IMS Bearing Replacement Overview

IMS Retrofit & Procedure Overview

Bentley Publishers has produced an excellent video on the IMS Retrofit procedure using the LN Engineering IMS Retrofit kit and IMS Pro Tool Kit based off the procedure developed by Flat 6 Innovations and LN Engineering LLC.

WE DO NOT PROVIDE SUPPORT FOR INSTALLATIONS! IF PURCHASED THROUGH A DEALER OR RESELLER, CONTACT SOURCE FIRST. PROFESSIONAL INSTALLATION RECOMMENDED AND REQUIRED for limited warranty.
For engines with a factory dual row IMS bearing, the appropriate dual row IMS bearing replacement kit must be used. Likewise, engines with a factory single row IMS bearing must also use the appropriate single row kit. Bearing kits are non-interchangeable.
Use PST2, PIWIS, or equivalent tester to read live DME values for camshaft timing. If there is more than 7 degrees of deviation, do not proceed with retrofit procedure. Deviation over 4.5 degrees on a 97-02 Boxster and 99-01 911 will require replacement of the Variocam chain wear pads (ramps) and the 4th and 5th timing chains, along with re-timing of the cams, before the IMS replacement procedure can be carried out.
Prior to starting this repair, drain oil, remove filter and oil pan and inspect for debris. If any foreign object debris is present IMS Retrofit procedure should not be carried out. NOT PRE-QUALIFYING A JOB PROPERLY VOIDS ANY WARRANTY.
Put engine at TDC, and lock out the pulley so the engine cannot turn over with lock pin.
Use appropriate long cam lock tool for 3-chain or short cam lock tool for 5-chain engine to lock cams prior to removing chain tensioners. Lock camshaft in head with tensioner accessed from underside of the engine, closest to flywheel.
Remove the IMS to crankshaft chain tensioner as well as the chain tensioner on the cylinder head for which you have locked the cam. If tensioners are worn or were noisy at startup, replace. NOTE: If the flange does not come off easily, the bearing is not centered, or you cannot reinstall the flange, then loosen and/or remove the third chain tensioner and verify or correct camshaft timing.
Remove hub flange. You should not have to apply excess force to remove the flange!
If the bearing has started to fail or is failed, STOP. You should not proceed further. Engine disassembly is required to correctly repair the engine.
If center stud/bearing support is broken or breaks during bearing extraction, use LN Engineering “Easy Out” Tool.
If it is a single row bearing, remove the snap ring. Retain original snap ring on single row bearing as you will re-use it, if fitting an IMS Solution or single row RS Roller kit. For dual row bearings, the retaining wire-loc is internal and will collapse as you pull on it. The Single Row Pro uses an internal wire lock, which requires use of the Faultless IMS Tool.
Thread hex bar adapter onto existing bearing support/center stud (already attached to bearing puller, sold separately). Tool kit includes 2 hex bar adapters – the one with the notches on circumference of hex is for pulling LN bearings.
Adjust nut until sleeve of bearing puller rests on the face of the intermediate shaft (around bearing housing bore) and lubricate puller before extracting bearing. When bearing is extracted, the bearing and puller will come away as a single unit; then clean out IMS tube. On engines with a factory dual row bearing or previously fitted with a Single Row Pro, be sure to account for all of the internal wire lock after extraction.
Remove nut from new bearing support (already pressed into new bearing in center race) and slide the aluminum bearing driver/installation tool over the stud, counter-bored side facing outside of engine. Leave spare 1.5×10 mm o-ring at base of center stud.
Before installing the new bearing, note if the old bearing shows movement on the outer race. If yes, measure the housing for ovality. Consider using a small amount of Loctite Bearing Mount on the outer race to prevent rotation. Loose fit can lead to premature bearing failure.
Place bearing and driver in freezer. When cold, holding the installation tool, use a Snap-On dead blow (red, plasticized hammer) and drive new bearing into place, ensuring the intermediate shaft is fully resting on the oil pump console.
If bearing goes in crooked or must be removed for any reason, do not re-use bearing—it must be replaced.
Install spiro-loc on dual row or snap-ring on single row bearing (single row pro uses an internal wire lock).
Inspect new hub flange seal and block bore for imperfections. If the IMS housing bore is not perfectly centered in the case opening, either the engine is not at TDC, camshaft timing is off, or you forgot to remove one or more of the chain tensioners. This needs to be corrected before moving forward or you will end up with oil leaks or will damage the new IMS bearing.
Lubricate o-ring on new flange and install with three M6×25 bolts, tightening in a star pattern slowly.
Once flange is seated, remove M6×25 bolts and replace with new micro-encapsulated bolts. Use flange sealant on bolt heads and torque to 7.5 ft‑lb (10 Nm).
Install and torque center bearing support 12-point nut to 7.5 ft‑lb, using flange sealant and thread locker on exposed threads and o-ring if needed.
Reinstall chain tensioners with new sealing rings and torque to 59 ft‑lb.
Install new cam plugs in cylinder head valve covers.
Replace accessible rear case perimeter bolts with new factory micro-encapsulated bolts.
Replace rear main seal with updated Genuine Porsche PTFE seal.
Verify engine timing after installation; re-time cams if deviation from pre-procedure timing exists.
Use Driven DT40 or appropriate Driven Racing Oil every 6 months/5,000 miles (street use). Reusing old oil or not observing intervals voids warranty.
Non-receipt of original bearing or not registering the installation voids warranty. The original bearing (with intact grease seal) should be sent to LN Engineering LLC, 125 Gladiolus St., Momence, IL 60954. Bearing registration must be done online at https://imsretrofit.com/warranty-registration-step-1/.