Projects My GN Cycle Car tribute build

Anywhere near Aylmer QC? When I visit friends I'll have to look you up. Good luck with the project! By the way, God's country is actually BC...

 

Hello, Zig!​

One of the best cycle-cars on steroids you choose as inspiration!

Probably that exact replica couldn't be built in any case, so you should build what you like and what you can – that would be your automobile built by yourself for yourself!

Just to say a few issues that you could solve or avoid if necessary:

1. All G.N. automobiles had quite a long chassis, from the fist cycle-cars to later special sport/racing versions; so, you could follow original wheelbase and get better proportions - as original has;
2. Body of G.N. JAP V-8 is minimalistic but cute and elegant: it seems that you are on a good way to have that, just take attention for long wheelbase, if you didn't until now (hard to see from photographed sketches); rear part of the body is small, because it does not have any role – just to partly cover transmission;
3. Front and rear suspension with quarter elliptic springs are quite a trade-mark for all G.N. cycle-cars and F.N. automobiles; it would be good if you could replicate such system, but if you can't - then "camouflage" in some way suspension that you make;
4. The same situation is with chain/sprocket transmission that is visible, but very difficult to replicate; it could be built in the UK by order, but probably would be quite expensive; there could be done some "cheating" - using ordinary automobile live-axle as trans-axle (jack-axle) under the seat, shortened a lot and then use 3-4 completes of chain/sprockets to the rear dead-axle as for go-karts (function of differential would be lost);
5. finally - visible V-8 air-cooled engine is the most noticeable signifying factor! I like old American flat-head engines, both in-line-six and V-8, but they shouldn't look alike near original; even OHV or OHC would look better, like mentioned ROVER V-8 3500 and less known TRIUMPH STAG V-8 3000;

I am not sure if they could easily and cheaply be bought in America, so you would use what you have and still have a cute special automobile, of own design and construction.
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Only V-8 air-cooled automobile engine that I know is from TATRA, Czechoslovakian automobiles, made from after the WW2 up to eighties! There are two versions, older one from model 603, with 2.5 litre and single camshaft between cylinders as in many American cars, that have something more than 100 HP, depending on a variant. Newer engines are from model 613 with 3.5 litres, double OHC (a pair over each bank of cylinders) and power from 160 HP up to 200 HP, depending on a version. Smaller engines have separate cylinder heads and look better. Both engine types are covered by tin shields and turbines for cooling, but without that, they look wonderful. I saw them “nude” at a workbench in Belgrade where my friend worked in service for SKODA and TATRA automobiles. I am not sure if they would work well without forced cooling, but for racing probably they could be good, having engine open in front. Additional reservoir for oil and bigger radiator/cooler for oil should help. Maybe they still could be found for sale in the Czechs Republic or Slovakia, but the issue is transporting it to the USA...










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For a street-legal variant, you could check with guys from hot-rod and street-rod or LOCOST circles, in your state (as I know there is not the same rules and standards for the entire USA). Probably that it would be easier to attested and registered it as reconstruction: using parts of chassis with printed numbers and proper title from some older car.

Happy, jolly and successful designing, building and driving!

Regards,
Zoran​

 

P.S.: my correction - on "your" G.N. JAP V8 - chain transmission isn't visible, so one problem less!
Z.

 

Yes, we're about 50 kms north of Alymer. BC is beautiful. Was in Vancouver a few weeks back.

 

Hi Zoran. I've seen many of your posts in the cycle cart thread. Thanks for the info. Without any really good photos, I've scaled what I could based on the rim size and tire used. Best I could determine the wheel base is 100", but I've already extended it at the front to approx 103.5" (2629 mm). I still may extend it further at the rear, but not sure yet. One concern was the short length of my drive shaft which at the moment will be approximately 18" (457 mm). I will be reusing the semi-elliptical springs from the Model A axles, but I will cut them into quarter ellipticals. I will also use friction shocks. Still debating whether I should switch to hydraulic brakes. I'll be using a modern 5 speed (Borg-Warner/Tremec T5) mated to the flathead, but I may add a linkage to keep the shifter on the outside like they were in the day. Using the air cooled Tatra would be the bees knees, but doing so would be so much more complicated as there is nothing here in NA that I'm aware of. I've seen a pic of their air cooled diesel in a rat rod, but the large cooling fan and associated ducting really kills the look IMHO.

