Now we’re going explain how to read your engine valves and valve-related components and translate what they’re informing you. The appearance of your intake and exhaust valves deserve to hint in ~ the present operating problem of her engineandforetell potential performance issues.

You are watching: How to identify exhaust and intake valves

Here’s what her valves might be trying to tell you:

Valve Deposits

*
Carbon deposits can kind on your valves for a couple of reasons.

Often, carbon deposits are the result of a rich fuel mixture. That can likewise be the an outcome of oil passing v a worn valve guide. In this case, oil is pulled with the input valve guide and also into the burning chamber, wherein it’s burned. Top top the exhaust side, a worn valve guide can allow oil to get in the exhaust manifold/header and also some that the oil may strike the valve and form deposits.Aloss that compression, negative combustion native a defective ignition, or cold-engine operation can also cause store to type on the exhaust valves.

If you watch carbon deposits on her valves, check your valve guides because that wear, make certain your ignition systemis operation properly, and check for a wealthy condition. If too countless deposits form, her valves may start to stickand cause your engine come misfire orperform erratically.

Valve Breakage

*
Valve breakage is regularly the result of extreme valvelashor a cocked valve feather or retainer that pressures the valve come one side every time it hits. Either one of these conditions can cause additional stress ~ above the valve and lead to metal fatigue. Replace the valve and then double examine your lash and valvetrain clearances.

Excessive warm cancause the valve to stretch and fail, so examine your cooling systemand look because that cloggedcoolant passages around the valve seats. Wrong can also be the byproduct of detonation or pre-ignition. In this case, you’ll need to up the octane, change ignition timing, and also make other typical adjustments to prevent these conditions.

Bent Valves

Bent valves usually take place from contact with the pistons.This regularly happens because of a damaged timing belt/chain or the not correct fitment the a new belt/chain. Other feasible suspects incorporate weak or broken valve springs (remember come upgrade your springs if friend upgrade her cam) and also insufficient piston-to-valve clearance.

Burnt Valves

*
Typically an exhaust valve problem, scorched valves room usually the result of hot combustion gasses escaping in between the valve and also valve seat when they don’t seal properly. Adequate sealing in between the two also enables combustion warmth to be performed from the valve and into the seat, preventing the valve from overheating.

Improper valve lash or a weak valve spring have the right to prevent the valve native seating properly.The difficulty can it is in exacerbated through aninadequate or poorly operating cooling system. Clogged coolant passages approximately the valve seat can cause valve seat distortion and overheated/burnt valves. Detonation and pre-ignitioncan also cause elevated combustion temperatures and also leadtoburnt valves. Make all necessary adjustments to ignition timing, spark plug warmth range, and fuel octaneto avoid these conditions.

Another reason of scorched valves is valve chair recession. In this scenario, the valve seat is slowly worn far from the burning chamber, changing valve clearance. If the valve no longer closes completely, the valve and also seat will certainly burn. Carbon store can additionally prevent the valve from properly seating and also lead to a burnt valve condition.

Other possible causes include:

Lean air/fuel mixture (adjust accordingly)Too littlevalvetrain clearance (check and also adjust)Loose valve guide (tighten together needed)Cocked or weak valve springs (check and also adjust)Valve challenge or Stem Wear

Excessive valvetrain clearance canmake the valveseat with hefty impact, leading to valve challenge wear. That also allows pounding ~ above the valve tip, which causes the tip end to mushroom out. Check all clearances and make the important adjustments

If excessive valvetrain wear is no the issue, valve confront wear might be the result of dust on the valve and seat. The cure could be as simple as cleaning or transforming your wait filter.

Sticking Valves

This is much more about valve behavior then appearance; however, a sticking valve have the right to be informing you the there arecarbon shop on the valve stem. This is most likely the an outcome of the problems we stated above: gum in the fuel, overly well-off air/fuel mixture, carbon from bad combustion, or even dirty oil. If your valves room sticking due to deposits, emphasis on these areas.

See more: Residenti A Roof With Four Planes Is Defined As A, Residential & Commercial Roofing Companies

Sticking valves can likewise simply be the byproduct that cold-weather operation. In this case, the valves will regularly work complimentary as the engine warms up. Other feasible causes of sticking valves include:

Worn valve guides (see charred valves above)Warped valve stem (usually the an outcome of overheating)Insufficient oil (add oil)

Proper diagnosis of her engine valves can assist your engine achieve maximum performance, far better fuel efficiency, and also a longer life.