Premature Camshaft / Cam Follower failure

Was the camshaft and the tappets replaced at last overhaul or the old camshaft reused?

Reusing the camshaft is IMO not worth it, a camshaft plus tappets is around a thousand quids, but the cost and hassle you have now is an order of magnitude higher.

Where do the Germans / French / Belgium’s etc. go for their Lycoming parts?

If you need to remove/open the engine, you better get it from the overhauler so that you have at least some sort of warranty for parts and work. For parts that you can install yourself or your mechanic, I usually use aircraftspruce.eu, they can ship most Lycoming parts.

BTW, I disagree with Peter that you have to ship your engine to the US to get a good overhaul/rebuild. The risk / delay / warranty issue is not offset by a better work result. You can get as good results from shops here and you can get terrible results from shops in the US (just read on the forums). All you need is competent and diligent staff, working on this 1950s tractor stuff is not rocket science.

I don’t agree. Putting these engines together does need a lot of skill and that implies a lot of currency.

Even a simple thing like slipping the front crankshaft seal over the propeller flange needs to be done the right way, otherwise you get a leak at the front, and the only fix is to take the engine completely apart again!

There is a lot of skill in doing the small end pins (or whatever they are called) where you can get the plugs grinding against the cylinder walls. Sure… not going to give you a sudden stoppage, but a builder who doesn’t know these things might have equally not done up the big end bolts to the right torque, or even used used ones (they are a mandatory replacement on any engine opening, but cost about $30 each). There are many cases of a cylinder coming right off, presumably due to over-torqued bolts. There is a monkey on every corner of GA and a lot of them work in the engine business.

The problem with the UK and I think Europe generally is that the volumes are low, the customers mostly loudly demand the cheapest possible job even if the engine is making obvious metal especially if they are syndicates and the business is generally accepting of such demands (when I had my 2002 prop strike, one CAA LAME offered to cut the last 20mm off each blade, saying that the engine didn’t actually stop so this is OK) and most aircraft owners are not pro-active on maintenance and just leave all decisions to their maintenance shop, which in turn uses their favourite builder. It is also bad form to post negatively about some firm, whose lawyers are likely to jump on any forum site owner. In the USA the volumes are far greater and the US forums are an effective information exchange on the good and bad ones. The paid-for Aviation Consumer magazine is also effective in naming and shaming – you will never see that in any UK printed magazine. The big US shops do indeed have a somewhat mixed reputation, and I would not suggest using them – but you have to if youa re G-reg because only the big ones can issue an 8130-3 with the EASA 145 approval number on it (not sure if that is actually required nowadays for a G-reg, since the FAA stopped doing the Export CofA on engines and props).

I used this shop in 2008 and would use them again anytime but they don’t have EASA approval.

Much is made of the warranty but realistically an engine warranty is generally worthless because any scenario where you have to activate it is going to be some sort of disaster anyway. And if an engine falls to bits after 50 hours, would you really want to go back to the same shop? It’s obvious that they screwed up with something big. Obviously, I would not touch that shop with a bargepole! The bottom line is that in GA you have to always be able to write a cheque for a new or totally rebuilt engine – say €40k. In the turboprop ownership business, the cheque becomes €400k or so.

…. seems that US engineers don´t have much of a clue about steel alloys or they do it on purpose: You don´t get a durable setup when you have a combination of friction loaded parts made of the same material: When lubrication is minimal after long periods of parking and the oil has drained down you start with tiny seizures on these friction partners that will grow to real big wear in time . I guess camshafts are produced of chilled cast steel – as followers will be from the same material with consequences. I am running an old Ford OHC that had same problems with lot of wear on followers and cams. In the end I welded a high chrome 10 % steel layer on the followers and that was it. The welding has ~ 55 HRC but the trick is the high chrome content that does it. BMW uses carbide inserts in the followers for their OHCs to that effect and I think RR Merlins get that for their followers now as cure for same problems. Allisons and DB 601 had roller followers – good idea. As was said, monograde oil will help as this does not drain down as multigrade does, so I´d prefer that, with careful warming up before setting high revs. " The more I learn ´bout US crap the more I love my radial …. " Vic

Or you could use Camguard.

I have oil analysis data (posted here in the past) showing a huge drop in the hard metals with Camguard, and I fly once a week.

For the oil, I use 50% Shell 15W50 and 50% Shell W80 – on the advice of Ed Kollin on this forum – the US inventor of Camguard.

Despite the use of unsuitable materials, most of these engines don’t fall to bits or make metal, before TBO or in most cases long after TBO.

So I tend to think that when an engine falls to bits very early, “something” must have happened to it.

Whether that “something” is a reasonable cause for the disaster is a separate debate, and most would agree that these old motors are far too sensitive to operating details like standing around.

For the oil, I use 50% Shell 15W50 and 50% Shell W80 – on the advice of Ed Kollin on this forum – the US inventor of Camguard.

Ed recommended against 15W50 (any PAO oil) but you wouldn’t want to listen Eventually he said 50% 15W50 is better than 100% 15W50 but it’s in no way his recommendation

The problem with the UK and I think Europe generally is that the volumes are low

I am not convinced the average US overhaul shop is larger than the average European overhaul shop. There are a few shops in Germany and they do nothing but repair and overhaul Lycoming / Continental engines so they have all the currency required. The one I worked with delivered excellent craftsmanship and I am sure there is nothing to be gained from going overseas. Often these companies here have operated since the 1950s when overhauling gasoline engines was very common (stationary motors etc.) and over time only the air-tractors were left as markets.

I think cam and follower spalling have not much to do with the engine shop. They all buy a cam and follower set from Lycoming and install it.

Sebastian has a valid point. All shops will use the same parts, if the manufacturer has a poor design, the shop couldn’t do anything about it. Seen it often with poor quality bendix drive, which seems to explode after a few starts, while the older parts where better. It seems some manufacturers are on the lookout to find a way to save money everywhere. This tappet problem is a similair common problem.

Even a simple thing like slipping the front crankshaft seal over the propeller flange needs to be done the right way, otherwise you get a leak at the front, and the only fix is to take the engine completely apart again!

This information is incomplete at least. A leaking front crankshaft seal could be replaced with the engine (Lycoming). If the boring is worn then it must get oversized which requires disassembly of the engine itself. If the seal itself is worn, it could be replaced using the correct tool.

I am not convinced the average US overhaul shop is larger than the average European overhaul shop. There are a few shops in Germany and they do nothing but repair and overhaul Lycoming / Continental engines so they have all the currency required. The one I worked with delivered excellent craftsmanship and I am sure there is nothing to be gained from going overseas.

I do agree with Achimha. There are good, or better shops in EU for almost everything. In the US more parts might be available. From what I have seen on component maintenance, such as magneto’s (having done them myself as well), I was not really impressed by factory quality. They don’t follow their own manuals for sure, and don’t seem to care to much. Having devoted people working on your aircraft or parts makes more sense IMHO.

So they sold you faulty parts and charged you an arm and a leg to install them. Today, they will offer to sell you new (possibly faulty) parts and charge you an arm and a leg to have them installed.

Welcome to the world of our great aero-engines where a certification stamp turns a turd into a gold nugget.

It is simply not true that these engines generally make TBO. I’ve asked an engine overhauler some time ago what the average age of TBO is. He said considerably less than 100 although they didn’t have statistics. We have a nasty mix of primitive and bad design from some decades ago combined with improper production techniques and materials found today. The good thing is that this does help the newer aero diesels although it’s still an uphill battle for them with the cost and their own share of technical problems.