All posts by Ronalea Karting

Tech Tuesday: The Crankcase

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Combustion in the combustion chamber acts on the piston with a pressure (force when multiplied by the piston head area) which generates a linear movement of the piston. This movement is then transformed into a rotating one since the piston is mounted on a reciprocating mechanism consisting of the crankshaft and conrod. The crankshaft rotates with the support of spherical bearings mounted in the crankcase referred to as the main bearings.

The force acting on the piston is transformed and transmitted through the conrod and crankshaft and must then be absorbed by the crankcase. The crankcase not only has to absorb these forces, it also has many other functions that make it an essential element of the engine. A fundamental role is to act as a pre-compression chamber. When the piston moves downwards in the cylinder, mixture is compressed and pushed into the transfer ducts, through the transfer ports and into the combustion chamber. In addition to this, the crankcase also has the function of being the bond between the engine’s different components such as the cylinder, crankshaft, carburettor, engine-chassis mount, ignition system and coil.

The material used to build the crankcases of modern 2-stroke competition engines, such as those used for karting purposes, is aluminium alloy, which reduces considerably the weight of the engine. Aluminium though has some weaknesses linked to the fact that it heats up more easily than cast iron and consequently deforms more. Its heating up generates a rise in temperature of the crankcase walls which consequently heats up the mixture in the crankcase. A fluid (mixture) that heats up increases in pressure and expands, reducing its density and the volumetric efficiency of the crankcase pump.

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The Crankcasing houses the real guts of the motor

Temperature increases also generate expansion of the aluminium alloy and therefore the walls of the crankcase (they reach around 100°C). This expansion will be different in different areas of the crankcase since the component’s walls vary in thickness and also fresh mixture can act as more of a coolant in some areas than others. Consequently, the crankcase will deform and generate negative effects. For example, alignment between the two main bearings that carry the crankshaft can be lost. Gas sealing between the crankcase and cylinder can also become critical. Another important effect is that the perpendicularity of the cylinder’s axis to the crankshaft is at risk. Finally, main bearings can change the tightness of assembly of the roller balls inside the cages which can produce seizures and breaking of the cages.

The limited mechanical strength of light aluminium alloys from which crankcases are constructed also needs to be taken into account with regard to the threads of the holes for the holding down bolts and the cylinder head studs. To avoid rapid damage to the threads it is advisable for the effective threaded length to be not less than 2.5 times the diameter. Assistance can also be given by the insertion of steel threads that are much more resistant, especially when studs and bolts are frequently screwed and unscrewed. Since the crankcase working as a pump needs reduced internal volume to be effi cient, it is constructed of two halves symmetrical with respect to a vertical plane perpendicular to the axis of the crankshaft. When joined, the two halves must be completely gas tight and to do this a gasket is also positioned between the parts. Mixture loss would reduce the efficiency and performance of the engine.

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The Crankcase houses the Gear box on shifters

To have good matching of the two symmetrical parts, production must be very precise. Cylindrical dowel pins also help couple the two elements. Sealing must also be obtained where the crankcase opens to permit the exit of the ends of the crankshaft. Oil seals are used on both sides and are rubber rings that have one or two ‘lips’ that seal the area around the crankshaft. The aim is to have good sealing but low friction loss generated by the ‘lips’ and the crankshaft that are in contact with one another. As already mentioned, the crankcase also has the role of absorbing all the forces transmitted by the crankshaft. To limit deformation of the crankcase it is built with ribbing all over its external surface. These ribs help both to strengthen the structure and to cool down the surfaces

Prepared to win: The military call it the 7p’s…

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I’ll paraphrase slightly as this is a family magazine and give you the 6p’s… Proper Planning and Preparation Prevents Poor Performance.

Top teams will tell you that races are won and lost in the workshop as often as they are on the track. Or to quote the other time-worn adage… To finish first, first you have to finish.

Working space

It’s all terribly exciting getting into karting, but calm down and stop for a minute. Even before you collect the kart, things need to be done that could affect the way things go for you ever onward. Set aside a working area. Ideally, this space is sacred with nothing else apart from karting stuff allowed there, but a garage or workshop that gets kept just for one purpose is a rare commodity indeed. However, an area with plenty of light and enough room to have the kart up on a stand and be able to walk around it easily is the minimum that you are aiming for. Once you have sorted this out, the working area needs to be kept clear of gardening tools, bicycles or any of the other paraphernalia that tends to build up. It doesn’t need to be laboratory hygienic but keeping the work area clean and tidy will make things far easier, as will having a rack or two for tools, parts removed and spares that aren’t needed all the time. Keep the floor tidy, the chances of dropping a vital spacer seems to increase in proportion to the amount of clutter on the floor. Now you can bring the kart home get it on the stand and get on with things.

