Prestolite vs. Sky-Tec

Jdm

Jdm

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Jdm
What’s best here? I know the skytec is lighter and turns a little faster, but how are they holding up, and how does the overall fit compare? I’ve flown a number of skytecs and never had a problem myself, but according to some groups this is not exactly the norm! I’ve been running an old Prestolite MZ4222 starter on the 172M (0320-E2D) for many years. 24 years to be exact! It’s now time to overhaul/exchange the Prestolite, or possibly swap to a skytec. I am running the Bogart extra ground cable STC, which would need to be a different length if I swap to a skytec. Not a big deal, just a little extra work.

Thanks!
 
Jdm said:
I know the skytec is lighter and turns a little faster, but how are they holding up, and how does the overall fit compare?
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Sky-Tec makes more than one. I heard the NL holds up much better than the LS.
 
asicer said:
Sky-Tec makes more than one. I heard the NL holds up much better than the LS.
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Good point. Yes, I saw this on their website. Haven’t gotten far enough along to see what’s available for this engine.
 
asicer said:
Sky-Tec makes more than one. I heard the NL holds up much better than the LS.
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I have an NL that has been trouble free for a decade. I also hear that Skytec’s lighter weight starter is a bit fragile.
 
n=1.

My experience with Sky-Tec on 4-cyl engines has been great.

My experience with Sky-Tec on 6-cyl engines has been poor.

On the bigger engines, I had cracking problems.

But the smaller engines is where the weight matters more. So all good....

YMMV
 
This is exactly what I’ve been hearing as well. I’ll check into the NL and see what options are available. Thanks.
 
You will need to move the starter power cable a bit with the NL as well. The stud is farther forward than on the Prestolite. Might also need to adjust any baffling around it.

The NL's brushes are good for an entire TBO. Good luck getting that out of a Prestolite. And the NL has an engagement solenoid. No more sticky bendix.
 
Good info. We actually got TBO and then some out of this old Prestolite.
I’m guessing the NL is a heavier version?
 
Jdm said:
Good info. We actually got TBO and then some out of this old Prestolite.
I’m guessing the NL is a heavier version?
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Still lighter than a prestolite. It's geared and has supermagnets.
 
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Have NL as well. It's about 9 yrs old, with approx. 800 hrs on it.
Only issue I've seen was the long bolts that hold the starter together became loose.
They were removed, cleaned, a dab of blue Loctite, torqued, and put back in service.
Spins that ol' 320 a treat.
 
I’m a bit surprised at the lack of info on Sky-Tec’s website. Very little detail. I’d have that website rocking with info if it were mine!
 
My OEM Prestolite on my Warrior outlasted two engines (2000 and 2925 hours) and is going strong on the third. All I've done is replace the bendix drive and replace brushes.
 
My first Skytec lasted about 5 years :-(
My AP wasn’t surprised by it’s quick demise.

We’ll see about #2, this is on a 4 cylinder engine.
 
IME as a CFI flying in all kinds of privately owned airplanes - the biggest factor in determining the lifetime of the starter is the human sitting in the pilots seat. The owners I saw having starter problems were the same owners that had no idea how the hell to hot start their aircraft and regularly got the starter too hot.

Given this, I would completely ignore "internet advice" about people's experiences with starter reliability. Unless you were there to observe how they operated it, there is a good chance they didn't operate it for **** if they had problems.
 
I called Sky-tec with questions about the various models available and recommendations for this application. Talked with a sales person, not tech support. I was told they have a number of models that’ll fit, but they recommended the NL or the Edrive. The difference being an automatic reset on the Edrive verses having to remove the starter to replace a pin on the NL in the event of kickback. I have zero desire to remove a starter to replace some pin. It’s not exactly an easy job! I asked sky-etc how likely, or common is this condition. They said they deal with calls every day about pin replacement.
So, my question to the NL users.. Are you really having to deal with this pin issue much? I’m not familiar with procedure.
 
The NL is bulletproof. I've had one for over 10 years with zero issues. The starting rpm is impressive. The Bendix drive on the original starter was a pain to properly maintain, and toward the end of its useful life it stuck increasingly often. The SkyTec is dead simple.
 
