Engine rebuild - UK recommendations?

[englishal]

I'm looking to get a Lycoming overhauled and zero timed, and just wondered if anyone had any particular recommendations for a UK engine shop?

I've had some great recommendations for US engine shops which I am following up at the moment, and depending on certain factors may go that way.

Time is not an issue which is why I am looking at the US too, though realise that it will need an export C of A to go into a G reg.

Is it normal to get the prop balanced at the same time or is this done later on somewhere else?

Thanks....

[SkyHawk-N]

Only Lycoming can zero time your engine, other overhaul shops can only do it to SERVICE LIMITS or NEW LIMITS. Your prop balancing is another job. I got mine done at MCA Aviation (http://www.mcaaviation.com)at Shoreham for £550ish (if I remember rightly), they did a nice job with it.

[smarthawke]

No problems with Nicholson-McLaren aviation for our last few engines.

Nicholson-Mclaren Aviation (http://www.nicholsonmclaren.com/aviation.htm)

PM me if you want a list of who not to go to - with valid reasons....

[IO540]

I would go to Barrett Precision (http://www.bpaengines.com), based on their excellent work for me.

Make sure you get an 8130-4 (export cofa) with the engine, unless going into an N-reg.

I don't think Lyco are the only firm which can zero time an engine in any meaningful sense. Unless a buyer has no brains, he will realise that an engine rebuilt by a highly reputable to NEW limits will be every bit as good and probably better than one built by Lyco to the same limits. The effect on the resale MV cannot be significant, and a rebuild by a reputable shop will only enhance it.

BP can also do proper dynamic balancing, which Lyco don't do.

Propeller dynamic balancing is a separate function and should also be done, after the engine has been done. Very few UK firms can do this. Worldwide Aviation in Bournemouth is one I know well. Arrow in Exeter used to do it years ago and may still do.

[Zulu Alpha]

Try Richard Isenberg at Southend 01702 547 490 . I have only heard good things about him and I am very pleased with the work he did for me. Very knowledgeable, very helpful. a real craftsman. I would 100% trust one of his engines. I doubt he would bodge anything even if you asked him to.

Give him a call and discuss what you need doing. His advice will be invaluable even if you go elsewhere, however, I bet you'll take it to him after speaking with him.

DJ

[englishal]

Thanks for the responses.

I'm waiting to hear back from a few of them, including Barrett. Dynamic balancing is one of the things I'd like done even though some engineers suck their teeth and say "you don't need that, it is to the original spec"....;)

Regarding "zero timing" the engine, if it has had a major overhaul does this not "zero time" the engine to all intents and purposes (regulatory / performance)?

[SkyHawk-N]

Regarding "zero timing" the engine, if it has had a major overhaul does this not "zero time" the engine to all intents and purposes (regulatory / performance)?

When a manufacturer zero times an engine he issues a new logbook and a new manufacturer warranty. You will get parts included in your 'new' engine that are potentially (probably) used, and you do not know the background to these parts. However, the parts are within new limits and the manufacturer will stand by their quality. The answer to your question is yes, to all intents and purposes the engine is zero timed, i.e it rolls back the engine time to 0 hours, but as I say you don't get issued the things I mention above.

[ericferret]

Richard Isenburg gets my vote as well. Sound advice always available and when we did have a problem with the engine (not related to the overhaul) we took the engine out and dropped it off at Southend for a speedy repair. Try that with an overseas overhaul agency.
The engine is still going strong after 15 years and 1400 hours.

[david viewing]

We looked at a variety of UK rebuilders in the summer and preferred Norvic (http://www.norvicaeroengines.com/current_news.html) (Now under new ownership and offering some very smart turn-round times) but eventually chose a Lycoming overhaul because of the hollow crankshaft issue. Lycoming will accept a corroded crankshaft with no penalty wheras independent rebuilders have to buy a new one (from Lycoming!).

If it is a hollow crank variety, I suggest you pull the plug and have a look before you go too far.

