Planning an engine overhaul

[rwhaid]

We are coming up on an overhaul for our engine and are trying to decide whether to escalate it. We still have 200-300 hours to go, but have been noticing a slight increase in oil consumption, very dirty spark plugs, and oil spills above 5.5-6 qts. Also a 20+ year old engine. Other than that the plane is flying great. What other factors should we be considering or looking at if deciding to escalate the overhaul? Want to err on the side of safety. Thanks in advance.

[waynemcc999]

Ryan, some thoughts in random order:
-- a new engine does not necessarily translate into an increase in "safety"... why?... "infant mortality".
-- I'm guessing you're in the USA and Part 91, so TBO is only a recommendation.
-- I've got 3050 tach hours on the original engine in my 2008 DA40 XLS... and replaced 1 cylinder at ~2200 tach hours and 2 more cylinders just as I passed 2900 tach hours... i.e. 1 cylinder is still original.
-- I fly often... most all of the 3050 tach hours are in the last 9 years... so YMMV.
-- I always cruise LOP.
-- I do Blackstone oil tests every oil change, and a full Savvy borescope protocol every annual.
-- IMHO, we should change engines only for a measured and/or observed reason... and TBO for me is not that reason.

[jwx96]

I agree with Wayne. TBO is just a guideline. One thing to take into consideration is the downtime involved in engine repairs, overhaul and replacement. Some shops are booked out for months. New Lycoming cylinders are hard to come by. An order for a Lycoming factory reman engine takes a year. You may want to order parts or schedule something a little early just to avoid the possibility of a long wait with your plane in the hangar. Also, if the engine is getting old so are some other things like the engine driven fuel pump, the ignition harness and the starter. Are the fuel pressures steady? Does the engine occasionally misfire? My engine is running strong at 2400 hrs, but I have a factory reman on order that should be here in less than a year. There’s no right answer so choose a course of action that seems best for you.

[krellis]

As others have already said, TBO is just a guideline for Part 91 operators. Our neighbor has over 4000 hours on their IO-360 equipped DA40. Both of our DA40's "spilled' oil above 5.5-6 quarts.

Oil analysis, boroscope and compression checks are great tools. If it's really starting to "burn" oil, maybe a ring flush is in order before you move towards a rebuild.

https://www.google.com/url?sa=t&source= ... ysfJa7cezH

[Steve]

I’ll second what others have said about lead times for engines. I thought I had it bad when a Lycoming rebuild took 4 months in 2021 during COVID. If it truly is taking a year, order your engine now. Don’t forget about the additional bits which will require replacement and may also be in short supply: engine mounts, hoses, etc.

[Johnrschaefer]

Joining the chorus here - my original engine will be retired soon with perhaps 2700+ hours, and replaced with a factory rebuild. Oil analysis at every oil change and borescope at every annual, as well as full attention given to the engine monitor data (also submitted to Savvy) help to understand the engine's condition. Even at 2700+ hours, it could be argued that I will euthanize my engine prematurely. Given the lead times for Lycoming factory rebuild, I chose not wait until a more urgent condition might emerge to place the order.

[rwhaid]

Thanks for all the input. We have a 2002 DA-40 with the original engine monitor (VM1000). Doing some kind of data analysis would be helpful, but we have an old engine monitor (VM1000, shipped with 2002 model). Has anyone been able to pull engine data from that? Theoretically there is a serial port behind the instrument panel but we have not yet explored this.

(EDIT: According to JPI, there is no memory on the original VM1000, so no ability to pull data beyond what you see in the interface)

[jwx96]

I once used my cellphone camera to “record” some abnormal VM1000 rpm values when I had a prop control problem. It helped to be able to show my shop what was going on. My 2003 DA40 went into the shop today to replace the VM1000 with a JPI EDM 930. One of the benefits I’m looking forward to is data recording.

[brenner]

Who would y’all recommend perform the engine replacement (and other related items) for a 2004 DA40; I’m in OK and now at 2000 hrs. Love all the comments about TBO and I too was just told expect 12 months to get a reman. Considering ordering the engine now and that way it’s ready at the point in the future when I think it’s time to do it.

Appreciate the inputs

[Chris]

I'm not sure I would believe 12 months for delivery. I received a note just this week from another DA40 driver who indicated that his Lycoming factory remanufactured engine, which was ordered 18 months ago and was supposed to be delivered this month, has now been dealyed until July 2026. That would make three years since he placed the order.