38 replies to this topic

[rrrocket]

Does anyone have information about the time it takes to perform the final assembly build of a contemporary F1 engine?

I remember reading some information recently on a web article on the subject, but didn't take a note of the site (? Toyota? ) at the time, and now I can't for the life of me find it through the usual methods.

[derstatic]

Can't name a source unfortunately but some years ago I recall reading about it taking two weeks for two engineers to build an engine. But I can't say if that was scratch building an engine or making a full disassembly and then reassembly of the motor. So this might be worth nothing, maybe someone else has more uptodate info with a source.

[ferrarifan2000]

100 hours


http://www.auto123.c...a/videos/505852

[gruntguru]

100 hours
http://www.auto123.c...a/videos/505852

Sounds too quick to me. Probably doesn't include any blueprinting or trial assembly.

[tristancliffe]

Sounds too quick to me. Probably doesn't include any blueprinting or trial assembly.

Do you honestly think an engine designed and made specifically for F1 will require trial assembly or blue printing as part of the final assembly process? Maybe if you are race preparing an A-Series Mini engine, but not when clever people have spent millions on that one engine alone.

[cheapracer]

Do you honestly think an engine designed and made specifically for F1 will require trial assembly

100% so.

There is no other way to check bearing clearance's for example. I can even imagine that they bring the components up to temperature to do so too. And I would like to believe that some things are still "felt" by hand as well.

Grunt don't forget that the engine shop would be a fully dedicated setup, every line borer, mill, CNC etc. would be setup with appropriate clamps, jigs etc. and to within a few .001"s ready to go with laser measuring etc.

I saw a Guy at Cosworth in 1980 (on TV) checking/matching pistons - he had a dedicated jig that had about 6 dial gages and he simply put the piston on a lever which lifted the piston from below and the dial gages touched various points of the crown and gave their readings - each piston took about 1 minute or as long as it took to read the 6 gages of course.

Now that would be done with laser I guess.

It may take only 100 hours but the workshop would have taken 100 days to setup in the first instance.

[tristancliffe]

100% so.

There is no other way to check bearing clearance's for example. I can even imagine that they bring the components up to temperature to do so too. And I would like to believe that some things are still "felt" by hand as well.

Grunt don't forget that the engine shop would be a fully dedicated setup, every line borer, mill, CNC etc. would be setup with appropriate clamps, jigs etc. and to within a few .001"s ready to go with laser measuring etc.

I saw a Guy at Cosworth in 1980 (on TV) checking/matching pistons - he had a dedicated jig that had about 6 dial gages and he simply put the piston on a lever which lifted the piston from below and the dial gages touched various points of the crown and gave their readings - each piston took about 1 minute or as long as it took to read the 6 gages of course.

Now that would be done with laser I guess.

It may take only 100 hours but the workshop would have taken 100 days to setup in the first instance.

But checking bearing clearances doesn't require the whole engine to be built. Even if it's done at temperature (which it will do - F1 teams don't care about room temperature fits) then it's a case of fitting bearings, measuring (do they use plastigauge? ), and removing the measuring medium...

I still don't think they'd take all the components (measured carefully and selected into batches etc), build the engine to make sure it all fits, take it to bits, and do it properly, which is what I would consider a trial fit. It's not like every single component hasn't been designed specifically for that engine under carefully controlled loads and conditions with CAD, CFD, FEA and highly experienced engineers... Trial fits are the domain of normal companies and human beings. I couldn't live without them personally

[rrrocket]

Thanks for your replies. The video was the one I remember, though the accent of the commentator was unfamiliar.

100 hours sounds credible, and certainly I can use it as evidence for what I need the Information time for (comparing assembly times in different industries). I would expect to see very little in the way of measuring of individual components on final assembly. A CMM can document more information about a piston in much less time than a fitter (remember that quaint old term?) with a jig and a bunch of dial gauges. In these days of sophisticated machine tools and SPC (Statistical Process Control), the variation in tolerances would be far less than 30 years ago, so I would expect to see more selective assembly of parts fully documented at any earlier stage in the process by a fully equipped inspection department based in a climate controlled room. There would still be selective assembly of things like the valve train to set the valve clearance to accomodate tolerance build up in individual components, but I am thinking that this would apply to fewer and fewer areas as the technology improves.

