- 4 cylinders, 2445 cc / 149 ci
- 92×92 mm bore and stroke, giving 1:1 bore/stroke ratio (“square” engine)
- aluminum alloy open-deck block with replaceable cast iron wet-liners
- aluminum alloy pistons with floating pins and two chrome plated compression rings
- aluminum alloy reverse-flow cylinder head with cermet valve guides & high-strength cast iron valve seats
- aluminum alloy intake manifold, 2-bbl carburetor
- overhead valves, cam-in-block, pushrod valve-train, solid lifters
- two compression ratios available – 8.2:1 (model 24D) or 6.7:1 (model 2401)
- max power output: 95 net hp / 110 SAE gross hp @ 4400 RPM (high compression)
- max torque output: 186 N·m / 137.4 ft·lb @ 2200…2400 RPM (high compression)
- very flat torque curve between 1500 and 3500 RPM
The absolute majority of GAZ-24 Volga cars were equipped with the four-cylinder gasoline engine, which was produced by Zavolzhsky motor plant (ZMZ) and available in two versions – the 24D and the 2401 – that differed only in compression ratio (D does not stand for “Diesel”; the 24D should not to be confused with diesel engines available on the Volga on some foreign markets). The 2401 engine, despite lower performance figures, was by far the most popular of the two, as it could run on lower grade fuel which was both cheaper and more available in remote areas of the country; most of the taxicabs were equipped with this engine as well.
The GAZ-24 Volga’s engine was largely derived from the GAZ-21 Volga’s powerplant, produced from 1957–1970, which itself had been originally developed for the GAZ-56 1.5-ton truck. The GAZ-21 engine also spawned a whole line of engines produced by Ulyanovsk Motor Plant (UMZ) and originally used in UAZ trucks and off-road vehicles.
In turn, the GAZ-24 engine eventually became the basis for the “torch-ignition” 4022.10 (1981–1994; 3 valves per cylinder, lean burn, stratified charge) and the 402.10 (1985–2005; larger exhaust valves, new water pump, “breaker-less” electronic ignition, added emissions control equipment) engines.
Altogether these powerplants form the venerable family of GAZ / ZMZ / UMZ overhead-valve, cam-in-block engines, which soldiered on until mid-2000s (a 2.9-liter version with EFI is still produced by UMZ and used in modern GAZ commercial vehicles).
In a nutshell, in its original factory configuration it is a pretty typical low-revving overhead-valve four-cylinder engine of its time, designed & built with ruggedness, durability and ease of repair in mind, but with relatively little care for performance or fuel efficiency.
That formed the basis for a popular myth that it is a low-revving engine by default, which is not true, as its low-revving nature is determined by the factory configuration of camshaft, intake, exhaust, carburetion etc., and not any fundamental limitations of the design itself.
In fact, it is a “square” engine (92×92 mm), and the 2.9 L version is over-square (100×92 mm). Its relatively low max revolutions and ability to deliver peak torque at very low RPM are not inherent features, but rather a result of the deliberate “detuning” by the factory. It was a trade-off for greater longevity, reliability and low-end torque, which was far more desirable in a mass-produced engine.
Racing versions of the Volga pushrod inline-four can safely rev up to 6500 rpm and produce 150 hp or more. Of course, they differ from stock engines as much as a NASCAR pushrod V8 engine differs from a stock pushrod V8. And yes – people did race on these engines, and some still do.
Lightweight aluminum alloy cylinder block (lighter than the much smaller Lada engine cast iron block) was injection-molded – a manufacturing process specifically designed for this engine at Zavolzhsky motor plant in the mid-1960s, heat treated and impregnated with a special resin to fill the pores of the casting. Replaceable wet-type cylinder liners (also called sleeves) were spun-cast from special high-strength alloy cast iron and machined to fit the block. Short dry-liners cast from acid-resistant cast iron were pressed into the upper part of each wet-liner to further improve durability.
During the assembly of the engine the wet-liners were fitted into the block and sandwiched between the copper seal ring at the bottom and the cylinder head gasket at the top. With proper assembly tolerances, this design was mostly trouble free for the whole life of the engine, unless it overheated badly, which could cause cooling agent leaks into the cylinders (wet liner nip clearance is especially important for the correct functioning of this design).
