While the engine is off ....

Ed Haywood

Ed Haywood

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Jul 12, 2020
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Tampa FL
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Display name:
Big Ed
Pulled the engine on my Decathlon and delivered it to the overhaul shop yesterday. Looking at 3-4 months AOG, assuming cylinders are available as projected and crank looks OK.

Here is my list of things to do or have done while the engine is off and access is easy. What am I missing?

Replace
  • Oil cooler
  • Fluid hoses
  • Lord mounts
Overhaul
  • Prop Governor
  • Electric fuel pump
  • Engine mount
  • Fuel system, mags, starter (engine shop)
IRAN
  • Baffles
  • Firewall fittings
  • Inverted oil system
  • Wiring
Engine mount "looks" ok. But acro birds are subject to a lot of stress in that area. Does that require specialized processes, or can I expect reasonable results from local A&P to strip, NDI, and paint?
 
There are shops that specialize in restoration of engine mounts. I'd send it to one of those.
 
Alternator internal inspection.

How many hours on the vacuum pump?

How long since prop NDI'd or overhauled?
 
Dan Thomas said:
Alternator internal inspection.

How many hours on the vacuum pump?

How long since prop NDI'd or overhauled?
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Alternator is 10 months old.

No vacuum system.

Prop has 250 hours. Sent it out for IRAN and reseal a few months ago.
 
Bob Noel said:
you will learn to fear/dread/hate the phrase "ya know, while you are at it...."

don't ask me how I know....
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Yeah, am definitely trying to resist the good idea fairy. But there is some stuff that is impossible to do without pulling the engine, so it really makes sense to get it done now.
 
Don’t put off any recurrent ADs or SBs on the airframe.

Spar nails?
 
Engine - nose gear mounts can distort and lose alignment w/o any visual evidence.

I’ve made it a practice to send them them out for ALL prop strikes and recommend at o/h also. Seldom do I need a report of no repairs needed.
There have been cases where the taxi characteristics improved dramatically.

It’s my belief that the repairs were legitimately needed and you could not ask for a better time to do so. When your shoes are off is a good time to change your socks!
 
Magman said:
Engine - nose gear mounts can distort and lose alignment w/o any visual evidence.

I’ve made it a practice to send them them out for ALL prop strikes and recommend at o/h also. Seldom do I need a report of no repairs needed.
There have been cases where the taxi characteristics improved dramatically.

It’s my belief that the repairs were legitimately needed and you could not ask for a better time to do so. When your shoes are off is a good time to change your socks!
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Fortunately my airplane does not have a nose gear, as the wheel is on the correct end of the airplane. :cool:
 
While it's all apart, Paint or polish firewall, and inside of cowling.
 
Ed Haywood said:
Bit far away, but that got me thinking. I'll search for an FAA certified weld repair station in Florida. Gotta be some nearby.
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I was going to suggest Kosola & Associates out of Georgia (they rebuilt my Maule mount a while back), but it looks like they got bought in 2013 :eek: by Aerospace Welding in Minneapolis (we used to use them quite a bit…they’re pretty good, too.)

FWIW, they should have actual jigs for your mount. Shipping a mount isn’t that expensive.
 
I’m going through a Major right now for my O-470R
  • Pinnacle Engines is overhauling. Their warranty is 3 years or TBO! Whichever is sooner.
  • Loree Air is first rate and they O/H my mount as well. They found unknown corrosion. Also years of A&P’s sanding away corrosion thinned the tubbing well below minimums in 2 places.
    Just because it looks OK doesn’t mean it is.
  • Absolutely replace the engine control cables. Should be mandatory. right now the labor is near free.
  • If you have a constant speed prop, it needs to be flushed of old oil. Also a good opportunity for IRAN or overhaul for those that need it.
  • All hoses
Also in my case I had the nose gear 100% O/H’d.

4C9974A5-B8AE-407C-ADE4-0D4CB0F24A0B.jpeg
 
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Larry Korona said:
I used this shop when I did my overhaul back in 2015. Very pleased with their work.

https://www.loreeair.com/
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Ed Haywood said:
Bit far away, but that got me thinking. I'll search for an FAA certified weld repair station in Florida. Gotta be some nearby.
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It’s way more complicated than a certified welder can fix. Loree Air has high precision fixtures to rebuild engine mounts. In fact some of the other big names in engine mount repairs send stuff to Loree under subcontract as they are the only company resolve some issues. I’ve been to their shop, and it’s impressive.

Very nice people too.

If you visit an engine mount shop you’ll get it in 2 mins why it’s a specialized job.