I understand the zero time thing is different here and in the US. Here an overhaul gets 'zero time' and a new log book wheras there only a rebuild qualifies for that. Lycoming just announced an extension to their 'summer special' where you can get a rebuilt engine for the price of an overhaul if your core is 'first run'.

Delivery (from US via Piper CSP) was very quick at 4-5 days.

[englishal]

Which engines have a hollow crank? Is this the 540 problem that has been widley reported?

This is a TO360 engine, first run.

Did you get the Lycoming one in the UK or via the USA?

Cheers

[david viewing]

O-320-D3G as fitted in the Warrior and other engines as described in the infamous Lycoming SB505 (http://www.lycoming.textron.com/support/publications/service-bulletins/pdfs/SB505B.pdf). Not all O-360's are affected and a friend just had his O-360 rebuilt by Norvic and apparently it has a solid crankshaft. Rebuild took less than 3 weeks.

Edited to say that I went to Piper CSP at Shoreham after looking at the complications of shipping and especially returning the core to the US and deciding there wasn't much in it. Added to which you have a UK warranty that my engineer speaks well of.

[MikeBradbury]

Another vote for Nicholson-McLaren. Great service when rebuilding our engine.

[englishal]

Great, thanks for the info.:ok:

[Doing Whats Needed]

To get an overhauled engine from the States it will need to have come from a shop with "Dual-Release" capability, that is the approval to sign an EASA Form 1, in addition to their FAR 145 Maintenance Approval. Alternatively, it would depend on your maintenance provider in this country, if the Part M Sub-part F approved and not a Part 145, and they have the right words in their management documents and your are not an AOC holder or a training establishment they can use an 8130. I realise it is a bit confusing.

PM me if you want some more info!

Doing Whats Needed

[englishal]

Thanks, yep all these numbers do get a bit confusing!

Someone has kindly pointed me to a shop in the USA which can get the 8130-4 export c of a. Not sure which route I'm going to go down yet, there are pro's and con's to each - as mentioned if there is a problem and the engine was rebuilt in the UK it is relatively easy to sort out. However I have heard good things about one shop in the USA who come highly recommended.

I suppose cost will be a factor too, I don't know what sort of cost we're looking at but I have been quoted Euro 24000 from one euro-shop which if the exchange rate were better might be a good deal. A lycoming "zero time" replacment under their present deal works out at £28,000++ (using their price list) so it'll be interesting to see what other places are charging.

I haven't let on to the wife yet how much all this might cost...:ouch:

[stickandrudderman]

I believe Nicholson Mclaren started out as very successful race car engine builders, so I'd definitely be having a look at them if I were in need of an engine o/haul.

[smarthawke]

NMA still do loads of race car engines at the same premises - very interesting stuff to look at there, lots of Cosworth DFVs and other engines.

Strangely, they keep the two well apart as the aircraft motors demand higher cleanliness, quality assurance etc than the race engines.

[IO540]

Any US engine shop can generate an Export CofA form (8130-4). They get a DAR to sign it - costs about $300.

You don't need to go to an EASA approved engine shop. Such shops can generate a dual-release 8130-3 which also carries the EASA approval # and is effectively equivalent to an EASA-1 form. But as I say you don't need this, and it does limit the choice severely, to firms like Lyco, Pen Yan, and a few others.

Dynamic balancing is one of the things I'd like done even though some engineers suck their teeth and say "you don't need that, it is to the original spec"....

Yes, a very British GA shop attitude. Can't argue; it saw us well through WW1 and WW2. The out of balance tolerances which the best US shops work to are about 1/50 of what Lyco work to.

[IRRenewal]

Dynamic balancing is one of the things I'd like done even though some engineers suck their teeth and say "you don't need that, it is to the original spec"....

You don't know what you are missing out on until you have flown a 'before' and 'after' aircraft. The difference can be quit remarkable.

Try General Aero Services at Thurrock.

