IO-540 : What to replace at Teardown

[David Clifford]

I purchased an IO-540 V4A5 Lycoming that had a light prop strike. It is a 2001 with 461 hours SNEW. The previous owner had a first prop strike @ around 300 hours and the engine was removed and shipped to Lyc for inspection and repair. The crankshaft was replaced at that time with a brand new one to comply with the crankshaft AD. New rings, bearings,,,ect were installed at that time. I purchased it after his second prop strike @ 461 hours. I disassembled the engine last Friday and am leaning towards Aircraft Specialties to check and repair the crank flange,,,it dials .008 so there is a good chance it can be repaired. My first question is if anyone can provide a recommendation on their services and second is just how far should I go in replacing parts? i.e. bearings and rings that have 160 hours use on them and are just barely broken in. I know that It would be a good idea to replace this stuff while the engine is apart, but considering the costs of Lycoming engine parts, I am trying to get this done as cheaply as possible. My thoughts are to just send out the crank and do a cleaning and inspection of everything else and verifing everything is within limits, just cleaning up the cylinders and pistons/rings, and reassembling the engine with new gaskets, the repaired crankshaft, and the cleaned-up parts. Any comments or suggestions from knowledgable aircraft engine folks here would be appreciated! Thanks in advance.

[Mark Burns]

Originally Posted by David Clifford

I purchased an IO-540 V4A5 Lycoming that had a light prop strike. It is a 2001 with 461 hours SNEW. The previous owner had a first prop strike @ around 300 hours and the engine was removed and shipped to Lyc for inspection and repair. The crankshaft was replaced at that time with a brand new one to comply with the crankshaft AD. New rings, bearings,,,ect were installed at that time. I purchased it after his second prop strike @ 461 hours. I disassembled the engine last Friday and am leaning towards Aircraft Specialties to check and repair the crank flange,,,it dials .008 so there is a good chance it can be repaired. My first question is if anyone can provide a recommendation on their services and second is just how far should I go in replacing parts? i.e. bearings and rings that have 160 hours use on them and are just barely broken in. I know that It would be a good idea to replace this stuff while the engine is apart, but considering the costs of Lycoming engine parts, I am trying to get this done as cheaply as possible. My thoughts are to just send out the crank and do a cleaning and inspection of everything else and verifing everything is within limits, just cleaning up the cylinders and pistons/rings, and reassembling the engine with new gaskets, the repaired crankshaft, and the cleaned-up parts. Any comments or suggestions from knowledgable aircraft engine folks here would be appreciated! Thanks in advance.

Hi David,
Hopefully you will get some replys from folks more qualified than I am.
I think your plan sounds ok. I would send the connecting rods and the crankshaft gear to Aircraft Specialties for inspection also. A prop strike could have damaged these items, and a visual inspection is not good enough.

In case you didn't already know it, you have to use new rod bolts and nuts.

I wouldn't do a thing to the cylinders if you aren't going to replace the rings.
I wouldn't even clean the pistons. Just keep everything with the correct cylinder and oriented properly.

Have fun!

Mark

[yakdriver]

What airplane was the guy flying. Two prop strikes in 160 hrs is a little much. Anyway I would do everything Mark said plus all of the accessory gears inclding oil pump gears. Not much more money for piece of mind.Depending on how long it has been sitting it wouldn't hurt to check the cam also. Don

[David Clifford]

Yes,,,I plan to replace the rod stretch bolts and nuts and it probably would be a good idea to send in all the moving parts as required per Lycoming's propstrike SB. I am wondering about the rep of Aircraft Specialties Inc. Any one use their services or had any dealings with them??

[az_gila]

...says that all of the parts listed in his Service Bulletin should be replaced if the engine is taken apart.
I guess a few parts probably "crush" into place and would be disturbed if the case is split.

http://www.lycoming.textron.com/supp...dfs/SB240T.pdf

Update - just read the SB carefully, and it seems that the bearings are OK to stay in if they don't get removed (or fall out......) when the case is split.

[David Clifford]

Originally Posted by az_gila

...says that all of the parts listed in his Service Bulletin should be replaced if the engine is taken apart.
I guess a few parts probably "crush" into place and would be disturbed if the case is split.

http://www.lycoming.textron.com/supp...dfs/SB240T.pdf

Update - just read the SB carefully, and it seems that the bearings are OK to stay in if they don't get removed (or fall out......) when the case is split.

