There isn’t a single universal torque spec for K24 head bolts. The correct value depends on the exact K24 variant in your vehicle (for example K24A1/A2/A3, K24Z1, K24Z7, and others) as well as whether the bolts are standard fasteners or torque-to-yield (TTY) bolts. To avoid engine damage, always use the spec from the specific service manual for your model/year.
Understand your K24 variant
The Honda K-series includes multiple variants used across several models, and each variant can have different head-bolt counts, bolt types, and tightening sequences. Because even small variations in the head-bolt design or gasket material can change the required clamping force, identifying the exact variant is essential before tightening anything.
Below are the practical steps to determine the right torque specification for your exact engine configuration:
Before referencing a list, note that you should verify every detail against official documentation or a trusted repair manual.
- Identify the engine code printed on the engine itself (for example K24A1, K24A2, K24A3, K24Z1, K24Z7, etc.).
- Locate the official service information for your car’s year, model, and region (Honda/ACURA Service Manual, Honda TSBs, or an authorized workshop manual).
- Look up “Cylinder Head Bolts” (or “Head Bolt Torque”) in the manual for your exact variant, paying attention to bolt type (standard vs. torque-to-yield) and the tightening sequence.
- Check for any revision notes or service bulletins that alter the torque specification or sequence for your specific part.
- Confirm whether the bolts are to be replaced (TTY bolts are almost always replaced rather than reused) and whether an angle-tightening step is required after initial torque.
Properly identifying the variant and following the exact procedure protects the engine from head-gasket failures, warped heads, or bolt fatigue.
What to do if you can’t access the official manual
If the service manual isn’t readily available, there are prudent alternatives to avoid incorrect tightening. Contact a Honda/Acura dealership or a qualified mechanic to confirm the precise spec for your exact engine code. Some credible aftermarket manuals and repair databases may list variant-specific figures, but these should be cross-checked against OEM documentation. Never substitute a guessed torque value.
- Ask a dealer or certified shop for the exact torque spec for your engine code and model-year combination.
- Use a reputable aftermarket manual as a secondary reference only after verifying it matches your engine variant.
- If you suspect you have an uncommon variant, treat the head bolts as potentially different from more common K24 configurations and seek confirmation before proceeding.
In all cases, if you’re unsure, it’s safer to delay reassembling and obtain the correct specification rather than risk damage from an incorrect torque.
Common considerations when torqueing K24 head bolts
While you await the exact figure for your variant, here are factors that commonly influence the tightening process and help ensure a reliable job when the correct spec is known:
- Cleanliness and cleanliness again: ensure the bolt holes, threads, and head surface are spotless before torquing.
- Torque-to-yield bolts: if your variant uses TTY bolts, replacement is typically required and the tightening pattern often includes an angle-tightening phase.
- Tightening sequence: follow the precise bolt-order pattern in your manual to prevent head warp or gasket failure.
- Lubrication: use the recommended lubricant on the bolts if the manual specifies it; incorrect lubrication can alter effective torque.
Adhering to these practices helps ensure the proper clamping force and long-term reliability once you secure the head with the correct spec.
A quick recap of the approach
Identify the exact K24 variant, obtain the official torque spec from the service manual, verify bolt type and sequence, and follow the documented procedure precisely. When in doubt, consult a dealership or an experienced technician to confirm the correct value for your engine.
Summary
The torque spec for K24 head bolts is not universal. It varies by variant (K24A1/A2/A3, K24Z1, K24Z7, etc.), bolt type (standard vs. torque-to-yield), and model-year. To ensure accuracy and avoid engine damage, locate the exact specification in the official Honda/Acura service manual for your car’s engine code. If the manual isn’t accessible, contact a dealer or qualified repair professional for the correct figure and procedure. Always verify bolt availability (TTY bolts usually require replacement) and follow the precise tightening sequence provided for your variant.
How much torque does a K24 have?
164-166 lb-ft
K24A2. 10.5:1 CR, 197-205 hp at 6800 rpm, 164-166 lb-ft at 4500 rpm, 7200 rpm rev limit.
What is the K value for tightening torque?
The most commonly used bolting K factors are 0.20 for plain finished bolts, 0.22 for zinc plated bolts, and 0.10 for waxed or highly lubricated bolts. The only way to properly determine the optimum tightening torque for a given application is to simulate the exact application.
What is the torque on the H22 head?
For the Honda Prelude H22 engine, torque the cylinder head bolts in a specific sequence to prevent warping. Start with an initial torque of 29 ft-lbs, then tighten to 43 ft-lbs, followed by a final angle turn of 90 degrees. Use a calibrated torque wrench and follow the manufacturer's bolt tightening pattern.
How many ft pounds of torque for head bolts?
Usually it is a two-step process; go through the pattern tightening the bolts to maybe 45 ft lbs and then going through the sequence again tightening them to their final torque of maybe 85 ft lbs. There is no one-size-fits-all.