IAG Performance Adjustable Timing Idler Kit for EJ20/EJ25 Subaru WRX, STI, LGT, FXT

IAG PerformanceSKU: IAG-ENG-5120

Sale price$179.99

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IAG Performance Adjustable Timing Idler Kit for EJ20/EJ25 Subaru WRX, STI, LGT, FXT

IAG is excited to announce that we have acquired the rights to LIC Motorsport’s Adjustable Timing Idlers. In an effort to continue offering an extremely popular and proven product to the Subaru community, IAG approached LIC in early 2020 with the intention of expanding their offerings to IAG’s growing network of retail and wholesale clients. Once terms were agreed upon, some very minor design tweaks and adjustments were made to the product.

The timing idlers were developed and extensively tested and proven in the LIC Time-Attack program. Over the past decade the eccentric idlers have become the installer’s standard in both street and motorsports applications, playing a helpful role in bringing cams back into proper alignment with heads or blocks that have been resurfaced or feature thicker head gaskets.

The IAG Performance Adjustable Timing Idler kit is specifically intended to properly align the camshafts on Subaru EJ20/EJ25 cylinder heads and/or blocks that were resurfaced (“Reducing” long block length), or utilize thicker head gaskets (“Increasing” long block length). The ability to adjust and properly align the cams is recommended for any performance built Subaru.

The product is precision CNC machined and hand assembled in-house. Each idler features a machined 10mm hex enabling your socket to hold it in place while you adjust the timing to perfection. The idlers come engraved with the IAG logo on the face and are manufactured to strict OEM tolerances.

How it all works:

  • Idler #1: This upper idler when adjusted affects the RIGHT (Passenger side) intake/exhaust cams.
  • Idler #2: This lower idler when adjusted affects the LEFT (Driver side) intake/exhaust cams.

The adjustable idler kit is designed for long blocks that were reduced in overall length due to resurfacing the heads during a rebuild or decking the block and/or both. When that process is done it effectively retards the timing, because the belt has not changed length and something needs to make up that difference in the slack (the tensioner can only do so much). Likewise if you utilize thicker head gaskets, the same issue is present (just vice versa, which is increasing the overall long block length).



  • (x2) OEM Quality Idlers with CNC machined Eccentrics (Single roller bearing design)
  • (x2) M10 Zinc Plated Bolts


Install Warning & Maintenance:

  • A professional install by facilities well versed with Subaru engine builds is highly recommended.
  • At no point in time should these idlers ever be maxed out and used as a means to suffice a poor quality block/heads that have been machined down too far. The idlers should never be used for timing components that are more than 1 tooth out of alignment. A motor that is off by more than 1 tooth has other underlying issues.
  • Inspection of threaded areas that the old idlers came off from is essential. Catastrophic failure can result from performing this job improperly.
  • Street cars should replace every 60k miles!
  • Race/Track cars should replace yearly and/or each engine teardown

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