“MIKRUS”TOURIST CAR | MODEL CONSTRUCTION

Practice Amateur autocostruzione, including my personal, shows that wagon layout with the use of wheels with tyre size 5X10 (motorized С3А) provides a very convenient and rational design of little micro-car. That is my “Mikrus”. It is stable, holds the road well, speeds up to 90 km/h the engine under the driver seat and the passenger increases the useful volume, makes the body more succinct. The interior is spacious, seats are arranged, which is convenient for overnight stay and rest. One cannot underestimate the capacious trunk: there is, for example, you can install a baby carriage, not looking. In the right corner of the trunk easy to install the battery, and in the bottom of the fuel tank from the car ZAZ-966. Made for the base, they both increase the load on the rear axle, which improves traction of the drive wheels. And convenient access to the engine: the hood folds with the seat, driver and passenger; repairing and explore without leaving the salon. For transportation of bulky goods — TV, washing machine, fridge — enough to move the back seat forward and fold the seatback or delete it. Get a small truck.

Engine “Micros” — from motorcycle K-750. Held a little refinement to increase its power. Stripped and polished suction channels in the cylinders, also machined on the outside diameter of the plate inlet valves. The engine is equipped with two carb-TO-125П and paper air filter of the car “the Zhiguli”. This improved throttle response and increased engine power from 26 to 30 HP the car has got good acceleration. The intersection I’m going faster than “Zaporozhets”, and on the long climbs often surely going to overtake. Fuel is supplied to fuel pump (from a car “Zhiguli”); a drive shaft generator — mechanical. Having a low height, the engine is well linked.

Cooling air, by a fan. To install it in the front axle crankshaft tapped M20X1,5 screwed and the platen of the fan impeller, and put the gear to start the engine with the electric starter. Used gear from the main gear motorized С3А (reverse), the ratio is 1 : 8.

I in detail don’t stop at design engine cooling and coupling the gearbox to the engine — there is no much innovation. However, if we talk about further improvements, instead of one centrifugal fan can produce two axial and continued to impose their shaft pulley and the crown to run the electric starter. And the gearbox is good to use a motorcycle MT-9 Dnepr: the car will have a reverse. It is also useful to set the engine on the frame on the pillows, and not on the rubber bushings, as is done in “Microse”.

The vehicle frame is welded of seamless pipes — steel tubes, thin-walled, Ø 70 mm and 40 mm. Two of them, Ø 70 mm — and the role of the main carrier element. At the ends welded to the shoes. These are mounted front and rear axles (motorized С3А) and the sub frame.

Front axle equipped with drum brakes. Was negativley new brake drums with discs attachment of the wheels increased track up to 1180 mm. brakes-hydraulic cylinders taken from the ZAZ-965. The bridge is reinforced shock absorbers of the motorcycle “Panonia”. For fixing serve as the new lower eyelet, fit the rubber grommet shock absorbers “Zaporozhets”. Upper bushing — tough, machined from PTFE. Both studs and shock absorbers Ø 12 mm. To the upper beam of the front axle welded to a bracket on the axis of which swings on bearings No. 203 a pendulum (similar to the design described in the “M-K” № 5, 1970).

The Car “Mikrus”.

Installation sub-frame:

1 — frame vehicle, 2 — under engine frame.

The differential Assembly:

1 — welded gearbox housing, 2 — connecting shaft sleeve.

The wheel suspension.

Rear axle (front axle used from SZA) is fixed to the frame, like the front, studs М14Х1.5, reinforced shock absorbers “anomia” with a new lower eyelets. This gives a homogeneous suspension.

The bridge in the block with gear main gear is subjected to a radical alteration. From the hub tubes cut and welded the brackets with the holes under the finger attachment to the levers. The ends of the brackets of the engine is also cropped; instead, they welded a sleeve, which has two ball bearing No. 203. (Taken closed bearings, especially the outer, or set of felt rings impregnated with oil.) Parts are welded in specially made jigs. To the upper and lower ball-whom the bridge is welded (at the place) brackets, which two pins M12X1,25 fixed gear of the main transmission. To preserve the locking bolt of the lower torsion bar mount gear is shifted to the right by 50 mm from the longitudinal axis of the vehicle. Therefore, the drive axles are different lengths: 310 mm right, left 360 mm. Both of them are completely homemade, but the same axle ZAZ-965. Redone and the wheel shaft, cut off the plug and welded a new cross — from cross ZAZ-965.