[IO540]

Dynamic prop balancing can make a huge difference.

Dynamic engine balancing may or may not, depending on how lucky you were to start with, and how much you care or notice. I saw a very noticeable difference.

The pistons should nowadays be bought as a matched set anyway, but the rest of the engine parts come with sometimes wide variations. Any shop can e.g. match an underweight piston to an overweight conrod small end, but there isn't anything much you can do about the crank/big-end matching unless you are an approved facility for balancing the crank, and AFAIK there are none outside the USA. One can do a little bit there but it is rather hit and miss because the crank can be light or heavy in different places - not necessary where the conrod is attached.

I was once offered a dynamically balanced crank, done in the USA, passing through the hands of a UK JAR-145 company, who for a nice charge of £800 or so generated a JAR-1 form for it (the usual scam. facilitated by the European certification system). But if you get the whole engine done properly, with an Export CofA, that is better. And that UK company went bust a while ago, IIRC.

The engine can in most cases be made to run smoother still by getting GAMI injectors - standard Lyco injectors matched in their flow rates to compensate for the uneven airflow in the basic engine design. They enable smooth running at peak EGT and into the LOP region if desired.

Dynamic engine balancing (standard in the good US shops), followed by dynamic prop balancing (c. £250), followed by GAMI injectors ($1000 last time I looked) results in a very noticeably smooth operation, which apart from the obvious benefits probably shows itself up long-term in an improved avionics life and generally fewer things dropping off the aircraft :)

There is talk that Lyco's QA has dramatically improved after their 2001/2002 crank fiasco (they reportedly nearly got shut down by the FAA) but as Clint Eastwood might say: do you feel lucky? Aviation certification is a largely artificial process; like ISO9000 being mostly to do with document handling and little to do with the quality / reliability of the end product. The US engine shop I used in Jan 2008 told me they still get brand new Lyco cranks coming in which are 50 gram-inches off balance, when their own tolerance is 1 gram-inch.

[Doing Whats Needed]

IO540

In my reply, I stated that the 8130-3 was acceptable if it was being installed by an EASA Part M Sub-part F organisation and being installed on a non-large aircraft not employed as commercial transport, their Exposition must detail how they will deal with these components. A Part 145 organisation has no such dispensation, AMC 613(a) refers.

Doing Whats Needed

[IO540]

I recall reading in one CAA tome that a Class A part (engine/prop) has to come with an Export CofA (8130-4) if fitted to a G-reg.

This applies to both new and used parts.

If the part is new but not Class A (e.g. a fuel pump) then an 8130-3 is acceptable for a G-reg.

If a part is used then an 8130-3 is no good for a G-reg.

Public Transport ops (which nowadays probably means AOC ops) require an EASA-1 form (or a dual release 8130-3) for everything - supposedly (and yes much of this crap is pretty unworkable) ;)

If you know otherwise, I am genuinely very interested in up to date references. I last researched this before Sep 08 which was a relevant date.

[john baines]

I had a very good experience with Norvic. I have a C-150 Aerobat - the one with the 130hp Continental/Rolls Royce engine. It was only low hours when I bought it, but it had a catastrophic failure in flight soon after. The company that had rebuilt the engine was not really interested in my questions, so I wanted to avoid them. I was recommended to try Norvic by my maintenance organisation.

Rebuilding these engines is not straightforward when almost everything needs to be replaced. Richard Boddie and his colleagues went to extraordinary lengths to get all the parts needed and still managed to charge a very reasonable price. I was constantly kept informed of progress and they gave a very professional service.

The engine has done almost 50 hours hours since I got the aeroplane back and it is now happily aerobatting again. I have Lycoming coming up for rebuild next year, and I will be very happy to use them again.

