I can not count how many overhauls we have done in our little shop over the years.... Have had only one engine seize. That engine and all of its parts were dropped off at our shop for assembly. Checked one piston for fit and made the mistake that since the one piston was good all of them must be the same... Well, two of the pistons were 10 over and all of the cylinders were standard bore... Still fixed it on our dime...

Only other problem we have had over the years are bad Re-Ground camshaft's go out within the first 20 hours of flight... We have gotten to the point where we will not use re-ground cams anymore...

We have done several engines where we let the owner get a lot of hands on experience cleaning parts and help with assembly... It makes a better pilot when they know more about the how and why things are put together... Another reason why we like to do owner assist annual inspections also..

Last engine we did was a 0-300... Cost right at around 13 grand when done...

Brian

Brian-StevesAircraft wrote:We have done several engines where we let the owner get a lot of hands on experience cleaning parts and help with assemblyBrian

I so want to do that when the time comes.

Hotrod150+30 got it right. The size of the shop certainly does not mean bigger quality.

I have had some of the worst engines from the factory. And plenty of problems from big repair station engine shops and one man show engine builders. One of the best tells is to check with local air taxis or flight schools. We are the folk that use an engines up in a few years but also need to save money.
Annother thing to consider is warranty. Most shops honor their engines and reputation and will do anything and everything to make it right. One thing the factory has is a ton of cores. I had a cam go bad In 540 right away. Never quit making metal. Told lycoming that I purchased an exchange engine because I could not afford the down time. Shipped me a new engine and never charged me for the 250hrs I put on the pos motor and paid for all the labor.

After a prop strike and subsequent major I took a week off of work to reassemble and install my C145 with the local shop. One mechanic handing me parts the other watching and checking my work. Goes down in my book as one of my great all time life experiences. The only thing original on the new engine was the case halves. The parts bill was unbelievable. Probably about 22K in the end but there may have been an extra charge to put up with me.

PAMR MX wrote: Hotrod150+30 .....

I like it!!

Part 2! We attached some cylinders. Thanks again Graham for letting me be a part of this (and probably slowing you down with all my questions.)

Fresh piston pins; I've always called them "wrist pins." They are steel with aluminum pressed-in end caps. The pin free-floats in the piston and connecting rod, and if it does make contact with the cylinder wall, that soft aluminum does not gall anything important.


2 attached.


4 attached.


So what happened to get to this point? First we re-torqued all the connecting rod bolts. Then we started with cylinder #5 as recommended by the TCM overhaul manual. There are very specific instructions about the orientation of the piston rings, mainly that the top and 3rd rings should be oriented toward the "top" and the 2nd ring and the oil scraper should be oriented 180 degrees opposite those. We slathered everything in AeroShell mineral oil for assembly and started the insertion.

This tool called a ring compressor makes life very easy.


With the piston mostly inserted into the cylinder bore, we attached it to the rod end with the wrist pin, then compressed the lower ring and pushed it in the rest of the way.


Did you know that these engines use no base gaskets? They have a large O-ring that fits into a chamfered part of the case opening, then it's metal-on-metal at the cylinder base. I thought that was odd, but given that I have only rebuilt 2-stroke engines, maybe it's not? Graham told me a horror story about a fabled mechanic who did use a base gasket material and the engine blew up after it compressed enough to allow movement of the cylinder on its studs.


Gently slide the cylinder toward the case and onto the stud bolts.


The manual calls for all bolts to be torqued with oil on the threads, so we hit them with a finger dab of oil and started torquing in the very specific cross-sequence called out in the manual. This is done in stages: First to 300 inch-pounds, then to 500 inch-pounds on a second pass. The through-bolts that pass through the case and through the cylinder base are torqued to 700 inch-pounds.



I now must have one of these after using it. It makes my old clicky Craftsman seem lame.


Tada!


Gratuitous starter adapter photo for the hell of it.

Very cool!

Zzz wrote:I've been bugging my friend who is an A&P IA to let me shadow him on the reassembly of an engine, to help me decide whether it's within my grasp to build up my own powerplant for the Bearhawk (do I want to?) He's building a new Continental O-470 for his Skywagon, so I finally got the call. Let's assemble some engine!

I started down the road of rebuilding my O-470S a few years ago, and after digging in decided to swap my core for an engine that was overhauled at a shop in Michigan. The knowledge and service was top notch, and the engine that I got runs stronger, smoother and more predictably than anything that I have ever flown behind.

Figured I could probably do a good job at rebuilding an engine, but there are folks out there who excel at this craft. The consequences of screwing something up are pretty large.

That shop looks awefully familiar! Let me guess...MMV airport, is the guy missing some fingers???

Graham did a fantastic job on our 182 when we took it to him a few years ago!

Tell him waz up for me!


Mike

182dude wrote:That shop looks awefully familiar! Let me guess...MMV airport, is the guy missing some fingers???

Graham did a fantastic job on our 182 when we took it to him a few years ago!

Tell him waz up for me!


Mike

That's the guy! Great shop, great mechanics, and a super clean hangar.

http://nwairrepair.com/

Graham was gracious enough to host the last 180/185 convention in his hangar. Super friendly guy with a cool dog and a nice 180.