As far as things like turning over the engine to see how it feels, like we all used to do with our A-series engines (happy days...), I seem to recall that F1 pistons are interference fits in their bores at room temp, and only free up when they are pre-heated prior to cranking by an external system (based on a domestic kettle, if memory serves).

Certainly, Toyota as a company is one I would expect to be able to reduce assembly times and tightly control their processes, as although it didn't invent the Six Sigma process, it was an early adopter and has rigourously applied it since.

[cheapracer]

I've almost no doubt they build the engine, run it in on a dyno, do cylinder drop tests etc. then pull it down again to check it then put it together again - I've certainly been involved this with a couple of race teams at a much lower level.

[cheapracer]

Thanks rrrocket, you just made me feel very old lol!

[rrrocket]

How do you think I feel? Engineering is a fast moving industry.

[J. Edlund]

As far as things like turning over the engine to see how it feels, like we all used to do with our A-series engines (happy days...), I seem to recall that F1 pistons are interference fits in their bores at room temp, and only free up when they are pre-heated prior to cranking by an external system (based on a domestic kettle, if memory serves).

An aluminium alloy piston runs much hotter than an aluminum liner, this causes the piston to expand more than its bore, so I would expect the opposite; a quite large clearence. But, if we were to run a steel piston in an aluminium liner or an aluminium piston in a brass liner (used on some very small engines), we are gettning towards an interference fit as the cylinder expands more than the piston.

But F1 engines use steel crankshafts and camshafts, and the crankcase aswell as the cylinderhead is normally in aluminum alloy. This means that the clearence must be very small when the engine is cold as the bearing housing expands more than the steel crank/camshaft. Especially since F1 engines use low viscosity oils for a low friction loss. A low viscosity oil demands a very fine surface finish, and if used with a large bearing clearence, the oil flow through the bearings would get too high, increasing losses. So it's the bearings that are 'tight' until the engine has reached operating temperature.

I've almost no doubt they build the engine, run it in on a dyno, do cylinder drop tests etc. then pull it down again to check it then put it together again - I've certainly been involved this with a couple of race teams at a much lower level.

They run them on a dyno for a check up for sure (perhaps they even use those spark plug mounted in cylinder pressure transducers), but I don't think they disassemble the whole engine after that. There are 'smarter' ways to check an engine if you have the equipment for it. If the engine runs like it should (and all sensor data looks ok), there are no external leaks (with production engines, trace additives that react to UV light are sometimes added to the oil and coolant to check for leaks), it sound like it should (i microphone on the test cell is common) and an oil analysis show no abnormal wear, the engine is probably accepted for racing.

If there is some problem with the engine, it's probably sent back for disassembly and check up.

[gruntguru]

They run them on a dyno for a check up for sure (perhaps they even use those spark plug mounted in cylinder pressure transducers), but I don't think they disassemble the whole engine after that.

Bill Jenkins' classic book "The Chevrolet Racing Engine" describes how he used to strip, hone bores and re-assemble after an initial dyno run. He claimed the power would always increase after that procedure. No doubt the cylinder bores would settle into a slightly different shape after a hot run with everything bolted together and the re-hone would true things up a bit.

Obviously not an F1 engine, but typical of the type of meticulous detail work that can find a few HP here and there.

100 (man) hours to go from new machined parts to an engine that is ready to dyno then race without further dis-assembly or assembly? Still sounds optimistic to me.

Edited by gruntguru, 03 May 2009 - 23:58.

[rrrocket]

So it's the bearings that are 'tight' until the engine has reached operating temperature.

Thanks for for the correction. The use of Beryllium (low CTE compared with Aluminium) for cylinder liners must have been some design challenge!

Which areas of the engine uses hydrodynamic lubrication these days? I assume the crankshaft and camshaft, but I recall pictures of rolling element bearings for the valvetrain drive, for instance.

A low viscosity oil demands a very fine surface finish, and if used with a large bearing clearence, the oil flow through the bearings would get too high, increasing losses.

This is an interesting area - perhaps dealt with better in a separate thread - about the use of the oil to cool the nether regions of the engine that are not easily accessible by the 'coolant'. I have seen pictures of oil cooling jets to spray the underside of the pistons to remove heat. What are the relative heat input figures for the water system and oil system for a contempory engine?

[cheapracer]

, the engine is probably accepted for racing.

Ahh interesting point, I agree with all of your spiel in principle but when we come to "probably" is where you lose me - I just can't see there being a probably anywhere in F1 nowadays.

