Club Homepage Forums Classified Ads Buy & Sell - Everything But Airplanes Looking for advice/opinions on buying an engine

Folks, as most of you know I am looking for an engine. I took an ad out on Barnstormers and am surprised at the kinds of reponses. I never thought that engines with less than 100 SMOH, but no logs prior to the overhaul would show up. I haven't talked to everyone yet, but one looks interesting. Pretty much all my responses have been zero time since overhaul/no previous logs.

My question is this: Would the absense of logs prior to overhaul be a deal breaker? How much of a hit on resale value would I take if/when it comes time to sell? And one that pertains to this engine: Is the crank being ground down .020 on the bearings a problem?

Here is the description of the overhaul sent by the seller:

The crank is .010 under on the rods and .020 on the mains ,the cylinders were overhauled by my IA and myself (my IA also runs a very reputable machine shop). All the case,crank,and cylinder work was done by he and I in his machine shop.Everything was cleaned,miked,magnifluxed,painted/powder coated,and inspected. The crank was re-nitrated,the cam was new,the bearings were all new (main & rods) the cylinders were reassembled with new giudes & seats,new rocker shafts,new pistons,new rings,and new seals.Everything on the cylinders are standard size. The oil pump is new,all the gears were magnifluxed and checked perfect. I do not know the total time on anything because there was no logs with this engine when I bought it. All the pistons and rods were weighed and balanced perfectly so she is a very smooth running engine.

And here is why it is for sale:

I had it on my taylorcraft that I had spent the last 8 years restoring. After only 2 flights it was setting on the ramp waiting on the 3 flight when a medivac helicopter landed too close to it and blew it over an embankment. I am once again rebuilding my taylorcraft but it will be at least a couple more years before I need an engine again and there is no point in letting this one set here that long. If it sets for two years I will probably do a tear down on it at that time just to make sure nothing has rusted so if I'm going to let one set it may as well be one that needs rebuilt anyway. When the airplane went over the embankment it did land on it's nose but the prop or crank never hit anything. It did crack the intake spider and bent the oil tank.I have another oil tank but no spider so you can keep your spider and accessories.

Whaddya think folks? At least there was attention to detail on the outside.

Rod and main journals are allowed up to a .020" undergrind on the crankshaft according to the manual. Oversized bearings are then fitted to the rods. The crankshaft main journals will not survive another grinding. (Not a problem until next overhaul.)

Logs only since overhaul are acceptable, with details describing all parts replaced, who did the magnaflux (required), who did the crankshaft regrind, accessories overhauled, etc.

Personally, a record of engine TTSN is a small advantage (it may be recorded in the new logs), but legally not a requirement when properly overhauled. All large shops, such as Mattituck, would at least know and log TTSN. Is this one "unknown"? Why? Where are old logs?

I would insist on a crankshaft flange runout check, regardless of reported lack of prop strike.

I've been working an Engine issue also. The shop doing my engine refused to work a logbook/data plate I found even though they completely disassembled my engine and inspected every thing (130 hour engine). He found me a core with logs all the way back to new. He used the log from that one and the accessory case (only part from that engine he used) I guess what ever it takes to be comfirtble. If it is a lost log engine 1st thing call TCM and verify it is a valid 0-200 s/n. That was my engine issue, S/N was not valid. Everything needs to be checked and mentioned Cases included. Time of last overhaul is important but often over looked is date of last overhaul. 10 years is recomended interval. If you want to rent it can be an issue. It is definently a buyers bargining chip with lost log statement.

Thanks, for some reason I thought going .020 under required a STC. I'll check the S/N before buying any engine.

He said that he bought the engine with no logs. The overhaul was recent. His first flight in the restored plane was June of this year.

I'm also hearing from people who have engines that were overhauled, run for a couple hours on a stand, and then pickled for years. If it was sealed well, is that a problem?

