Q: I have an O-320-E2A engine that is rated at 140 horses. What is required to add an additional 10 horses to that engine? I heard that all I need to do is change the cylinders and pistons. Please provide guidance.
Bob Agledor Sr.
A: Bob, you may be in luck when it comes to increasing the horsepower on your engine to 150 from 140 horsepower.
The interesting thing about your specific engine model was that it was actually certified at 150 horsepower at 2700 RPM with an alternate rating of 140 horsepower at 2450 RPM.
That seems to say that if you increase the RPM to 2700 on your engine, you’ll get the 150 hp that you were looking for at no additional expense for cylinders and pistons that you had mentioned.
However, you’ve heard the old saying “there is no such thing as a free lunch.”
Even though there doesn’t appear to be any cost to upgrade the engine to 150 hp, you may end up having to install a different prop, so please keep that in mind.
Both the 140 hp and 150 hp engines were installed in the Piper PA-28-140 and the Piper PA-28-150, so there’s another clue that it can be done.
In your case, even though the engine is certified for a dual hp rating, the question remains is your aircraft certified for a 150 hp engine?
I suggest you do a little research with your local FAA office, which should be able to tell you if your aircraft is approved for that horsepower.
As I recall the typical aircraft magneto ignition system with two mags grounds one mag while the starter is engaged. Releasing the key or starter button returns both mags to operation .
On the V35 Bonanza with shower of sparks the ignition key in the start position grounds both mags during the start and the engine will run with retarded timing until the key is returned to the start position.
Haven’t “thought about” these systems for decades.
The POH and engine operator’s manuals should have a full description.
I’ll have to go back into my textbooks. I’m sure that the Internet has pages that Google will find IF you use the correct search terms.
I don’t know if it’s typical. My 185’s IO-520 uses both impulse coupled mags for starting when the mag switch is positioned to Start.
I believe the TCM 470 and 520-series engines can be equipped with the Bendix “shower of sparks” system, or be equipped with Bendix or Slick impulse coupling type mags. Whatever the TCDS or an STC allows is approved. To my recollection all 360-series have impulse mags……at least the ones I had maintained.
Regards
That panel switch must energize the “shower of sparks” system independently of the starter switch. I think the system mag points are gapped at .019″…… that would retard the spark a bit.
We had four C310s and a C402B with the “ss” system, but no panel switch. No handpropping there, plus you’d have to be a gorilla.
I only had one buzz box go bad in 10 years of maintaining these aircraft.
All this is from memory, as I maintained these ships 40 years ago.
Yeah, maybe that was it, the switch energizing the SoS system. I assumed it retarded the spark so it wouldn’t kick back, but now I can’t see how a switch could do that to a mag. Yes, 40 years ago for me as well. But the 210 had the same engine as the 310, so gorilla-level strength was required there, too.
The shower of sparks (Bendix) vibrator box gets its power during the cranking cycle only (starter button). The magnetos are out of the circuit at that point until the starter is energized. There is a separate “P” lead that takes the excited voltage out to the magneto forsaking the magneto rotation as points are now “hot’.
Thanks for the info on “shower of sparks”.
The shower of sparks feeds battery power to the ignition system while the starter is engaged rather than depending on the magneto. An impulse coupling “winds up” a spring and then releases the wound spring to spin the magneto at a higher speed and it also reards the spark for starting.
Hand propping an engine with a shower of sparks system is difficult and dangerous because it only works with the battery charged and on-line and the key is in the start position.
The impulse coupling works only while starting and the fly weights engage. Once rpm is about idle the coupling runs solid.
Got it, thanks
Paul: another topic;
The manual for my Lyc IO-360- M1B states: “Never lean beyond 150 degrees rich of peak”.
My question: why? What exactly does that mean?
Merci.
There is no practical reason to not do that. Lycoming and Continental have changed their stance on lean of peak since those POH’s and OM’s were initially published. An engine is an engine is an engine.
Search the web for “lean of peak”. There is more info than can be discussed in this venue. The truth is out there.
Thanks, Manny. Do you have any thoughts about why Lycoming would be against leaning 150 degrees RICH of peak? I don’t do it but it seems to be an odd restriction with no explanation…
John
I do, but this forum doesn’t allow the detail required. Search: lean of peak, GAMI, Advanced Aviation Seminars and John Deakin’s articles on LOP. It’s an education backed with data.
Thanks.
J
Contact RAM Aircraft for the STC to make the change legally.
Again about the Arrow. The POH says that I have only four minutes from start to takeoff. Why the rush? It has the 360 fuel injection.
My Arrow has a “shower of sparks” starting system. Is this superior to the old impulse coupling? How does it work, and are there any drawbacks? Thanks
Any aircraft system will have certain advantages, and also drawbacks.
The “shower of sparks ” system is the trade name for the Bendix system for starting the engine, and involves both the magneto and a “buzz box”, oftentimes mounted on the inside of the fuselage.
In a nutshell, an impulse system used by Slick, Wico, Case and others is mechanical in nature, and “snaps” the magneto upon starting the set engine by a pawl and spring arrangement to get the necessary magneto rotational speed to generate a spark at the spark plugs. An impulse system is relatively trouble free, but is subject to wear over time due to its mechanical nature. There has been at least one AD note issued regarding loose impulse pawl rivets. With most impulse magnetos, the impulse system can be removed from the old one and installed on a new magneto when mag replacement is necessary. The impulse system is also used on magnetos installed on older automobiles and farm machinery.
The “shower of sparks” system is not mechanical, but is electrical in nature. Upon engaging the engine starter, the “buzz box” provides not one, but a series of sparks at the spark plug. This is done through a second set of points in the magneto, or “start points”. It must be remembered during maintenance that the start points and run points are gap-set differently….one at .016″ and the other at .019″. This system also is relatively trouble free, although buzz boxes can internally fail. Also, I do not believe an engine equipped with a “shower of sparks” system can be hand propped……I may be wrong.
I once owned a 1961 Cessna 210 with a shower of sparks system, and did have it hand propped once. In fact, there was a switch on the panel that you had to flip if you wanted to prop it. I assume that changed the timing or something, but it’s been too long to remember exactly. But my mechanic hand-propped it for me, and he was a big guy – which you’d have to be to start a 260 HP engine. But it worked, so you can do it.
The bush guys I know in AK like the impulse coupling in case they have to prop it with a dead battery during an incoming tide on a beach landing. I limit my beach landings and carry a spare battery (IO-520). Bendix 1200 mags are still the hot ticket.