 

I got goosebumps a little bit when I opened this thread, as I can very confidently say that Richard's car, is my top personal favorite of any car. Something about that style, and just the amount of fun he seems to have blasting around in it just gets me every time I see it. Cars like the Jap GN, the Beast of Turin, and just cyclecars and Edwardian/ Brooklands era speedsters/ race cars are really what got me interested in cars at a young age so maybe im a little biased.

Absolutely subscribed! cant wait to see it progress

 

Lol. I just watched a few vids on the Beast of Turin. I'm just mesmerized by sound of that fire breathing engine. A big part of what Richard did was getting it to look like a 100 year old automobile. That seems to be another art in itself.

 

Great thread! Nothing like a low riding speedsters and cyclecars! I have several Roadsters including my 32 but nothing compares to my Morgan 3 Wheeler.....”The closest thing to flying without leaving the ground! Albert Ball WWI British Fighter Pilot




Todd
High Noon Speed Shop

 

I look like a monkey sitting on top of a foot ball on my Sportster (I like the Mr. Potato Head phrase). Any of us over six feet all have that issue....

Sent from my Moto Z (2) using The H.A.M.B. mobile app

 

There is, of course, the other air-cooled V8 engine:

Magirus-Deutz diesel, around 13 litres and relatively lightweight for a heavy-commercial engine. The basic design dates from c.1955, but minus its cooling tins it could have a rather Edwardian-monstrosity character, quite in keeping with a build that is all about extreme scale contrasts.

As for sound, if you've ever visited Greece you may have encountered the Magirus-Deutz-V8-powered buses operating in Athens. I don't know if they are still in service: I heard them first in the late '70s and then in the mid-'90s. I've never heard buses with a nicer sound.

 

Some slight alterations to the cockpit opening. I started thinking about steering last night and after some checking I needed to open up the cockpit to move the steering wheel further away from me and to allow some clearance between it and the body. Now the opening more closely resembles that on the GN. That gives me roughly 21" from my shoulder joint to the position on the wheel. To accommodate a 20" x 20" typical flathead radiator, I need to keep the tail section approximately where it is if I mount the radiator vertically. The dimensions of the body from the front to the cockpit closely resemble that of the GN probably within a few inches. Top front of cowl will be just over 36" high with 6.5" of ground clearance, with top of cockpit and tail section around 42". I really want to firm up the layout so I can actually start some fabbing. Picking up my bell hsg, oil pan adapter, and trans adapter on Saturday. Any thoughts about using the Model A steering column with integral box?

 

There is the possibility of coupling 2 Wisconsin V4’s off a welder or pump. Saw 1 for sale just the other day here in BC

 

Lol. I had looked at those early on. They are very heavy SOB's. Sticking with the flathead.

 

Not too much progress recently. Had to move the engine upwards to gain a little more ground clearance (5" with the clean out bolts and nuts) and to have better alignment with rear pinion (approx 3.5 degrees). With stk intake and carb, I will just have a couple of inches of clearance under the bonnet to the top of the carb. It was difficult to find some drawings on line of the flathead, but I managed to find one. I also moved the driver's seat rearwards another two inches just give give me a little more elbow and leg room. Still not sure about the shape of the tail section, but next is to do a top view to ensure I have frame width nailed down which previously I sketched out at 28".

 

I like seeing someone actually drafting instead of doing it on the computer. I will be watching your build.

