Hydraulic lash adjusters
Types of lash adjuster
The same hydraulic element, packaged four ways depending on where the cam is and what carries the load to the valve. Each layout asks something different of the part, and of the shop making it.
Four layouts
Where the adjuster sits in the valve train
- Direct acting bucket
- The cam runs directly on an inverted bucket, and the adjuster sits inside it bearing on the valve tip. Common in twin cam heads. Low mass, no follower, and the bucket outside diameter and its bore in the head are a second precision fit alongside the adjuster’s own.
- End pivot element
- The adjuster is a stationary post in the head. A roller finger follower pivots on its ball head at one end, rides the cam in the middle, and presses the valve at the other. The most common layout in current cylinder heads, and the one that pairs naturally with the rocker arm assemblies built here.
- Pushrod lifter
- In a cam-in-block engine the adjuster is the lifter itself, sitting in the block and riding the cam with a flat or roller foot. A pushrod carries the motion up to a rocker. The body is longer and carries the foot, and the roller adds a needle bearing and an axle.
- In the rocker arm
- A centre pivot rocker carries the adjuster in its own end, bearing on the valve tip. The adjuster travels with the arm. Oil is fed through the rocker shaft and the arm, so the feed path is part of the assembly design.
What each layout asks of the part
The element is shared; the envelope is not
- Same inside every time
- Plunger, bore, check valve, chamber and spring are the same problem in every layout. The fit and the leak-down rate are set the same way, and proved the same way.
- Different outside
- A bucket wants a thin, light, precisely ground outside diameter. A pivot element wants a hardened ball head with a controlled radius. A lifter wants a long body and a foot. A rocker element wants a compact body and a feed path through the arm.
- Where the assembly comes in
- End pivot elements and rocker elements are routinely supplied as part of the valve train assembly rather than as loose parts. That is the arrangement already in place for rocker arm assemblies, and the adjuster is added to the same purchase order rather than starting a new one.
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A clear answer inside a working day
A 2D or 3D file, the quantity and the date you need it. You will get a considered reply within one working day, including the reply that we are not the right shop for the part, which is worth knowing early. A mutual NDA is issued first on request.