Clean and green

We are assuming that your first kart is very likely to be pre-owned so the first thing that you need to do once you get it home is strip it down as far as your expertise allows and set about giving it a deep clean. Even if you have bought a brand new machine you should spend an evening or two giving it a thorough spanner check before use. Deep cleaning or spanner checking a kart after buying it serves a very useful purpose, as it familiarises you with your new machine and forces you to look closely at every part of it. No matter how careful you have been with your purchase you could be amazed at what you find once you start, better to tackle it now than at the first track session.

The deep clean needs to become part of your kart preparation routine, after getting back from any meeting (or practice session) your kart should be stripped (at least partially) and cleaned. This will also allow you to check for cracks, loose nuts and bolts and damaged component while you are at it.

An MSA scrutineer of my acquaintance tells me that he is still amazed and appalled that karts are presented for inspection dirty. He has in the past sent karts away to be cleaned before he was prepared to look at them. “A waste of my time and theirs” was how he described it. He also added that it was rare for him to find any safety issues on a clean kart but often found fundamental preparation errors on dirty machines, reasoning that if you can’t be bothered to clean your machine you won’t be bothered to spanner check it either.

Wet and dry Running in the wet is like having somebody with a high-pressure hose spraying water and abrasive paste at your kart. This filthy mixture will creep everywhere and manage to penetrate every orifice. As soon as you get home and before you collapse into your favourite armchair give the kart a thorough dousing with water dispersant spray (careful with the brake though) to keep rust at bay until you can clean things properly.

The proper way to deal with a kart that’s been out in the wet is to strip it to the bare frame and then re-build, cleaning everything as it is put back on. Why so fussy? Because if you don’t, the grit that has managed to penetrate everywhere will act like very effective grinding paste and everything will wear at a phenomenal rate, look at the sidepod fixings after a wet run and you’ll notice dirty little trails creeping along the chrome and paint. That’s a mixture of grit and worn away metal coming from the joints. Leave the grit there and it will continue to nibble at the fixings as the kart flexes.

Nuts

Anybody who is serious about preparing their kart properly should consider that the Nyloc nuts are for one use only. However, on some less critical applications I will use Nyloc nuts a couple of times. The nuts are fitted plain for their first use and if I have occasion to remove them they are put back on with the addition of a blob of yellow paint on the nut. I then know that any nuts that have this blob of paint are on their second use and should be replaced if removed again.

Find your local fasteners stockists and buy at least 200 of each of the Nylock nuts you use (usually M6 and M8) then there is no excuse not to replace nuts after one use. While you are at it invest in a couple of bags of plain washers too.

One man, one job It’s great having a few mates over to help you prepare a kart but it can lead to problems, it might seem officious but if a
group of you are working on the machine allocate jobs to each person and make them totally responsible for that task. Get a couple of people on one task and there is always the chance of the “I thought that you had checked it” scenario. Make sure that each specific task is completed before you pack up; leaving a job in the middle is asking for trouble, if it can’t be avoided make a note of where you have got to and what needs to be done before the task is completed. Top tip… A whiteboard and a dry marker pen will pay back their cost many times over.

Ultimate responsibility

Somebody needs to take overall responsibility for all the final checks. That’s you!

Not on Friday night

If you need to be up bright and early on Saturday morning ready to travel to the meeting, Friday night isn’t the time to be spanner checking your kart ready for the weekend’s racing. Not only does it make the evening potentially fraught when you should be relaxing, it doesn’t leave any safety margin. Better to be doing the final checks on a Wednesday evening at the very latest, working on the theory that if you find anything that needs attention or worse still needs replacing you’ve still got a couple of days to get it ordered, delivered and fitted.

Spares box

A tough plastic box is ideal to stack with all the odds and sods that you are going to need for the weekend. Keeping a spares box stocked with all the essentials that you might need during a meeting ready packed and ready to go will save a huge amount of time when loading.