 

Doing some more layout of front suspension, and it seems my Model A front spring when cut in half matches very closely with that on the GN JAP (approx 15" long) and 2" drop in static position. According to theory one should use a shackle, but the GN JAP and most cars from that era seem not to use one. Not sure how that works as their is no "give" when flexing. I still need to figure out what the spring defection will be with a loaded chassis to properly design the bracket geometry. On another note, and for the first time, I just noticed that they may have used some type of steel subframe at some point as some pics show a type of structure below and inside the wooden frame rails. Strange indeed.

 

Might be a belly pan to catch oil and other fluids.

 

Go back and look at the front suspension on the GNs a bit closer. there are two springs or a spring and linkage piece on each side working like a 4 bar type linkage to the axle. That keeps the axle from twisting and holds the caster alignment on the front axle.

 

That makes sense. I recall reading something about a mod to minimize the oil "spillage" from the total loss oiling system, but it appears he installed some kind of "direct" oil injection system, but the belly pan perhaps is a track requirement for some events.

 

Agree, but all four points are fixed, with lower spring acting as part of the four link, so I'm guessing the top "link" is designed to flex being that it looks relatively thin, but who am I. I may replace that top link with a friction shock, but not quite sure yet.
Continuing with the layout, and it seems the front engine mount off the water pump will be about 4.5" above the frame rail which doesn't make sense to me when I look at typical flathead installations which show the water pump feet fairly close to the frame rails. The only thing that comes to mind is either I have some dimensions screwed up, or my frame rails are much closer to the ground than that of a typical hot rod. Rubber isolator is the small rectangle above and to the left of the top corner of the oil pan. I'm just roughly laying in the bracketry for the front axle attachment points and the motor mount. Next will be trans mount and rear spring supports and axle mount, then on to the top view.

 

Actually, in this pic you can see the upper "link" broke and was welded back together. Hmmm...

 

Seems a friction shock was added when this pic was taken. Interesting.

 

I have a picture of a Miller 4-bar quarter elliptic front suspension, and a home built Crosley powered mini-Miller replica with a spring and link 4-bar front and rear.


Some friction shocks as well. The cord wrapped spring is a nice touch.

 

Maybe this pictures are helpful for you ,they are from 3 different Curtiss powered GN/Frazer Nash
With moving the friction damper forward or backward you can adjust the inclination of the kingpin and so you will find a compromise between straight spillway and steering force.For that the friction damper has a slot hole on the side which is fixed to the chassis.

 

Thanks. Great pics. I still kinda wonder how the geometry works with these kinds of setups, but as @64 DODGE 440 pointed out, it is effectively a 4-link design. I'm guessing there might be slight changes in chamber as the suspension moves up and down, but I'll do a bit of a layout just to satisfy myself.
I like the idea of being able to adjust the suspension camber with an adjustable friction shock mount. I also want to be able to adjust my ride height as well in case I screw up. I actually like the reverse front rake of the 3D model in my avatar which is only a couple of degrees. I will probably copy the idea of clamping around the front axle to mount the springs/ shocks as I'm not sure if the legal authorities will permit mods to axles. That won't be so easy on the rear axle as the tubes are tapered. Something I need to confirm sooner rather than later.

 

Are you confusing camber with caster?

 

This is a great project! Can't wait to see it come together.

 

Beat me to it.
If the working length of the spring and the upper link are close to the same the caster should not change, especially with the relatively small ride height variations involved.
On the subject of attaching the suspension to the axle, could brackets not be made that would attach to the original spring perches? Building a bracket that would clamp to an I beam section axle would be difficult as opposed to the examples in the photographs with tubular axles. Depending on the width of the frame a bracket attached to the spring perch boss would most likely have to be offset inwards from the boss somewhat.

Roo

 

D'oh. Yes, I should know better as my lifted truck has zero caster which makes for lively driving on the highway.

 

Is there ever an instance where a change in caster as the axle compresses is good? Would more caster as the front end dives be good? Or less? This could be done very easily with a spring on top (or bottom) and a longer link for the other bar.