[topoverhaul]

I also will add my vote for Nicholson McLaren

[RWheeler]

Hi,

Our C177 is in for its annual and a significant amount of copper colored metallic was found in the oil-filter. On pulling all 4 cylinders they discovered significant wear on the piston-rod end-caps in 3 & 4 (not 1 & 2) and more worryingly signs of severe overheating on the con-rod ends of 3 & 4
They have the Rollason engineer take a look and he is offering a strip to assess for £700
Can you advise
1) Good and bad engine shops in UK ( I know of Rollason and Isenberg)
2) COuld Airspeed Aviation at Derby carry out such work (replacing the con-rods?)

ANy advice much appreciated

Rgds

Rod

[Victorian]

My aircraft is maintained by Airspeed. When the 0-320 camshaft expired almost 2 yrs ago having them rebuild it was certainly an option. However their advice was to look around so that we knew what we were getting into.

I'm glad we did because it quickly came to light that the crankshaft was a write off and that most UK rebuilders would leave you to find that out after they had started work.

It was a no-brainer to get a Lycoming factory rebuild because they would accept a core regardless of crankshaft condition. Everyone else would charge for it.

The rebuilt engine came in less than 3 weeks and has run 150+ hours now with no problems and negligible oil consumption.

[Zulu Alpha]

RWheeler,

I would recommend a call to Richard Isenberg. He is very familiar with piston plug wear and always advises you to fit Superior gudgeon pins which have the caps attached.

The standard lycoming ones create a seal and as the piston warms up the pressure builds and pushes them onto the cylinder walls. There are supposed to be small holes to release the pressure but they get blocked.

He will probably be able to tell you about the cause of the overheating. A very nice helpful chap with lots of knowledge. Even if you don't use him you will get some good advice (and I bet you do use him after speaking with him).

[wsmempson]

Neil Andrews at AEP ( Aero Engineering & Powerplant - About Us (http://aepengines.com/index.php?section=1054) ) has got the IO540 out of my Saratoga and is doing a really nice job. Unlike the man who overhauled the IO360 on my Arrow, who reduced it to a pile of bits on his floor, then upped the cost by 50% ("If you don't like it, you can take it all away") and took 5 months to turn the job around - so far Neil is on time and on budget and the engine looks spanking.

I also hear good things about Nicholson McClaren and Richard Isenberg, but have no 1st hand experience. PM or email me for info on who NOT to go to under any circumstances.

[smarthawke]

Personally I'd go with Nicholson-McLaren Aviation who have done excellent work for us over the last few years. Neil Andrews is a good guy too.

The one not to go to has been mentioned by the recent poster (though spelt incorrectly, and with the 'good' and the 'bad' the wrong way round) and it isn't Isenberg or Airspeed. Said person, so rumour on the runway, was allegedly visited by a couple of people from Eastern Europe recently who explained things their way on behalf of their employer....

[A and C]

A few years back I exchanged a very good O-235 that had reached 2880 hours using the full 20% extention and was still running sweetly for a Lycoming factory exchange engine.

This engine has been apart at 750 hours due to piston pin plug failure and then at 1290 hours (2400 TBO) the engine started making metal, and so came apart once more.

The result of the inspection found internal corrosion in the crankshaft dispite the PID treatment, the conclusion was that the corrosion was in the crank when it left the Lycoming factory, as you can guess it turned into a very expensive overhaul.

I would not expect Lycoming to pay for the engine overhaul but clearly the crankshaft had left the factory in a less than satisfactory state and I did contact Lycoming about this, the reaction was basicly "not Lycomings problem".

I have no doubt that Lycoming know that this engine was well below their normal standard but just won't admit this and would not supply a replacment crankshaft.

So I conclude that if you have a good engine that is running well then get it overhauled at an engine shop where you can see it. If it is a pile of junk then get a Lycoming factory exchange and except that you are taking the chance, the probability is that you will get a good engine back from Lycoming but if you later find that it is well below standard you can expect no support what so ever.

[IO540]

Lycoming are notorious on their warranty handling.

