Renault J8S engine
Content
In the late 70s, the French J engine series was replenished with a diesel engine, which was successfully used on many popular Renault cars.
Description
The diesel version of the J J8S family of power units was developed and put into production in 1979. The release is arranged at the company's plant in Douvrin (France). It was produced both in aspirated (1979-1992) and turbodiesel (1982-1996) versions.
The J8S is a 2,1-liter in-line four-cylinder diesel engine with a capacity of 64-88 hp. with and torque 125-180 Nm.
Installed on Renault cars:
- 18, 20, 21, 25, 30 (1979-1995);
- Master I (1980-1997);
- Traffic I (1980-1997);
- Fire I (1982-1986);
- Space I, II (1982-1996);
- Safrane I (1993-1996).
Additionally, this engine can be seen under the hoods of Cherokee XJ (1985-1994) and Comanche MJ (1986-1987) SUVs.
The cylinder block is made of aluminum alloy, but the liners are cast iron. This design solution has significantly increased the compression ratio.
The cylinder head is also aluminum, with one camshaft and 8 valves. The head had a pre-chamber design (Ricardo).
The pistons are made according to the traditional scheme. They have three rings, two of which are compression and one oil scraper.
Belt-type timing drive, without phase shifters and hydraulic compensators. The belt resource is quite small - 60 thousand km. The danger of a break (jump) lies in the bending of the valves.
The lubrication system uses a gear type oil pump. An innovative solution is the presence of special oil nozzles for cooling the bottom of the pistons.
A reliable injection pump of the VE type (Bosch) is used in the fuel supply system.
Technical specifications
| Manufacturer | SP PSA and Renault |
| Engine volume, cm³ | 2068 |
| Power, hp from | 64 (88) * |
| Torque, Nm | 125 (180) * |
| Compression ratio | 21.5 |
| Cylinder block | aluminum |
| Block configuration | in-line |
| Number of cylinders | 4 |
| The order of injection of fuel into the cylinders | 1-3-4-2 |
| Cylinder head | aluminum |
| Cylinder diameter, mm | 86 |
| The piston stroke, mm | 89 |
| Number of valves per cylinder | 2 |
| Timing drive | belt |
| Hydraulic compensators | no |
| Turbocharging | no (turbine)* |
| Fuel system | Bosch or Roto-Diesel, forkamery |
| Fuel | diesel fuel (DF) |
| Environmental standards | Euro 0 |
| Resource, outside. km | 180 |
| Location | transverse** |
*values in brackets for turbodiesel. ** there are modifications of the engine with a longitudinal arrangement.
What do modifications mean?
Based on the J8S, several modifications were developed. The main difference from the base model was the increase in power due to the installation of a turbocharger.
In addition to power characteristics, much attention was paid to the exhaust gas purification system, as a result of which the degree of environmental emission standards was significantly raised.
Changes in the design of the internal combustion engine were not carried out, except for the elements of fastening the motor to the car body, depending on its model.
More details about the characteristics of the J8S modifications are indicated in the table:
| Engine code | Power | Torque | Compression ratio | Years of issue | Installed |
|---|---|---|---|---|---|
| J8S 240* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1984-1990 | Renault Espace I J11 (J/S115) |
| J8S 600 | 72 l. s at 4500 rpm | 137 Nm | 21.5 | 1989-1994 | Renault 21 I L48, K48, B48 |
| J8S 610* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1991-1996 | Space II J63 (J/S635, J/S63D) |
| J8S 620 | 64 l. s at 4500 rpm | 124 Nm | 21.5 | 1989-1997 | Traffic I (TXW) |
| J8S 704 | 67 l. s at 4500 rpm | 124 Nm | 21.5 | 1986-1989 | Renault 21 I L48, K48 |
| J8S 706 | 63 l. s at 4500 rpm | 124 Nm | 21.5 | 1984-1989 | Renault 25 I R25 (B296) |
| J8S 708 | 86 l. s at 4250 rpm | 181 Nm | 21.5 | 1984-1992 | Renault 25 I (B290, B29W) |
| J8S 714* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1989-1994 | Renault 21 I L48, K48, B48 |
| J8S 736 | 69 l. s at 4500 rpm | 135 Nm | 21.5 | 1988-1992 | Renault 25 I R25 (B296) |
| J8S 738 | 86 l. s at 4250 rpm | 181 Nm | 21.5 | 1984-1992 | Renault 25 I (B290, B29W) |
| J8S 740 | 72 l. s at 4500 rpm | 137 Nm | 21.5 | 1989-1994 | Renault 21 I L48, K48, B48 |
| J8S 758 | 64 l. s at 4500 rpm | 124 Nm | 21.5 | 1994-1997 | Traffic I (TXW) |
| J8S 760* | 88 l. s at 4250 rpm | 187 Nm | 21 | 1993-1996 | Safrane I (B54E, B546) |
| J8S 772* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1991-1996 | Space II J63 (J/S635, J/S63D) |
| J8S 774* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1984-1990 | Area I J11, J/S115 |
| J8S 776* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1991-1996 | Space II J63 (J/S635, J/S63D) |
| J8S 778* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1991-1996 | Space II J63 (J/S635, J/S63D) |
| J8S 786* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1989-1994 | Renault 21 I L48, K48, B48 |
| J8S 788* | 88 l. s at 4250 rpm | 181 Nm | 21.5 | 1989-1994 | Renault 21 I L48, K48, B48 |
*turbocharged options.
Reliability
Diesel J8S does not differ in high reliability. All versions before 1995 were especially weak in this regard.
From the mechanical part, the cylinder head turned out to be problematic. Their contribution is made by the low service life of the timing belt, the complexity of some positions when repairing the motor, and the lack of hydraulic lifters.
At the same time, according to the reviews of many car owners, the engine easily takes care of more than 500 thousand km without significant breakdowns. To do this, it is necessary to carry out scheduled maintenance in a timely manner and in full using high-quality (original) parts and consumables. At the same time, it is recommended to reduce the terms of maintenance.
Weak spots
In this matter, priority is given to the cylinder head. Usually, by 200 thousand km of run, cracks appear in the prechamber of the third cylinder. Jeeps are especially susceptible to this phenomenon.
In 1995, the manufacturer issued Technical Note 2825A, strict adherence to which reduced the risk of head cracking.
With improper, harsh and aggressive operation, the internal combustion engine is prone to overheating. The consequences are deplorable - a major overhaul or replacement of the motor.
The internal combustion engine does not have mechanisms for damping second-order inertial forces. As a result, the motor runs with strong vibrations. The consequences are the weakening of the joints of the nodes and their gaskets, the appearance of oil and coolant leaks.
It is not uncommon for the turbine to start to drive oil. Usually this happens to 100 thousand km of its operation.
Thus, the engine requires constant and close attention. With timely detection and elimination of faults, the reliability and service life of the internal combustion engine are increased.
Maintainability
The maintainability of the unit is satisfactory. As you know, aluminum cylinder blocks cannot be repaired at all. But the presence of cast-iron sleeves in them indicates the possibility of a complete overhaul.
Finding parts and assemblies for restoration also causes some problems. Here, the fact that most of the spare parts are unified comes to the rescue, that is, they can be picked up from various modifications of the J8S. The only problem is their price.
When deciding on restoration, you should consider the possibility of acquiring a contract engine. Often this option will be much cheaper.
In general, the J8S engine turned out to be not very successful. But despite this, with proper operation and timely quality service, it turned out to be hardy, as evidenced by its high mileage.
