An Entertaining & Informative Vintage Automobile Internet Magazine


Richard Scaldwell’s Sensational JAP V8-Powered GN Cycle Car

Editors note: In the age-old British tradition of building specials from available components Richard Scaldwell put together this remarkable GN Cycle Car over fifteen years ago. It has been a crowd-pleaser at VSCC and other events ever since. The GN was the forerunner of the well-known Frazer Nash. Most of the photos in this post are courtesy of Stefan Marjoram, who took these images on a journey from England to France this past summer. Also on the trip was the 1905 Darracq 200 HP Land Speed Record Car of Mark Walker covered here earlier, and Duncan Pittaway’s Curtiss OX5 V8-powered Monarch.

  • Richard Scaldwell's  JAP V8-Powered GN Cycle Car
  • JAP V8-powered GN Cycle Car – 200 HP 1905 Darracq – 1913 Monarch.

By Richard Scaldwell:  My GN JAP is constructed around the rebuilt remains of what was originally a belt drive pre-World War I GN V-twin using only original parts and technology which were available in period. Now upgraded to four-speed dog clutch-shifted chain drive like the post war cars; it does however retain a wooden chassis, GN clutch and tiny rear wheel brakes.

What many people find to be the most amazing part of the car is the air cooled V8 JAP engine. It was built towards the end of 1908 as JAP decided to build a range of engines aimed at the budding aeroplane industry. The firm already had a very good knowledge of building engines for motorcycles and industry. John A. Prestwich’s keen interest in early flight made this a perfectly reasonable next step, and both V8 and V4 engines were constructed.

  • Richard Scaldwell's  JAP V8-Powered GN Cycle Car
  •         1908 JAP 305 c.i. (5 litre) V8.

The engine in the GN is one of four known surviving overhead valve JAP V8 engines and is in fact the prototype V8 which was re-acquired by the factory at some point to be kept on display along with a small collection of their most innovative and interesting projects. This collection of engines was still on display after the demise of JAP and their acquisition by Villiers Engineering, and subsequently fell into private hands after the closure of that manufacturer.

As for the others, the Shuttleworth collection has an overhead valve V8, which powered the famous Willows Dirigible airship on its 1910 flight from Bristol to London. The London Science Museum has the JAP monoplane with its side-valve V8 and a partially sectioned overhead valve V8. The Belfast Aero Museum has one in a replica of the first Fergusson flying machine.

Richard Scaldwell's  JAP V8-Powered GN Cycle Car

The car as it exists today still runs tiny 400 x 19 inch wheels and tires, but weighs only 1039 pounds (470Kg) complete, so with the lazy 305 c.i. (5 litre) low-compression engine running quite happily up to 2500 rpm with the high gearing, the performance is quite remarkable.

We have regularly used the car for road trips to the south of France, but have also raced and hill climbed with great success; 37 seconds at Shelsley Walsh is quick by any standards! But the great thing about this car, and one of the greatest pleasures, is the ability to drive to and from events and still be very competitive.

Richard Scaldwell's  JAP V8-Powered GN Cycle Car

Although the original multi-jet JAP carburetor has now been changed to a twin-choke Zenith made for an early Curtiss V8, the engine is almost entirely original and is an extraordinary work of engineering of the period. The original flat-plane crank is one piece and drilled right through the journals and runs in five babbitt (white metal) main bearing shells. The side-by-side one piece rods (more like a racing motorcycle or a GP Bugatti) are assembled by threading them along the crank. Next the big end ball bearings are pressed through the opposite rod into split-ball races which are machined and pinned onto the journals.

The attention to detail and weight saving of the crankshaft present an amazing work of industrial art, but it also makes it extremely delicate and spindly, seeming as much like a beautiful flute as a crank shaft. As it is now well over 100 years old, I have elected to admire it on my library shelf. It has been replaced with a new crank, so as to ensure the safe preservation of the engine in its current competitive life.


Driving the car is of course, like any good GN, an experience to be savored, more like a powerful motorcycle than a car. It is extremely responsive to the throttle and all cornering is conducted sideways because of the solid rear axle, drifting beautifully as it was designed to do. It looks a handful but is really a delightful predictable pussycat!

When I first put the car together in the late 1990s it still had its open auxiliary exhaust ports drilled in the cylinder barrels, so the complete chaos of oil, smoke and flame was quite hilarious. Many period flying magazines had letters from young pilots acclaiming the marvelous engine, but bemoaning the impossibility of flying for more than about 20 minutes. By that time, the oil soaking they received in the propellor wash forced them to descend and mop themselves down! To address the problem and pass modern pre-race inspection, small copper bands now close the drilled barrels and a nice period JAP oil pump is used to run a dry sump lubrication system.


One of the main reasons why the engine is so lovely to look at is the fact that everything, you’d expect to be inside, is actually outside on display. The camshaft is completely exposed (in the vee) with its lever type followers and pushrods. The cam, the rockers and the timing gears are oiled with an oil can before running and seem to be surviving amazingly well. No discernible wear is showing after the many thousands of miles exposed to the road dirt and rain. A quick oil squirt is always entertaining to the inevitable audience that the car attracts…… I like to allow my beautiful wife to do this while I watch the amazement on the faces around!

I made the body loosely based on the first few GN racers which Ron and Archie Nash built in their youth. It has the flavor and feel of these cars, but you can’t tell exactly which one! It certainly captures the excitement of the great cycle cars of the period.


For those of you who have asked, you can watch a short video of Richard running the car up the Prescott Hill Climb during the 2010 La Vie en Bleu event below. The video is courtesy of razorlight.