Unseen internal corrosion and old pitting which was hidden under smooth paint. A mount that looked rock solid, was not.
 

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I cleaned mine up while I had the engine out....it was a lot of work but well worth it.
 

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NordicDave said:
It’s way more complicated than a certified welder can fix. Loree Air has high precision fixtures to rebuild engine mounts. In fact some of the other big names in engine mount repairs send stuff to Loree under subcontract as they are the only company resolve some issues. I’ve been to their shop, and it’s impressive.

Very nice people too.

If you visit an engine mount shop you’ll get it in 2 mins why it’s a specialized job.


Unseen internal corrosion and old pitting which was hidden under smooth paint. A mount that looked rock solid, was not.
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I get the need for specialized equipment and skills for repair. But seems like a local shop should be able to handle media blasting to bare metal, inspection to determine whether repair is necessary, and repaint if repairs not needed
 
My contacts include welders that can “weld the crack of dawn”. However ; their equipment does not include fixtures to return alignment to factory specs. Proper alignment can be difficult to determine.

Related: 150/152 had a prop strike and I sent the Mount out. We discovered there was a problem when “ finishing up” and the COWLING WOULD NOT GO BACK ON.

Further investigation revealed that the “ 152 Mount “ we sent out was exchanged for a repaired unit that was in stock. On finding the problem we asked for our
“ original “ back but it had been resold! Eventually we determined that the original Mount was anything but. It was a C-150 Mount that had been altered/repaired by the Hangar Fairies. Years later I found out the aircraft was involved in a nose gear collapse and was repaired by the Owner. He did some nice welding but fit and alignment was one of a kind.

During this time the Conversion STC was not active. Numerous calls with the late,great Harry Delaker ( Del-Aero) and we were able to move forward. Harry had just acquired the STC and set an engine up in his shop for angles , spacing etc and
the situation was resolved.
 
Ed Haywood said:
I get the need for specialized equipment and skills for repair. But seems like a local shop should be able to handle media blasting to bare metal, inspection to determine whether repair is necessary, and repaint if repairs not needed
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Be careful with media blasting. Depending on what they use and how they do it that might necessitate a repair itself.

Just send it to an engine mount shop and be done with it. Especially on something that it appears that you do some aerobatics with.
 
These mounts are 99.999% of the time in need repair for most GA owners. The spec is 10% material loss. One good pit and that tube section needs replacement. The pair of tubes straddling the exhaust always need replacement.

The guy you take it to must have to have the ability to determine tube thickness in relation to the original specifications and the other non-destructive tests that are required. Having a weld shop strip and inspect can look for obvious pitting, but they do not have the other testing procedures as the repair centers use to determine integrity of the mount.

And if there is a problem, which there will be, now you’re gonna pay these guys to repaint it, or it will flash rust prior to sending it to a shop which will then re-strip it and perform the analysis.

The engine mount repair centers will tell us when asked, that half or more of their customers are convinced their mount was healthy and just needed inspection and repaint.
 
Wait, so the shop that specializes in mount repairs says that the mount needs repair 99% of the time? o_O
 
Ed Haywood said:
Wait, so the shop that specializes in mount repairs says that the mount needs repair 99% of the time? o_O
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The response would be the same if you asked an engine shop about the condition of your engine. And both would be accurate.
 
When I help remove my engine, I was shocked by small size of the 4 bolts through the firewall, I think less than a 1/4 inch in diameter.
I replaced them with new.
 
MooneyDriver78 said:
When I help remove my engine, I was shocked by small size of the 4 bolts through the firewall, I think less than a 1/4 inch in diameter.
I replaced them with new.
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The bolts on mine are 7/16, so quite substantial. I will replace.
 
455 Bravo Uniform said:
It amazes me how flimsy planes look when they have their skins off. And amazing that triangulation of skinny tubes makes such a strong structure that can take loads. Thanks for sharing.
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I agree. Think about the physical forces generated by aerobatics. Rapid changes of pitch and yaw applied to a 55 pound 6 foot diameter propeller disk spinning at 2600 RPM. There are thousands of Decathlons, Pitts, clipped Cubs, and other aircraft with 1930's construction technology flying aerobatics for decades. Can't speak for other makes, but I am not aware of a single Decathlon failure in that area.
 
455 Bravo Uniform said:
It amazes me how flimsy planes look when they have their skins off.
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If you think of the fabric and metal boot cowls on a tube constructed airframe as merely a bug shield, it tends to explain the "flimsy" side. Those tubes are the structure which come with an increased weight penalty when compared to a monocoque built aircraft. One reason the fabric was dropped from some early helicopter airframes was it wasn't needed and saved them a little weight.
 
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