Do valve springs close the valves?
The main function of valve springs is to keep the valves closed to build up engine compression. The second function is to maintain specific pressure on all moving parts to follow the camshaft lobe. So, the camshaft, pushrods, lifters, and rocker arms, do all the work in opening the valves.
How often should you change valve springs?
It is recommended to check ALL spring pressures once a year or every 15K miles. That does not mean they will need replacing, that is proper maintenance. Depending on the lobes used and if properly installed, certain springs can last 30+k, some less some more. I have had the springs in my car for over 20K miles.
Are stiffer valve springs better?
Higher spring rates mean greater force on the camshaft and consequently more resistance to rotation. The flip side to this argument is that stiffer valve springs control the valves better at high speed and provide better prevention of bouncing valves, which can create more power.
What happens when valve spring tension is too high?
If spring tension is too light, valve float and eventual engine damage can occur. If the spring is too stiff, friction-related horsepower loss and accelerated valve train wear will result. Improper tension, excessive wear, heavy valvetrain components, and repeated over-revving can also contribute to valve float.
Do heavier valve springs add horsepower?
Re: Heavy valve springs don’t use more HP We have done A-B-A engine dyno tests, and you do not lose HP with heavier springs. However, too light (seat pressure) can be VERY bad for the valve train, especially the roller lifters themselves.
Can you have too much valve spring pressure?
But can a valvetrain ever have too much spring pressure… yes, definitely. A normal flat tappet cam core is limited to about 145-155 pounds seat and 400-pounds open pressure.
How do I know if my valve springs are weak?
Symptoms of Weak Valve Springs Weak valve springs will typically cause misfiring and a loss of power as engine speed increases. The engine may start and idle fine, or run normally up to 3500 to 4000 RPM.
How do I know if my valves are floating?
How is it identified?
- Mild valve float can be felt as power falling off quickly at high rpm.
- Severe valve float will be heard as a sputtering sound at peak rpm.
What does a bad valve spring sound like?
Re: What does a broken valve spring sound like? At idle it will most likely sound fine. When you drive it “normally” it will sound like you have an exhaust leak (“tick”) and will sputter and hesitate. If you floor it it will backfire and sould horrible.
What happens if a valve spring breaks?
Broken valve springs cause excessive valve noise, compression loss and can cause severe internal engine damage. Actions following the breaking cause the most serious damage to the engine. When spring breaks, it may collapse just enough to allow the valve to drop into the cylinder, where the piston may strike it.
Can I drive with bad valves?
Q: Can you drive a car with a bad valve? A: The “bad valve” will not “preclude” you from driving the car, BUT the internal damage will increase with operation, eventually resulting in engine failure which WILL prevent further operation.
How much does a valve job cost?
On newer engines (V6 or V8), a valve job can cost up to $125 per valve that needs repairing, with the cost increasing for engines with over 12 valves. Therefore, a total valve job can cost upward of $1000.
How much does a valve adjustment cost?
So how much does a valve adjustment or check cost? Generally speaking the average valve adjustment cost is around $300. However, valve adjustment cost depends on the type of bike that you ride, the amount of valves that your engine has, and whether those valves are operated by overhead cams or pushrods.
What happens if valves are not adjusted?
The valves in your engine open and close through a complex, precisely timed system. They open to accept fuel into the cylinder, close to form compression and open again to release exhaust. Without an adjustment, they may not open and close efficiently, reducing your car’s overall performance.
How do you do a valve adjustment?
When the exhaust valve just begins to open on the first cylinder in the firing order, adjust the intake valve by loosening the adjusting nut slightly while spinning the pushrod until you feel lash in the rocker arm. Tighten the adjusting nut until the slack is taken out of the rocker arm and pushrod.
How do you perform a 3 angle valve job?
The basics of a three angle valve job: On the inlet valve, the lap marks should be placed on the outer edge of the 45° valve face. This takes full advantage of the diameter of the valve. When the lap marks sit inside the outer edge of the valve, the overhanging portion of the valve serves as an obstruction to flow.
What is a 3 angle valve job?
A 3 angle valve job is the process of machining the contact area of the underside of the valve, so that the mating surface is smaller or sharper, and making the seat angle greater. This allows the valve to seal faster and more tightly.
How do you check a valve seat angle?
One way to check this is to use valve-lapping compound that etches a light gray mark on the valve to reveal where the 45-degree seat contacts it. Some engine builders prefer to use red machinists’ dye instead so the compound does not cut into the carefully placed angles.
What is Valve face angle?
The valve face is that portion of the valve that creates a seal at the intake and exhaust ports. A valve face is typically ground to an angle of between 30 and 60 degrees to form a seal against the valve seat when the valve is closed.