Basically, engine warranties are meaningless unless absolutely obvious negligence is provable which causes a rapid failure (and I can't off hand think of an obvious example where the negligence won't be covered by the subsequent damage as the thing comes apart) and the best thing one can do to go to a highly reputable engine shop.

I have also seen some apparent evidence that UK-based main dealers for Lyco/Conti have an incentive to cover up stuff they find. One would think they would have an incentive to dig up as much work as possible but in some cases this does not apply. I am thinking of internal corrosion caused by improper long term storage. The overhauler does not want to open that can of worms because if they, in their "official Lyco distributor" capacity, condemn an engine but the factory does not back them up, they are legally liable under EU consumer protection and will lose out big time.... I am particularly thinking of one company which is no longer trading.

Incidentally, what is the latest regulatory position on US-overhauled engines with an 8130-3 fitted to EASA-reg planes?

It used to be that an 8130-4 (an Export CofA, signed by a US DAR) was mandatory on Class A parts (engines and props). But the FAA stopped doing the 8130-4 recently so an 8130-3 is the only option. An 8130-3 is always fine for an N-reg but possibly not fine for a G-reg unless the overhauler is an EASA 145 company and their approval number is on the 8130-3 (in which case the 8130-3 is essentially equivalent to an EASA-1).

Also an 8130-3 was never fine for a G-reg for a used part, and your own engine overhauled becomes a "used part" so you could never have it back :) This was a major issue at one time, until Lyco/Conti got EASA approvals. The big US engine shops (e.g. Pen Yan) also have EASA approvals but their quality record is not as exemplary as certain small firms e.g. Barrett Precision.

[Victorian]

My engine had had the 'PID treatment' (some paint) but that didn't stop it being rusty and pitted inside the bore. It's easy to find out (just pull the core plug in the end of the crankshaft) and worth doing before you make the overhaul decision. There's no machining tolerance, so if it's rusty, that's it.

I did wonder what happens to the old crankshafts ...

[RWheeler]

Thanks to all for the very helpful feedback. The group did make contact with all the companies mentioned and as suggested had fantastically helpful advise from Isenberg, Norvic, Airspeed and NMA. In the end we have decided to go with NMA for the initial assessment and see where we go from there. Will feedback any useful info. Rgds.

[JW411]

Richard Isenburg did mine and I'm very pleased with it.

[rogcal]

Richard Isenberg did the engine in my old Tommy and was still going well at 3000 hours when I sold the plane.:)

[pcjk]

"it was a no-brainer to get a Lycoming factory rebuild because they would accept a core regardless of crankshaft condition. Everyone else would charge for it."

Our crank shaft is ok, but crank case needs overhaul. We were told that would we ask for a Lycoming factory rebuild, we would lose our core deposit, or atleast a majority of it due to the state of our engine.

But you write that you were not charged. Would someone be able to elaborate? As before going ahead with a 20k+ zero-time overhaul we would obviously like to know our oprions.

Thanks

[A and C]

What type of Lycoming? we might have a set of crankcases for that engine.

[Victorian]

PCJK

Here's what Lycoming's agent told me in August 2009:

Lycoming did come back to me this afternoon stating that corrosion itself is not disqualifying but some other points.

1. Active, the core must have accumulated “flight” time and had maintenance performed on it within the past year.
2. Assembled, the core must be in an “as removed” condition. Cores that have been disassembled by a field overhaul shop do not meet the “assembled” condition.
3. Complete, the returned core must be configured in a similar manner as the replacement engine. Cores that have had engine components or accessories removed for use on another engine will fail to meet the “complete” requirement.
4. Operable, the core must have been able to perform to a level that safely permitted its use “in flight” up to the time it was removed for replacement.
5. The valid engine data plate must be attached and returned with the core.
6. Total time since new or factory rebuild must be provided.

This discussion was about corrosion and failed PID treatment but I was led to believe that they would accept the core regardless of condition subject to the above. That was then and maybe not now!

[pcjk]

Victorian:

Cores that have been disassembled by a field overhaul shop do not meet the “assembled” condition.

