13 replies to this topic

[ceesvdelst]

I watch a fair amount of European hill climb racing, or Berg Cup in Germany and other places like Switzerland and Austria and have noticed a recent (last few years maybe) trend of drivers in the Group H small classes (old style cars like Polo, Golf, Kadett, Nova etc maybe 1600 or lower), using performance motorcycle cylinder heads on their cars. 

 

I am presuming this is to allow better breathing and perhaps also the use of the entire bike injection system rather than a bespoke setup using a set of carbs or a new injection system. Obviously this breathing suits smaller, revvy engines  that match a bike engine. And then also the bottom end can be further lightened and built to match this increased rev range. 

 

I have never seen this anywhere else in motorsport much?

 

I am aware that a lot of guys use Minichberger to do this, a specialised VW tuner really, but also involved in other cars.

 

How on earth do they get the heads to match the blocks of the car engines?  They must be far narrower and more tiny compared to a car block?  A bike engine is usually very narrow and very thin in comparison?  Plus a lot of bikes run camchains internally I think?  Must be a hell of an undertaking.

Does anyone know any other motorsport where engines use a mixture of bike and car tech together?

 

 

 

 

[gruntguru]

I have seen this done on Minis (old A series engines) where a certain BMW head is popular. In this case the advantages are obvious. The standard head is pushrod, 2 valve and with only 5 ports (3 siamesed). The bottom end is obviously lower revving than the bike engine which seems like a mismatch but the stroke is longer giving greater displacement and therefore similar airflow requirements.

 

Not sure how they adapt these things. Clearly the chosen cylinder head will need to have similar bore spacing. Fasteners will need to be re-located - probably in the head rather than the block - aluminium is easier to work with and the load path (compressive) in the head is more forgiving than the tensile path in the block. No doubt water passages through the face will need to be welded up and re-machined to match the block - same for oil galleries and drains.

[Fatgadget]

http://www.16vminicl...read.php?t=7850

[ceesvdelst]

Interesting stuff.

 

The ones Ia have seen mainly in Germany are smaller engines, usually 1600, but all makes, VW, Opel, peugeot, Toyota. All using bike heads to really pep up an existing lump. The mods allowed are unlimited engine wise leading to screaming engines, extreme aero, but very trick, often beautifully engineered at home cars. 

 

I was aware of numerous attempts to do this with Mini's, but wondered if any UK hillclimb folk have tried it, sadly the interest in proper cars rather than single-seaters in the UK is limited in comparison to Europe where in certain series they are dominant numbers wise. 

[Bloggsworth]

Vanwall?

[Kelpiecross]

 An interesting conversion was a 2.4 XK Jag head on a Mini.  Turns out that it was a specially-made block -  so it amounted to a four-cylinder Jag  engine.  Oddly enough  Jag themselves in 1948, when the new XK engine came out,  had a four cylinder version of the XK engine they called the XK100.

 

Vanwall?

 

 Based on the design of four  Norton "Double Knocker"  cylinders, I think. 

[djr900]

 An interesting conversion was a 2.4 XK Jag head on a Mini.  Turns out that it was a specially-made block -  so it amounted to a four-cylinder Jag  engine.  Oddly enough  Jag themselves in 1948, when the new XK engine came out,  had a four cylinder version of the XK engine they called the XK100.

 

 

 Based on the design of four  Norton "Double Knocker"  cylinders, I think. 

 

or was it - 4 x Manx Norton  ?  

I am not sure either 

[Kelpiecross]

or was it - 4 x Manx Norton  ?  

I am not sure either 

 

 I thought a Manx and a Double Knocker were the same thing? 

[Charlieman]

 I thought a Manx and a Double Knocker were the same thing? 

See:

https://forums.autos...es-in-500cc-f3/

 

Tony Vandervell had business connections with Norton, so when he wished to build a GP car engine he had access to Norton technicians. The cylinder diameter of the 500cc Norton Manx and Vanwall 2.0 litre GP were similar, thus making it easy in retrospect to add one plus one to make two. However the fuel composition* and engine rev range of the engines differed sufficiently that the GP cylinder head was much more than four bike heads joined together with water cooling.

 

* The first Vanwall GP cars ran on a dope fuel mix but races were long distance. Bikes ran a different dope mix for shorter races. Later Vanwalls ran on Avgas.

[ceesvdelst]

There was a bike called a Quantel, it used the basics of a twin cylinder Norton, and also lots of bits from a DFV!!!  Was a beast of a thing and a dominant bike in twin cylinder racing.

 

I think the Aprilia 2002 GP bike also had some very strong links with Consworth at the time, as it used pneumatic valves and the bore and stroke were very similar to a V10!!  It was an unruly beast too!

 

Odd though that car engines are using bike bits.

 

I know in the 1400 BTRDA rally class, a lot of guys were using bike carbs, but not sure if they were using heads too, maybe not great homologation wise?

[kikiturbo2]

I think it is simple really... those hillclimb cars are mostly homebuilt low budget cars, and often in such low cc categories.. so they use existing gearboxes (with dogbox internals of course) so have to use the stock block. Those are also often old cars so to improve the breathing sticking on a cheap bike head is not such a bad idea..

[ceesvdelst]

I realise that kiki

 

What amazes me is how few other people in all sorts of racing have not really done it.

 

I would also suggest that you watch some of it, those cars are certainly NOT low budget!!

 

IN comparison with big league stuff yes, but most are developed over many years and honed to perfection by a dedicated group of tuners and drivers. They are very serious bits of kit. 

[kikiturbo2]

Well, an even cheaper, and better solution is just to use complete bike engine... you get a 200 hp/litre engine and dogbox in one cheap package.... just your car really needs to be a mid engine prototype with chain drive.. No wonder Radical started like that..

In reality you need to be a good engineer to fit a bike head to a car engine and do it properly.. so, a better developed OE head might just be a good idea at that point. All in al, I think that building your own engine is about the worst way to start building a race car..

 

What I have seen in central european hillclimb is that most cost effective way to good speed is just to buy a older well developed circuit car and try to learn to drive it. HIllclimbs are so short that a WTCC 2 litre car (souper touring or whatever it is called) will do years of hillclimbs without a need for an engine refresh... and you can get them somewhat cheap on the market.. If you have big cohones then a formula renault or something like that.. So homebuilt is not always the most cost effective way...

[ceesvdelst]

I think you might be simplifying things a bit there.

 

there is a rigid cc based class system, so a lot of the bike engined cars are in sort of 1600cc or less classes, makes sense due to the engine size of something like a Hayabusa top end, its induction systems and mating to a race spec old style block.

 

The cars re not circuit cars, you are talking 70/80/90's shape Kadett's, Polo's, Golfs, Scirroccos with very special engines, some using interesting aero ideas, and seemingly they had exhausted the existing N/A tuning and found a new way to ever higher revs, some of these guys are revving fairly old style blocks to over 10,000 rpm.

 

It is all based on the old Group H type racing really.