Drive and RestoreAlfa Romeo JTS engines explained: what JTS means and what to watch for
When the Twin Spark was retired, Alfa Romeo replaced it with JTS: its first petrol engines with direct injection. They powered the 156, GT, 159, Brera and Spider, and they are still common on the road. Here is what JTS means, how the different JTS engines are related (some aren’t related at all), and what to look out for.
What JTS stands for
JTS stands for Jet Thrust Stoichiometric. The key technology is petrol direct injection: fuel is injected straight into the combustion chamber instead of into the intake port. That allows a higher compression ratio and, at light loads, lean running, both of which help efficiency.
The 2.0 JTS (2002–2010)
The first JTS arrived in 2002 in the Alfa Romeo 156. It was developed from the 2.0 Twin Spark, with a cast-iron block and aluminium 16-valve head, and dropped the second spark plug: with direct injection it was no longer needed.
- Displacement: 1,970 cc
- Power: 165 PS (121 kW), 206 Nm
- Variable valve timing on the intake camshaft
- Belt-driven camshafts, plus a balancer-shaft belt
It was fitted to the 156, the GTV and Spider from 2003, and the GT, until the end of production around 2010.
The 1.9 and 2.2 JTS (from 2005)
Despite the name, the 1.9 and 2.2 JTS are different engines. They use a block from General Motors’ Ecotec family, from the period when Fiat and GM cooperated, with Alfa’s own direct-injection head, and their camshafts are chain-driven.
- 1.9 JTS: 1,859 cc, 160 PS
- 2.2 JTS: 2,198 cc, 185 PS
You find them in the 159, Brera and the 2006 Spider.
The 3.2 V6 JTS
The 3.2 V6 JTS in the 159, Brera and Spider has nothing to do with the Busso V6 (see our Busso V6 story). It is derived from GM’s High Feature V6, built by Holden in Australia, with Alfa’s own direct-injection system and cam phasing on both intake and exhaust. It makes 260 PS.
What owners and specialists report
These are the issues most often reported for the JTS engines, especially the 2.0:
- Camshaft wear. Worn cam lobes are the best-known 2.0 JTS problem. The engine is demanding on lubrication, and low oil pressure, old oil or the wrong oil speed up wear. A rough idle, ticking, loss of power or a check-engine light can be signs.
- Carbon on the intake valves. A general weakness of direct injection: fuel no longer washes over the back of the intake valves, so oily deposits from the crankcase ventilation build up there over time.
- Oil consumption. Some engines burn oil. Check the level often, because running low hurts the camshafts too.
- Variator and oil pump. The cam phaser (variator) and oil pump suffer if oil changes are stretched.
- Belts. On the 2.0, the camshaft belt and the balancer-shaft belt are service items; a failing balancer belt can damage the timing belt.
How to keep a JTS healthy
- Change the oil on time or early, with exactly the grade and specification in the handbook, and check the level between services.
- Replace timing and balancer belts, tensioners and the water pump together, on schedule.
- If a 2.0 JTS idles roughly or ticks, have the camshafts inspected before more damage is done.
For a car you plan to keep, use original-specification parts for the belts, tensioners and valvetrain. On these engines the tolerances matter.
Sources
- Wikipedia: Alfa Romeo JTS engine
- MyMotorList: Alfa Romeo 2.0 JTS (937A1000) engine