This design was neither cheap nor easy to produce; e.g., the liners had to be manufactured in several different sizes for individual fitment to a particular cylinder block, which was the only way to ensure proper nip clearance for each liner. However, it had a substantial economical effect, as replaceable liners saved a tremendous amount of time, labor and costly machining time during engine rebuilt.
For this reason, almost all Soviet-designed car engines had aluminum blocks since about mid-1950s, as well as many truck engines (UAZ & V8 powered GAZ trucks; ZIL used cast iron blocks with wet liners). No critical corrosion problems, usually associated with aluminum engines with wet-liners, were experienced even when water was used as the cooling agent, which had been the case until 1975 when the cooling system was modified to properly work with antifreeze (today it is strongly not recommended to use water as cooling agent, nonetheless).
Due to light weight, relatively large displacement for the inline-four layout, heavy pistons and lack of balance shafts to smooth it’s shake, the Volga’s engine suffered from inherent more-than-usual amount of vibration, worsened by relatively crude balancing technology used back then. To counter it, the designers employed thick rubber engine mounts, extra-soft coil-spring rear transmission mount (after 1976) and elastic rubber joint in the transmission tail shaft housing (after 1976). In the 1980s, a crankshaft harmonic damper was added to further improve the effect. Yet, the engine still was not as smooth as an inline-six of the same displacement could have been. Severely out-of-tune, or assembled without proper attention to balancing, it could turn the otherwise comfortable Volga into a traveling fatigue machine. If properly tuned, however, it runs reasonably smooth and quiet.
This engine yielded a quick torque rise, with 175+ N·m (130 lbs. ft.) at as low as 1,600…1,700 rpm, and its torque curve was almost flat (±10 N·m) between about 1600 and 3500 RPM. That means that most of its power was available to the driver at very low RPMs, which, combined with an unusually “short” gearing of the rear axle (4.1:1), provided decent acceleration in 0-70 km/h range.
In city driving, little gear shift was involved as 3rd and 4th (direct drive) gears were sufficient for almost any task other than starting from stand-still. After about 3500 RPM, however, the volumetric efficiency of the intake system swiftly deteriorated, determining a rapid drop of the torque curve at this point and leading to anemic acceleration at speeds over 110 km/h (70 mph), at which point it started to feel as though the engine was working too hard.
Powered by this engine, the Volga was by far not a performance car – about 20 second 0-100 km/h and a top speed of just under 150 km/h (100 mph), but at least on par with (or, should I say – as slow as ?), e.g., Chevy Nova with the 153 CID four, or later GM X-bodies powered by the 151 CID “Iron Duke” 4-banger, or late-1970s Chrysler M-Body Dodge Diplomat with the 225 CID Slant-6, delivering slightly better fuel economy than the six. Among the Soviet cars of the epoch, it was just a bit slower than most Lada models or the newer Moskvitch-412 and 2140, but still faster than the veteran Moskvitch-408 or the Zaporozhets.
In the USSR, there were no speed limits for intercity roads until 1976, when a county-wide speed limit was set at 90 km/h / 55 mph. Later, a special 110 km/h / 70 mph speed limit was added for specifically designated highways.
While the Volga was considered gas-thirsty compared to other (smaller) Soviet cars, with engine displacement usually not exceeding 1500 cc, it was actually reasonably fuel efficient for the time and considering it’s size, weight and engine displacement. According to the manufacturer’s specifications, on the highway at steady 80 km/h (50 mph) it consumed creditable 10.5 liter of gas per 100 km (22.4 MPG). Under actual driving conditions, fuel consumption figures were higher, but still decent for a 1500 kg / 3000-pound car with a 2.5 liter engine, not going anywhere beyond 17-18 l/100 km / mid-teens MPG (see the graph). And, considering the fact that gas was ridiculously cheap in the Soviet Union, the Volga more than made up for the fuel it consumed in power, driving comfort and durability.
