Replacement or installation process camshaft The legendary ZMZ-406 engine is one of the key procedures in the overhaul or deep tuning of the power plant, which is installed on Gazelle and Volga cars, has a chain drive of the GRM, which imposes its own features on the installation procedure. Assembly errors can lead to catastrophic consequences, up to the meeting of valves with pistons, so each stage must be approached with maximum responsibility.
Before starting work, you need to make sure that you have not only a new set of shafts, but also high-quality ones. hydrocompensatorOften owners overlook the condition of the circuit and sedatives, believing that once the engine was working, the chains will still work. However, when opening the engine to replace the shafts, you can not save on the associated elements of the timing, since the stretched chain will negate all efforts to fine-tune the timing phases.
In this article, we will discuss the technological process in detail, paying special attention to the setting of labels and the correct order of tightening the bearing covers. ZMZ-406 It has its own design nuances that distinguish it from modern foreign cars, and knowing these subtleties will save you time and nerves. Proper installation will ensure smooth engine operation at idle speeds and decent traction throughout the range.
Engine preparation and dismantling of attachments
The first step is to get access to the cylinder head, you need to remove the intake manifold, the throttle assembly and the receiver, and you need to pay special attention to the coolant drain, so that when you remove the pipes, antifreeze does not get into the cylinders or into the hot exhaust parts, and you also remove the ignition module and high-voltage wires, which are quite compact on the 406th engine.
After removing the intake system, the valve cover must be removed. It is important to carefully disconnect the crankcase ventilation hoses, since the rubber on older engines often smacks and breaks. Before removing the lid, it is recommended to clean the surface around it of dirt and oil to prevent abrasive particles from entering the motor when opening.
⚠️ Attention: When removing the valve cover, do not use sharp objects for tweaking, so as not to damage the landing plane of the head of the block or the lid itself. Unevenness will lead to leakage and oil extrusion.
Then you have to remove the top tensioner of the chain and the chain itself from the asterisks of the camshafts, and you have to turn the crankshaft to match the mark on the pulley with the mark on the lid of the GRM. This is critically important, because it is the position of the crankshaft that determines the correct installation of phases. If the marks are shot down, the engine may not start or work extremely unstable.
In parallel with the work in the engine compartment, check the condition tensionerOn the 406th engine, they can be automatic or mechanical. If you're planning to install tuning shafts, you often recommend switching to mechanical tensioners that allow you to more accurately control the tension of the circuit and eliminate the risk of dragging it in certain modes of operation.
Removal of old camshafts and defects
The process of dismantling old shafts begins with turning the bolts of the bearing covers attachment. There is a strict sequence of actions: bolts are released evenly, from center to edges, to avoid distortion and deformation of the shafts. Sharp unwinding of one bolt can lead to a jamming of the shaft in the bearing.
Once the mount is loosened, the lids are removed and the shafts are removed. It is important not to confuse them with subsequent installation, although they are marked. Intake shaft (INT) and exhaust shaft (EXH) have different cam profiles. Before installing new parts, you need to carefully inspect the beds of camshafts in the head of the block for the presence of bullies or effluent.
Mandatory procedure to be checked hydrocompensatorIf you've seen bullies or slacks on old shafts, there's a good chance that the hydraulic compressors have been damaged, and replacing them with shafts is not a marketing move, it's a necessity to ensure long-term service of the unit, and the noise of the engine is often due to wear and tear.
Also check the asterisks of camshafts. Teeth should not be slicked or have significant wear. When installing new shafts, it is recommended to use new asterisks, as the pitch of the chain on the old and new part may differ, which will lead to noise and rapid wear.
How to check the hydrocompensators?
To test hydraulic compensators, you have to press them with your finger or tool. If the compensator fails easily and effortlessly, it's faulty and requires replacement. If it's rigid and it doesn't get squeezed, it might be able to be repaired by washing, but it's better not to take the risk.
Installation scheme and tightening of the covers
Installation of new camshafts is a piece of jewelry work that requires compliance with the timing of the tightening and the order of action. Bearing covers are numbered, and it is strictly forbidden to confuse their location. Each lid is installed strictly in its place, according to the marking on the head of the block.
The bolts of the covers are tightened in several stages. First, all the bolts are tightened by hand, then a preliminary tightening is made with a dynamometer key, and only then - the final one. The puffing moment for the ZMZ-406 is about 2.0-2.5 kg / m (20-25 Nm), but it is better to check the technical documentation for a specific year of engine production.
Lubricate the cams of the new shafts and necks with pure engine oil before installation. Dry start can cause instant wear of the friction pair in the first seconds of engine operation until the oil pump creates pressure in the system.
☑️ Checklist for shaft installation
Once the shafts are installed, they should be able to rotate freely by hand, and if you feel a bite or a tight slap, you need to remove the lids and find the cause, and often the problem is skewed lids or dirt.
