I would swap the damaged parts only i.e. do an IRAN. How many hours to TBO?
Re FIKI, is there an “EASA FIKI”? The FAA “FIKI” cert maps onto US wx services, which even an N-reg outside the US is not likely to be using, so the legality (or not) of a departure into likely icing conditions is meaningless.
First, do no harm… don’t fix what is in good shape already unless a regulatory issue is forcing you to do so.
An overhaul versus repair decision at 600 hrs SMOH depends on whether there are hassles associated with operating on condition, beyond e.g. 12 years since last overhaul. There is probably little reason to completely overhaul the engine on a practical basis, with one cam lobe being the only bottom end issue.
I have an engine that has never been completely apart since it was manufactured in 1971. It’s still a mid-time engine by hours and there’s nothing obviously wrong with it, but I wouldn’t mind doing a disassembly and inspection. I might put new cylinders on it since they are only $4K total to replace but the only benefit to me of an overhaul logbook entry is potential resale value.
Sorry to hear that. Now it is water under the bridge for you but I am obsessed about lifter and cam damage on these engines.
I faced a similar decision with my former IO360 Lyco at 600hrs TSO on a 2000TBO when I found a case crack. I had very good trace since new for all parts incl crankshaft, cyls etc and decided to go for an IRAN at PennYan. There must be some posts in the forum, back in 2008. Since the cases were split, access to lifters requires them to be split (unlike Contis), and the camshaft was not new at last OH, I went ahead and replaced all lifters and camshaft, to ensure increase the likelyhood that I would not have to open again on the way to TBO. I never had to but a lucky buyer took it from me 200 hrs later.
On my current Conti TSIO-520, I go as far as removing all lifters and inspecting all cams every 200hrs max, and whenever I am removing induction and exhaust for other reasons. The tiniest pitting drives a lifter into the bin. I have replaced five of the twelve lifters in 350 hours (three on the first inspection, and one on each subsequent ) at a parts cost of about USD800. Labour is about 15-20 manhours to inspect them all, but maybe four if access is gained (ie exhaust and induction removed) for other reasons. Last time, I had some few ferromagnetic particles in the filter (difficult to find) and went straight to remove all lifters until I found the culprit on some pitting on an exhaust lifter before it could cause some cam damage. Thus far (fingers crossed) I have managed to save my camshaft at 1000TSO . I use Camguard, single-weight W100, dehydrators and minimum biweekly flying.
The only other TSIO520 I have inspected in detail also had particles in the filter (much less than Conti’s threshold for any action) pitted lifters and damaged cams.
I am betting all 470/520/550 engines flying out there have some level of lifter and possibly cam damage unless the above procedure has been regularly followed. It will add maybe 15 mh every year but in my view it is worth it. Also a more careful filter particles inspection than that required by Conti will hopefully lead you to an early warning of lifter damage. The idea is if you remove a lifter early enough you will avoid it causing any camshaft damage and subsequent case opening.If you still have the unopened oil filter, I may be able to assist you in determining what you should be looking for on your next oil changes to detect early lifter wear…or perhaps you already found out!
This is amazing feedback. Thank you Peter, Silvaire, Antonio. I will remember Antonio’s lifter inspection advice.
After exploring other avenues. IRAN looks like way to go.
Would you replace crankshaft bearings and other such parts per Conti SB or just disregard if they are good?
Antonio: ferrous particles?
AFAIK you do replace the crank sleeves. Possibly regrind the crankshaft, depending on dimensions / remaining case hardening depth and then you install next size down sleeves. That’s normal stuff and it re-uses proven components while extending life. But a good engine shop should know all this.
Flyingfish wrote:
After exploring other avenues. IRAN looks like way to go.
Very sorry to hear of your troubles. Who is taking on the work? Cermec? They are pretty close to Geneva and I found them to be very good indeed.
Thanks Mooney Driver! Actually we have not thought about Cermec because I am working with Airbase and they have a very skilled old mechanic in house. They will let me work with him on the project and that alone is a reason to rejoyce ! Also, by doing the dirty low-skill work myself, I save 100 € per hour … they told me this would cut the cost of manpower in half
Peter: yes my shop certainly knows but I am trying to educate myself from more than one source. Zero experience with engine rebuilds and scrambling to learn before things start and reuse/replace decisions must be made on the fly. I am grateful for the advice.
On the very positive side of all this, taking down the engine now will be great opportunity to do a big cleanup of all the mess between engine and firewall. I am thinking of doing a CAD model and laying out every single duct and cable with carefully placed fasteners .
Chafing is a recurrent issue in this tightly cowled monster…
Flyingfish wrote:
Would you replace crankshaft bearings and other such parts per Conti SB or just disregard if they are good?
Yes, they are easy to replace and it’s unusual not to replace them if the crankshaft or con-rods are removed. I would not grind the crankshaft unless it needs it, ever, and although it is not impossible I would not expect it to be needed after 600 hrs.
You are absolutely doing the right thing taking the opportunity to work hands on with your engine.
Ok understood, thanks again. Silvaire, just to clarify: my engine has approximately 1400 hours not 600 and we’ve rebuilt it ( an extensive IRAN followed by a top overhaul) 600 hours ago. I wish I had had Antonio’s advice about checking lifters earlier – it is very difficult to do on my engine but we did take down the exhaust several times and these would have been relatively painless opportunities..
IRAN makes a lot of sense because we’ve done so much work that would be wasted if we did a full blown « legal » overhaul plus, as I said before, new parts may bring new problems, especially the cylinders.
So we’ll carefully measure all cylinders, and I will get very personal about precision balancing pistons, pins and conrods.
This had already been done once but sadly we had to do the top overhaul shortly thereafter.
Oh well… expensive, but it is going to be an amazing project.
Antonio wrote:
On my current Conti TSIO-520, I go as far as removing all lifters and inspecting all cams every 200hrs max, and whenever I am removing induction and exhaust for other reasons.
This kept me thinking for a couple of days now. I hadn’t heard of anybody doing this. Are you sure that the risk of maintenance induced problems isn’t higher than the benefit with this approach?
I do most of the maintenance on or TSIO360 myself under the supervision of my A&P. I had to replace cylinders (with our previous engine) and I know how much work it is to remove and reinstall the exhaust with the turbo, the baffles, the rocker arms and all the rest.
After thinking about it I will not do it every 200h but I will certainly inspect all the lifters as soon as I find the slightest trace of ferrous metal in the filter or get any unusual oil analysis results.
EDIT: Sorry for hitchhiking this thread, Flyingfish.