Axle equipped with drum brakes with hydraulic drive.

The driveshaft also homemade: seamless steel pipe Ø 45 mm. It consists of two crosspieces from ZAZ-965 and rubber couplings.

Reducer main transmission made using gears rear axle ZAZ-965. The gear wheel with helical teeth, ratio of 4.63 : 1 (37 X 8 teeth). The differential bevel, with two satellites. The gear case welded.

The opportunity to cast its light alloy I had, and when processing the cast body one lathe will not do. Welded the same body, though heavier, but easier to manufacture.

From seamless steel pipe Ø190 mm sliced ring height 100 mm (blank). It is machined on its outer diameter and both sides othertown; welded ring flanges. To the body welded two sleeves to connect the gearbox with the rear axle. Exactly in the center, perpendicular to the forming, welded to another bushing for the neck of the housing shaft pinion gear.

A sequence of further works. In the center of the opposite wall electric grab boss 0 70 mm — for installation of the housing and the lathe, face piercing holes, the neck, and then ring-flanges welded to the hull, butt, removing the uncertainty of electric welding. Face piercing holes in the casing at the inner diameter to the wall thickness of 4-5 mm. For tubes of accumulation and drain the oil cut thread М16ХІ.5 and М14Х1.5, respectively.

The leading gear is made with the shaft diameter of 25 ± 0.1 mm. Therefore, the shaft is applied a layer of chrome, and then grind for landing bearings. The first of them back, No. 7205, roller, tapered. It takes the main axial and radial loads. The other two — ball, No. 205, for radial loads. Front and second rear bearings are fixed in the glass retaining ring. The gap is adjustable race rear mounting flange of the propeller shaft.

To install side clearance gear are two adjustment nuts, which are fixed stoppers and pressed a flange with a rubber protective cover the axle shaft. Side clearance between the teeth leading and driven gears must be within 0.08—0.22 mm. the bearing Housings of the differential adjusting nuts taken ready-made, are attached to the housing cover bolts. Details application prefabrication simplifies the manufacture of the gearbox and, most importantly, increases its reliability and durability.

The body of duralumin panels 1.5 mm thick. the Basis of it serves as a frame to which is attached by bolts M8 frame, riveted corners of duralumin 45X45 mm. For the relief of the frame in the corners of the welded holes Ø 18 mm.

The bracket of the gearbox.

The suspension arm.

Rear axle.

The jointing of panels is reinforced with overlays. The nose and tail rounded frame is enhanced with a scarf sheet of aluminum with a thickness of 4 mm. the surface of the body is thoroughly cleaned, irregularities embedded putty on epoxy resin.

Taken from the windshield of the car “Moskvich-412”. For curved glass frame from dural area with panels in the corners in the form of glass strips with a thickness of 1.5 mm of aluminum and duralumin in two layers! Frame covered with fiberglass epoxy resin. The design of it was hard.

The profile of the front part is made also by pasting strips of aluminium with a thickness of 1 mm and of glass epoxy resin.

Seat foam rubber and foam rubber. To reduce the noise level in the car inside, glued felt, the engine hood is lined with foam on the inside and outside.

The variant of the car and hard top, but the preferred installation is easily removable awning as made on the “Microse”.

Fans, who will undertake the construction of similar micro-car, only, I suggest to replace the steering knuckles (hub) of the front axle. Installation of fists with ball joint (front axle ZAZ-966) the great difficulty. Another option is to make a new bridge using the same details. Ball joints are sealed and are more durable, much stronger compared to the same host bridge motorized С3А. They will improve ride quality inputs to directly affect reliability.

A. STREMOUSOV, locksmith, Orenburg

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