Suzuki LC10 engine#LC10

File:Suzuki Fronte Nialco Race Car 1969.jpg

The engine was first seen in air-cooled form, equipped with three Mikuni VM carburettors, in the 1967 LC10 Suzuki Fronte 360. Displacement was {{convert|356|cc|cuin|abbr=on}}, from a bore and stroke of {{convert|52x56|mm|abbr=on}}.Ozeki, Suzuki Story, p. 28 Originally developing {{Convert|25|PS|kW|1|abbr=on}}, a {{Convert|36|PS|kW|1|abbr=on}} SS version soon appeared, with a stunning {{cvt|101.1|PS/L|hp/CID}}.Ozeki, Suzuki Story, pp. 34-35 For the conventionally laid out Fronte Van, Estate, and Custom a single carburettor version was used.{{cite book | title = 360cc: Nippon 軽自動車 Memorial 1950→1975 |trans-title=Nippon Kei Car Memorial 1950-1975 | language = Japanese | publisher = Yaesu Publishing | year = 2007 | page = 94 | location = Tokyo | isbn = 978-4-86144-083-0 }} Combined with a lower compression ratio of 6.8:1, this meant a max power of {{convert|25|PS|kW|1|abbr=on}}.{{cite journal | journal = 月刊自動車 [The Motor Monthly] | title = New Fronte (フロンテ) 360 | language = Japanese | page = 21 | volume = 11 | number = 8 |date=August 1969 | id = 3439 }} For 1971, the LC10 engine received Suzuki's new self-lubricating "CCIS" system (Cylinder Crank Injection and Selmix).

In 1969, Japanese racing car manufacturer Nialco built a single-seater called the RQ which utilized the triple-carb LC10 engine and competed in the RQ ("Racing Quarterly") Minicar Racing Tournament.Ozeki, Suzuki Story, pp. 48–50 Their best result was a fourth in the 1969 meet at Fuji, with Kikuo Kaira (future co-founder of Tommy Kaira) at the wheel.{{cite web | url = http://www.jaf.or.jp/CGI/msports/results/race/result.cgi?race_id=1969000163 | title = 競技結果: R.Q. ミニカーレース大会 |trans-title=Competition Results: RQ Minicar Racing Tournament | language = Japanese | publisher = Japan Automobile Federation | accessdate = 2011-11-11 }}

Applications:

• 1967.04–1970.11 Suzuki Fronte 360
• 1970.11–1973.07 Suzuki Fronte LC10 II ("Sting Ray" Fronte)
• 1969.01–1972.03 Suzuki Fronte Van/Estate/Custom LS10/11, {{Convert|25|PS|kW|1|abbr=on}}
• 1970.08–1971 Suzuki Fronte Hi-Custom LS11, {{Convert|30|PS|kW|1|abbr=on}}

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File:Suzuki LC10W Engine 001.JPG

In May 1971, as kei cars were becoming more and more sophisticated, a water-cooled version was presented.Nippon Kei Car Memorial, p. 79 The air-cooled versions were soon relegated to use only in the cheapest versions,Suzuki New Fronte (catalog), Suzuki Motor Corporation: 1972, p. 4 and disappeared entirely after 1973 as emissions standards became more stringent. The watercooled versions also had slightly better weight distribution (38/62 versus 37.5/62.5), due to the radiator being mounted up front.Ozeki, Suzuki Story, p. 56 This, the LC10W, was the only engine ever to be installed in the iconic Suzuki Fronte Coupé, whether in domestic or export market cars.{{cite web | last = Schaefers | first = Martin | title = History of Suzuki Kei Jidosha | publisher = Far East Auto Literature | url = http://www.xs4all.nl/~mjs/suzukik.html | accessdate = 2010-11-07 }} The new 1973-1976 "oval shell" Fronte received the new LC20 chassis code but retained the LC10W engine code. In May/June 1974, power outputs dropped as the engine received additional emissions cleaning equipment. A version using Suzuki's Twin Catalyst ("TC") system was announced on the Fronte LC20 in May 1976 but only 61 examples were built.{{cite web | url = https://ameblo.jp/5-dice/entry-12704797096.html | archive-url = https://web.archive.org/web/20250307054047/https://ameblo.jp/5-dice/entry-12704797096.html | archive-date = 2025-03-07 | title = フロンテクーペ生産台数の考察.2　セダンとクーペ。 | trans-title = Consideration of Fronte Coupé production numbers: 2. Sedans and Coupés | language = ja | work = 黒いダイスが俺を呼ぶ | date = 2021-10-18 }}

From 1973 the LC10W engines also received Suzuki's SRIS (Suzuki Recycle Injection System), a method for lowering visible exhaust smoke by collecting and burning residual oil/gas lying in the bottom of the crank chambers. This was first seen on the Suzuki GT750, GT550, and GT380 motorcycles. In an effort to reduce CO, HC, and NO_x emissions, the EPIC (Exhaust Port Ignition Cleaner) system was also installed.Ozeki, Suzuki Story, pp. 58–59

Applications:

• 1971.05–1973.07 Suzuki Fronte LC10 W
• 1971.09–1976 Suzuki Fronte Coupé
• 1973–1976.05 Suzuki Fronte LC20

Specifications

A bored-out version {{convert|60x56|mm|abbr=on}} of the air-cooled LC10, called the LC50 in reference to its near half-litre displacement (actually {{convert|475|cc|cuin|abbr=on}}) appeared in January 1969.Ozeki, Suzuki Story, p. 57 In street applications, this engine was only for export, and was only ever made with air cooling. Like its smaller brethren, the LC50 breathed through triple carburettors.

Water-cooled {{convert|475|cc|abbr=on}} triples were built for racing purposes, producing {{convert|60|PS|kW|1|abbr=on}} at 9,000 rpm. These took part in the JAF Grand Prix Formula Junior class as well as "MR" (Minicar Racing) meets. Thus equipped, the Can-Am style Fronte RF with Mitsuo Itoh at the helm took the victory at the 1970 "Junior Seven Challenge Cup" race, held at Fuji International Speedway, with an average speed of {{convert|130.9|km/h|mph|abbr=on}}.{{Cite web | title = Motorsports Results: Junior Seven Challenge Cup Race 1970 | publisher = Japan Automobile Federation | url = http://www.jaf.or.jp/CGI/msports/results/n-race/detail-result.cgi?race_id=1699&window_flg=1 | accessdate = 2010-11-08 }}

• 1969.01–1970 Suzuki Fronte 500
• 1970–1973.07 Suzuki Fronte 500/LC50 ("Sting Ray")

In response to the changed Kei car regulations taking effect on January 1, 1976, Suzuki developed a bored out and cleaner version of the LC10W, featuring Suzuki TC (Twin Catalyst, a double muffler in which uncombusted fuel was burned) emissions equipment. The watercooled {{convert|443|cc|cuin|abbr=on}} engine's bore was {{convert|58|mm|abbr=on}}, while retaining the {{convert|56|mm|abbr=on}} stroke. Sometime between 1973 and 1976 Suzuki had changed their system of naming engines, so this engine became the T4A. This meant that it was the first ("A") engine with a 0.4-litre displacement. The T4A was fairly short-lived (only used in the Fronte 7-S for a little over two years), and was soon replaced by an unrelated "full size" (550 cc) engine called the T5A/T5B. The emissions strangled T4A put out {{Convert|25|PS|kW|1|abbr=on}} at 4,500 rpm in its final "TC53" form: specific power was 54% of what a 1972 Fronte GT had managed.

• 1976.05–1977.10 Suzuki Fronte 7-S SS10/SS12

• List of Suzuki engines

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LC10

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