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Bendix Kicking Out after 2 Blades

JimRice

Well Known Member
I recently began experiencing an issue with my starter on my O-320D1A on my RV-4. It is a regular Prestolite (IIRC) starter (not Sky-Tec or other lightweight starter).

It always seems to crank fine cold on first start of the day, but on subsequent starts, the prop will only turn two blades and the Bendix will kickout/disengage. I let it spin down, try again with same results. My battery (Power Sonic) is less than 2 years old and stays on a Battery Tender when in the hangar.

I'm going to dig into this this weekend but wanted to inquire here first for some ideas where to check first.

Since it always starts well after coming off the battery charger without kicking out, I'm leaning towards this being a battery, relay or grounding issue. I don't think it is a problem with the starter or ring gear, but will definitely be looking at them too.

I am thinking there is sufficient voltage for first start due to battery being topped off by Battery Tender, but it loses charge after sitting even a couple of hours without being charged. When it first happened, once I got it started and flew home, once I landed I shut it down and immediately tried starting and it started just fine. Three times. At that point I thought I might be having a switch issue (Typical keyed switch with starter position). The next time, I went to fly, it started well for first flight, but after sitting at a buddy's strip for 2-3 hours, it did the 2 blades and kicked out again. Once again, I was able to finally get it started, trying two blades at a time and flew home. Once again, when I got home, it started just fine.

My plan tomorrow is to open it up and begin inspecting/troubleshooting. I think first thing will be checking voltage drop at the starter...I may go out and take the charger off overnight so it won't be freshly charged. If it isn't the battery, I suspect the relay may be going bad. I'll also be checking the grounds as I've seen a poor ground cause lots of different problems.

My alternator appears to be charging properly as it shows a short charge after starting and a discharge when I turn on landing lights but comes right back up...though occasionally, I have had the "waving ammeter needle"...again intermittently which I've been unable to track down.

So, I'm open to whatever suggestions folks might have on possible problems and where to start.
 
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Do a load test on your battery. You can buy an inexpensive carbon pile load tester at HF. Experience has shown that SLA/AGM batteries, like the odyssey and power sonic, do not do well with constant trickle charges. The charger has likely destroyed your batteries capacity. It starts well when just off the charger, but is not recharging properly with just the alternator. The trickle charging is masking the capacity issue. The trickle charge get the battery up to a decent level, but it loses it quickly, as the core capacity is not there to hold a charge.

the power sonic has a VERY low internal discharge rate and there is no upside, but plenty of downside, to using a trickle charger. If your battery sits for more than 6 months, just top it off with a traditional battery charger. These are not the same a flooded lead acid batteries.

You may be able to bring back some life a few deep cycle discharge/charge cycles with a proper battery charger.

Does your starter have a solenoid that pulls the bendix drive into engagement? If so, that also could be failing and heat is making it worse. If it is an inertial bendix, I would not expect problems only with heat. I would expect the opposite.

Larry
 
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I'm not the builder so I'm not sure about the Bendix.

THanks for info about battery. May pull it this evening and see about doing a discharge/charge and see if that makes a difference. Though the pain to pull my battery might be cause for simply replacing the battery! :)
 
?Battery Tenders?

Using a battery tender is the quickest way to ruin a battery. What happens is that the battery develops a ?memory factor?; and slowly loses its amperage capacity. Even though a charger may indicate the battery is fully charged; it will actually be at 20-25% of full charge & not be able to start the engine. It may crank over when the engine is cold (lower compression & less internal friction); and will fail to when the engine is hot. And that may not be at your home Airport; leaving you stranded.
We are just now replacing our Concorde battery in our RV6; and it was installed in 2004. This battery has never been on a ?Battery Tender?. It was only charged for 1-2 hours; if we had not flown for 30 days?which was not often.
Invest in a charger specifically designed for these batteries?Vans sells them.
 
If you have an edrive starter, the early models of this had a dropout circuit in them and would quit when the voltage dropped too low, I had this problem, sent it back to them and they fixed it free. That's been a few years back now so things may have changed.
 
Using a battery tender is the quickest way to ruin a battery.

Tracer 10/Chief, thanks. I guess some things never change. I've been retired from the Army 14 years myself. Seems I still need wise CWO advice from time to time. I was a RedLeg and worked with a bunch of CWOs in Maintenance and Target Acquisition. Were you an aviator? I was FSO attached to 11th Avn Regt for a couple of months in TF Hawk/Albania. :D
 
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New Battery

The stars finally aligned and I finally had all the following; battery (vendor sent wrong one first time), free time and tolerable weather.

