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How To Repair The Valve Spring Of Diesel Generator

Sep. 05, 2023

There are generally two methods for the maintenance of diesel generator valve springs: cold and heat treatment.


1. Cold treatment.

Place the spring on a shaft so that the outer diameter matches the inner diameter of the spring. Put one end of the spring and the round shaft on the lathe, fix the moving rod on the tool holder of the lathe, and file the head of the moving rod into a groove slightly larger than the diameter of the spring wire, so that the spring is embedded in the groove. Press down with the tool holder and gradually run the chuck. Each turn, turn one turn, gradually run the chuck, each turn, the moving distance is 1~2 mm larger than the shrapnel. As the spring is rotated, lightly tap the spring with a small hammer to harden the surface of the spring, thereby increasing its elasticity. However, springs repaired in this way have a shorter lifespan. Therefore, it can only be used as a last resort, and in general, a new spring is still used.


2. Heat treatment method.

The method of heat treatment and maintenance is: place the valve spring in the iron box, fill the iron filings with iron filings (casting filings can prevent the surface of the spring from oxidizing), the furnace temperature is about 925 ℃, and the heat preservation is about 1h. Then put the iron box into the air to cool, then take the valve plate to the air to cool, take out the valve plate and put it into the cylinder, put the cylinder into the air and the cabinet with the maintenance fixture. The case body is made of 6mm thick cast steel plate and is cut into grooves according to the pitch of the new valve springs. The mandrel of the spring is pressed into the valve spring, then the clamp is heated to about 810°C, then the oil is quenched, then heated to 310°C, and then cooled in air. At this time, it should be RC41~42.


Yuchai Power Generator Set

In addition, the inspection and repair methods for the valve spring lock and spring seat of the diesel generator are as follows:

1. Technical requirements.

(1) When the valve spring lock plate of the diesel generator is fixed on the valve stem, the outer cone surface and the seat cone hole should be in close contact.

(2) The end faces of the two locking pieces should be below 2.5mm.

(3) The valve spring lock plate is fastened on the valve stem, and there should be a gap of more than 0.5mm on each side of the separation surface.

(4) The height difference between the two locking pieces is within 0.3mm.


2. Inspection (technical appraisal).

(1) Check whether there is obvious wear and damage on the inner and outer surfaces of the two locking pieces and the cone hole of the seat, and should be replaced.

(2) Measurement or comparison, if the height difference between the two locking pieces exceeds 0.3mn, the same one should be replaced.

(3) If the gap between the two cleat separation surfaces has disappeared, it should be replaced.

(4) If only one end of the lock piece is connected to the base, when the machine is working, due to the single head opening, both the lock piece and the valve rod will be worn out, and even the lock piece will jump out, so it should be replaced.

(5) If the convex strip on the surface of the locking piece is worn, it should be replaced.


3. Repair.

(1) If the gap between the separation surfaces of the two locking pieces is too small or the height of the two pieces is inconsistent, a file can be used, but the inner and outer surfaces should be complete, and the outer tapered surface and the seat surface should be matched.

(2) If the contact surface is not firm or has burrs, the surface should be polished off.

(3) New parts generally need to be replaced under other circumstances.


Guangxi Dingbo Power Equipment Manufacturing Co., Ltd. is one of the earliest manufacturers of generators and diesel generator sets in China. The company was established in 2006 and the company occupies an area. It has service departments across the country to provide users with one-stop service of design, supply, debugging and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details sales@dieselgeneratortech.com

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