What do you pack? The short answer is anything that you imagine that you might need at the track. Trusting that the trackside kart shop will have what you need in stock isn’t the way to go.

To get you started… Spare chain or chains, if the amount of adjustment on your engine is limited and you need differing lengths to accommodate larger or smaller rear sprockets. Then there are the sprockets themselves. A box of nuts and bolts of a few different lengths, in the sizes used on your kart is always useful, as is a big bag of zip ties and a roll of gaffer tape, chain lube, spark plugs. Don’t forget the spare hubs if you use different lengths for different conditions. The list goes on, only you know what you really need. So grab a cup of tea, sit down with paper and pen and make your own list.

Wet tyres and rims need to be bagged up ready to use, keeping them in a bag serves a double purpose, it keeps them together and makes them easy to transport while excluding the light which is one of the things that degrades rubber. When you get home from the track, make one of the first jobs you do the replacement of any parts that you took from the box during the meeting, this way you won’t be caught short next time.

Tool time

Although some karters take a huge tool chest containing a mini work-shop full of stuff for those just-in-case moments this isn’t strictly necessary. However, having a small easily portable box containing essential tools is a must. It makes sense to have at least two separate compartments, one for the tools that you will be using all the time like the plug spanner (you might need to grab these fast) and the other for
the tools that might be used but probably won’t. Some even go to the length of having one set of tools for when they are at the track and another set of workshop tools; it all depends upon your budget.

Sensitive souls As karting becomes more complex the equipment to run them becomes similarly advanced. If you have invested in things
like set-up lasers and timing gear it would be foolhardy not to buy some proper hard cases with padded internals to protect them. The all important tyre pressure gauge needs to be packed separately too, to keep it safe from knocks that might harm its accuracy. Also think about where they and other expensive items like crash helmets will be kept, these need to be both safe from harm and away from prying eyes.
It’s an unpleasant thought but these are easy to steal, getting several hundred quids worth of kit nicked will sour even the most successful day’s racing.

Packing your van or trailer

There is huge wisdom in the saying “a place for everything and everything in its place”. Taking some time to do a trial pack of the van or trailer and work out where everything should go will pay dividends in the long-run. When you are happy that everything is in and the weight is balanced, then develop some sort of securing system for them. I’ve seen everything from light ratchet straps fastened in place to clever over-centre catches allowing boxes to be clipped into position in a few seconds. Merely chucking everything in and hoping for the best won’t do. Imagine if you have an accident on the way to the circuit, nobody wants to be hit in the back of the head by an unsecured tool box or have their entire spares stock strewn across the motorway.

Strapping a kart down securely can be a nightmare. Some teams always carry theirs stood up on end and fastened to the van sides, others park them flat. Either way they need to be held in such a way that they can’t jiggle around and bash into things, or for fixed gear karts snatch at the chain which is bad for the motor. Nor must they have pressure from the fixing straps on anything vital. One of the most elegant solutions I have seen to carrying a kart flat was in a trailer. This had a set of four U-shaped blocks fixed to the floor. The kart wheels dropped into the blocks and straps went over the tyres. Once secured this kart couldn’t move and there were no fastenings chafing or pulling at the chassis.

It’s only a mistake if you make it twice Inevitably you will discover that you have left something that’s needed at the circuit at home. Learn from this and make a note of what was forgotten. Do remember to do something about it when you get home though! Buy the book
Buy several pens, a good hard-backed notebook and one of Karting magazine’s set-up data books (c’mon we had to get a plug in somewhere!) and keep them all with your kit. In the set-up book note and record everything from the date, circuit and weather conditions to tyre pressures,
sprocket choice, lap times etc. In the hardback book record all the other stuff, for instance what you have forgotten to bring or parts used from the spares stock. Keep them safe, these will become your karting bibles.

Home again

Even if you get home at midnight, tired and dirty, kart clothing will need bringing in and unpacking so that it can dry and air, a sweaty helmet after 24 hours in its bag, eugh! If you are confident that the rest can be left safely without unpacking by all means do so, but don’t forget to waft the water dispersant spray over the kart if it’s been wet, overnight can be long enough for rust to take hold on unprotected components.
When you do unpack make it your rule that nothing is put away damp or dirty. If you do it is almost guaranteed you’ll forget something until the next time it’s time to use it, then it’ll be too late.