Jdm said:
The difference being an automatic reset on the Edrive verses having to remove the starter to replace a pin on the NL in the event of kickback.
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I would estimate that the majority of kickback events in a 172M are the result of pilot error. Who else flies your plane?
 
asicer said:
I would estimate that the majority of kickback events in a 172M are the result of pilot error. Who else flies your plane?
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What exactly are pilots doing wrong to cause such a kickback condition? I’ve not noticed kickbacks before. Not just on my airplanes, I haven’t noticed kickbacks on any of the small airplanes that I used to CFI on years ago when working at a busy flight school. Certainly don’t remember any maintenance having to be accomplished because of it.
It’s just a couple of us who fly this airplane. I’m the only one who works on it though, so I definitely don’t want to create more work:)
 
Jdm said:
What exactly are pilots doing wrong to cause such a kickback condition? I’ve not noticed kickbacks before. Not just on my airplanes, I haven’t noticed kickbacks on any of the small airplanes that I used to CFI on years ago when working at a busy flight school. Certainly don’t remember any maintenance having to be accomplished because of it.
It’s just a couple of us who fly this airplane. I’m the only one who works on it though, so I definitely don’t want to create more work:)
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Not meaning to derail the thread but...
Over the years I've tended to get a lot of starter kick-backs...I've broken 4 starters over 25 years on 4 different airplanes due to kick-backs...now here's the funny (or not so funny) part: I have no idea why. In my current plane, I've had a kick-back or two when I've released the starter too soon, so I'm careful that the engine is truly starting, and not just sputtering, before I release the starter. I think, and this is just a guess, that in the past I've released the starter too soon and that creates the kick-back, but honestly I'm not sure. Maybe I'm just not "positive enough" with how I move the starter switch, causing a "stutter"...IDK...I've had them with both key starter switches and push buttons...I'd love to hear what others say about that.
 
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Kickback can happen if the mag switch is not jumpered to ground the non-impulse mag during start. It could fire at full advance if it's in good condition and the cranking speed is fast enough.
 
Jdm said:
What exactly are pilots doing wrong to cause such a kickback condition?
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Outside mechanical/electrical issues, improper throttle/primer usage or start technique and pushing a weak battery are the main induced issues in my experience. But there usually are underlying system issues that assist with the previous conditions. Regardless, kickback is not a good thing and has been known to break some expensive parts.
Country Flier said:
I'd love to hear what others say about that.
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FYI: most of the kickback issues I've troubleshot were due to existing issues with the mags or starter circuits. If kickbacks are a common occurrence you may want to have those systems checked for serviceability. Also may want to review your starting techniques as well.
 
Country Flier said:
I think, and this is just a guess, that in the past I've released the starter too soon and that creates the kick-back, but honestly I'm not sure. I'd love to hear what others say about that.
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Thanks. Good info! I’d like to know as well.
My gut feeling is that if you’re experiencing a lot of kickbacks it’s probably due to poorly maintained engine (timing, carburetor issues, manifold leaks etc.) but it could be a pilot issue of some sort. Problem is that maintenance items such as these happen all the time. Don’t recall any of these common malfunctions causing issues with the old Prestolites starters.
Definitely appreciate the feedback!
 
Bell206 said:
FYI: most of the kickback issues I've troubleshot were due to existing issues with the mags or starter circuits. If kickbacks are a common occurrence you may want to have those systems checked for serviceability. Also may want to review your starting techniques as well.
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Jdm said:
Thanks. Good info! I’d like to know as well.
My gut feeling is that if you’re experiencing a lot of kickbacks it’s probably due to poorly maintained engine (timing, carburetor issues, manifold leaks etc.) but it could be a pilot issue of some sort. Problem is that maintenance items such as these happen all the time. Don’t recall any of these common malfunctions causing issues with the old Prestolites starters.
Definitely appreciate the feedback!
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I'm a maintenance fanatic, and my engines usually start on one prop turn...I've had it occur on 4 different planes (all owned and meticulously maintained by me), so I'm thinking more likely its my starting technique...problem is, I'm doing my starts "by the book" in all cases, following the poh. I honestly think I might be "stuttering" with the starter, like I'm expecting my engines to start too quickly, or not being "positive enough" with the starter switch, but still I don't know.
I've had it happen on a nearly new factory remain with new mags AND carb, and older engines, and everything in between. On one of them (the third one I think), my mechanic went through the mags and carbs, but couldn't make it happen until I started it, and it did it on my first start! Frustrating.
 
