cam timing questions

when you use a grade scale then: yes - but then also you have to adjust the valve clearance to 0,5 mm for the 1st and 7th cylinder
if you use the marks on the cams then all those 4 marks on the cams are only good if the cyl 1 is in TDC

 

You can use any cylinder as long as you start with that cylinder at TDC.

 

the timing marks at the cams are so, that you put cyl. 1 to TDC and the 4 marks at the cams may match with the marks on the upper half shells of the camshaft bearings. if you adjust so the engine will always run, but it is not perfect. the marks on the cams cyl. 7 to 12 has nothing to do with the TDC of one of those cylinders, because cyl 1 has to be in TDC as I remember right??? but I will have a look later in my basement where there are 2 more TR engines to make sure. but also in the WSM it says the same.

the "test valve clearance" to adjust right the timing is 0,5 mm. so you may use a shim that the clearance then between the cam and this shim is 0,5 mm, but don´t forget after this adjustment to change again the shim to the right size

 

I just come out of my basement and have to cofirm what I have written before:

the marks on the cams are ALL for cyl. 1 is in TDC

so when you turn the crankshaft 720 ° that cyl. 1 is again in TDC then all marks on the cams have to be equal with the marks at the housing

 

Hi Tommie,
There are a lot of threads on this forum regarding opening lift and cam duration. I set the cams on mine a few months back while doing the major service.

First off, the diagram in the WSM shows the rotation counterclockwise, that is an error as one member has posted an amended pdf diagram which makes more sense.

Second, the confusion of what is termed át .5 lift' for the duration checking was confusing; as too many opinions have been posted. I had to apply commonsense and trial and error to get it right.

The degree wheel has to be reset to 0deg TDC for #1 and #7 . IIRC the lift referred to is the distance the valve has moved off its seat for the opening duration to begin and it returns to that setting(.5mm) for the conclusion of the closing travel. If your shim clearance is correct on all of yr valves (inlet and exhaust clearance) then the duration at .5mm lift and back to .5mm again as it closes will correspond to the degrees of duration for each of the inlet and exhaust durations stated in the WSM.

One thing I found was, 2 of my valves had extra clearance of .02mm, a seemingly insignificant amount; however the amount of cam rotation used to get the valve to .5mm lift is reducing the duration of the valve being open for its optimum efficiency. In other words, it opens quite few degrees late and closes an equal number early.

If you are not aware of the amount of variation between the shim clearances, you may well chase yr tail for quite a while thinking the cams are out...but in reality it is showing the opening at .5mm lift later and showing the close earlier. I took the rotational duration for each in/exh duration and it was the same angular variation each side of the 'segment' which confirmed the open/close- before/after TDC/BDC.

I hope this has been of some help if it is decipherable - as comprehension and explanation are sometimes not a given.

Cheers
Pete