I replaced the battery yesterday. Cold start was fine, but hot starting while improved still wasn't 100%. When I was restarting after fueling up at a nearby airport, it turned a couple of blades, fired (kicking the bendix out) but didn't catch. On next attempt, it turned 2 blades and kicked out like before. I let the starter wind down and waited a couple of minutes and tried again. It turned twice and kicked out and then on next attempt, turned like normal and started up.

So, the battery, wasn't the sold culprit. I assume it wasn't putting out quite optimum power, which coupled with other issues, caused the problem. Consequently, I've ordered new Master and Starter solenoids and diodes for each. I'm going to replace everything since I'm about to begin the Condition Inspection anyway. Seems the inconsistent performance could be due to a relay contactor arcing/not making good contact. All the new parts cost less than $70 and the originals have over 1000 hours. I'll have to also check the resistance of all my battery cables/starter cables as well to make sure they aren't the problem, but visually, they all look fine. All grounds/attachments also checked good, but will be double checked during replacement of solenoids.

The starter appears to be fine given it cranks normally most of the time...when it gets sufficient power.

I was able to resuscitate old Power Sonic battery by significantly discharging and recharging a couple of times. It now checks as well as the new battery when both are fully charged. Still, given the cheap price and pain to change, I went ahead and installed the new battery. I don't trust the old one. It will likely end up on my lawn mower.
 
Still Kicking Out

So far, I?ve tried about everything and still having problems. New battery, new cables, new master and starter solenoids and took starter to local armature shop and they say nothing is wrong with starter, yet I am still experiencing same problem. I?ve cleaned and reconnected all connections. After 2-3 blades, the bendix kicks out. Motor continues turning normally, but Bendix disengages. Occasionally, I?ll get 6-8 blades before it kicks out.

Today, after changing cable from starter solenoid to starter with #2AWG welding cable and new heavy terminals voltage drop during cranking was 0.4 volts from 12.5 to 12.1V . Voltage drop on ground side was only 0.15V.

Despite what armature shop says, I think I have an internal starter issue. I guess next step is a new starter. My starter is a Delco-Remy Prestolite. I don?t really want SkyTech or B&C lightweight starter because I need the weight up front the old starter provides. I already have the Landoll balancer ring.

Anyone know a shop who will rebuild an old starter? Not sure I want to take back to same local shop who said nothing is wrong. Not sure they will want to rebuild it. They have done a good job for a couple of friends so I know they are capable and are reasonably priced. They charged a friend $100 to overhaul his. It is sitting on a shelf as a spare for his RV-4 since he bought a new Skytec for his Cherokee. I am going to ask to borrow it to see if it works to confirm mine is bad.

This is last thing between me and finishing Condition Inspection completetion. After a cold wet winter and record rains recently, I?m finally about ready to fly after being grounded for two months. I?m open to suggestions on about anything.
 
Is this kicking out happening when the engine fires? If so I would suggest that a check of the mag timing may be a good idea, maybe the retard is not working correctly.
 
Sounds like you have changed everything except the actual part that is giving you a problem. The alternator shop is probably correct - the electrical portion of the starter is fine; however the mechanical portion that engages the pinion gear is what sounds like the problematic area.
I would disassemble, clean, and lubricate that section - looking for any broken parts. Be sure to use the proper lubrication (from memory I think silicone ?).
 
If the starter keeps spins when the drive kicks out then I suspect a Bendix problem. Some of the older starters had a clutch type Bendix and could fail in this way but hard to diagnose on the bench. The starter repair shop could probably verify this.
 
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Starter problem

Jim: I have a used Skytec 149-12PM starter you can have for $150 plus shipping. Perfectly operational. If it will work for you and you are interested send me a PM or email to [email protected].
 
Reviewing Everything and Found this today.

Pulled starter back off today and while I was underneath decided to take another look at the ring gear using a very bright light as well as feeling. Previously looking from above in ambient light, I failed to see this. Today, I noted the rear corner of several teeth had been knocked down/chipped off? It is a small area. Is this enough alone to be cause of my problem. Still, I am ordering a new ring gear to replace this one. I am assuming it contributes as it makes two blades and kicks out almost every time.







And yes, I feel like an idiot for having missed this the first time I looked before tackling the electrical and starter track.
 
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Looking at your pictures it looks like the starter gear is contacting the back of the ring gear and not even engaging the teeth. Look closely at the alignment of the starter.
 
Teeth?

Jim,

Do you know the number of teeth the starter is set up to run? I have an old Prestolite (should just be Presto...nothing light about it) in the shop I'm not using. You might either use it as is or just change the gear if you need the other tooth count. PM or email me if you like.

Maj
 
Jim: I have a used Skytec 149-12PM starter you can have for $150 plus shipping. Perfectly operational. If it will work for you and you are interested send me a PM or email to [email protected].