Anyway, i don't know may try to find out out of interest sake.

[Tony Matthews]

I just can't see there being a probably anywhere in F1 nowadays.

You're probably right. I have refrained from posting my two pennies-worth on this topic because I'm not sure if I imagined it, or was told a long time ago, that it took two guys two weeks to re-build a DFV.

[J. Edlund]

Bill Jenkins' classic book "The Chevrolet Racing Engine" describes how he used to strip, hone bores and re-assemble after an initial dyno run. He claimed the power would always increase after that procedure. No doubt the cylinder bores would settle into a slightly different shape after a hot run with everything bolted together and the re-hone would true things up a bit.

Obviously not an F1 engine, but typical of the type of meticulous detail work that can find a few HP here and there.

100 (man) hours to go from new machined parts to an engine that is ready to dyno then race without further dis-assembly or assembly? Still sounds optimistic to me.

With modern bore shaping and nikasil coatings I doubt that is the case for a F1 engine.

Ahh interesting point, I agree with all of your spiel in principle but when we come to "probably" is where you lose me - I just can't see there being a probably anywhere in F1 nowadays.

Anyway, i don't know may try to find out out of interest sake.

Since I don't know for sure how they do, so I can only say 'probably'.

My guess is that they have some sort of checklist they go through, and if everything checks out the engine is given ok to race. Then I would assume that some engines are picked out of the assembly line for a longer test.

[Nathan]

The recent F1 Racing magazine has an article featuring Toyota's engine builds. Toyota claims when they first came into F-1 it took 200 hours to assemble each engine, it now takes two mechanics four days to build one, that includes all clearance checks etc, majority of the time going into the cylinder heads.

I don't know how long a working day in Germany is, but I will guess that means 64-96 hours/unit.

[cheapracer]

You're probably right. I have refrained from posting my two pennies-worth on this topic because I'm not sure if I imagined it, or was told a long time ago, that it took two guys two weeks to re-build a DFV.

Got the pun.

Probably right because the rebuild machines were hand driven and measured not CNC and lasered.

[cheapracer]

I don't know how long a working day in Germany is, but I will guess that means 64-96 hours/unit.

Depends on which current beer festival is happening.

[J. Edlund]

The recent F1 Racing magazine has an article featuring Toyota's engine builds. Toyota claims when they first came into F-1 it took 200 hours to assemble each engine, it now takes two mechanics four days to build one, that includes all clearance checks etc, majority of the time going into the cylinder heads.

I don't know how long a working day in Germany is, but I will guess that means 64-96 hours/unit.

I think a normal working week in Germany is 38 hours, so four days for two people should be around 60 hours.

[Fred.R]

With all respect i dont think you can compare a F1 engine with a small block chev engine or any other road based motor, "rebuilding" usualy involves throwing lifed parts in the bin, not remachining, and precision machining not hand fettling etc, i dont think parts would be made with a margin to be "reconditioned" 200 hours sounds excessive, 5.2 man/weeks

[Canuck]

The use of Beryllium (low CTE compared with Aluminium) for cylinder liners must have been some design challenge!

They didn't as far as I know. They may have used a beryllium/aluminium matrix from BrushWellman called AlBeMet, or something similar but I'm not aware of any all-beryllium products used in F1. I do know Brush, McLaren and Perfect Bore worked together but I don't recall if it resulted in liners, con rods and pistons, liners and rods or just rods (AlBeMet rods were run during the 2000 or 2001 season in the McLaren at the very least). For the (I think) immediately-following season and later, FIA banned the use of beryllium specifically, ostensibly on safety grounds (health reasons) at the behest of Ferrari, or so the story goes.

I spent some time dealing with Perfect Bore on a since-aborted project. I would be exceedingly surprised to find out there was bore work done after assembly and running.

[gruntguru]

They didn't as far as I know. They may have used a beryllium/aluminium matrix from BrushWellman called AlBeMet, or something similar but I'm not aware of any all-beryllium products used in F1. I do know Brush, McLaren and Perfect Bore worked together but I don't recall if it resulted in liners, con rods and pistons, liners and rods or just rods (AlBeMet rods were run during the 2000 or 2001 season in the McLaren at the very least). For the (I think) immediately-following season and later, FIA banned the use of beryllium specifically, ostensibly on safety grounds (health reasons) at the behest of Ferrari, or so the story goes.