24 responses to “Richard Scaldwell’s Sensational JAP V8-Powered GN Cycle Car

  1. Vintage racing done right. I’m certain this car is not for the socially shy. Who wouldn’t jockey for camera position as one examines the many mechanical marvels affixed to that quant wooden chassis?

    Thanx for posting! I just wish I could take it for a short cruise around my small hometown. I doubt I could go far with that stream of 40wt dripping from my widely grinning teeth.

  2. Have loved this car for a while, thank you for the informative article highlighting a lot of details I have not had the pleasure of learning about before!

    Does anyone know by chance, what species of wood was used in the rails?

  3. Unbelievable ! All that “primitive” mechanical beauty and it goes ! I have trouble changing spark plugs as I get older and guys like this ….well, as I said, unbelievable. Thanks for the astonished, happy, looking time I got this morning !

  4. That car is just wonderful! I assume some artificial patina was added to certain areas, and it is perfect. I dream of building something like that someday. The late David Thirlby wrote several good books on GN’s and Frazer Nash’s, which you can still find.

    • Richard is a master at it and had this to say about the surface finishes: “The patination and feel of the Jap is not an attempt to fool anyone that it’s the “Real” thing, but it’s what I think the real thing should look like and feel like; just like a well worn antique”.

  5. First of all, it isn’t John A. Prestwich it is James . Second , If you examine the individual Air cooled cylinders, you will see MORE than a similarity to the 500c.c. J.A.P. engine cylinder setup used on earlier J. A P. Motorcycles. THIS SAME SINGLE cylinder setup is utilized on Flat Track Racers with a very light frame (such as the Jackson ROTRAX ) which has been famous for winning races for decades, Another cofiguration of this single and a light frame is used in Scandinavian ICE RACING. A V-TWIN version (same cylinder setup) is used on the CLASSIC MORGAN THREE WHEELER , with a similar chain sprokets/dog clutches shifting setup. Now, of course all one has to do is apply aero engine lightness , to a a multiple cylinder crankcase ,a correct camshaft, crankshaft, INlet carburetion and a quality eight cylinder MAGNETO and you have a Lot of horsepwer available; One JAP cylinder on racing alcohol renders at least 40 H.P. , so IF your “slip-stick ” is handy and by setting the C & D scales, you get at least 40 X 8 = 320 H.P. , more or less. A formidible opponent!!! My statement is simplified ,but Leo Goosen used a Slide Rule , “if you get my drift” Find a picture of an early JAP single and you will see 1/8th of this V-8 engine!!! I used to “Mechanic ” for “55X”, Dick Aurandt, at Ascot Park , —and I also worked for Jerry Fairchild , when younger, So I can attest to the amazing H.P. & torque of JAP engines and their “CLONES”. Many early Motorcycle manufacturers selected the J.A.P. engine. A very early-on design that was good from the “Get Go”!

  6. I acquired an ohv V-twin JAP engine in the early 1980’s which has barrels clearly off the same drawing board as this V-8, sparce finning and beehive valve springs. It had previously been in a motorcycle called “The Shorts Jap” which was built, and/or owned by one Edwin Everett who was someting of a special builder. He died not so long ago and I have been in touch with his daughter. All this probably in Kent, UK, it came as a box of bits, “Found in a Kentish barn”.and Shorts had a factory on the Medway. The bike had no gearbox, belt drive and Triumph type forks with a horizontal spring. I have his drawing of the machine.
    I got the engine running using later parts, I think it dates from 1908, and it is very impressive. The bottom end is like a traditional JAP twin of the era with twin camshafts and miraculous lubrication, barrels like stovepipes with only 5 fins, bore and stroke 85mm. I ran it for several year on a 2-speeder Morgan, the mechanical noise was frightening, fuel consumption low and performance remarkable. It would haul a fairly light Morgan over Newlands pass in the English Lake District in top gear. If you went out at night the barrels glowed red on long climbes. A bit of methanol in the fuel helped. Its currently resting because the inlet manifold castings are crumbling and there are repeated cracks between the valve seats. There is no removable cylinder head, you have to grope up the bore to grind in the valves like some Bentleys.

  7. I Love this car! Add the fact that it’s not just driven, but RACED, makes it 1000 times cooler. I’d seen pictures of the car before, but did not know the details. Thanks for sharing the pics and video.

  8. Hi Gentlemen. Thanks a lot for the article, I found out some new references. Being a modeler by ages, from a whyle I’m playing with the idea of to scratchbuild a 1/12model of this masterwork. May someone help me with sizes comparisons? Only idea I got of the size of the caris that it run 19 inch rims, but it looks me that it would be bigger that the 3 mtrs I got resizing the car starting by the rim’s size.Any idea? The V twin size also may be a starting poit to achieve a decent size comparison. Thanks a lot for any further dimensional info that I’ll use to start to design my model, regards from Italy!

  9. We are going to fly a replica Harry Ferguson Monoplane in Northern Ireland. It doesn’t look right with a Rotax on the front and really needs a V8 JAP for authenticity. Having identified Richard’s fine example and seen the one at the Old Warden Hangars from the airship I can realistically only get my head around either finding the other 2 that are believed to exist or we have to start fabrication.
    Is anyone is interested in either of these options or possibly proposing any other solutions. We can guarantee BBC coverage if required!


    Northern Ireland

Leave a Reply

Your email address will not be published. Required fields are marked *

Please note: links to other sites are not allowed.