Would a starter switch that has oxidized contacts, or a starter contactor with oxidation or weak pull-down cause kickback? It’s almost like someone stopped cranking, with no ignition event whatsoever. The prop moves backwards a few degrees...you can see the same on shutdown sometimes.

I would guess in your case @Country Flier that the consistent piece of equipment on each of the 4 planes is you, so maybe you’re right.
 
Country Flier said:
my mechanic went through the mags and carbs, but couldn't make it happen until I started it, and it did it on my first start! Frustrating.
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Don't forget the starter system is part of that equation. Electrical/battery issues are always at the top of my list when it comes to any starting problem. T/Sing kickback can be a pain at times as one issue can affect another but there is guidance that can get you in the right direction. Sometimes when T/Sing intermittent issues like this I'll get someone unfamiliar with the specific aircraft but familiar on type and have them go through the motions to see if anything pops up.
455 Bravo Uniform said:
a starter contactor with oxidation or weak pull-down cause kickback?
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Yes. Any drop in voltage that does not allow your starter to achieve its required RPM can lead to kickback and other starting problems. The majority of the starting problems I've dealt with were related to the electrical side. Rarely did I replace a starter unless it had reached its FUBAR stage or was unmistakably worn beyond its limit.
 
Kick back really sucks when you are the starter. I had it happen once while hand-propping an A75 that wasn't equipped with impulse couplings. Whacked my fingers pretty good, but didn't need to replace any pins. In that case, the error was me not putting enough force into the start attempt.

As to it occurring on an airplane with a starter - there isn't enough force being exerted from the starter (bad starter or weak power), or the timing at the moment of start is wrong. Depending on the installation, it may be related to one mag not being disabled, or a shower of sparks system not working..etc..depends on the particulars of each ignition system and whether those particulars are working properly. I suppose a pilot could cause it to happen in a perfectly maintained airplane if he had a habit of releasing the switch at the most perfectly inopportune moment.
 
Good article Dan-

Are they even making new Prestolite starters anymore? All I’ve seen are overhauled ones. Apparently new Lycoming engines are being shipped out with sky-tec starters from the factory.
 
Jdm said:
So, my question to the NL users.. Are you really having to deal with this pin issue much? I’m not familiar with procedure.
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I'm aware of the possibility, but haven't experienced it in ~10 years.
 
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Good article.

Another point is the mag itself. The Impulse Coupling is a chunk of steel on the end of the the Rotating Magnet. Surprise! Occasionally it gets magnetized. This can cause the Flyweights to fail to extend and engage the Stop Pin. The result is a weak , ADVANCED Spark. aka Kickback.

Some mags have tiny Springs to assist with Flyweight engagement. They can also fail; with the same result.

So it may not even be the Starter or the person doing the starting.
 
Bell206 said:
The Prestolite name gets thrown around a lot but I don't believe they are of the older vintage... unfortunately.
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I don’t have the starter off to see but here’s the tag. Says it’s a Prestolite
 

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455 Bravo Uniform said:
When/if this gives out, rebuild or go newfangled?

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For the large Continentals, do your research. Lamar had one for that application, and it caused a bunch of starter drive failures. The drive on that engine is not cheap. The problem was with the permanent-magnet design that tends to lock the armature once the current is cut off, and the armature won't allow the big spring inside the drive to unwind and release the crankshaft stub, so it gets burned out There were also some geared starters that would do the same thing. I was just reading that the starter needs to have no more than 5 inch-pounds of rotational resistance. https://www.aopa.org/news-and-media/all-news/2020/october/14/aircraft-maintenance-do-your-homework
 
Dan Thomas said:
For the large Continentals, do your research. Lamar had one for that application, and it caused a bunch of starter drive failures.
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I believe TCM came out with a SB that dealt with kickback on the larger engines and the damage it could do. Another issue that can lead to kickback is repetitive start attempts without allowing the starter to cool down between start cycles. Even with a good battery/GPU connected an overheated starter will not perform to spec.
 
I seem to remember ABS suggesting to stay away from sky-tec for the io520 and io550s. For an
o320 however it might make sense based on what I’m seeing here.
 
Does anyone know how much baffling work has to be done to fit the NL properly? 172M O320E2D
 
Jdm said:
Does anyone know how much baffling work has to be done to fit the NL properly? 172M O320E2D
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Didnt require any on the RV-6. Since it sits under the engine, I can’t see why it would involve baffle work.
 
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