I definitely appreciate the offer, but it does not appear that model will fit on my plane as it is configured.
 
I am thinking that the damage you are finding on the ring gear is a symptom of your problem, and not the cause. The mechanical mechanism that engages and disengages the pinion gear is not functioning properly.
 
I am thinking that the damage you are finding on the ring gear is a symptom of your problem, and not the cause. The mechanical mechanism that engages and disengages the pinion gear is not functioning properly.

Thanks. That reinforces my thoughts as well. I'm trying to track down a replacement Bendix drive assy 480388 F8 to swap out as well.
 
Had the same problem on an old Pontiac years ago. Changing the bendix drive itself is what fixed my issue.
 
Ring Gear and Bendix Drive

I have both a new 72566 ring gear and EBB-131A Bendix drive on order. I really don't think the ring gear teeth were chipped before, but were caused by the Bendix withdrawing while still under load. Several folks have reinforced that belief. Now it is hurry up and wait. :)
 
I have both a new 72566 ring gear and EBB-131A Bendix drive on order. I really don't think the ring gear teeth were chipped before, but were caused by the Bendix withdrawing while still under load. Several folks have reinforced that belief. Now it is hurry up and wait. :)

As others mentioned, it looks like that wear is from the bendix holding the gear in a partially engaged state. That wears does not appear to have been caused by the withdrawl of the gear.
 
Starter Bolt Torque?

I'm in the process of getting everything put back together. New ring gear installed and new starter Bendix drive. I've found all the info I need but one piece is missing.

I have a Props Inc wood prop and Jeff told me 16-18 ft-lbs on 7/16 bots for the wood prop. It is one with many laminations. From Saber website I found 35-45 ft pounds for the prop extension to the crankshaft for 7/16" bolts. Hoping to torque those down, check prop track and safety everything up soon.

What I'm missing is, what is proper torque value for starter flange to engine case mount? The 5/16" studs and single bolt (front outboard), as I recall, are coarse thread and are threaded directly into the aluminum case. I'm not sure the torque setting for course thread steel bolts into aluminum. I believe it is in my Aircraft Mechanic Handbook, but I don't have it nearby and don't want to rely on it being there and find it isn't and be stopped in my tracks.

Thanks,

Jim
 
thought so, but checked: 100 in/lbs

from SkyTec's install instructions [just another reference]:
"Use the existing 5/16? bolt and nuts, or replace, as indicated by condition.
Replace any and all washers with four (4) AN936-516 internal tooth ?star? lock
washers supplied or stock AN split-type lock washers. Do not use flat
washers. Torque the bolt and nuts to 100 in. lbs. "
 
from SkyTec's install instructions [just another reference]:
"Use the existing 5/16” bolt and nuts, or replace, as indicated by condition.
Replace any and all washers with four (4) AN936-516 internal tooth “star” lock
washers supplied or stock AN split-type lock washers. Do not use flat
washers. Torque the bolt and nuts to 100 in. lbs. "

Looks like an error in the skytec info:

Lycoming torque values list the 5/16 bolt/nut at 204 in/lbs.
(The 100 in/lbs is for 1/4" fasteners)
 
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Looks like an error in the skytec info:

Lycoming torque values list the 5/16 bolt/nut should be 204 in/lbs.
(The 100 in/lbs is for 1/4" fasteners)

Is that for steel bolt into steel threads? That was my concern. I certainly do not want to strip the threads in the case, but also don't want my starter coming loose. I couldn't find a specific reference in the Lycoming manual for the starter nor a chart for aluminum mating surface.

Thx,
 
Another thing to keep in mind. There are service instructions. Mine was doing the same at one time. And be sure to spray the bendix periodically with a silicone or LPS1. Nothing any thicker as it can attract dust and such. But the bendix can begin to stick, not letting it go out as far as it should.
 
And be sure to spray the bendix periodically with a silicone or LPS1... But the bendix can begin to stick, not letting it go out as far as it should.
I believe that last sentence has been your problem all along. Incomplete gear engagement due to a sticky Bendix. Most of the Bendix drives I seen have a sticker on them calling for 25 hr lubrication intervals. Yes it is a PITA, but if followed, I've found much of my starter angst goes away. However installing a B&C starter eliminated all my starter problems and no more frequent cleaning and lubing and the access hassle that comes with that. I feel it was money well spent.

George
 
New Bendix

The Bendix indeed seems to have fixed the problem. Good thing is now I should have no starter troubles for some time now. I've rebuilt the entire system from battery to starter, with exception of mag/starter switch. At this point I'm tempted to go ahead and get a kit for it and rebuild it too.

Just waiting for some decent weather to go flying after having plane down for extensive Condition Inspection. :D
 
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