only requires about 10′ of cable and half dozen ends, less than $100 worth of materials for each engine.
N4140QApril 15, 2013 at 9:17 am #98384
I suspect you could just get a custom cable made up from Bogert for the starter using copper and do it as a field repair with an updated W/B. Some of the rules are hard on changes to the electrical system so it would not surprise me if a 337 was needed.
Why are you removing the FAA approved Aluminum firestarter for something unproven like Cu wire? I think with a little elbow grease you could reuse the cable you have. It didn’t look totally charred – only where it was supposed to connect to the terminal.April 15, 2013 at 11:05 am #98385
The engine had been hard starting but that might have been due to the end going bad. Bogert got an STC for the copper cable, it is a low loss type that improves starting. I know that aluminum housing wiring was a bad idea, it was used because of a shortage of copper not because it was better. Most of that have been replaced so I assumed that the same issues would be there in the aircraft. I am going to call Boget later today (they are on the west coast) and see what they have to say. If they don’t make one I might have to repair the one I have.April 15, 2013 at 12:08 pm #98386quote EPANNING:
I’d agree with the first paragraph. The copper will add a couple pounds, so the 337 is probably required more than anything to account for that. Kinda like a 337 for the SkyTec starters we just put on. The plane lost 15 lbs with them. So I figure that’s more than sufficient to allow for copper cable when the time comes.
As to the second paragraph, I think the aluminum cables have been proven to be a bad idea. While they do save some weight, aluminum is not a great conductor. Its fatigue properties also ensure that resistance will increase with time and vibrations, hence the problems many of us face. I’m sure when you compare good aluminum to good copper the difference is less staggering, but it is still there. My experience with copper cables has certainly beeen positive.April 15, 2013 at 10:58 pm #98392quote TDUPUIS:
Ted, you are very diplomatic! I was totally kidding in the 2nd paragraph! Aluminium wires in houses and airplanes have been a total disaster. The fact of the matter is I am just not funny or ironic enough. 🙂
Barry, whatever you do, don’t reuse that cable for anything. In an emergency you would be much better off going out to a battery shop and getting them to put crimp terminals on copper welding wire (what most of the experimental community does). I wonder if that would sort of fit the definition of an owner produced part? The experimental community liked the copper welding wire because it is very flexible, rugged exterior sheath, tested for high currents, and relatively inexpensive.April 16, 2013 at 2:08 am #98398
OK, here is what I learned today talking to Bogert. If I change the metal I have to have an STC but if the metal is the same all I need is a 337 saying replaced with like or better. While the cable is silver looking, they think it is really copper with a tin coating. I have to cut it to really tell. They said if I had copper connectors on the ends then it is more likely copper as they don’t use copper ends on aluminum. On a 43 year old aircraft all bets are off as to how what got where! Bogert is also recommending that I use 1 gauge wire, it is stiffer but has less loss. They do not have an STC for the 310 so if I change the metals I have a problem. They also said while they don’t have a cable kit for the 310, if I give them the lengths they will custom make them. The price is $20.20 for the first foot with the two ends crimped on, cable marked and the paperwork. Additional length is $7.25 for each additional 6″ per cable. Because of the base price you have to figure each individually, so if there are 3 cables per engine, that would be 3 times the $20.50 plus the extra inches for each. They said the 1 gauge is stiff and mechanics don’t like to use it. The 3 or 4 gauge would be cheaper.
I talked to my A&P and he said the stiffness is only a part of the issue. Everywhere you pass the cable through holes they have to be bigger, the 1 gauge is about 1/2″ and the 4 is only about .328″. I can see where it would be a big issue running the cable from the left side battery to the right engine. Still more research before I go with a solution.
I friend showed me a piece of welding cable and it is a lot easier to bend and work with, I don’t think you could get a signoff for using that on a production aircraft. It would be a breeze to use. I am going to check with a couple of AI’s and see what they say. I will keep this post going until I figure this all out.
N4140QApril 16, 2013 at 3:32 am #98399quote EPANNING:
I’d hoped you were joking (and thought you were far too intelligent to like aluminum cables), but the lack of a smiley made me question. 😉quote BSmith2:
Be curious to see what the others say. My A&P didn’t seem to think there was any problem with just replacing the aluminum with copper, but Bogert is also trying to sell STCs. Keep in mind as well that, while it shouldn’t be this way, when you go from one FSDO to another they’ll sign off different things for 337s.
On the other hand, this is one of those areas where it is completely insane that a 337 or STC be required. Sigh…April 16, 2013 at 10:43 am #98401
That is a good point, it might be a good reason the visit the FSDO. I live outside of DC and if I remember correctly they are right next to National Airport and I am down that way a lot. I think you are also correct that Bogert, since it has STC’s, would be all about promoting the requirement as it makes them the go to place!
N4140QApril 16, 2013 at 11:26 am #98402
I have been looking for the part number for the starter cable but my A&P said to look for a battery cable. Turns out he was correct. Here are the numbers that I found in my parts manual.
0870090P2 Cable – Battery From Battery to main relay
0870090K3 Cable – Battery From Left Relay to left starter
0870090K6 Cable – Battery From R Relay thru L wing root rib
0870090K6B Cable – Battery From R wing root rib to Right starter
0870090K6A Cable – Battery From R wing root rib to L wing root rib
Now to research and find out what they are made of!
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