Thanks Gil,,,,that is the SB I was looking for and will comply with. Now for one other question as to how the engine will be classified after I do the work. Is the engine now an "experimental" engine since I am doing the work???? It does not matter to me but I am wondering how my DAR will look at it in a couple years when I get the final inspection for the airworthyness certificate. Do I make any notations in the engine log book?? And by the way,,,for anyone wondering, splitting the case was very easy. After the jugs were removed the through bolts were easily identified. I fabricated a steel threaded cap to pound the through bolts out but they did not budge so I used 1/2" washers and stacked them under the cylinder hold down nuts to pull the through bolts out using an impact wrench at low speed pulling the bolts out about 1/2" at a time before stacking more washers under the nut and doing it again. The bolts pulled free after about 1-1/2" and the case popped open after a couple light taps with a plastic dead blow hammer.

[az_gila]

Originally Posted by David Clifford

Thanks Gil,,,,that is the SB I was looking for and will comply with. Now for one other question as to how the engine will be classified after I do the work. Is the engine now an "experimental" engine since I am doing the work???? It does not matter to me but I am wondering how my DAR will look at it in a couple years when I get the final inspection for the airworthyness certificate. Do I make any notations in the engine log book?? And by the way,,,for anyone wondering, splitting the case was very easy. After the jugs were removed the through bolts were easily identified. I fabricated a steel threaded cap to pound the through bolts out but they did not budge so I used 1/2" washers and stacked them under the cylinder hold down nuts to pull the through bolts out using an impact wrench at low speed pulling the bolts out about 1/2" at a time before stacking more washers under the nut and doing it again. The bolts pulled free after about 1-1/2" and the case popped open after a couple light taps with a plastic dead blow hammer.

...the best thing to do would be to find a friendly local A&P and have him look over your shoulder and inspect your work. Try asking at your local EAA Chapter.

If he signs the log books, the engine can stay "certified".

The FARs require that you make engine log book entries, and perhaps a more detailed collection of papers should be kept with full details of the parts and services you use, in case of future ADs or SBs from/about your vendors.

Remember, the FAA does not use the word "log book" - they refer to aircraft/maintenance records.

More thinking -- The FARs require that you make engine log book entries - well, perhaps not during the actual construction, but certainly after the plane is given an airworthiness certificate. It does make sense to keep the records though.

[rocketbob]

Aircraft Specialties is the best in the business and they will take care of you. Also they have the best prices on new parts. Make sure when you disassemble the rods from the crankshaft, pay close attention to the orientation of the tongue and grooves in the rods, as they have to be oriented the same way at reassembly and there is only a one-liner in the manual that mentions this. At a minimum you will need new rod bolts and nuts, if I recall the rod bolt part # correctly its a 75060 and the nut is 12186. To be on the safe side you'll have to bolt the case halves together and measure the main ID's with bearings in place to determine if your bearings are good, and you will have to mic the crank. Rod bolts are initially torqued to 35ft/lbs then mic'ed for stretch, max 50ft/lbs to achieve the right stretch. The mains will have springback to them so they should be good to reuse. After all you have to torque case halves minus crankshaft with to check your clearances, and so if the crush is lost when tightened it would be lost before you put the crank in for the first time. Bearings aren't that expensive however, so for a couple hundred bucks you could put new ones in. If it were mine I'd just reuse them, since technically the only wear they should have is from cold starting.

[rgbewley]

ASSI is a high quality shop, and they will take good care of you on repairing your crankshaft. If you plan on reusing the lifters, I hope you marked their location at tear down. If there was any pitting or scoring, you will need to have the cam reground and replace lifters anyway. Chad is good to deal with on buying parts.

Good luck!

[pierre smith]

Originally Posted by David Clifford

..... Is the engine now an "experimental" engine since I am doing the work???? It does not matter to me .....

.......if you're not an A@P. We overhauled our own engine and had to remove the data plate that came from Lycoming and flipped it over, re-engraved "Smith/Morgan 0-360" and gave it the same serial # as our airplane.

Regards,