Cambelt-change

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Info non-talk.png Original write-up by Pantz, located here: http://www.rupertbear.f2s.com/LOTUS_ELAN_SE_TURBO/lotus_elan_cambelt_change.htm

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Hi there.

So you're brave enough to attempt to change your Elan M100 cambelt. It's quite a frustrating job. The hardest bit for me was working out how to undo the bottom pulley nut. You either need to jam the fly wheel or jam the pulley itself. There probably are other ways of getting around this , but I opted for a straight-forward option and made this tool to lock the pulley.

Cambelt Pulley Tool

Once I had loosened the nut, the job took about 4 to 5 hours. When I was getting frustrated with it I just grabbed a coffee and surfed the net.

Treat this as a guide and read pages EC 16 to 19 of the Elan Workshop manual. I aim to improve this write up with input from others. The actual fitting of the belt is straightforward, it's the limited access that is the problem. If I managed the job then I am quite sure you can too.

Tools you'll need

I am waiting for input here. As I completed this job over a year ago, I am waiting for someone to remind me of all the socket and spanner sizes.

If you already have:

  • Metric socket set
  • Metric spanner set.
  • Metric allen key set.
  • Metric spline set.
  • 1 x Standard Lotus jack
  • 1 x Trolley Jack
  • Massive Swear Box...

You will have sufficient tools to complete the job.

Removing the cambelt

If you have not done this job before on this car allow all day and be pleased with yourself if you do it quicker because, after all, there's no hurry and you're going to be saving a lot of money.

I used the standard jack on the jacking point, and a small trolley jack under the engine.

  1. Loosen Right hand front wheel nuts.
    1. Position both jacks.
    2. Remove Wheel.
  2. Remove bottom pulley: 17mm socket you need to jam the pulley or the fly wheel to undo this nut (if you can't undo this nut don't go any further!). Lotus recommend setting the TDC before taking the pulley off. I did this slightly differently because you are better off making sure you can get the pulley off before dismantling all of the engine mount/belts/camcovers because you would be quite sick if you spent a couple of hours undoing everything to find you cannot undo the bottom pulley nut !
  3. Loosen Alternator belt and PAS belt tensioners
    1. Remove these two belts.
  4. Take weight of engine with trolley jack (I used rubber mat on jack so not to damage sump). You shouldn't really jack the car up like this because you can warp the sump, but as it was only taking the engine weight I went ahead as I couldn't see anywhere else to stick the jack)
  5. Remove Right hand engine mount.
    1. Remove the bolt securing the engine bracket to the right hand engine mounting rubber.
    2. Remove the four bolts securing this to the engine.
  6. Remove all Bolts on the cambelt covers
  7. Make sure the engine is set at TDC. That is the two marks on the top pulleys facing each other. Use the long bolts from the cam cover to lock the two top pulleys. Don't worry if the engine is not at TDC. Just pop the bottom pulley on and rotate the engine this way. Don't be tempted to turn it by using the top pulley bolts.With the top pulleys locked you cannot make any mistakes and put all of the timing out.
  8. Elan Cambelt
    This photograph shows:
    1. Cambelt direction
    2. TDC (two red dots facing each other)
    3. How to lock the top pulleys in a safe position
    4. How the cambelt tension should be adjusted
  9. Remove the cambelt, use a spline socket wrench to loosen the tensioner pulley clamp bolt and an allen key to hold the hub, and rotate the pulley clockwise to slacken the belt. Slide the belt off the pulleys.

IF YOU'VE GOT THIS FAR YOU'RE HALFWAY THERE. AND WILL BE FULLY CAPABLE OF FINISHING THE JOB !

Now for some more fun: let's put it all back together again.

Warning.png WARNINGS FROM THE LOTUS MANUAL
  • Don't pry or stretch the belt with a screwdriver or any other tool.
  • Don't force the belt to bend or twist excessively or damage may be caused to the belt core.
  • Don't get oil or any other chemicals on the belt.
  • Store cam-belt in a cool place. Don't expose to heat or direct sunlight. (I suppose the engine's a cool place to store it)
  • Don't rotate the crankshaft or the camshafts with the belt removed or damage may be caused to the valves and pistons


Installing the new belt

Here's a picture of the all the pulleys and the routing of the belt.
  1. Make sure the belt is the right direction.
  2. Slide the belt over the pulleys as shown in diagram. I started from the top and worked the slack downwards. Centralise the belt on all the pulleys.
  3. Tension the belt (roughly at this stage). Check that the timing marks are still aligned (making sure you haven't disturbed these during belt fitting. Then turn the engine two revolutions in the normal direction to settle the belt. (remember to take the two locking bolts out)
  4. Tension the belt. Lotus recommend tensioning the belt at 60Degrees ATDC(After Top Dead Centre) this made no sense to me..
  5. There is a hexagonal socket so you can tension the new belt using an allen key, turn anti-clockwise to tension. The socket is also used to hold the hub from turning while the clamp bolt is tightened. The belt tension should be measured at the position shown on the picture using a firm finger pressure and to the tension shown.
  6. Then, in classic Haynes style, everything goes back together reverse order


Notes from Geoff

Please read in conjunction with Lotus Service Manuals


Remove the bottom pulley

Remove the offside engine mount

You can now get to the plastic cam belt cover and remove all of the bolts (10mm head) from it, lifting it away to gain access to the bits inside!

The tensioner and water pump bolts were all easy to get at and undo (might be a bit harder with the head still on, though, but quite possible). The only tight one was the idler pulley which is on the head, so at least it is easier to reach.

Remember to clean the face where the water pump joins the block with emery cloth to ensure a good joint, use a new gasket and tighten all 5 bolts (12mm head) evenly to keep the pump ‘flat’ to the block.

When replacing the tensioner, the spring has to go the right way round, and can be a bit fiddly – perseverance from underneath was the way I got it done, but with flexible, thin fingers, it should be possible from above.

With the new timing belt fitted, tension the belt from underneath using a 10mm spanner and a 5mm allen key to get the tension correct (as per the manual). Then replace the plastic cover – it is easier than tensioning it through the hole in the cover (with the rubber bung).

Additional Reference

There is a very complete write up with lots of photos of cambelt change, replacing camshaft and crankshaft seals, replacing water pump, cambelt idler and tensioner. It was done by Aamir BT of Isuzone and there is a copy at http://www.kact.co.uk/lec/replacing_timing_belt.pdf