Engine overhaul / repair shop recommendation

I looked up Superior cylinders for my wide deck O-320 at (US) Aircraft Spruce and find they have none, and per their website are expecting a shipment on December 7th.

Extra demand, it seems from the above reply.

But if you use a good shop, they can probably still get them.

And does anyone know why there is such a delay in obtaining Continental and Lycoming cylinders?

I have this info from a good US source:

There is an issue getting cylinders at the moment both from Continental and Lycoming. Superior is currently outselling their monthly manufacturing capacity by a good margin. Of course there are cylinders that they do not have PMA authorization to make such as Lycoming angle head cylinders or the Continental cross flow heads (IO-550-N, TSIO-550-E). Continental steel barrel cylinders are easier to get than nickel, but it can be challenging.

I spoke to someone who had an O200 rebuilt in the US recently. Short wait for cylinders, which were Superior, no other problems.
But it will likely depend on your engine.

I had a look at their website and they don’t list EASA approval so they would be OK for an N-reg only.

They also do the cryogenic option discussed here.

I will email my usual US shop to ask about the general issue.

Has anyone here ever had a Victor Aviation overhaul? They have a high reputation in the US but are expensive. They recommend using one of their preferred installation facilities and the only one listed in Europe is Motorflug in Baden-Baden. Has anyone ever used Motorflug for any work?

Also, I’ve been told that there is a currently a huge problem getting some parts including cylinders, especially from Continental but not limited to them. I was told by a local mechanic that timelines are up to a year or more and Continental isn’t responding any more to requests. Anyone else heard anything similar or have a contradicting experience, especially with Continental? Is this a real problem or just hearsay? If real, just Europe or USA too?

Any crankshaft is balanced as part of its manufacturing process, a procedure that depending on engine configuration involves adding temporary weights to achieve the correct imbalance. The necessity to rebalance might be considered after journals are ground slightly undersize at overhaul, and balancing an opposed cylinder aircraft crankshaft is relatively easy. Any automotive crankshaft balance shop could do it under A&P supervision.

A careful valve job with multi-angle ground seats probably does as much as porting. Porting is regardless being done on certified engines beyond the removal of casting flash, because that’s a fuzzy definition, but probably not to the extent of complete reshaping with epoxy added and so on. When done to a limited extent it’s hard to see visually how much material has been removed. I once had a little A-65 with cylinders overhauled by a well known shop, and it made good static rpm

I am told:

• pistons nowadays come in weight-matched sets anyway
• one is absolutely not allowed to remove any metal from a conrod, so a heavy-small-end conrod would need to be matched with a piston which had some metal removed (which is allowed, around the skirt)
• crankshaft balancing is done by some US shops which have FAA approval for it (no European shops AFAIK) and the metal is removed in specific places
• on certified engines you can remove casting flaws (called “flash”) only; on uncert engines you can do more, but on Lyco/Conti engines the dyno power gains are very small

It’s real but the manufacturer did most of that list on the engine originally, perhaps to a looser tolerance. ‘Flow matched’ cylinders would be an exception and you can probably get a bit more power if it’s done right. ‘Flow matched’ is presumably a euphemism for ported, modified outside of the TC & MM in a way that doesn’t show much visually. However I have my doubts that C.R Axtell has been reincarnated at many US aircraft engine overhaul shops.