Prop Strike

[Bruce Fenstermacher]

If Aircraft Specialties says a crank is good, it's good. I wouldn't waste a moment worrying about it.

[bagarre]

Give the shop specific instructions NOT to render the part useless (destroy or mutilate) if it doesn't pass their inspection so a second opinion is an option.
There have been stories of shops drilling jokes in props and welding up intakes on cylinders when they deem them unairworthy.

[wingnut]

Always send instruction along with case and crank that if it rejects, you want it unmolested. That usually puts a stop to unnecessary culling. If they still reject, always get a second opinion.

[krines]

I had a prop strike 6 months ago. Avemco for insurance. Avemco paid for new prop and tear down inspection. Crank failed at Aircraft Specialties for corrosion. I ended up having to pay for a replacement C145 crank which is very expensive. I had 1100 hours on the engine and just decided to major the engine as insurance was paying for some of the bill. Ended up putting on all new continental cylinders. It is likely that in this inspection they will find parts that dont pass inspection due to wear and corrosion and not damage from the strike. This will be out of your pocket. One other consideration is that cylinders rarely make it to TBO without needing work. I think the average time to needing a top overhaul is something like 700-800 hours. Once again insurance is paying for some of this work so you might as well bite the bullet on the cylinders at this time. My engine shop allowed me to participate in the disassemble and reassemble of the engine as well as install. That was a great experience. I hate to say it but I think your going to be out a good chunk of money. In the end it is reassuring to know you have a solid engine especially when flying over the rocks. Good luck. Steve

[Waterboy]

Update. My engine is nearing completion. In the commercial helicopter industry when the mechanic says it will take X amount of time, you can count on double that. I am learning in private GA airplanes it takes 4 times as long. Almost done, I think?

I decided to go ahead and fully overhaul the engine. The inspection turned up no damage related to the propeller strike. My crank was free of cracks but needed to be ground slightly under size to true it up (undersize .010). It turned out OK and is back from the crank shop. The engine case did not fare as well. A crack was found in one of the oil galleys. Its was not related to the propeller strike.

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My shop was able to find another case for the same price that it would cost to repair mine. This was recommended, apparently weld repairs in that area don't always turnout well. One connecting rod and a few accessory drive gears will also be replaced.

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I am going with Continental cylinders with the new style push rod tubes. The reviews on cylinders are all over the place, I am told Continental may have the more reputable warranty at this time, and my old style push rods leaked like a sieve. By replacing the cylinders I no longer need to worry about the AD on my old ones.

The insurance company is covering the cost of the prop strike inspection $8000. My total overhaul cost is $22,000. I am also replacing my pull starter with a push button and it is included in the price. Below is the quoted work that will be done.



This quote is for the major overhaul of a Continental C145-2. Our engines are overhauled to factory new tolerances. Applicable AD Notes and Service Bulletins are complied with.

Price: $22,000.00 – as long as your crankshaft grinds ok. I expect it to.

The following is included: Carburetor, magnetos, harness, massive electrode spark plugs, light weight starter with remote push button installation kit, inner cylinder baffles and engine mounts.

The following is not included: Exhaust system, vacuum pump, generator or alternator, removal, installation and freight on the engine to and from our facility. Baffling, other than the inner cylinder baffling, is not included. Fluid hoses are not included.

Terms: Remaining balance is due in full upon our completion of the engine overhaul.

Time Frame: Once we have your approval we need to have the crankshaft ground. Once that is back we can assemble the engine. Expect 3-4 weeks from your approval to completion.

The engine will have received the following work:
Case will be replaced with a repaired crankcase.
Crankshaft will be ground undersize, magnetic particle, ultrasound and dimensionally inspected. New blade bushings are installed.
Counterweights are inspected. New bushings are installed.
Rocker arms are inspected. New bushings are installed and sized.
Rods are inspected. New bushings are installed and sized. Alignment and dimensions are checked.
Magnetos are replaced with factory rebuilt Bendix magnetos.
Starter will be new.
Carburetor is exchanged for a factory overhauled carb.
Ferrous parts are magnetic particle inspected. Non-ferrous parts are liquid penetrant inspected.
External steel hardware is cadmium plated.
The crankshaft, counterweights, connecting rods and pistons are balanced.
Camshaft and lifter bodies are repaired or replaced with repaired ones.
The engine is assembled according to the Continental Manual and test run.