Does that mean that if our engine is stripped at themoment it would not qualify according to those criteria?

A and C

Our engine is a Lycoming IO-360-A1B6 engine (serial no. L-7813-51A).




Also do any of you have any info /experience on IO-390 for Cessna Cardinals?

Many thanks....

[Zulu Alpha]

I have an IO390 and am very pleased with it.

However I didn't think you could fit it to any certified aircraft and that it was only for use on Experimental/homebuilt aircraft.

One thing to realise is that it has slightly higher compression than the std IO360 and so cannot use Mogas.

Fuel consumption is about 10% higher than the angle valve IO360 that I had before.

It comes as std with the counterbalanced crankshaft and the roller tappets.

[pcjk]

Thanks for the info I thought it was certified for the c177rg.

What about maintenance is that more costly?

Where did you order it from?

[Zulu Alpha]

Mine came from Lycoming. Maybe they have now certified it for your aircraft. You can search the US TCDS's to find out.

Its only 70 hrs old so no maintenance issues yet. It does use different spark plugs and oil filters.

Otherwise, apart from the extra power and the slightly higher fuel consumption it is the same as the IO360

[Victorian]

Does that mean that if our engine is stripped at themoment it would not qualify according to those criteria?


My engine had a cylinder removed and lightly replaced (that's how we knew about the camshaft). That wasn't a problem.

If the crankcase has been split then I could imagine that would be an issue. You will have to ask Lycoming...

[upupandup]

I have had experience with most of the overhaulers mentioned in these posts in the past twenty years, some have been bad and some have been good. I personally only send my engines to Ronaldson and have done for the last 10 years. The newer companies on the scene I have only tested with component work to see what they are like. I have not being impressed enough to send an engine. I like to be open minded and try new company’s or 'reborn' company’s as they appear to make sure I am getting the best return for my £. I certainly do not believe in the cheapest being the best and certainly a high price doesn’t guarantee quality.

It is interesting to read ‘rumours’ about certain people or organisations. In my experience there does not tend to be much truth in them and they are normally vendetta based. I can only state the facts based on personal experience and as such can state that in approximately thirty engine repairs/overhauls I have only had two problems.
One was a faulty generator and the other a starter that packed up after a few starts. Both of these items were replaced during the repair/overhaul so were not down to Ronaldson. With that in mind, the replacement generator appeared within 24 hours of my call and within 3 hours the starter (delivered by courier). That is a level of service that is rare to find in the aircraft industry. The only negative I can say is that he does not suffer fools gladly (if this is a negative) and I guess he has seen a fair few of those in his time. I have always been up front and paid my bills on time and have never experienced any issues. I do query items when I don’t understand them but I have always found the explanations to be justified.

The other facility I have always found useful is the telephone support, this has been late at night or on weekends on more occasions than I care to remember. The support or delivery of parts has resulted in aircraft flying when owners thought it impossible.

In more recent years there has been a lady called Rachel that answers the phone, she is very good at technical support and chasing down parts at short notice. She also seems to deal with schedules and has made sure that shockloads have been turned around in a week and overhauls in 2 weeks when I have need them. The standard turnaround times are very good and pretty well are always as I need them.

[A and C]

A first post and so very suportive of a company with a mixed reputation................................. All I can say is good luck!

[smarthawke]

There's many of us here that have been around long enough and can provide much more than 'rumours' about who not to go to....

True, the end products are good enough but that may be okay if you don't watch the component serial numbers or mind paying for genuine Lycoming cylinders and find out that you've got 6 engines fitted with ECi cylinders that have to be retired at 2000 hrs - potentially 400 hrs early on each engine.

As A&C said - good luck with who you go to....!