Female Focus: Does Sexism Still Exist in Karting?

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Stock-Girls

As I mentioned briefly in my first article karting is an incredibly unique sport. It is one of very few activities out there that lets us females and males compete against each other on a level playing fi eld. Motorsport began as primarily a male dominated arena where males would flaunt their new vehicles and take part in lengthy ‘staged time trials’ around main roads.

The first time women were introduced into this exclusive fold was when the chaps decided they were worthy of sitting in the passenger seat and giving directions, although I do wonder if there were many arguments over whose fault it was for missing the left turn ahead. However, now it’s a completely different story altogether with women such as Danica Patrick in the forefront of NASCAR racing. Perhaps because of the increase in women succeeding and dominating in the higher ranks of motorsport this is spurring on more females to step into racing.

I remember my first experience of the karting world aged nine. Like many others I started off at what I originally believed to be the largest kart circuit in Essex. However I was soon to fi nd out that this ‘epic’ 250 metre track was probably about the same length as the straight at Kimbolton! After being shown the ropes for a while I was ready to go. Obviously on my first go out I spun… a lot, and I hadn’t quite grasped the concept of needing to brake for a corner. Nonetheless I was enjoying myself and that’s all that matters right? Well, apparently not. Once I’d had my little ‘test session’, seven other arrive-and-drive racers were let out on the track, all boys. I was determined to prove I knew what I was doing.

In the end I turned out to be faster than them. Expecting some kind of warm welcome I greeted them and was told that, “Girls aren’t meant to come here, go and buy a doll’s house”. Fortunately I saw the funny side, and decided from that point onward I would make it my aim to continue to prove my worth in this male dominated sport.

In the eleven years I’ve been racing I have come across some nasty stereotypical insults about my driving, but as I’ve matured I’ve grown to ignore it and realise the best way to silence a chauvinistic pig is to just go out and there and beat him! Having said this, I wouldn’t do karting if I didn’t enjoy it, and I’d say the majority of the males I race or have raced with have no issues with me being a female, and because of this we have a mutual respect for one another. I’ve made some amazing friends over the years. This, however, is merely my view and my experience, so I headed down to my local track (Shenington) to find some male and female karters and see what their views were on this whole issue. Fortunately I found two willing male and female participants, Dean Patrick and Sarah Drew, and decided to interrogate them. They both race Junior Rotax, but only at Shenington club rounds.

How long have you guys been racing? Have you experienced any hostility from other racers in this time?Dean: I’ve been competing since I was 10 and when I first started I was quite nervous and felt the guys with painted lids were like Gods or something. I’d literally let them past, and when I started getting good they didn’t like it. That’s the only hostility I’ve ever had.

Sarah: I’ve only been racing for three years, since I was 12. I think a lot of people welcomed me after I’d been doing it for a while, but to start with I don’t think the guys liked the fact I was there because we were all young and a bit immature. I remember getting knocked off the track a lot at the beginning.

Dean, what are your views on ‘girl racers’?

Dean: Personally I’ve never had a problem with it, although I can see why some guys get frustrated when a girl is quicker than them because other racers could tease them. It’s probably harder I think for girls to gain respect on the track, because I know a lot of guys that aren’t that quick and still don’t get punted around as much as some girls I know. Motorsport is seen as a male thing, but so many girls do it now it shouldn’t be an issue any more.

What do you think, if anything, could be altered to change some people’s attitudes?
Sarah: I don’t think anything in the sport itself could be altered as it’s all down to the person’s views. I think it’s encouraging for girls to see loads of other women competing and winning in motorsport.

Dean: Like Sarah said, it’s hard to change a person’s opinion. I think karting is a great sport and, compared to a lot of others, people are more open and accepting to girls. If a guy can’t handle a girl beating him then he probably shouldn’t be racing! Sexism in any sport is always going to be a tough issue. In the 21st century we’d like to think it would be non-existent by now and we’d all be holding hands under a rainbow. However, despite the distinct lack of any rainbow, once you have your helmet on it doesn’t matter who you are. Just what you can do.

Tech Talk: Transmission Ratio

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Stock-Old

Transmission ratio is determined by the gears of the engine and the rear and front sprocket. In KF classes only front and rear sprocket act on transmission ratio.

