Valve seat for the head. Choosing garage technicians: a simple and safe way. Machining a new seat

Here is the racing head in Borovsky with alloy seats inserted. Even for a race brake engine that only runs for a few seconds, we coat the titanium valves, says Hooper, because with aggressive cams they open and close so hard.

The reverse angles on the valve and the radius that fits into the stem are additional variables that contribute to performance air flow. Again, there are many theories regarding the number of reverse angles and their transitions, as well as the choice between tulip or nail valve designs.

"The general idea is that a tulip release valve helps everyone," says Rier. This is not the case if the throat is too small. Then it's better with a nail. On the chamber side, the motors also operate with different valve edge thicknesses and also have the option of tilt or field radius. One consensus on valve design is that the exhaust gas reserve should be thicker than the intake.

Long engine mileage

Here are two titanium intake valves that look almost identical, but there are subtle differences that would be useful for specific applications. To the right is a 52-degree, 0.050-inch seat with 35-degree backlighting and a 0.80-inch edge. On the right is a 0.50" 50-degree seat with a 35-degree backlight and 0.70" edge. Both shots are 0.80 inches wide.

“It's typically 0.01 to 0.020 inches wider at the exhaust end,” says Hooper. "You can go 0.40 inches on the intake and 0.60 to 0.80 inches on the exhaust." Top fuel has nothing but 55 degrees, with real thick edges on the exhaust side, says Urrutia. "You want to get the radius in the corner so it doesn't expose itself to hot spots."

"You have to be very careful not only with the thickness of the brim, but also with the back angle to plate angle ratio if you decide to pop the valve," warns Manley. “The clearance angle depends on the valve lift and the shape of the valve,” adds Rier. Some can work very effectively with one angle, and some will do better with two. You make the transition to the valve on the seat the same way you make the transition to the valve hinge on the seat. And these transitions change depending on the cam and the lift curve.

Installation of new saddles

This cylinder head will run on an alcohol scavenge engine. The copper beryllium seat is processed with a 50-degree seat and a 40-degree top angle. Just under the seat is a very narrow 60-degree cut, which Ertman says helps 50-degree flow as much as 55-degree. The next three corners are wider than normal to minimize large fuel droplets associated with alcohol.

Cylinder head

Clearly, the synergy between the valve seat area and the valve head is critical for optimal air flow and engine performance. Much of the development and improvement comes from trial and error and flow testing through fluid dynamics simulations, offering additional information on all the angles that need to be considered. But how hard do racers push to pick up a couple of horsepowers before the bottom line hits?

Removing lead from fuel removes your engine's lifelong protection. Will this problem affect my Healy? It may, depending on the condition of your cooling system and the way you manage it. Highway use and towing are the most likely promoters of valve seat wear. Dirty and contaminated cooling systems are also culprits.

Angle between valve face and seat

It's hard to generalize, but wear can be quite rapid when unfavorable conditions, but barely noticeable in mild conditions. The initial symptom is a quieter running engine as the valve clearances gradually disappear and the associated knocking noise stops. The next symptom would be a severe misfire due to valve burning and failure.

There are several options for choosing fuel and engine modifications. Your choice will depend on how you use your car and the state of your finances. Problems may not arise for several years. Replacement gasoline contains alternative additives to combat valve seat wear. These additives are certainly less effective than lead, but will provide limited protection. They are widely available but moderately expensive.

Use unleaded fuel with proprietary additives. These supplements have different chemicals and recommendations should not mix them; pick one and stick to it. Please note that some of these supplements are also available with an octane booster component.

It has returned to the market at select gas stations. Engine and other modifications. So-called fuel catalytic pellets can be installed in the fuel tank or in feed feed mode. They are inert and will not cause harm, but they will not provide any protection.

Installation of inserted sealed valves. Specialized manual machines can machine your cast iron valve seats and press press-fit valve seat slides that will resist wear and allow the use of unleaded fuel without additives. Only the exhaust valve seats need to be replaced. The cost is moderate and the performance should be reliable if the job is done correctly. If this is not the case and the inserts fall out, you will likely need a new head and engine rebuild.

Heads from aluminum alloy are preparing with special valves and seats. You can run unleaded fuel indefinitely, receive best characteristics engine due to improved head design and carry much less weight!

The valve seat should not be too wide for sealing purposes and not too narrow for good heat transfer. It must also maintain its shape without the previously protective lead coating. The valve seat can be remanufactured and replaced when the engine or cylinder head is rebuilt. In addition to the 45° valve seat angle, it has two correction angles of 15° and 75°. Other angles are possible here. Milling on the valve seat makes it wider, milling on the correction angles makes it narrower.

Valve seat rings are sometimes an important topic for the end user, for example. For example, when it comes to a classic car that has been used for more early species fuel with lead tetraethyl. The valve starts, leaks and eventually burns out.

Machining a new seat

The most important monitoring measures here are frequent valve clearance checks and, of course, installation of the correct rings when remanufacturing the cylinder head. But even engines that have been converted to run on gas can develop problems at this stage. It also shows a high load if the valves with their armored surfaces with a ten thousand fold closure are suddenly slowed down here. At the same time, an intact valve seat provides much-needed heat transfer from the valve disc to the cylinder head.

And, of course, it must seal one hundred percent. Steel alloys predominate in valve materials, also in valve seat rings, but are manufactured by centrifugal casting. The resulting centrifugal forces lead to some compaction of the microstructure. The sintering process is completely different. Here, the metal powders are pre-compressed and, being a relatively loose composite, their structure is only achieved through actual heat treatment, in which only the components of the compound are melted. In both cases, of course, precise measurement is required as post-processing.

Besides, welding the valve and seat and then knocking it out is nothing more than the latest piece of wisdom. Here you need to grind it specifically so as not to burden the structure of the cylinder head. In contrast, inserting new saddle rings is an easy game because you can create enough freedom of movement with heat and cold.

Due to their rigidity, valve seats in the cylinder head must be machined using milling, grinding and turning tools. The valve seat in the valve head or cylinder head is restored using a valve spring. It must be ensured that the choice of milling head matches the exact same cut as specified in the repair manual. For valve seat are used heavily different angles. The order of use is also mandatory. Therefore in in this case you start with a 75° cutter head, start feeding with a 45° cutter, and finish milling the valve seat with a 15° cutter.

On the one hand, a high quality kit, but also a more convenient kit for use in small workshops where the kit is only used for a few applications. When milling, the pressure must be applied exactly vertically from above. Milling should be done smoothly and carefully and only until the valve seat width reaches the specified width. It only needs to be reworked until a uniform threadless area is achieved without any marks.

Below are instructions for using valve manifolds. A simpler valve set has two spring heads. First, the head is placed on the pilot. The pilot with the frying head is then guided vertically into the valve sleeve. Once the angle and width have been reached, milling head is replaced by a grinding head, and the surface is thoroughly ground until the surface is evenly smooth. It's easier with an offer of more High Quality. The pilot is placed in the valve guide socket.