Do any F1 engines run pistons direct in the block? There are numerous production engines doing this with hard coatings in alloy blocks and I know this technology has been used in F1 engines.

[Tony Matthews]

Do any F1 engines run pistons direct in the block? There are numerous production engines doing this with hard coatings in alloy blocks and I know this technology has been used in F1 engines.

I thought the first Cosworth 2.4 V8 was linerless - there was concern about the cost as of course the entire block had to be junked after it's 'life'

[rrrocket]

I thought the first Cosworth 2.4 V8 was linerless - there was concern about the cost as of course the entire block had to be junked after it's 'life'

I did hear that. The block was lifed at one race, yet the crankshaft was good for several rebuilds. as were the cylinder heads.

[rrrocket]

They didn't as far as I know. They may have used a beryllium/aluminium matrix from BrushWellman called AlBeMet, or something similar but I'm not aware of any all-beryllium products used in F1. I do know Brush, McLaren and Perfect Bore worked together but I don't recall if it resulted in liners, con rods and pistons, liners and rods or just rods (AlBeMet rods were run during the 2000 or 2001 season in the McLaren at the very least). For the (I think) immediately-following season and later, FIA banned the use of beryllium specifically, ostensibly on safety grounds (health reasons) at the behest of Ferrari, or so the story goes.

I spent some time dealing with Perfect Bore on a since-aborted project. I would be exceedingly surprised to find out there was bore work done after assembly and running.

Agree with your point about 100% Be: this would not comply with the maximum Specific Modulus regulation, although I can't remember what year that kicked in. I have used AlBeMet in the past, it is available in four specs with varying Be content to comply with the regs, with Specific Modulus ranging from 52 to 91 ( with Be being 164). I was told at the time that it had been used for pistons and liners, but don't recall any mention of rods.

Strange stuff to handle when you pick it up for the first time: produced a good ring when I banged it on the desk. An absolute bear to machine.

Boralyn (Aluminium/Boron) was another material in contention, lower Specific Modulus, but I think the F1 threshold value was lowered over the course of a couple of years.

[Canuck]

Ah yes - pistons, not rods. I've lost my little PDF from Brush about working with McLaren and PB - seems I've already forgotten what it said.

[Melbourne Park]

This is from a marketing thing of Toyota's, due to one of Toyota's reasons for being in F1 was to inform more people and companies about what Toyota was/are about. It would be on the net. This is just a bit of it. Its a few years old, so well out of date. Some of the time data has been removed. But its maybe helpful. Incidentally Mechachrome used to assemble the Renault F1 engines. I think they still do, although why they would do so now with the lack of engine development, I do not know. They might tell you how much time it takes?

OPERATION: CYLINDER HEAD

For those involved in designing racing cars and engines it’s a fact of life that there is a frustrating wait before the fruit of their labours can be tested on the track or the dyno. It takes time to manufacture parts to the exacting standards required in Formula 1, and everyone has always accepted that. But what if you could reduce that production lead time by a significant degree, and in the process also ensure that the quality of the product was better than before?

That was the clear aim when Panasonic Toyota Racing decided to apply the principles of the Toyota Production System to the manufacturing of cylinder heads, one of the most critical areas of any race engine.

“One of the biggest gains in engine performance is port design,” says Technical Director Engine Luca Marmorini. “So the quicker we can change a port, the better. A cylinder head is quite a time consuming part to make, and if we actually have to scrap stock, it’s a highly expensive part. So really the minimum stock we have, and the more flexibility to change the design of the port, the better it is purely for performance gains.”

As soon as TPS was introduced to cylinder head production in 2002, it became quickly apparent that major gains could be made.

“It took 67 days to produce a cylinder head, from the moment we received the casting to fitting it to an engine in the workshop,” says Andrea Schmidt, Senior Co-ordinator for TPS at Toyota Motorsport. “It was far too long, because whenever we had a new specification it took that long before the workshop had the new cylinder head, and then half of the season was over! So we were not flexible enough. We wanted to give design more flexibility, so we had to reduce that lead time.

We knew that another leading F1 team needed about four weeks. We wanted to set ourselves a challenging target, and that target was two weeks. So from nearly 0 weeks, we had to get down to two. Everybody said, “Forget it, this is impossible.” We thought we might get down to five weeks or six weeks, but we can’t beat four weeks…”

Despite their own initial scepticism, Schmidt and her colleagues began to study this extraordinary challenge. The first problem was that there was very little information on paper – the process appeared to have developed organically, with no real thought put into streamlining it.

