RECOIL TREAT REPAIR KIT UNC 7/16
Thread Repair Kit UNC 7/16-14
For L-head engine cylinder head bolts
Professional thread insert repair kit for restoring damaged or worn cylinder head bolt threads in the engine block. Specifically designed for the 7/16-14 UNC specification as used on the Willys 134ci L-head engine. Essential tooling for any restoration where cylinder head thread holes are damaged by years of use or incorrect assembly.
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Thread 7/16-14 UNC (Unified National Coarse) |
Application Cylinder head bolts engine block |
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Type Helicoil/thread insert system |
Engine type Willys 134ci L-head (Go Devil & Hurricane) |
Features
- For 7/16-14 UNC cylinder head bolts
- Includes thread inserts, drill and tap
- Permanently repairs damaged threads
- Suitable for all L-head 134ci variants
- Stronger connection than original thread
- Prevents further damage during repeated tightening
- Essential for engine block restoration
★ This repair kit is indispensable when restoring aged engine blocks. After 75+ years of use, thread holes are often weakened — professional repair with thread inserts prevents costly subsequent damage.
Application
Suitable for all vehicles with Willys 134ci L-head engine: MB (1941-1945), GPW (1941-1945), CJ-2A (1945-1949), CJ-3A (1948-1953), M38 (1950-1952), Station Wagon (1946-1953), Pickup (1947-1950), and Jeepster VJ (1948-1951). Original cylinder head bolts are WO638635 specification: 7/16 x 14NC-2 x 2¾ inch.
Installation notes
When fitting the cylinder head, it is highly recommended to preventively inspect ALL thread holes. Use grease on drill and tap to catch metal swarf. Ensure perpendicular drilling — use a guide jig if possible. The L-head cylinder head must be re-torqued 4-6 times during the running-in period; weakened thread holes will not survive this without insert repair. Consider using stud-and-nut combination instead of bolts for improved longevity.
Compatibility
Only for 7/16-14 UNC thread as used on L-head 134ci engine. NOT suitable for later F-head engines (CJ-3B, M38A1) which use different fastening methods. Note: early MB/GPW may have variant bolt sets — always verify SNL (parts manual).
Historical context
Cylinder head bolts are a known weak point on aged Go Devil engine blocks. Due to repeated disassembly and the necessity of multiple re-torquing after overhaul, the cast iron thread holes in the block are heavily stressed. Thread insert repair has been the accepted method since the 1950s to permanently restore this critical connection.
⚠ Spotted an error in this description? Report it to info@willys.be
This part is intended for the restoration of historic military vehicles. Fitting, aligning, deburring or reworking is part of that work and is inherent to the nature of these goods. Dimensional variation also exists between original vehicles.
Installation requires technical knowledge of the vehicle. Unsure whether this part suits your version? Ask us before purchase at info@willys.be.
ALL_CATEGORIES : Upper Engine CJ2A, UPPERENGINEHEAD CJ2A, UPPERENGINEHEAD CJ3A, Upper Engine M38, UPPERENGINEHEAD M38
This part fits:
| Model | Years |
|---|---|
| Military jeeps | |
| Willys MB (early) | 1941, 1942 |
| Willys MB | 1942, 1943, 1944, 1945 |
| Hotchkiss M201 | 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966 |
| Willys M38 | 1950, 1951, 1952 |
| Willys M38A1 | 1952, 1953, 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971 |
| CJ series | |
| Jeep CJ-2A | 1945, 1946, 1947, 1948, 1949 |
| Jeep CJ-3A | 1949, 1950, 1951, 1952, 1953 |
📐 Diagrams & technical drawings
From the original Technical Manual CJ2A_PL_1949 — Parts List — only for Willys CJ-2A / CJ-3A (1949)
