Chevrolet X20D1 and X25D1 engines

Both powertrains are the result of ingenious engineering work by General Motors Corporation, which has implemented advanced tasks in engines. In particular, they concerned the increase in power, weight reduction and efficiency. This was achieved thanks to the competently done joint work of diverse masters, vast experience and the use of light metals, universal advanced formulas.

Description of engines

Six, 24-valve engine

Both motors are structurally similar, therefore they are described together. They have the same method of fixing under the hood, the same seats, attachments, sensors. However, there are differences that involve the working volume of the chambers and throttle control. Although the latter function may also depend on the year of manufacture of the motor, as well as on the implementation of a specific upgrade. For example, the owner, with due skill, is able to easily, without any consequences, replace the throttle assembly with a more advanced one.

On the other hand, it is wrong to talk about the complete interchangeability of both engines. It must be borne in mind the ECU or electronic control unit. He will require to intervene in the firmware, to make fundamental changes.

Here are the general differences between the motors in technical terms:

• X20D1 - 2-liter engine producing 143 hp. With.;
• X25D1 - 2,5-liter engine producing 156 hp. With.

Both engines are powered by gasoline, equipped with 2 camshafts according to the DOHC scheme, and have 24 valves. These are in-line, transversely arranged “sixes”, there are 4 valves for each cylinder. The block is made according to the scheme with an open deck, cast-iron sleeves are used. The cylinder head drive uses a single-row chain, the rotation comes in pairs from the camshafts. The units were developed by W. Bez.

X20D1	X25D1
Engine displacement, cc	1993	2492
Maximum power, hp	143 – 144	156
Fuel used	Gasoline AI-95	Gasoline AI-95	01.01.1970
Fuel consumption, l / 100 km	8.9	9.3
engine's type	Inline, 6-cylinder	Inline, 6-cylinder
Add. engine information	multipoint fuel injection	multipoint fuel injection
CO2 emission in g / km	205 – 215	219
Number of valves per cylinder	4	4
Maximum power, h.p. (kw)	143 (105) to 6400	156 (115) to 5800
Supercharger	No	No
Maximum torque, N * m (kg * m) at rpm.	195(20)/3800; 195 (20) / 4600	237 (24) to 4000
Engine builder	Chevrolet
Bore	75 mm
Piston stroke	75.2 mm
Root supports	7 pieces
Power Index	72 h.p. for 1 liter (1000 cc) volume

The X20D1 and X25D1 engines were installed on the Chevrolet Epica, a not very popular car in Russia. Motors were placed on sedans and station wagons.

For versions coming to the Russian Federation, most often they installed a 2-liter power unit assembled at the Kaliningrad Automobile Plant.

Since 2006, X20D1 and X25D1 engines have been installed on Daewoo Magnus and Tosca.

Engine X20D1

Interestingly, the new "six" has made many useful changes to the Daewoo. It allowed the use of all-wheel drive, made it possible to obtain a large breakthrough in power and a simultaneous reduction in fuel consumption. Thanks to the new motor, Daewoo is ahead of its age-old competitors.

The new engine, according to Daewoo's engineering management, uses a high-quality clutch. It is the best in the class, in addition, the motor offers the following advantages.

1. Inertial forces are balanced, and vibrations are almost not felt.
2. The operation of the engine is not noisy, which is due to the design feature - the block and oil pan are made entirely of aluminum, and the design of the internal combustion engine is compact.
3. The exhaust system is ULEV compliant. This means that hydrocarbon emissions are reduced due to rapid warm-up. The latter is ensured by the use of elements made of soft and light metals produced using Silitek technology. In combustion chambers, there are almost no narrow volumes with obstructed flame fronts.
4. The design of the engine as a whole is compact, the overall length of the motor has decreased compared to conventional classic options.

Malfunctions

The main disadvantage of the X20D1 and X25D1 engines is rightfully called rapid wear due to improper or excessive operation. To carry out repair work with these internal combustion engines, one must have extensive experience and specific technical knowledge in the field of modern engine building. Almost all malfunctions of these motors are associated with accidents or wear. The first can be prevented, the second is in no way impossible, because this is an irreversible process that comes sooner or later.

Epica engine

Indeed, there are only a few real masters of these engines in Russia. Whether this is due to the fact that Epica has never been our bestseller or the motor is simply structurally complex is unknown. Therefore, many owners of cars equipped with these units are faced with the question: how to find a suitable replacement, because repairs may not give anything worthwhile.

About the knock

Engine knock is seen more often on a 2-liter unit with a manual transmission. And on Epik, in 98 cases out of 100, this leads to turning the liners on the second cylinder. The oil pump jams, as the lubricant is produced, loses its original properties, a lot of excess burning or chips are formed inside the pump. The oil pump stops due to the fact that it starts to rotate tightly in such a situation, because it is of a rotary type. He has both gears quickly overheat and expand.

The oil pump on Epik is connected directly to the timing chain. Due to problems with the pump (tight rotation), there is a large load on the gears associated with the crankshaft. As a result, the pressure disappears, and the oil on this engine comes last to the second cylinder. Here is the explanation of what is happening.

For this reason, if the liners on the engine have turned, the oil pump and rings should be changed at the same time. There is also an original way to get rid of the repetition of such a situation. It is necessary to carry out modernization - to finalize the timing gear pump chain.