“We examined the complete process from the moment we received the casting, the complete production area to the engine workshop included. We couldn’t just take out pre-machining, or final machining, or de-burring, we had to look at the complete process – all 67 days. We knew it would be a lot of work, and it would take us a lot of time, and we had to do it on top of our normal jobs.

“First we looked at the complete material flow. We had nothing on a sheet of paper, so we had no idea what the complete process looked like. Where does an operator get his information? Does he need to collect the part? Does he need to deliver the part? What is his process time? It took nearly a month to write the whole process down and have something that we could start from and discuss.

“We also had to look at quality. Green-stickered parts are 100% to drawing, and in the first season we raced with cylinder heads which were not greenstickered. So what we did was implement jidoka, which means whenever we have a problem, we stop production. It’s the responsibility of the operator to stop the production line.”

This is a fundamental principle of TPS. It is far better to stop production and tackle problems rather than allow faults to be picked up later by quality control, when it may be too late to pinpoint the source and even more parts will have been produced with the same concern.

With each stoppage a meeting was called to discuss solutions. It took a while for everyone concerned to get used to this method, as there was a natural reluctance for individual operators to call time consuming halts. However, they soon learned to undertake increased responsibility for their areas.

The TPS principle of eliminating muda, or waste, can be applied to time as much as materials, and it was clear that things could be done much faster.

“We looked at waste of time regarding the movement of parts. We took the layout of the department, and followed the path with a pen. Each piece was being passed from one station to another, and this is where we lost the time. If you just added up the machining time, it was a week. This showed us that many weeks were just wasted, and the part was just lying around.”

This inefficiency was to some degree a result of Toyota Motorsport’s dramatic expansion over previous years. During the rapid transition from rallying through the Le Mans programme to Formula 1, the whole Cologne operation had to grow and adapt, including the production side. There was no real opportunity to start with a clean sheet of paper and plan things in the most efficient and logical manner.

“We had expanded the existing building and whenever we needed a little bit of space we moved a machine in there without thinking if it made sense. Thus we had to move parts over the corridor, and we lost a lot of time. So we changed the layout – we moved some machines so the operator now only had to go one or two metres. He didn’t have to transfer the part over the corridor to a different area, and maybe leave it laying there with no one looking after it.” One of the biggest problems was that the department had operated without sufficient consideration to where the end product was going.

“We had more than 90 cylinder heads in production, there were parts everywhere, and we had no real idea where our parts were. At the time our philosophy was to run the machines for 24 hours, producing cylinder head after cylinder head. But in the end if you looked at the number of races and tests, you could only use a certain amount. This is when we decided to produce just in time – when you need one, you produce a new one. It doesn’t make sense to produce more than the engines you can build.”

Producing only what is needed when it is needed is one of the main pillars of TPS, and the principle has been widely adopted across industry in recent decades. To make it work properly requires the use of kanban, in effect an ordering system that ensures that cylinder heads are now only put into production when they are required, rather than just to keep the machines busy.

When an operator gets a metal ticket from the engine workshop, it’s the signal to start producing a cylinder head. In fact they get two cards, for a left and right hand cylinder head. Previously the department was not necessarily able to deliver sets of a left and right side. Now the operators had to make sure that they delivered sets, and if there was quality problem with a left hand one, ensure that another was introduced into the system.

If the idea of the department producing unnecessary parts sounds illogical, it was to some degree because the operators felt compelled to stay busy. There was a natural human concern that jobs might be at risk should they appear to be surplus to requirements, but those fears have been addressed. Any free time was to be devoted to other tasks such as training, which further enhances quality and productivity. One of the key aspects is to involve the operators. Taking their ideas into consideration is essential to make TPS work.

“We also wanted to help people to improve the processes themselves, for example de-burring. We made standardised work charts, and worked together with the operators to decide the best way to deburr a cylinder head. In fact it depended on the operator. One needed eight or nine hours, another 5 or 6. We all decided to standardise the process and method to assure both quality and speed at 0 hours. The result not only improves the process but improves the ability to plan – you can’t plan with a range from eight to 6.” Planning, free flow of information and gaining people’s understanding and involvement is vital. Daily meetings were introduced, and tasks outlined on charts that everyone could refer to.

