BIGBOBO wrote:
But anyway, I'll measure them myself this weekend if I have the time.
But I have no clue how to replace them.
Normally you need a special tool no?
No, you don't need any special tools, to check them
(a tourque wrench would be good thou).
Remove the throttle cable tripod thing, remove the 2 cam covers, these can be a bit of a pig, don't use a screwdriver unless you really can't shift them as it's easy to damage the head, I use a hide mallet to tap the side, resonable force can be used, the wooden shaft of a hammer can also be used.
Make sure there is room in front of the car, and on level groud, put the car into 4th gear.
Take off the handbrake, and rock the car forward, the cams will turn slowly allowing you to be accurate with thier placement.
When the bottom of the cam lobe is in line with the shims, measure the gaps and note them down.
Repeat above until all gaps measured.
If, you find any of the gaps are out of spec then you need to proceed to the next step, if not, take out of gear, reassemble and drive
I am a metric man, but I always measure shims in thou's
(imperial), why?, easy, my feeler gauges are imperial
The haynes manual quotes Inlets as 6-10 thou and exhausts as 8-12 thou, I aim for 8 thou on inlets and 10 on exhausts, in the middle of the range.
So, if you have some gaps that are too big/small, then you will need to remove the shims.
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Method 1, use the special shim flipping tool, I have never had my hands on this, so I am unable to comment on how to use it, do a search for
"Shim bank", you may be able to borrow it.
Method 2, no special tools
(apart from a torque wrench), just takes longer
Remove the plastic cam covers, turn the engine to top dead centre
(I use the 4th gear rocking method for this).
Mark the cam belt and timing pulleys with paint/tippex so you can re-align them easily.
Loosen the cam belt tensioner, you will need a long-reach socket for this, a good one, it's easy to mash this up.
Slip the cam belt from the pulley's, place a spanner on the molded
"nut" on the cam(s).
Undo the 14mm bolt holding on the pully(s) and put
to one side.
Undo the bolts holding the metal bracket
(the one the plastic covers bolt to) you will need to ease this forward to remove the cams.
Slowly undo each cam bearing cap, a small amount at a time, until all are off, place to one side, remember to keep them in order.
Remove the cam(s)
Now the easy part, using a magnet on a stick
(£shop special), remove the shim/bucket.
Measure the shim and calc as follows.
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Example on an exhaust shim
(10 Thou wanted).
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Measured shim size
Measured gap
118
(thou)
14(Thou)
We want 10 Thou so 14(measured)
- 10(wanted)
= 4 Thou difference.
As the gap is to big we need a thicker shim
(this one always makes me think a bit) so, 118(measured shim)
+ 4
(difference)
= 120 Thou shim needed.
It's the similar if the gap is too small, except we subtract the differnce.
Measured shim size
Measured gap
118
(thou)
7(Thou)
10
(wanted)
- 7(measued)
= 3 difference, 118(shim)
- 3
= 115 thou shim needed.
It's pretty easy, sit down, have a cuppa, and work them out
I normally find that I can shuffle shims around
(gaps too big for gaps too small) and only need to buy/get a couple of shims
(search
"shim bank" again).
The reassembly is a reverse of the strip down, make sure that the crank and cams have NOT moved, you may also need to reset the distributor.
Obviously tourque settings for all bolts etc should be observerd, and it's a good time to replace the oil-seals on the cams
I would go into the re-assembly further, but my fingers are tired, and most of you have probably fallen asleep by now!
It does sound alot worse than it is to do, it takes me about 2-3hrs to do the above, at a slow, unstressed pace.
If anyone can provided a picture of the shim flipping tool, then this would be good as maybe I can make one, and there will be 2
(or more if anyone else wants to make 1) to share around!
I hope this helps, and I havn't made you run for the gin!