1. Fasten the oil pump gear and timing gear together.
2. Center both stars.
3. Drill a hole with a diameter of 2 mm so as to insert the needle bearing from the cross from the Zhiguli inside. First you need to saw off a pin from the bearing of the desired size, then insert it as a retainer. A strong piece of hardened metal will securely hold both gears.

The pin plays the role of a universal retainer. If the oil pump starts to stick again, then a homemade piece of bearing will not allow the gear to turn on the new crankshaft.

Epicurus	Epica motors must be carefully and correctly operated and properly serviced by knowledgeable craftsmen, otherwise the “ass” will come sooner than you think!
planchik	To fix a cranked motor yourself, you need 40 k, for the master to repair it, you need 70 k, depending on how much he takes for work, and if you take a contract, then it is at least 60 k so that 4 or 5 stars the quality of the assessment at the auction was if it was from behind a hillock, but in order to establish a contract for 60 you need fluids and gaskets of various 15 k and replacement work around 10 k and then diagnostics so that everything is clear and buy the little things that the sweat with the hood will break another 5k for sure, well, iridium candles total 90 k for a pig in a poke, of course for such money will capitalize it for you in the most expensive auto center, just figure X to your nose yourself
UPI	No one knows what pressure should be on a serviceable motor. sort of like 2.5 bars according to autodata, but also far from a fact. I personally have 1 bar on XX and 5 bar at 3000 rpm. So, is this pressure normal or not?
Sugar is not honey	One minder told me that the X20D1 oil level must be kept above the middle, just for easier operation of the pump, so as not to load it.
Mamed	The oil level has nothing to do with it, it’s not enough for the operation of this motor, not 6 but 4 liters, this has nothing to do with it, the main thing is the quality of the oil for the pump itself, which is already worthless for the operation of the motor itself, as it is aluminum and sleeves in nikasil
Themselves with teeth	What oil would you recommend for this engine? so that there are no problems? and another question if the oil filler neck is sooted, then what do you think about it? I personally think that since this is the highest oil point and the oil from the chain is constantly sprayed there, then there is nothing to worry about)
planchik	The fact that it is in soot is, as you noticed, the highest part of the engine and not all the space is filled with oil, this one is just gases that break into the crankcase from the piston leave soot, just soot from oil, and just the same, if there is a thick layer of it, then be afraid that it does not fall into the crankcase and does not get into the oil pump))) and if it is within reason, then hammer it. and it’s better to pour the oil that is recommended in the same place 5w30 GM DEXOS2, it seems like, by the way, the motor didn’t take this oil from me at all, but the MOTUL 5w30 with a DEXOS 2 approval took the motor for 1000 about 100 grams.
mildboy	I have an EPICA with an X20D1 engine on the mechanics (after an accident) and there is another EPICA (ideal) without an engine, brains and box, everything else is in place, it used to have an X25D1 Automatic, both 2008. I want my engine (respectively with a box and brains) to put on the second. What problems can arise, alterations ???
Alexey	You have almost a complete set of spare parts, now you need to correctly rearrange the pedal assembly with the clutch, the gear selector with two cables and, accordingly, the box with baits, because those drives that were with the automatic transmission most likely will not work, and the main thing is that all these units fit on your new body and commute
Dzhigit77	sell the 2.0 engine a box and you will just have money for a used 2,5 engine. If I can help you buy. are available. the engine costs around 3,5-3,7 + shipping costs on your part
Guru	Can be redone. The schemes are almost the same. Small differences will be easy to change
Alek 1183	Hello. I am repairing the Chevrolet Epica 2.0 DOHC 2.0 SX X20D1 engine. Mileage 140000. The problem is high oil consumption, plus when heated, the engine began to diesel. Runs quiet when cold. The pressure on the cold, at idle, is about 3,5 bar, as it warms up, around 2,5 bar, the arrow begins to twitch a little !? and on a warm engine 0,9 bar. When removing the head found fresh oil on the pistons. Looks like it got into the cylinders along the valve guides. When measuring cylinders, there were such data 1 cyl: cone 0,02. ellipse 0,05. diameter 75,07. 2cyl: 0,07. 1,5. 75,10. 3cyl:0,03. 0,05. 75,05. 4cyl: 0,05. 0,05. 75,06. 5cyl: 0,03. 0,07. 75,06. 6cyl: 0,03. 0,08. 75,08. The second cylinder has very small scuffs. The block is sleeved from the factory. There is no information anywhere about what is sleeved. It seems to me that they are cast iron, because they are magnetized by a magnet. Everywhere they write about different coatings on the sleeves. But I highly doubt it. I tried to scratch with a clerical knife, scratches remain. The question is, has anyone tried to sharpen this block with the selection of pistons from other machines? Piston size d-75, pin d-19, pin length 76, height from pin center to piston edge 29,5. Piston height 50. I have already picked up pistons approximately: Honda D16y7 d75 + 0.5 is almost perfect either d17A. Or alternatively Nissan GA16DE STD d76. Can anyone suggest piston options? The question is, is it worth trying? Or just a sleeve (it comes out very expensive) and it is very difficult to find cheap sleeves for this size. And really did not like the connecting rods. They are chipped, liners without locks. When removing the connecting rods, some liners remained on the crankshaft. Is it normal?
Connoisseur minder	No repair pistons? On the connecting rods and liners - this is normal. Measure only. Have you determined the cause of seizures in one cylinder? Maybe the mechanism for changing the geometry of the intake manifold began to fall apart? If, of course, he is there.
Sergei	Set the piston from 2.5 to 77mm, you have a cast-iron sleeve filled in.