Are you a DIYer or a mechanic and want to know the Chevy 4.3L V6 firing order? The firing sequence is always 1–6–5–4–3–2. Reversing or getting it wrong significantly affects the engine’s performance. But what if you have other Chevy engines?
Maintaining the engine’s firing order is necessary to maintain balance. If that is not the case, you might experience a rough ride or excess vibrations in the cabin.
Read on to know the firing order and cylinder numbers of Chevy 4.3L, 3.8L, and 3.3L V6 engines.
4.3L V6 (4.3 Vortec) Firing Order and Cylinder Numbers
4.3L V6 Engine Overview
The 4.3L V6 is one of the most successful engines among other Chevrolet 90-degree V6 engines. It first featured in 1985 and was given the numerical number 4300. The engine’s displacement is 4,300 cubic centimeters (263.3 cubic inches) and boasted 155 hp when it first appeared.
The 4.3L V6 engine has a 4-inch bore and 3.48-inch stroke, the same as the 5.7L Chevy V8 engine. Its crankshaft has a 30-degree offset between each rod pin with a much larger rod journal of 2.25 inches. But that is not all. The 4.3L V6 engine also has larger valves, with the intake valve measuring 1.94 inches and the exhaust valve 1.5 inches.
Chevy 4.3L V6 engines were upgraded in 1986 and 1987, with a one-piece rear main crankshaft oil seal replacing the two-piece one. New center bolt valve covers and hydraulic roller lifters were introduced in 1987. Another main upgrade occurred in 1992 to allow the installation of a balance shaft in the block.
This engine was still in production in 2013, even though the distributor had stopped in the early 2000s. A coil-on-plug ignition system was introduced. Due to the new design, the 4.3L V6 became incompatible with the 1996-06 LU3/L35, leaving it only for GMT900 light-duty trucks and vans.
The 4.3L Chevy V6 engine replaced the 3.8L V6 engine in Chevrolet El Camino and Monte Carlo. It also substituted a 4.1L in full-size trucks and full-size vans.
Read more: SBC BBC V6 Chevy Engines Specs and Sizes
4.3L V6 Firing Order
The firing order of this 4.3L V6 engine is 1-6-5-4-3-2 and rotates clockwise.
4.3L V6 Cylinder Numbers
The number one cylinder is the first one on the right when looking at the engine from the front. And the one on the opposite side is cylinder number 2. The cylinder sequence on the driver side motor viewed from the front to back is 1, 3, and 5, and that on the passenger side motor is 2, 4, and 6.
Read more: 4.3L Vortec Engine Problems and Reliability
3.8L V6 Firing Order and Cylinder Numbers
3.8L V6 Overview
The 3.8L (229 cubic inches) engine first came to the market in 1980. It replaced the 4.1L straight-six engine in full-size Chevrolets and Camaros as the favorite base V6 engine. The 3.8L Chevy V6 engine also appeared under the hood of Chevrolet Malibu and Monte Carlo, where it replaced a 3.3L V6 engine. Some Buick models had this 3.8L V6 engine. Checker Motors Corporation also used 3.3L V6 in 1980 All Taxi and A12 marathon Sedans.
The 3.8L V6 has the same 3.736-inch bore and 3.48-inch stroke as the Chevy 5.0L V8 engine. It also used the same 2.45-inch main bearing and 2.1-inch rod bearing as a 3.3L V6 engine. And like the 3.3L V6, the 3.8L V6 engine used a crankshaft with the 18-degree offset throws and the same 5.7-inch connecting rods.
3.8L V6 Cylinder Numbers
The cylinder numbering on the 3.8L V6 is quite different from that of the 4.3 V6 engine. In this case, the #1 cylinder is the one you first see on the left looking at the engine from the front of the vehicle. The sequence then continues to the right as 1, 3, and 5. Other cylinders are on the rear side with sequence numbering as 2, 4, and 6.
3.8L V6 Firing Order
The firing order for 3.8L V6 Chevy engines is 1-6-5-4-3-2, and the distributor rotates clockwise.
3.3L V6 Firing Order and Cylinder Numbers
3.3L V6 Overview
The 3.3L (200 cubic inches) engine came out in 1978, replacing a much larger 4.1L in Chevy’s downsized intermediate line. It has a 3.5-inch bore and 3.48-inch stroke. These are the dimensions used in 5.0L and 5.7L V8 engines.
This 3.3L engine uses 2.45-inch main bearings and 2.1-inch rod bearing diameters as small-block V8 engines. Its crankshaft has individually connected rods that throw an offset of 18 degrees for each rod pair to eliminate rough running. This required connecting rods with narrower ends, leading to an engine block with a semi-even firing.
3.3L V6 Firing Order
The firing order of a 3.3L V6 is 1-6-5-4-3-2
3.3L V6 Cylinder Numbers
The cylinder number arrangement is #1-3-5 on the driver side front to back and cylinders #2-4-6 from the passenger side front to back.
If you are a mechanic or an advanced DIYer, you should first master the firing order before opening the hood. Reversing or failing to follow the sequence will make your engine produce intermittent power. That causes a rough ride and sometimes excess vibrations in the cabin.
The car repair manual always has the firing information and cylinder numbering. So, you can refer to it if you are dealing with any other engine apart from the Chevy 4.3L, 3.8L, and 3.3L V6.