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Using the GO 480

Started by Louis, June 02, 2011, 10:20:35 AM

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Saw this when i was looking for something else:

Operating the Lycoming G0-435/ GO-480/Go-540 Engines

The Lycoming geared engines have acquired a bad reputation over the years, quite undeserved.

These are very solid, reliable engines, but only if operated correctly!

Operated like the engine on your Cessna, they have a tendency to be quite short lived, and very expensive. Treated with care and flown by someone who knows how to operate the engine, they reliably make TBO time and time again.

Tips to make TBO

This information has been derived from conversations with very knowledgeable people. Freight operators, Lycoming engineers,

Aero Commander “old-timers” and many Lycoming Shops.

In a nutshell, the secret to long life of your GO-series Engine is to Never Ever let the air turn the prop!

The Lycoming planetary gearbox is pretty stout, things really begin to bang and clatter if you don’t have a solid, positive power setting.

Always keep the manifold pressure up.

You will be able to hear the gearbox “whining” if you come down final at too low a throttle setting.

Don’t push the prop levers forward upon arrival at the airport.

This probably goes against everything you were ever told by your instructors, but when running a GO-series engine, you’ll be doing the gearbox a BIG favor by keeping the RPM back at 2700-2800 rpm until landing.

If you need to go around, it is perfectly safe to advance the throttle fully before bringing the RPM up- unless you are running a supercharged engine, GSO-480, ect.

Keep your idle speed up, below a 1500 RPM idle will “chatter” the gearbox causing rapid wear of the outer planetary ring gear, a $3500.00 part

Move the throttle VERY SLOWLY!

Lycoming recommends a minimum of 30 sec. from fast idle to takeoff power.

Follow this rule when going the other way, go even slower.

If your GO-series engine has a Bendix pressure carb, follow the operator’s book: maintain Full throttle during climb. The Bendix carb. has an “auto-rich” compensation circuit that allows the engine to run rich at full throttle setting, if you pull the throttle back during initial climb, the carb goes “auto-lean” and you will risk over-temping the engine. Again, follow the book!

Fly often

This is the single biggest killer of any aircraft engine. Lycoming engines especially, suffer greatly from non use. Corrosion on the cam lobes, cylinder rust, and valve damage occur rapidly on engines that don’t run frequently.

How to tell if you need an overhaul,

There is a service bulletin that specifies an allowable play measured on the prop. You are allowed ½” in play 4ft from the center of the prop hub; make a pencil mark at the point on the blade. Place the tape measure on the ground with one blade in the horizontal position and measure how much free play you have in the gearbox (move blade up and down)

If you have a distinctive “stop” at each end of the range of movement,

chances are that everything in the gearbox is OK. If there is more than one “clank” or contact when moving the blade around, the plate that holds the stationary gear may have partially sheared the attach bolts. Worn gears are not going to self destruct, but if that stationary gear shears the bolts, then the whole gearbox may come completely unglued!

I have heard that it can be pretty exciting.

A “CW turn-clunk, CCW turn-Clunk” check is always part of my Preflight.

Follow the above steps, and you will have a happy motor.

Doug Johnson

I have a couple  questions just exactly what is Helio mod 45, GO-480-G1D6 and what all is involved in it?

How about the Deviation of 45, and the  GO 480-F2A6 derated to 285hp. so you can burn  80/87 octane  fuel whats involved in it and is it the answer to the fuel problem.

I keep seeing 100LL in the AvWeb news and nothing really good.



I believe it is changing the cowl on the 391 to a 295/395 cowl i have a copy of it at home i will post when i get home in a week


Sorry mod 48 is changing the cowl- 45 is changing over to the 480 but also includes mod 48.

Ray Dorsey

Mod 45 Changed the fuselage& wing structure to except the GO-480 torqe an hp change by adding tubing or increasing tubing size in the fuselage The Firewall is 395 the cowl 395.Gross is still 3000.Basic an early 395A/395. A couple were done . I,m Not doing the Firewall and cowling
since these are hard to find parts.