In the USSR the gas prices for individual motorists during most of the 1970s stayed at 1 rouble per 10 liters of 83 octane AI-93 and 75 kopeks per 10 liters of 76 octane A-76. This is roughly equal to 11 and 9.8 roubles per 1 liter in 2013 roubles, or ¢36.5 and ¢32.5 respectively in 2013 US cents. 1 gallon is equal to 3.78 liters, so that would be $1.38 and $1.23 per gallon in today dollars. Just to remind, in the USA gas was about $2 per gallon in today dollars just before 1973 price shock. Fuel crisis didn’t hit in the USSR until 1978, when the gas prices instantly doubled.
It was a robust engine, easily capable of at least 200,000 – 250,000 km (125 000 – 155,000 miles) before first overhaul, if maintained properly. Gentle driving could extend it’s life to 300,000 – 350,000 km (190,000 – 220,000 miles) or even further, and such mileages were quite common for privately owned cars. The highest recorded mileage before first overhaul was 700,000 km (440,000 miles) by a GAZ-24-04 (station wagon taxicab) with low-compression 2401 engine.
After the first overhaul, the engine could run happily for another 150,000 – 200,000 km at the least, and many of them have had second or even third overhauls, sometimes boasting 1,000,000+ km of total mileage.
Starting in 1973, a V8-powered version was produced in limited numbers, too, mostly for the law enforcement agencies, including the (in)famous KGB.
The V8-powered Volga was designated GAZ-24-24 (24-34 in 1987-93) and nicknamed “the double” or “the catch-up”. Some of these cars indeed were used for pursuit applications, however the vast majority of them lived a more humble existence of an escort vehicle for VIP motorcades.
The aluminum V8 was a regular production engine without any performance upgrades, it had a displacement of 5.53 L / 340 ci and produced 195 DIN hp with one 4-bbl carburetor (possibly slightly more for the later cars which had better flowing cylinder heads derived from GAZ-14 Chayka and, sometimes, two 4-bbl carbs).
It was a later design than the four-cylinder engine, and is often cited as a better one. It was coupled to a 3-speed (in fact, 2-speed with a manually engaged first / low gear) automatic transmission, which dated back to 1950s-vintage designs and never received a proper upgrade (unlike the Chayka automatic transmission that was significantly improved during the transition to GAZ-14, including the addition of a parking pawl and an improved hydraulic control system that allowed the transmission to automatically start in first gear in Drive).
All cars came with body reinforcements, heavy-duty suspension, standard power brakes (four-wheel drums with non-organic linings, except for some late production cars which had disk brakes with 4-piston calipers up front) and power steering (with a separate power cylinder). Some of them also had electric window regulators, air conditioning and other creature comforts usually not found in regular Soviet cars (most such cars were used by high-ranking officers of various security agencies).
GAZ-24-24 managed 0-100 km/h in 13-14 seconds and had a top speed of 170+ km/h (105 mph) – not a muscle car by any means, but absolutely adequate for the job it was built for.
The initial plan was for the “civilian” top-spec version of the Volga to be equipped with a 3.0 L 60° V6 engine, this version being intended mostly for private motorists (as opposed to taxicab service and other vehicle fleets) and export sales.
Several versions of this engine were developed by GAZ (with aluminum or cast iron block) and by late 1960s it was being prepared for mass production at ZMZ. However, for various reasons these plans never came to fruition. Which is a real shame, as this engine was objectively a much better design than the inline-four could ever hope to be.
The primary cause of this project’s failure was the lack of production facilities at ZMZ motor plant – and, less officially, that plant’s administration’s lack of enthusiasm for it. By early 1970s, ZMZ was already producing three completely unrelated families of engines – the inline-four for the Volga, the old side-valve six for the trucks and various versions of the V8. Putting into production yet another completely new design without hampering the existing workflow seemed to be an impossible task.
Regardless, the V6 was still cited to be an ongoing project as of mid-1973, but the 1973 fuel crisis came to be the final nail in the coffin, as, among other things, it led to a dramatic fall in popularity of large-engined cars in Europe, making the V6-powered Volga much less marketable abroad and essentially rendering its production economically unviable.
Later on, GAZ started to equip some production cars with imported V6 engines, mostly as a cheaper and more fuel efficient alternative for the V8.