What happens is that torque generated by the engine on the crank-shaft acts on front sprocket. Since torque is equivalent to a force multiplied by a length we can consider the force (Ffs) acting on the rear sprocket teeth tangent to the sprocket equal to: Ffs = Tcs / Rfs, (1) with Tcs the torque on crank-shaft and Rfs is the radius of the front sprocket.

Now the same force Ffs acts along the chain to the rear sprocket. So torque produced on rear sprocket is: Tra = Ffs · Rrs, (2) with Rrs the radius of the rear sprocket. The torque acting on the rear axle is just the same of course and so is the torque on rear tires. So the force acting horizontally on the tire print in the direction in which the kart accelerates: Fra = Ffs · Rrs/Rrt, (3) With Rrt the radius of rear tires. This means that the greater the radius Rrs of the rear sprocket and the greater the force Fra moving the kart forward.

The opposite situation is generated by the front sprocket. In fact substituting equation (1) in (3) leads to: Fra = Tcs/Rfs · Rrs/Rrt, Which means that the greater the radius of the front sprocket (number of teeth) and the lower the value of the force moving the kart. The conclusion is that if we increase the number of teeth of the front sprocket we will have lower acceleration of the kart, but we will be able to use the torque for a greater range of speed, instead we will have the opposite result with less teeth.

With greater teeth of rear sprocket we will instead have more acceleration of the kart for a smaller range of speed and vice versa for a lower number of teeth. It is also interesting to notice how much tire radius (Rrt) also effects transmission ratio. Such radius must be measure when changing tires, but also we should also consider that tire wear leads to lower tire radius and so transmission ratio can also change because of rubber coming off the tire print surface.

Competition Mind: Identifying Stress in Children

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Stock-Grid

Several times in this series of articles we have looked at the implications of placing undue stress and pressure on children, and we have also looked at ways of communicating with children. In this month’s article we are going to look at some of the signs that your child may be suffering undue pressure and stress that very often go unnoticed because they tend to appear gradually rather than just happen overnight.

There are a great many signs that signal that a child is suffering, too many to go into all of them but we will look at some of the more common ones that will give you as either a parent or manager the opportunity to do something about it. However, it is also important to be clear that stress shown at the race track might also be coming from other sources and that racing may just be the place where it becomes more apparent. One of the many things to take into account as a possible source of stress is schooling.

Very often the pressure to perform and do homework, get good results and be in a higher grade of class can place huge amounts of pressure on a child so that when it comes to having to perform at the track this can very often be the place where the child feels it the most because their results and performance are on show for all to see. Medical issues are also on occasion to blame; if you have any concerns at all then medical issues are always and should always be the fi rst port of call to get ruled out.

Sibling rivalry is another potential source of stress, having to match up to perceived parental expectations of a more successful brother or sister whether academically, in sport or simply just competing for attention. Sometimes it can even be that the child has a successful parent and this is always being thrown at the child. Other times it can be from a parent who has had a go at sport and been less than successful and they are putting pressure on the child to be a success and live their dreams through their child. Less common but nonetheless to be considered is that a child may be being bullied at school, they sometimes can be derided for being involved in motorsport by children less fortunate and jealous of the child lucky enough to be able to participate. Another common source of stress is the “Do you know how much we spend on you?” This is usually a last ditch threat placed by the parent(s) in a bid to control the child in some way which invariably ends up with the child feeling pressure which in turn will hamper their performance and make them tense.

By now you will understand that stress in a child can come from many different sources and in many different ways and can have a profound impact on their performance on the day. Now we will explore some of the more common signs, again we emphasise that stress and some of the other things we are going to describe to you should always be checked out fi rst by a G.P. simply to rule out anything medical.

More often than not however, stress and the physical signs are brought on by psychological stressors. Over-reacting with tantrums following a poor result is a common one and is very often a way of the child saying with actions “If I am outwardly showing how distraught I am, hopefully you will leave me alone”, or, “I want you to see I am angry, so please keep calm as I want you to avoid being angry and embarrassing me”. The latter though could be modelled from a parent that uses this type of behaviour when they mess up! Nervous tics – these are commonly of physiological origin and are mostly seen by way of involuntary twitches, sometimes with erratic blinking, screwing facial muscles up, erratic sideways twitching of the head. They have even manifested themselves as what appears to be some bizarre pointing of the index fi nger, again involuntarily done and created as a release of stress.

