348 Cam timing procedure

I'm going through the cam timing procedure and on page B68 of the workshop manual there is a note about fitting temporary shims in order to set the valve clearance on cylinders 1 & 5 to 0.5mm.

Has anyone done this before and is this step really necessary?

My plan is to obtain the positions of valve lift and then ensure the midpoint of the dwell period is in the correct place to match midpoint of the published timing specs.

I'm just wondering if there is any other reason why the gap needs setting to 0.5

 

Thanks that's confirmed what I was thinking. I will be checking valve clearances and setting the clearances and timing to the non catalyst spec.

I checked the clearances on one intake cam last weekend and all were below spec, 0.1 to 0.15 against a spec of 0.2 to 0.25. Despite this there is no sign of wear on the dwell part of the cam so appear to have got away with it but I have the feeling ill be resetting every single valve clearance on this engine.

 

Will do, I'd assumed it was stretched valves but have not had the heads apart to check the valves or seats. Has good compression and very low oil consumption so had not planned to go in there.

The car is showing 30k miles and the rest of the engine looks and 'feels' congruent to that mileage in terms of general wear and cleanliness.