Lude Generation

Some time shortly, I'm gonna tackle checking & adjusting my car's valve clearances.

I have some queries...

1) According to the workshop manual, the clearances are:

• Intake: 0.24 - 0.28mm (0.009 - 0.011 in)
  Exhaust: 0.28 - 0.32 mm (0.011 - 0.013 in)

Is it best to adjust the clearances to the higher end of that range or the lower end?

2) I assume no specialised tools are essential for this? I understand I can buy a valve clearance adjuster tool which makes things easier but it isn't essential. I've also read about some sort of special tool for turning the crankshaft, but I get the impression that a 19mm socket on an extension does the job?

3) My newly purchased Draper feeler gauges are straight. Do I have to bend them?

I thought the h22 clearances were 0.006-7 and 0.007-8

h10ndr wrote:I thought the h22 clearances were 0.006-7 and 0.007-8

Oh buggerations! Yes, I was looking at the pages for the F20A4 & F22A2.

The H22A valve clearances are:

• Intake: 0.15 - 0.19mm (0.006 - 0.007 in)
  Exhaust: 0.17 - 0.21 mm (0.007 - 0.008 in)

Done my a little while ago, I did it so there was a little drag on the feeler gauge on the lower value although I would check the values as I don't think they are right. no special tool necessary, turn crank with the socket and extension bar you stated just remove plugs and it will be easier. straight gauges are fine as you are measuring between cam shaft lob and tappet.

I would imagine the optimal measurement would be smack bang in the middle and they have given you a tolerance.

remove spark plugs.
jack passenger front wheel off the ground
put car in 4th gear.
turn the wheel by hand this will then give you great control when getting the valve lift at its highest.
no good for autoboxes though.

Its fiddly to adjust intake valves as they are hard to reach, and the adjustment always tightens up when u do the lock nut.

Set them, then recheck them just to make sure

As said I set them to the middle value and use the 2 either side to check it's the correct tightness

Yep, the japs will have set them up to the nominal value wherever possible, not the tolerance.

I remember at Universty we had a worked example from industry based on reliability of shared design gearboxes between Ford and Mazda. They were finding that gearboxes manufactured in Mazda factories (parts from Jap suppliers) were quieter and never failing, whereas gearboxes manufactured in Ford factories (parts from European suppliers) were more noisy and were suffering from premature failure in some cases. They expected to find differences in the manufcturing processes or that the japs had refined the design etc before/during manufacture. What they found was that everything was exactly the same design and no real difference in manufacturing process, just that the japs were manufacturing to the nominal, whereas the europeans were manufacturing to the tolerance...

I'm gonna tackle this task after work today. I've read conflicting stuff on the interweb as to the correct place to check the clearances. Some say between the cam lobe and rocker arm? Some say between rocker arm and valve? I think these are the names of the parts which I've read about.