Excessive crying and tears for no apparent reason – usually this is exaggerated by tiredness and very often can be brought on by seemingly minor incidents or minor comments that would otherwise be taken in context and lead to normal dialogue. At its worst these easily released tears and upset can continue and sometimes become uncontrollable during times of the most heightened stress and pressure. It could also, to be fair, be that the child has discovered that this is the best way to manipulate, to get their own way. First though it is important to discover if there is any underlying stress that maybe hasn’t been communicated because the child is in fear. Outbursts of rage – this one can often be seen in the paddock. The child is given some form of criticism, even minor, and they just erupt with rage. Frequently there will be excessive arguments accompanying the anger and rage and it all escalates. This is usually a form of defence and also a modelled behaviour.

Sometimes it can be a cry for help to the parent to actually listen rather than continually attack and criticise. Obviously in some cases hormones can also play a part! Obsessive compulsive behaviours – these can be in various different forms which can be like touching rituals or some other form of seemingly odd behaviour which a child has adopted and for them must be done, this offers the child comfort. Bedwetting – this is more common than you would think, so if you happen to have a child who is bedwetting you are far from alone with this distressing issue. Again it is important to have any medical conditions ruled out before you look at the psychological aspect, in any event it is usually caused by underlying stress. These are only some of the many outward signs that there could be an underlying problem which could affect your child’s performance. If you have any problems with these then as we say the fi rst port of call is the G.P. to have it checked, then to have open and honest dialogue with your child and get them to open up.

The next step is to look at how you may be treating your child, think about how you are communicating, what pressures are you placing on the child, what are you holding them to ransom over, do you make them feel guilty, are you continually comparing them to other children, are you over-working them, what is the atmosphere like at home and when travelling to an event. It is also important to consider the relationships that your child has with other children, that includes school friends, brothers and sisters, the other children in the street that they might play with, the other children at the race track, as again it could simply be that the other areas of your child’s life are fine but the children at say the race track are name calling and generally being obnoxious and are picking on the child.

So be more aware of the bigger picture of what is happening in your child’s life. The hardest job in the world is to be a great parent, it is a constant battle. We aren’t given a magic book when a child is born that tells how to do it right and to cope with and understand the constant changes they go through. The best place to start is by listening to them, nurture and care, encourage and support, help them to become independent and confident. If you have any questions then you can contact me via Karting magazine or alternatively email me at neil@competitionmind.co.uk.

Tech Talk: Machining Transfer Ducts and Ports

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We can analyze a big difference in tuning possibilities after having studied in the last two issues the diverse solutions used for the surface of the cylinder: cast iron or chrome bore. With cast iron it is possible to machine the cylinder. This is done when the cylinder liner surface has to be renewed, after a seizure and also when the surface is worn down, by honing the cylinder. But the possibility to machine the liner surface, since it has no chrome cover, also gives the opportunity to work on the ports and ducts of the cylinder to improve gas and mixture flow. Let us see the route that the mixture follows from carburetor to combustion chamber. Once the mixture has entered the crank-case through the carburetor it is then pushed through the transfer ducts (generally three or five) into the combustion chamber, the volume closed between the piston crown, the liner and the cylinder head.

Then compression phase starts with the piston squeezing the mixture by moving upward along the cylinder and reducing the volume in the combustion chamber when all ports are closed. The spark plug lights up the mixture that burns quickly increasing the pressure in the combustion chamber by about ten times. Once the piston moves downwards, thanks to such pressure increase, and opens the exhaust ports the burned gases exit the cylinder through the exhaust duct. So when tuning the engine to optimize gas flow in the engine we must follow the flow from the crank case to the exhaust duct. When, in fact, the mixture moves from the crankcase through the transfer ducts the walls of the ducts must be possibly converging and without any sharp edge to avoid any turbulence which reduces gas flow in the ducts.