It was not an instant solution, but as each stage of the process was subjected to improvements, the benefits of TPS began to be felt, so the department became more and more efficient. A target that had initially seemed out of reach was achieved and then exceeded.

“It came down in stages,” says Andrea. “And in the end we are able to produce a new cylinder head in two weeks. To beat that other Formula 1 team was a real motivation for the people, and we beat them, so now we’re able to give design the flexibility to bring in a new specification. The only thing we spent some money on was moving machines into the right areas, but that was nothing. Everything else was just for free.

After one year we delivered the first green stickered cylinder head. When we had specific quality problems before, we couldn’t find out the cause, because we had so many parts and such a long process. We tried to do something to avoid it for the next cylinder head, but until we found out that it really worked, we already had over 20 other cylinder heads going through the same step! Now we know after the first or second one whether it works or not.”

Crucially the department can now also guarantee delivery on time, whereas before it was much harder to meet deadlines.

“This target of 4 days was set by the General Manager of Production & Procurement, and it was for us such an unrealistic target. He said this is your aim, and I will support you, and I will make sure you have the time to do this.

Noritaka Muramoto, a visiting supervisor from Toyota Motor Corporation, showed us how to do this, look at the material flow, the information flow, look at the layout, look at the quality, and we just learned by doing it.

It has been an interesting project. I must say I was one who said at the beginning this is for mass production, it can’t work in Formula 1 ! I’ve changed my mind totally, and learned so much since this project started.”

John Howett concludes: “The best part of TPS is that the work never stops, as we are constantly looking for the next improvements in-house that will lead to the next crucial tenth-of-a-second on the track.”

Edited by Melbourne Park, 18 July 2009 - 02:12.

[cheapracer]

Do any F1 engines run pistons direct in the block? There are numerous production engines doing this with hard coatings in alloy blocks and I know this technology has been used in F1 engines.

Personally don't know but geez, for example how long has Kawasaki been doing production nikasil bores for now - 40 years maybe?

The 70's GM Vega Cosworth twin cam ran cast iron pistons directly in the aluminium block if my memory serves me correctly - Mac? Also are they considered rare or historical mistakes in the US?

Ahhh Wiki, how did we survive before! Wow, what interesting reading re; Aluminium Engine Block
http://en.wikipedia....um_engine_block

Edited by cheapracer, 18 July 2009 - 03:30.

[Tony Matthews]

Cosworth EA

[McGuire]

Can't name a source unfortunately but some years ago I recall reading about it taking two weeks for two engineers to build an engine.

Sounds about right. With four engineers it would take four weeks, etc.

[Tony Matthews]

Sounds about right. With four engineers it would take four weeks, etc.

[McGuire]

While the effect is linear (to a first first-order approximation) in smaller populations, in larger numbers there is a trap-door function. Given, say, twelve engineers with sufficient funding, there is no reason it couldn't take forever.

[Tony Matthews]

While the effect is linear (to a first first-order approximation) in smaller populations, in larger numbers there is a trap-door function. Given, say, twelve engineers with sufficient funding, there is no reason it couldn't take forever.

The Brithish Government and its mulititude of quangos knows all about that!

Edited by Tony Matthews, 20 July 2009 - 14:02.

[Greg Locock]

The Mythical Man Month describes IBM's experience with developing large systems - basically the more people they added to a team the slower the development went.

http://en.wikipedia....hical_Man_Month

Oddly I have found the best CAD guys are 4 to 10 times more productive than average ones.

[cheapracer]

The Mythical Man Month describes IBM's experience with developing large systems - basically the more people they added to a team the slower the development went.

related management idea...

Some manufacturers employ casual staff to be trained on machines in house by the machines Operators. This is actually a ploy to improve quality standards as the Operator is given and feels responsibility to carefully train the casual Guy with responsible, by the book correct procedures. It's acts as a refresher course for the Operator as well.

[cheapracer]

. Given, say, twelve engineers with sufficient funding, there is no reason it couldn't take forever.

And in Oz thats actually 10 because one of them will always be on holiday and one will be on sick leave which may actually improve the time frame!

Edited by cheapracer, 20 July 2009 - 05:05.

[Tony Matthews]

I seem to remember that the UK was at its most productive during the notorious Three-Day Week phase...