Description
Product Overview
The iFJF Lost Motion Assembly (LMA) is a direct replacement for the VTEC rocker arm mechanism in Honda B-series engines — including the legendary B16A, B16B, B18C, B18C1, and B18C5. The LMA is a spring-loaded plunger that maintains tension on the VTEC rocker arms during low-RPM (non-VTEC) operation. When LMAs wear out or seize, you get the dreaded "VTEC tick" — a rhythmic ticking noise from the cylinder head, poor VTEC engagement, and potential rocker arm damage. This kit of 8 LMAs replaces all units in a single cylinder head.
Key Features
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Complete Set of 8: One head requires 8 LMAs — this set provides everything needed for a full replacement. No need to piece together individual units.
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OEM-Grade Spring Tension: Precision-calibrated internal springs match factory spring rates for correct VTEC rocker preload and smooth engagement/disengagement.
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Eliminates VTEC Tick: Collapsed or seized LMAs are the #1 cause of rhythmic cylinder head ticking at idle and low RPM. New LMAs restore quiet operation.
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B-Series Specific: Engineered for B16 and B18 VTEC cylinder heads. Inspect the tip condition and overall length to verify compatibility before installation.
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Restores Lost Power: Worn LMAs cause incomplete VTEC lobe engagement — you lose the high-RPM power bump that makes VTEC engines special.
Compatibility Table
| Make |
Engine |
VTEC |
Applications |
| Acura |
B18C1 / B18C5 |
DOHC VTEC |
Integra GSR / Type R |
| Honda |
B16A / B16B |
DOHC VTEC |
Civic Si / Civic Type R / Del Sol VTEC |
| Honda |
B18C |
DOHC VTEC |
Integra (JDM), Civic (swapped) |
Specifications
| Specification |
Value |
| Part Number |
312-05-0200 (OEM equivalent) |
| Application |
B-Series DOHC VTEC Cylinder Heads |
| Quantity |
8 LMAs (Complete Head Set) |
| Material |
Hardened Steel Body, Spring-Loaded Plunger |
Symptoms of Bad LMAs
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Rhythmic ticking from the valve cover area at idle — sounds like a sewing machine running at half engine speed
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VTEC engagement hesitation or "surging" during crossover (typically 4400-5800 RPM depending on engine)
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Loss of top-end power — dyno charts show a flat or declining power curve after VTEC should engage
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Metal debris in oil from severely worn LMA plunger faces
Installation Notes
LMA replacement requires removing the valve cover, camshafts, and VTEC rocker arm assembly. This is an advanced engine-internal job. The camshafts must be removed in the correct sequence to avoid warping. Use assembly lube on the LMA bores and soak new LMAs in engine oil before installation. Always replace the valve cover gasket and cam seals while you're in there. After installation, bleed the LMAs by letting the engine idle for 10-15 minutes before taking it above 3000 RPM.
Frequently Asked Questions
Q: Are these compatible with B20 (non-VTEC) engines?
A: No. The B20B/B20Z does not have VTEC and does not use LMAs. These are strictly for DOHC VTEC B-series heads.
Q: Can I just replace the noisy ones?
A: You can, but it's false economy. The labor to access LMAs (cam removal) is the same whether you replace 1 or 8. If a few have failed, the rest are not far behind. Replace all 8 as a set.
Q: How do these compare to OEM Honda LMAs?
A: These meet the same dimensional and spring-rate specifications as OEM Honda part 312-05-0200. They are a cost-effective alternative for engines where OEM parts have become discontinued or prohibitively expensive.
Q: What's the difference between intake and exhaust LMAs?
A: On B-series DOHC VTEC heads, the intake and exhaust LMAs are the same part — they are interchangeable. All 8 units in this kit are identical.
Q: Do I need to bleed or prime these before installation?
A: Soak the LMAs in clean engine oil for 10-15 minutes before installation to pre-fill the internal oil passages. After assembly, idle the engine for 10+ minutes to allow full oil pressure priming before driving.
