What makes valve guides go bad?
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The valve guides experience a lot of wear; because of the constant friction between the guide and valve stem. Side forces on the valve stem, caused by changes in valve train geometry; or by direct acting overhead cams further contribute to guide wear.
What causes valve stem and guide wear?
A valve stem tends to stick in extreme temperature conditions – due to gumming deposits when it is cold, or carbon packing between the stem and guide when the engine is hot. Either way, the sticking of a valve stem is a symptom of another issue that can lead to bigger problems if the root cause is not identified.
Should I replace my valve guides?
If the clearance is too large or the valve guides are worn out-oftrue, conical or flared, they must be replaced. For valves with a skirt diameter of less than 8 mm in particular, knocked out valve guides have a big impact.
When should you replace valve guides?
How do valve guides get lubricated?
By engine design, the oil is moved under pressure from the crankcase by the oil pump, through ports and galleys at the top of the head, an area just inside the valve cover. The lubricant then flows along the head to the valve stem(s) and once there, flows down the stem, lubricating the stem and guide.
What is the function of a valve guide?
The Valve Guide supports the intake/exhaust valve stem, stabilizes the valve attitude and allows heat to escape to the cylinder head side, hence, it needs to be durable and made with great precision.
How much does it cost to replace worn valve guides?
The cost of replacing your valve guide seals will vary according to the make and model of your vehicle. The good news is the cost of the parts for valve guide seals is between $30 to $100 on average. The bad news is that you are looking at about 2 to 4 hours of labor if you take your vehicle to a mechanic.