JP Group Valve Adjusting Screw, 9 mm (M9) | VW Air-Cooled Type 1 & Type 3, Vanagon Wasserboxer | OE 025 109 451 (JP-8120-0)
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JP Group Valve Adjusting Screw, 9 mm (M9) — VW Air-Cooled & Vanagon Wasserboxer (JP-8120-0)
Short answer: JP-8120-0 is a 9 mm (M9) valve adjusting screw, the threaded tappet screw in the end of each rocker arm that sets valve lash. JP Group cross-references it to VW OE 025 109 451 (JP ref 8111351706). EMPI lists it for air-cooled VW Type 1 and Type 3 rocker arms. It is also the 9 mm screw used on the 1983–1991 Vanagon Wasserboxer. Sold each; eight per engine.
Part numbers: JP-8120-0 · OE 025 109 451 · JP Group 8111351706 · Dansk JP81200 · UPC 707924524550.
Fitment
| Years | Vehicle | Notes |
|---|---|---|
| 1961–1974 | VW Karmann Ghia | Per EMPI, 8 required |
| 1966–1973 | VW Type 3 Fastback & Squareback | Per EMPI, 8 required |
| 1973–1974 | VW Thing | Per EMPI |
| 1978–1979 | VW Beetle (late 9 mm rocker arms) | Per Heritage Parts Centre for OE 025 109 451 |
| 1983–1991 | VW Vanagon 1.9 / 2.1 Wasserboxer | Per FCP Euro / Heritage for OE 025 109 451 |
| Any | Rocker arms with 8 mm threads | Does not fit — most 1961–1977 Type 1 rockers use the 8 mm screw 043 109 451. Measure your thread first. |
Fitment note: VW used both 8 mm and 9 mm adjusters on the air-cooled engine depending on the rocker arm. EMPI's own fitment list is partly cut off, so confirm your thread size before ordering. Your existing screw is 9 mm if the thread measures about 9 mm across (M9 x 1).
Specifications
| Spec | Detail |
|---|---|
| Brand | JP Group (Denmark), distributed by EMPI |
| Part number | JP-8120-0 |
| OE reference | 025 109 451 |
| JP Group reference | 8111351706 |
| UPC | 707924524550 |
| Thread | 9 mm (M9 x 1) |
| Weight | Approx. 0.05 lb (estimate) |
| Sold as | Each — 8 per engine |
What's Included
- One valve adjusting screw.
Not Included
- Lock nuts (sold separately; order the 9 mm nut to match)
- Rocker arms, rocker shafts and valve cover gaskets
Why It Matters
The adjusting screw is the contact point between the rocker arm and the valve stem. Each time the valve opens, the ball end of the screw pushes on the stem. Over many miles the tip wears flat or pits, and the slot and thread get chewed up from repeated adjustment. A worn tip makes valve lash impossible to set accurately: the feeler gauge reads right, but the clearance is wrong because the tip is dished. That leads to a noisy valve train, burnt exhaust valves when lash closes up, and lost power. Replacing worn screws is cheap and is the first fix for a valve train that will not stay quiet after adjustment.
Installation Notes
- Adjust valves only on a cold engine. Bring each cylinder to top dead center on its compression stroke.
- Back off the lock nut, unscrew the old screw and thread in the new one with its lock nut.
- Set lash with a feeler gauge to the specification for your engine (see the Bentley manual or the sticker on the fan shroud), hold the screw with a screwdriver and tighten the lock nut.
- Re-check lash after tightening, and fit new valve cover gaskets.
Frequently Asked Questions
Does this fit my 1971 Beetle?
Only if your rocker arms use 9 mm screws. Most 1961–1977 Type 1 rockers use the 8 mm screw. Measure the old one before ordering.
8 mm or 9 mm — how do I tell?
Measure the threaded shank of the old screw with calipers. About 8 mm across is the 8 mm version; about 9 mm across is this part.
Is this the same as OE 025 109 451?
Yes. EMPI and JP Group cross-reference JP-8120-0 to VW 025 109 451.
Does it fit a Vanagon?
FCP Euro and Heritage list 025 109 451 for the 1983–1991 Vanagon Wasserboxer, which uses the same 9 mm screw.
How many do I need?
Eight per engine, one per valve. Many owners replace all eight with new lock nuts.
What else do I need?
Matching 9 mm lock nuts and a set of valve cover gaskets.
Is it new?
Yes. New, supplied by JP Group of Denmark through EMPI.
Explore Related Categories
Engine Parts & Performance VW Type 3 Parts VW Karmann Ghia Parts VW Vanagon Parts
California Prop 65 Warning: This product can expose you to chemicals including lead and/or lead compounds, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov. Legal for use on pre-pollution-controlled vehicles only.
