Valve clearences?

[s car go]

Hi all,

Can anyone tell me do the valve clearences tend to increase or decrease please??

Regards

Mark

[TonyN]

Valve seat recession will make gaps smaller, wear on the shims/cam lobes or a bent valve will make them bigger.

[s car go]

Thanks Tony,
What I was expecting. Valve clearances seems to be the untalked about subject,as everyone knows they should be done,but no body wants to do them.
The question was prompted by me doing the head change on mine recently,and obviously I had to lap the new valves in.Six out of the eight valves were within tolerance,and the last two were .05 over,close enough in my book!!! Not bad for valve gear with nearly 300k on.

Cheers

Mark

[TonyN]

Yeah, I've do it now and again, but not often, its a pretty good low wear setup for big milages as long motor is serviced regularly.

They can be a pain as unless you have lots of size shims in stock its a bear to measure gaps, remove shim, measure shim, work out new size shim needed order expensive shim from Toyota, and wait around, etc... before you can put it back together.

I've always keep shims from junk motors and have loads now so can mostly do job at once for people.

There's about 18 different sizes @£6-7 a pop from Toyota.