Depends on your intended use. Recomend calinder time between overhuals is baised on date of overhaul, not date put in services. If you want to rent it out it could be an issue. If it was pickeled and your using it for personnel use it should be ok as long as it was done properly. The call to TCM is real important. I had a log book and Data Plate for my engine. It had an invalid S/N also. That was 2. My engine and a log book/Data plate. Guess the third time was charm. Found a core, ran the s/n through TCM and it was a good one.

A pickled engine is only as good as the preservation method used. TCM Continental's recommended method for temporary storage of O-200's is found in the O-200 overhaul manual, is detailed and time consuming to do, and is only good for 90 days, at which time the engine should be depreserved, run, and represerved! ("Flyable storage" procedures should be observed for installed engines when inactive periods are expected to exceed 7 days, but not over 30 days!) Who takes the time for that?

Similar procedures are outlined in TCM Continental Service Information Letter SIL99-01 [tcmlink.com].

Very few GA piston engines come anywhere near the recommended level of protection after field overhaul, or even between flights! Long term preservation depends on the proper use of special preservative oils, and the inside then being completely sealed off from the outside, with the use of dessicant bags and dehydrator plugs that MUST be changed at regular intervals, etc. Even this is never 100% affective against corrosion for an extended period of time. It still requires periodic depreservation, running the engine, and represervation.

I know of no-one who does the whole procedure properly, so results will vary accordingly. If it's been sitting in a corner of the shop for any extended period from several months to years, internal corrosion is still a good possibility, no matter how thorough the preservation procedure used. A good inspection before purchase is always good insurance. The stories about the derilect aircraft being started and successfully flown away after decades of neglect may be true, but they are noteworthy only because they are the very rare exception!

For comparison, military piston and turbine engines (and even components) are meticulously preserved and then placed inside nitrogen filled containers under pressure, and can withstand decades of storage with only a regularly scheduled check of the nitrogen pressure. They come out of those containers exactly as they were preserved and like new. A lack of nitrogen pressure requires an uncanning, de-preservation, inspection, test cell run to verify engine condition, and then a represervation and canning of the engine. Your tax dollars are well-spent here (for once)! Some commercial airline and GA turbine engines are stored with this same military preservation procedure, size and cost permitting.

I was thinking this, then saw you mentioned it -

Who the hell has the time and money and manpower to do all that anyway?

Yep! There are no quick answers to Eric's questions, because there are just too many variables involved. There are no guarantees against corrosion, even on an engine currently being flown. Every airworthy engine I've ever come across has had a period of inactivity at some point, and it often only takes a week or so of sitting for rust to begin forming on the camshaft, cylinder walls, and other components. I've had brand new cylinder walls form a solid coating of surface rust in only 30 minutes while sitting on a workbench following a cleaning. It was easily removed with an oily rag, but allowed to sit for a week, I'd likely have had to hone the cylinders again.

I feel safe in saying that every piston engine on every airplane has some degree of steel rust and aluminum corrosion inside and out, just as does every airframe (including mine). Corrosion in itself doesn't deem a part unairworthy, although it could if severe enough! A certain amount of corrosion is acceptable in may areas, and doesn't affect anything if kept in check. The question isn't whether or not there IS corrosion (there is), but rather how much and how serious? The trick is to locate it and determine it's impact, then treat it (where possible) and try to prevent it's recurrence or growth before it does further damage requiring repair.

Even the Aeroshell "plus" series of oils or Av-Blend additives will not protect any engine indefinately! Even special preservation oils won't do that. Eventually, any oil will drain from the constant tug of gravity, or even evaporate, exposing large expanses of bare metal for the onset of corrosion. Corrosion is your airplane's biggest enemy, and sitting dormant provides the enemy the least resistance. The camshaft is in the most danger of attack in any of these engines, regardless of make or myth.

All Eric can hope for is to find the least corroded engine available that's still serviceable, and that might still require pulling a jug or more for verification.