Saturday, November 13, 2010
Bling!
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With the engine decision fairly set in my head, I have been keeping
my eyes peeled for parts that I will need. Whilst there is no major
urgency, it seems sensible to watch out for any bargains that might
turn up. And so, a couple of things have appeared this week. The first find was a pair of standard cams for a 1600 Sigma engine. These may not actually be required, but having a spare pair which could be used for exchange or a regrind could be handy, and given that these cost me the grand total of just £5, it seemed rude not to. |
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| The other thing I spotted was a set of throttle bodies. Whilst I was idly searching for a set of Jenvey TBs, I turned up a some from AT Power. I'd not heard of them before, but a quick bit of research seemed fairly convincing that they should be pretty good. Their primary selling point seems to be that the butterflies are spindleless, and that this gives a less disrupted airflow. I'm not entirely sure that it makes alot of difference, as it would only have any effect at wide open throttle, but they have a few other nice features. They are direct to head, which means that you can bolt them straight to the cylinder without the need for a manifold - this is defintely an advantage in terms of flow over using a generic DCOE style body on a manifold, and the closer you can get the butterfly to the inlet valves, the better. Additionally, they have a nice modular design, and are made from billet rather than cast. |
| Anyways, I think/hope I got a good price, as pricing up the same thing new comes out at almost three times the price I have paid. The only downside, I found on receiving them, is that the blue anodising has not fared that well, so cosmetically they aren't in A1 condition, but mechanically they seem to be. With the package, I got: the bodies with extension pipes and trumpets, fuel rail, injectors, throttle position sensor, wiring loom, and ITG air filter. The engine they were previously fitted to made 190bhp with some headwork and cams, so they should make good power. I spent a little time dismantling them to clean them up, and have packed them away into storage for now. |
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Monday, November 01, 2010
Engine Choice
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After a load of thinking and researching, I have reached a decision
on the choice of engine. As much as I would love a 5-cylinder, I don't think it is a realistic option really in terms of cost, and, having seen how the bonnet line of the Stylus causes issues with even the Vauxhall, physical size and weight. Unfortunately, the same argument goes for the F20 VTEC engine, and the B16 is not at all straight forward to use in a rear-drive configuration. The Zetec is certainly cheap, plentiful, and can easily produce enough power quiet easily, but it is a bit of an old and heavy design of engine, with an iron block. More recent engines are better. The Duratec is the obvious more modern alternative, but it is physcially slightly large, and I am somewhat worried about what I will be able to fit under the bonnet (as I want to get rid of that horrible bulge), and seems to be a bit more expensive to tune it. So that leaves a K-series or Sigma. I was fairly sure that I was going to go with the K, as I sort of know a bit more about it, some of it's issues, and how to overcome them. But the more I looked into the Sigma, the more it made sense. Physically it is very similar to the K, in terms of dimensions and weight (~80kgs). What the Sigma has in it's favour, is none of the problems that the K has! Yes, they can be worked around, but that all costs money, so why do that if you don't have to? The Sigma can be revved to 8000rpm with only a change of big end bolts and valve springs, everything else stock. It is simple to get to ~160bhp with just an exhaust, ECU, and throttle bodies, and nearer 200bhp can be achieved with the increased revs, some mild headwork and upgraded cams. All from a 1600 which is plentiful and you can buy from a scrapper for £400. |
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From what I can see, there isn't alot of choice of gearbox, for a
front-engine rear-drive configuration, with the Sigma engine. In
standard use by Ford, it is a transverse front wheel drive engine,
and as such has a gearbox for this purpose (known as the IB5).
