What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

Aztec 540 engine, last overhauled 1996 - thoughts?

B

bimmer1980

Active Member
Friend
Guys,
I'm potentially looking at a IO-540 from a piper Aztec that was last rebuilt in 1996, has about 560 hours. Supposedly good compression and good bore scopes from May of 2026. I have asked for those details.

What are your thoughts on running that "low time" engine on a RV-10 as is?

Or do you recommend a full tear down and IRAN or overhaul?

What other questions do I need to ask?

Its about four hours away from, so I could go look at it with out too much trouble.

Thanks!
Brad in York, PA
Slow build Rv-10
 
Purchasing a used engine has it risks, for starters a review of the logbook and details of the last overhaul are a must. A proper overhaul will be documented including p/n's and yellow tags/8130's as required. Is the engine currently flying? What is the history for the last 30 years? If still interested then a borescope inspection and crankshaft runout would be in order. Additionally any accessories such as magnetos etc: may be timed out. Be sure the IO-540 variant is compatible with your build.
Good Luck.
 
I would want to know what the TT is for the crank and crankcase and how far the crank has been turned. I would also want pics of the accessory case through the mag holes to look for rust on the gears. That would be an indicator of rust elsewhere.

It could be a good deal at the right price.

I’d OH, IRAN, or fly it based on condition…
 
My engine was torn down around and 2004 if I remember correctly. I put it on my airplane 8 years ago and it has been great, very few issues. However I went through a few years of very little activity, at this point if my lifters go it'll be from the abuse I've put it through, not it's overall age.
 
When you buy an engine like this, you are basically buying the case and crankshaft. I would want to know if the crankshaft is standard diameter or if it has been ground down. Nothing wrong with ground down, but you don’t want one that’s at -0.010 because there is no “meat” left to work with if it has any problems with the bearings.

So with that said, I’d buy it at whatever you are comfortable spending on a case and crankshaft. I’d try to get an agreement from the seller on a price if the case or crank fail inspection.

This is coming from someone that’s bought two “good” used engines that the seller believed were good. The sellers didn’t purposely deceive me, there is just no way to know until you disassemble it and send it out for inspection. Both had a bad case. One was able to be repaired, the other was rejected. The one with a rejected case quickly became a $6k loss.

From having this experience twice, I’d either want a guarantee of good case and crank (which most sellers likely won’t agree to), or I’d simply prefer to purchase good parts.
 
Last edited:
-what is your get in the air timeline and interruption to flying tolerance down the road?
I my case, I would install, fly, and monitor. If I got lucky then I live happily ever after. If not, I can tolerate an IRAN down the road cuz I have other flying opportunities.
Some would dread the idea of pulling an engine and grounding the plane. If so, hang the forever engine up front. Some can’t wait to fly. If so, hang it and fly.
In either case case the price base to be right.
Good luck!!
 
Thanks for the inights!! I appreciate it.
Follow up - what would be a decent price for this engine? Also, giving merits to runable as is, versus "core" prices? What would you spend on this package?

I've been checking a few options (barnstormers, colorado airparts, bas, Facebook...) and plan to check some more, but any two cents would be helpful.

Pending all this, I need to determine what all components come with it -- exhaust, engine mount, etc etc. (Sell off unneeded parts, etc)
I had originally planned to go SDS, but in some respects, running the current factory FI to keep it simple has some appeal too.

Thanks
Brad
 
Another potential hidden cost...

My 10 is using a C4B5 off of a later model Aztec. It's been many years so the specifics may be off. I had to switch out the mount ears on the engine from the larger diameter mounts to the smaller ones. I think the Lycoming PN on the smaller ones is 70456 and have a 1.38" diameter hole required for the Van's motor mount. The Aztec mounts from the donor were the 72306 mounts with a 2" diameter hole. My engine builder had them and swapped them for me. They can be expensive otherwise. Back when I was sourcing them, they were $300ea for lycoming branded parts no clue today.

I had a rebuilt bendix fuel servo off of a Piper Commanche that went on the engine. As a result I don't recall what, if anything, came w/the core motor. The mags, starter and alternator all needed changing from what may have come w/the core. I paid $10,500 for the core that had 1430 TSMO but that was way back in 2008.
 
Last edited:
I can’t speak highly enough of the SDS CPI2 and standard fuel ignition if you opt to keep it simpler than full EFI.
As for price: It’s so subjective. I wouldn’t consider it a running engine as removed unless I could see it run and talk to pilots that flew behind it and mechanics that maintained it.
In other words: How much consideration would you give to the engine as it sits if you were buying the plane to own and fly?
1996 is a long time ago for 600 hrs.
If they are asking more than core price and it’s already off the plane, insist on pulling a couple of jugs and look inside.

Edit:
The C4B5 is placarded at 250 HP at 2550 RPM. Many are installed on -10s and Rockets and are turned at 2700 RPM to make the same 260 HP as the D4A5.
 
Last edited:
I bought a good airframe with sketchy engine log in 2023 because I reasoned engines are easy to repair/replace, A/P-IA did a prebuy inspection. I’ve been grounded since October 2025 waiting on a popular engine shop to rebuild it. Case cracked and rejected, crank already milled to minimum with additional corrosion, rejected. I would suggest that unless you have experience working on Lycoming or have someone willing to help with lots of experience, a “cost savings” used engine could be the most expensive and time consuming option.
 
I bought a IO-540C4B5 for my Christien Eagle. We were able to use a bore scope to see most of the inside of the engine, paying special attention to the cam lobes and lifter faces. I had to find the small hole mount ears. The C4B5 is apparently the same engine as the 260HP D4A5 used on the Pitts S2B, the difference being the governor's set redline of 2700RPM and of course the data tag. A friend was able to obtain "airboat" billet mount ears for a very reasonable price. I don't know if there are are any of those still being made or by whom.
 
Tough to really say what issues this engine may or may not have. Its purely a gamble. Borescope is very limited in what it can see. I would attempt to purchase with the plan for an iran. Further, i would want a guarantee that both case and crank can be serviced. Negotiate credit for failure (unserviceable, not the cost of reworking it) of either and hold that money in escrow.

You can plan for worst case parts and labor cost plus machine work and factor that into engine cost, then compare with other options. Given what you posted, i would not likely pay top dollar and fly as is.

I bought my 540, also, from an aztec, from a used engine seller. It was a prop strike. They agreed to refund if case or crank was red tagged. Terrible corrosion on crank, but was able to grind it out, though now .010” under. Price was good and was able to overhaul myself and have like new engine at less than half of new price. Able to reuse many of the pars from that engine . I found ears on ebay, though probably harder to get now. Back then there was an aftermarket company making them.
 
You must log in or register to reply here.
Back
Top