Labeling of the GRM and chain installation
The most important step is to install the circuit and to label the 406th engine, and it is important to correctly align the asterisks with the plane of the cylinder head.
There is a common mistake when the labels are placed on the 1st and 4th cylinders incorrectly. For the 406th engine, when the tags on the pulley of the crankshaft and the lid are combined, the pistons of the 1st and 4th cylinders must be in the upper dead point (BMT), you can see this by inserting a thin screwdriver into the candle hole.
The table below will help to orient in the position of the marks for various modifications of the engine:
| Parameter | ZMZ-4062 (Volga) | ZMZ-4063 (Gazelle) | ZMZ-405 (Euro) |
|---|---|---|---|
| Type of chain | 70/72 links | 70/72 links | 72 links |
| Tensioner | Automatic machine/mechanics | Automatic. | Automatic. |
| Phase (degrees) | Standard. | Standard. | Modified |
| A mark on an asterisk | Upstairs. | Upstairs. | Upstairs. |
When you put on a chain, make sure it doesn't jump off the crankshaft star teeth. If it does, you'll have to take the bottom of the GRM apart again for re-exposure. Use wire or tape to temporarily fix the chain on the asterisk of the camshaft before installation.
⚠️ Attention: Never turn a crankshaft counterclockwise when the circuit is installed. This can lead to chain jumping and disruption of the gas distribution phases, which can lead to valve impact.
Adjustment of thermal gaps and assembly
Although the 406 engine uses hydraulic compensators that theoretically do not require adjustment, in practice, it is often necessary to install adjusting washers when using tuning shafts. If the profile of the cam is changed, a standard hydraulic compensator may not have time to choose a gap or, conversely, be constantly open.
For standard engines, after installing new shafts and hydracs, it is enough to put everything in reverse order. However, if you install sports shafts with a high lift, the calculation of washers becomes mandatory, this is done by measuring the actual gaps with a probe and selecting washers of the desired thickness.
When you assemble, make sure to apply the sealant to the valve cover. Use a quality heat-resistant sealant, applying it in a thin continuous layer. Excess sealant, squeezed out during tightening, can enter the oil channels and clog them, leading to oil starvation.
Use only a special engine sealant (usually red or black) Sanitary or universal sealants are quickly destroyed by contact with oil and high temperature.
After the final assembly and filling of the oil, you need to turn the engine manually behind the crankshaft pulley two full turns, this is to make sure that there are no mechanical obstacles and check if the marks match after a full cycle. If the shafts turn tightly, look for an error in the assembly.
First start and check of operation
The first run after the camshafts are installed is an exciting moment. The engine may not start the first time, because the hydraulic compensators need time to fill up with oil and select all the gaps. Don't spin the starter for more than 10 seconds in a row, let it rest.
Once the engine is successfully started, it can run with increased noise in the first minutes. This is normal for new hydraulic compensators. However, if the knocking does not stop after warming up, it is worth turning off the engine and checking the installation. Constant metal knocking may indicate an incorrect gap or defect in the part.
Be sure to check the system for oil leaks and antifreeze. Warm up the engine to operating temperature and make sure the cooling fan is switched on correctly. It is also worth checking the angle of ignition, since phase displacement may have affected the crankshaft position sensor readings.
Successful installation is confirmed by a smooth idling, the absence of extraneous noise after warming up and stable traction throughout the rev range.
In the first 500-1000 kilometers of mileage, it is recommended to operate the car in a gentle mode, without sharp accelerations and high speeds. This will allow the parts of the timing to get lost with each other. After running, it is advisable to replace the oil to remove the products of initial wear.
Frequently Asked Questions (FAQ)
Should I change the chain when replacing the camshafts?
A stretched circuit will not accurately set the timing phases, and the new camshaft will not work efficiently, and the old circuit can quickly fail due to altered loads.
Can I put camshafts from 405 engine on 406?
Physically, they will stand up because the seats are identical, but the cam profile may differ, which will change the specifications of the engine, and it may require a reflashing of the ECU (electronic control unit) to work properly.
Why does the engine triple after replacing the shafts?
There may be several reasons: incorrectly exposed GRM tags, faulty candles or ignition coils (which are often changed along with the shafts), or air pumping through the gaskets of the intake manifold.
What is the point of tightening the bolts of the camshaft covers?
The moment of tightening of bolts of the bearing covers of camshafts for ZMZ-406 is 20-25 Nm (2.0-2.5 kg). Puffing is carried out strictly according to the scheme from the center to the edges to avoid distortion of the shafts.
Do I need to wash the water compressors before installation?
New hydraulic compensators usually come in a lot of conservatory oil, and they don't have to be washed, but you don't have to shake the oil out of them before installation, they have to be filled with oil for the primary work, and the old ones are better replaced with new ones.