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Sunday, 15 February 2015

Timing belt change

Haynes recommends approx. 100k miles to renew the timing belt & elsewhere on the web I've seen recommendation of anywhere between 75-100k miles and 10 years whichever is sooner.

The car only has around 5,500 miles on the clock, but the engine was manufactured in 2004 - so, partly for the sake of  a challenge, I decided to replace the belt.

For reference - the one that came off had no signs of wear, no cracking when folded on itself etc & the idler and tensioner looked brand new.

I'll not describe the whole procedure, I used a Haynes 2004 Ford Focus manual for the main reference , a couple of youtube videos and some chatting on RhoCar before starting.

Things to consider on this process/learned checklist:
  • An impact wrench makes things much easier (possible even) - cam sprocket bolts are T55 torx
  • The cam sprocket holding tool I had was not designed to hold the crank pulley too (protruding lugs too large diameter)
  • The timing tools to lock the cam shaft & the crank are a must have
  • Cam sprockets and crankshaft sprocket are held on by friction/correct torque on their respective  bolts - no woodruff keys
  • The water pump pulley does have to come off because the middle cover plate has a torx bolt behind it.
  • The alternator bottom bracket has to come off to allow the belt middle cover to come off - fiddly due to lack of room even on the wider GT chassis
  • Never loosen anything with the timing cam lock or crank pin in place - any torque on them and things can bend/brake, but at the same time be conscious too much movement will cause damage to the valves.
  • Always turn the crank clockwise (see exception when turning back 1/4 of a rotation mid job)
  • The cam locking bar might not 'slide in' with the original belt in place - a little movement flex in the belt means it could be very tight to slide the bar in at this stage - in any event its not needed until later
Parts
  • The timing belt kit for the 2.0 Blacktop: SKF VKMA 04214 this includes the belt and replacement pulleys.
  • Cam cover gasket search for: Ford Focus 2.0 Gasket kit (eBay).
Covers off reference shot - it was at this point I discovered I had no chance of getting the crank bolt out with a breaker bar and settled on impact wrench approach instead.

Intermediate stage - cylinder 1 @ TDC, intake valve just closed exhaust not opened yet - i.e. compression cycle. Double checked with a dowel(Paintbrush through the plug hole) & the cam locking bar offered up and visible at the back of the engine on the second shot.

Loosening the sprockets with the impact wrench, & spanner on the cam shaft flats. 
Cam lock bar & crank pin is removed. At this point I rotated the crank 1/4 of a turn anti-clockwise, thus if anything moved while loosening the sprocket bolts there is no force on the locking bar, and no chance of a valve hitting a piston.

Lots of steps not pictured (theres nothing to see), its a reasonably straightforward process, with crank turned clockwise against its timing pin and camshafts locked on their bar - pulleys & new belt back on, torqued then careful 2x turn of the engine by hand to ensure everything still lines up & the tension pulley in the same place, 2x manual turn again as a double check, then re-assembly and good to go!

Bottom belt cover

I had a plan re the bottom pulley which didn't quite pan out. I ran into issues tring to remove the crank/pulley nut (before I obtained an impact wrench, 115nm torque) so instead removed the bottom belt cover with the pulley in place. The intention was to reuse at least the top half of the cover - but in the end pretty much destroyed it during removal.

Plan now will be some ali floor just under the pulley to reduce chance of any debris ingress, + restore at least the top half of the bottom cover.

Update - new bottom belt cover installed

Test run

Just back from a test run down the motorway/back roads & everything seems to be fine!

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