The engine will receive the following new parts: Continental cylinder assemblies, rocker bushings, piston pins, rod bushings, rod bearings, rod bolts and nuts, counterweight pins, plates and snap rings, counterweight bushings, crankshaft bushings, main bearings, gasket set, shaft seal, spark plugs (massive electrode), harness, starter, and engine mounts. Other parts replaced as required.


Hope to have the plane back in the air soon.
And hope this is helpful to others if they end up in a similar situation.

Ken

[GAHorn]

Looks good but I"d make one change... a NEW cam.
CAm and lifter bodies should be nitrided, IMO.

[Waterboy]

My engine arrived from the overhaul shop yesterday. After numerous delays. It looks great! It looks so good it should make an extra 100hp.

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I added a lightweight push button starter to the overhaul. I am planning to put the start button in the hole where the pull cable was located. An oil filter will be added soon. I'm pretty well tapped out on upgrade money and ready to start buying avgas again. The warranty forbids Mogas so I will be burning lead for the next year.

One of the airport locals asked if I was going to polish the fire wall. I had not thought about it. Has anyone here polished their fire wall? Any recommendations?

[c170b53]

Yours looks pretty good as is but it's a great opportunity to clean stuff up like your ground cables and also try to remove the dirt between the battery box and firewall. I use a good stream of WD-40 for many tight ares to flush junk out. New rubbers for your mount to firewall and bolt her in.

[hilltop170]

One of the airport locals asked if I was going to polish the fire wall. I had not thought about it. Has anyone here polished their fire wall? Any recommendations?

The firewall is galvanized steel and won't polish very well. It's best not to use harsh abrasives as the galvanize is soft zinc and can be removed without too much effort which will remove its corrosion protection. A good cleaning with mineral spirits and a stiff bristle brush to remove caked-on deposits is about all that should be done. Do not use a metal wire brush.

[T. C. Downey]

One of the airport locals asked if I was going to polish the fire wall. I had not thought about it. Has anyone here polished their fire wall? Any recommendations?

The firewall is galvanized steel and won't polish very well. It's best not to use harsh abrasives as the galvanize is soft zinc and can be removed without too much effort which will remove its corrosion protection. A good cleaning with mineral spirits and a stiff bristle brush to remove caked-on deposits is about all that should be done. Do not use a metal wire brush.

actually it's coating is aluminum.

[GAHorn]

What bothers me with the lifting eye is the stress it places on the backbone of the crankcase at that very point where cracks have been known to appear on Continentals.

I'd like to see it supported at the prop-flange and the mount-legs or dynofocal using straps.

[hilltop170]

actually it's coating is aluminum.

Thanks for the correction Tom. Same cautions apply.

[Waterboy]

Well I will make sure the engine is better supported next time it needs to be lifted. Sounds best to leave the firewall alone and just clean up the old gunk. It sound be flying tomorrow afternoon. Fingers crossed there will be no more delays.

[Waterboy]

The engine is in and runs great! I flew it for an hour at full throttle yesterday afternoon to start breaking it in. I am very happy with the power output and not a drop of oil leaking.

There are a couple of issues I could use some advice on. The oil pressure ran right at the red line for the entire hour. I am using Aeroshell 100 mineral oil for the break in. The oil pressure line was bled at the gage. Prior to the overhaul oil pressure was always in the normal range. Is high oil pressure normal on an overhauled engine? Our current plan is to watch it for a few hours and see if it comes down.

The other issue, the Alternator would not come on line. It was wired incorrectly on installation. The wire connections were corrected and will still not come online. Could the improper wire connections have fried the Voltage regulator or the Alternator? Thoughts on trouble shooting? Its a Skytronics Jasco 50amp, and worked fine prior to engine removal.

Thanks, Ken

[Bruce Fenstermacher]

I would not worry a bit about redline high oil pressure. It will only come down as the engine wears and there is really anything you can do about it anyway assuming you have a correct bypass spring and it is within tolerance.

If you find the spring is at fault and a little strong there are probably several people here on the forum who would like to have it.