Since when the engine is mounted the single parts such as cylinder and crank-case halves are tied together, they might have some surfaces not perfectly matching which create edges, there is a way to machine the adherent areas to smoothen them down and create a good match. This is done by mounting one of the two halves of the crank-case together with the cylinder and machining the two matching surfaces aligning them as best possible around the area of the lateral transfer duct (or ducts) and the central transfer duct (called T duct). Same thing must be done mounting the other half of the crank case with the cylinder. We have now a smooth entrance of the mixture through the first part of the lateral transfer ducts and the T duct. T duct can also be machined in its internal surface that often has a sharp edge given by industrial machining. Rounding such edge optimizes mixture flow. To be sure that such job reaches full result we must also verify that the gasket which is positioned between the cylinder and the crank-case does not obstruct gas flow inside the lateral transfer ducts and the T duct. If the gasket is wider than the duct there is no negative effect on gas flow, but if the gasket is narrower than the duct, an edge is created and turbulence generated. To avoid this, cut the gasket to the right dimension with a paper cutting blade.

Another area to check is the contact line between the cylinder liner and the aluminium of the cylinder. Often in fact the mounting of the liner inside the cylinder, which is done by heating the cylinder (so it expands) and partially forcing the liner inside, may finally not be perfect and create some edges that need to be machined to obtain a smooth surface which helps gas flow. Finally mixture reaches transfer ports. These must be machined in the edges to avoid having them too sharp. Sharp edges in fact create turbulence of gas which leads to resistance to flow. The effect of turbulence is equivalent to a reduction of the port area, and the result is the same as having mixture passing through a narrower duct. Machining has the aim of rounding sharp edges of the transfer ports. This reduces considerably turbulence when mixture exits the transfer duct through the ports into the combustion chamber. There is though a limit to rounding edges of the ports. It is in fact true that an excessive rounding generates an imprecise opening and closing of the ports when the piston passes over them. This can lead to bad scavenging and lower performance of the engine. Rounding should be as limited as possible to avoid sharpness.

Marussia Virgin F1 to sponsor KGP

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Marussia Virgin Racing Kart Grand Prix

The Marussia Virgin Racing Formula One team is to support new karting category Formula KGP with effect from this season.
Virgin F1 driver Jerome D’Ambrosio took part in a launch test at PF International on 26th February and was delighted with the kart. Special Projects director Marc Hynes said “We’ll have trouble getting him out of the kart and to the Barcelona test next week!”
Formula KGP is a new seven-round National Karting Championship, which joins the Super 1 Series. Marussia Virgin Racing will use the collaboration as the foundation of its young driver programme, the first stepping stone for exceptional young karters to progress all the way through to Formula One.
Karting is the first step to gauging the potential of a future World Champion and Marussia Virgin Racing will be keeping a close eye on the stars of the future. At the end of the season, the top three drivers and one ‘wild card’ – a driver who has demonstrated outstanding ability in the new Formula KGP Championship irrespective of points placings – will win a Formula Renault test.
Hynes, who was deeply involved in British karting during his own racing career said “We think that karting needs to have a pinnacle again. We’d like nothing more than to find the next D’Ambrosio in KGP. Because we’ve been so successful in Formula Renault with Manor with the last three BRDC Young Driver of the Year winners we would like to put something back and give someone the opportunity in Formula Renault. When there were lots of drivers in the top class there would always be seven or eight looking to move into cars and now there isn’t that many then there’s only eight or so on the grid in Renault. We were concerned about backing something that would put people out of business but the tuners can still tune and people can

use whatever chassis they like. If they want to do KF2 in Europe they can just take the front brakes off and bolt the engine on.”
To underline its support for the category, the Marussia Virgin Racing logo will also appear on the karts, drivers’ suits and helmets as well as being integral to the Championship identity.
John Booth, Team Principal, Marussia Virgin Racing, said “Karting is the beginning of a long but ultimately very rewarding
journey. I believe very strongly in nurturing the talent of tomorrow and providing opportunities for drivers to move through
the ranks. It’s not an easy progression, so if  the talent is there, it should be supported. As a team, we have to think today about the drivers of tomorrow and that means ensuring there is a rich pool of talent to draw from further down the line.”
Andy Cox, Managing Director, Formula KGP said “Formula KGP is delighted to form this collaboration with Marussia Virgin Racing. Karting is a crucial step in the development of a driver; perhaps in many ways it could be the very discipline that defines a driver for the future. With this collaboration, karting connects directly with a Formula One team and an
entire grid can race under the gentle eye of Marussia Virgin Racing, with such an innovative approach a future talent could be discovered. With a test drive in Formula Renault at the end of the season, I can’t think of a better situation for a driver to
showcase their talent to a Formula One team.”