Every Helio I owned had either the GO-480-G1D6 or the A6, the latter has the high output alternator.

Both went to 1800 hours. If you know how to treat the Gopher 480, they are bullet-proof..

Doug Johnson


Article that appeared in the February 2001 issue of Light Plane Maintenance,

What we actually do see is that the high-RPM engines -- the geared models -- rarely have a problem in break-in, even if they might be nightmares to operate later on. We have yet to hear of a Duke, Cessna 421, P-Navajo or Helio-Courier coming back into the overhaul shop for glazed cylinders because the rings just wouldn't break in.
Even with the detergent and multigrade oils, these engines seem to always break in easily and are usually fully broken in at 40 or fewer hours. (Good thing; these are among the most expensive engines to overhaul.)


The Cessna 421 and Commander 685 used the GTSIO-520. You were lucky to get to 1000 hours with these.

They mention the Duke, sorry, but the Duke has the top intake direct-drive Lycoming TIO-541 which was also used in the A56TC Baron. TBO was or is 1600 hours for these and were only produced for these airplanes.

The Lycoming TIGO-541 was used in the P-Navajo rated @ 425 HP a side.

Doug Johnson

I found this mention of upgrading a 391 to Go-480. Steve Schaffer says it cant be done legally.

HK-612P 1957 H-391B c/n 058 damaged beyond repair Columbia

in the middle, was this high-wing taildragger, no wings (unbolted at the carry-through), no engine, or doors, in prime, landing gear but no wrappers, I looked at the main gear poking out the front, turned to the kid and said: "Helio Courier".

Went around the copilot's side, sure enough, early one with a porthole.

So, since no engine or prop, I looked up the owner and asked which version Helio it was.


Yeah, I know that, but there were at least two models, one, lighter duty and less lift, smaller engine and two bladed prop, other bigger engine, three bladed prop, and more lift.

He had no idea.

The other main difference is the cannot upgrade an older one to the bigger engine and prop without the heavier duty tailfeathers....I know, as I was accident investigation lead/parts recovery on HK-612P (c/n 058) outside of Mitu, Columbia, and we had to bring back the tailfeathers (originally light duty version, but last O/H had H/D tailfeathers installed).

Spent a lot of time in Helios......lots of odd little tailwhell and fork falling off on takeoff......and the recovery with a Cushman 3-wheeler.......welded it up, back in the air in 45 minutes.....or the tire on a tailwheel blowing up out in the jungle, destroying the rim and no parts......pilot had a local carpenter make a new one out of Ironwood, flew it home.
the jungle, destroying the rim and no parts......pilot had a local carpenter make a new one out of Ironwood, flew it home.

Anyone Have any thoughts opinions?

I had heard that there was also a bunch of tubing that had to be changed to from .040 to .050.



Take the data tag off the 435 nose case and stick it on the nose case of the 480, same nose cases. ;D Problem solved.  Who says it is a upgrade. That would be a matter of opinion.

Doug Johnson

how do we get past the rather obvious two blade three blade prop change?


It is the same gear box. even the shaft.    You know i am just kidding about this. :o  My point is the 2 engines are very close to identical except for the bore size the valve train is identical cam and rockers are interchangeable in the right configuration, stroke is the same, same acc.  ect.  There is not many people /mechanics that would not be able to tell the difference if you put a 480 data tag on a 435, not that anybody would ever do such a thing nor do i suggest doing it.

Doug Johnson

Of course I know you were joking. I was just throwing the prop in because even if you were trying to pull a fast one it wouldn't do any good because the darn extra prop blade sticks out like a sore thumb. But maybe if we got an extra long two blade to soak up that extra power no one would notice.


There are plenty of people who have run the 2 bladed prop on 480s.  It will handle it no problem.

Doug Johnson

Now you really have aroused my curiosity. How does performance on both ends compare to three blades. Larry Montgomery told me that they experimented with a longer two bladed prop but didn't have enough ground clearance, he said it worked better but you had to be careful with it. I don't remember him saying anything about cruise performance.