Obviously, this is no good for rear wheel drive though when you
rotate the engine around into a longitudonal mounting. Previously,
there was alot of commonality between Ford engines and gearboxes,
and in the good old days, there a few different vehicles with rear
wheel drive, so you could bolt up a number of different gearboxes to
engines. |
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So, for the Sigma, there are a few companies around who will sell me
a bellhousing to connect a Ford Type 9 gearbox. The Type9 was Fords
first RWD 5-speed box, and was used in the Capri and Sierra (and few
other things). As it has a separate bellhousing and can therefore be
mated to all sorts of different engines, it is a popular choice for
kits and conversions. It is still relatively available, and fairly
cheap, though as Sierras are becoming a bit more scarce, I'm sure
that will change. There is also a thriving aftermarket for these
boxes, so parts and upgrades are readily available. The ratios in
the standard box are not ideal for a light car - well first gear is
way too short really - but that can be lived with and tuned using
the diff ratio to an extent. Ultimately, putting a nicer aftermarket Type9 box in will be a good plan, but for starters, a standard box will do just fine. |
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Speaking of diffs, it is my intention to replace the live axle on
the car (currently sporting huge spacers to widen the track) with a
home-brew independant rear suspension setup. Sounds scary, but in
essence what you need to do is build a diff cage hanging off the
back of the tunnel / rear bulkhead, and from that you can hang
double-wishbones. Now there is a little more science to it than that
to get the strength and geometry right, but it can't be too hard,
can it...? As such, a diff also needs to be chosen, and again the most widely used in kit car circles is from a Ford Sierra. There are other, more modern choices around, but the Sierra unit is well known, cheap, a range of ratios, and again there is decent availablility and an aftermarket for it. Also, rather conveniently, Richard (my next door neighbour) has a limited-slip version sitting forlornly in the corner of his garage, after he upgraded his to a different ratio by changing the whole thing. |
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| So there we go, 1600 Sigma engine, through a Type9 gearbox, to a Sierra diff. Done (hopefully). |
Friday, October 29, 2010
Engine musings
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With the car grounded, I've been busy trying to work out what I am
going to do with it. Firstly, the Vauxhall. I think the first thing to try is an engine flush and oil change - this may clear out any crudded up lifters or oil galleries, which will then allow them to pump up properly. Beyond that, I will then need to take the cam cover off, with a view to getting the lifters out for a clean or possible replacement. Something else I can check relatively simply, is to extract the oil pressure relief valve which is located in the oil pump housing, and make sure that is not sticking. Oh and getting the oil pressure gauge working woud be a reasonable plan too. Just need to find some time for it. My thoughts have also been busy with working out what engine I want to put in the car. Here's some options I've been thinking about and researching... |
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Rover K-series The K is nice engine, I have owned a couple of cars with them before. They have a reputation for being fragile, but I think the problems are pretty well understood now, and can be engineered out. It is a light engine and available in a range of capacities, there are alot of tuning options around, and it can create a good amount of power. The K is quite common in kit car circles, so a pretty well known quantity. The downside is that getting it to work reliably and in a decent state of tune is not going to be the cheapest thing, and it was never really designed to be bigger than 1400cc. |
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Volvo B5254 I absolutely love the sound of 5-cylinder engines, and swore that I would fit one to my next kit project. The Volvo engine from the 850 is the best option for this, as it is relatively cheaply available, and also quite light for what it is. Whilst it is fairly prevalent in turbo-charged form, it can also run normally-aspirated, and in this configuration can be made to rev quite hard. The downside is that it is obviously quite a big engine, and whilst possible, isn't going to be that cheap to tune it. Also it might actually be too powerful for what I want to achieve! |
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Honda F20 or B16 I'm a bit of a Honda fanboy really. I previously had a CRX with a very sweet 1600 VTEC engine in it, and this engine would be just about perfect, but unfortunately it near enough impossible to use in a front-engine rear-drive configuration, as the crank spins "the wrong way" to mate it to any of the common RWD gearboxes. There is also the S2000 engine, which is natively a RWD car, and produces more than enough power as standard, but this is again a physically large engine, particularly in height, which makes fitting one under a bonnet quite tricky (without cutting holes in it, which I really don't want to do). |
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Ford Zetec E The Zetec engine first appeared in the early 90s, and has been fitted to a wide range of Ford cars for over 10 years. It is widely used in kit car circles, so plenty of knowledge and tuning options, and it is cheap and makes decent power fairly easily. On the downside, it is quite heavy as it is a cast iron block, and not particularly modern engine technology. |
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Ford Duratec HE The "Duratec" (this name has been used to refer to most Ford engines since the first one, the HE, appeared) has emerged as the successor to the Zetec. Designed in conjunction with Mazda, it is becoming more commonly used in kit cars, and it sort of an updated version of it. It has an alloy block, and again there are plenty of tuning options to make good power quite easily. It seems to be proving to be a strong and reliable engine, and whilst it is quite lightweight, it is also quite large, physically, and reasonably expensive to tune. |
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Ford Sigma / Zetec SE The Sigma (aka Zetec SE) engine has been around for a while, and was developed in conjunction with Yamaha at a time when Ford were struggling along with some old engines, particularly in the smaller engine capacities. It is a physically quite small, lightweight revvy engine, which in its larger capacities can produce a fair amount of power (for its size). In the last few years it has been adopted by a number of the main kit car manufacurers, and there is a reasonable amount of tuning options available for it. It doesn't seem to be as prevalently used in kit cars, but that seems to be slowly changing. |