[Bliss1]

I had a fantastic experience with Norvic Aero Engines (Lycoming TCM Teledyne Continental Franklin Experimental aircraft engine overhaul exchange shock load repair - Norvic Aero Engines (http://norvic.com)). Have had experience of them under Jade and more recently under Norvic and the new owner – dramatically improved. My overhaul came back early, on price and has proved extremely reliable and runs really very well. They used genuine original manufacturer’s parts and have experienced engineers working for them for over 20 years (who else can say that?). Highly recommended

[stiknruda]

Anyone have current contact details for Brian Mills (Mercury)?

Thanks

[A and C]

Looking to get your money back?

[stiknruda]

I'm unable to PM you, A&C.

[wsmempson]

Just a quick update on my earlier post which, when I wrote it, had my engine in the late stages of coming back together in the hands of Neil Andrews at AEP.

The engine is now in, has done the first four hours, and is running beautifully. So, in short, the engine has turned up on time, on budget and works straight out of the box. Respect!:D

As with all service industries, the 'consumer' can be quick to complain and slow to praise and I'd just like to break that mould.

(And just to say I have no connection to Neil's business whatsoever!);)

[A and C]

I have rather hacked off the pprune managment the past so thay took away my PM's if you wan't to contact me IO540 will be happy to pass on the msg.

[twelveoclockhigh]

You could try:

Corvus Aircraft (http://corvusaircraft.net/content/contactus.php)

[englishal]

turned up on time, on budget and works straight out of the box
Must be a first for Aviation products!

[wsmempson]

If memory serves, Brian Mills dresses rather unconventionally when working. A friends wife was reportedly rather taken aback, on a visit, to find him in his workshop labouring over a Lycoming, wearing nothing but a short skirt and no pants (or anything else, for that matter)....

[IO540]

The UK engine and accessory overhaul scene has a lot of stuff going on in it which is thoroughly unsavoury.

I've just seen a pretty shocking example of such, where the CAA and a solicitor will be the next step.

That's why I normally get stuff done in the USA.

[SNS3Guppy]

I don't think Lyco are the only firm which can zero time an engine in any meaningful sense.

If "any meaningful sense" means a legal zero-time, then yes. The manufacturer is the only one.

Regarding "zero timing" the engine, if it has had a major overhaul does this not "zero time" the engine to all intents and purposes (regulatory / performance)?

No, it does not.

Overhaul means to inspect and find within tolerances. A common misunderstanding is the belief that overhaul means to make like new or refurbish. The fact is that an engine inspected and found within tolerances is considered overhauled, and engines are often sold as "overhauled" when many of the same used parts are put back into the engine. Be careful when making assumptions about what's been done to the engine based on an "overhaul," or confusing terms such as "zero-time," "rebuilt," and "overhaul." These have very different meanings that don't interchange.

[A and C]

UK or USA you have to be careful who you use, I have done a lot of flying in the USA and seen that there is a big difference between the best and the worst.

I am sure that Silvaire1 & SNS3Guppy could tell a few tails about who not to go to in the USA just as they could recomend some reliable workshops who will do a good job at a fair price.

I know that you have the ear of a few people in the UK maintenance business, they can tell you who will do the job to a high standard and have the paperwork to back it and more impotant those who don't and can't.

[IO540]

There are good people everywhere and there are bad people everywhere, and everything in between.

The thing which I have found, during my 9 years of aircraft ownership, is that it is almost impossible to find a UK company about which there is a consensus on them being good. It is extremely easy to find a company on which there is a strong consensus of them being dodgy. For the USA, OTOH, it is not hard to find a company with a good reputation. You have to ask on US pilot forums, etc.

I would never suggest the USA doesn't have d*ckheads in the business; there are loads and I think their avionics business is just as hit and miss as the UK scene is on the whole. The USA has just the same % of avionics shops capable of delivering a new HSI installation with the glideslope reversed; the main difference being that it is a lot cheaper to get work done out there :)

However the undeniable thing is that a US engine shop (e.g.) will be 10x bigger than a UK engine shop and this means they are going to be doing any given type of engine a lot more often, and it also means that if they screw up there will be many more owners writing about it. So due diligence is much easier to do.