Cam timing K Series

[Mikey UC]

Cam timing using standard non Vernier pulleys.

 

Think I mucked up all the timing marks when I changed the head gasket so I need to set my cam timing from scratch.

 

It seems that the inlet / exhaust marks on the pulleys line up horizontally when the engine is at 90 BTDC, with the exhaust arrows pointing to the left.

 

However, how do you find 90 BTDC? – I know there is a mark on the cam belt cover and another mark on the engine block that lines up with two marks on the crank sprocket , but that seems to be a bit hit and miss.

Is it best to find TDC with a dti and rotate the crack back 90 degrees ?

 

Many thanks for any help

 

[Ray Pearce]

I have seen a thin steel ruler used down the plug holes of no. 1 & 2 cylinders.

 

Measure the depth of both pistons and tweak the crank until they are the same.

 

[revilla]

Simples - There are timing marks on the crank pulley.

 

I tried to find some good pictures online and came across this thread which has all the information you need. Just be really careful rotating the crank and cam to get them lined up as the valves may touch the pistons in the meantime. If I were you I would leave the cam wherever it is then rotate the crank very gently to the "safe" 90 degree position via the shortest route, left or right. If you take the plugs out it should turn over easily so you should feel if anything touches. If it does, back the crank off to gain some clearance before attempting to rotate the cams a bit as the cams won't want to rotate slowly, they will jump and flick around under pressure from the valve springs.

[SLR No.77]

To add .... it needs to be 90º BTDC for no.1 cylinder, ie. the piston starts to move upwards when the crank is rotated clockwise (viewed from the front).

 

Stu.

[Mikey UC]

Many thanks gents.

I’ll line it up with the pulley marks and check it by measuring the 1 & 2 piston positions.

 

[Slipper man]

It is dead easy with the no. 1 and 2 pistons. All you need is two rods of the same lengths (like two old head bolts) and at 90 deg, both are level.

[Mikey UC]

Cheers Gents

 

Checked the cam timing using two bits of tube down 1 & 2 cylinders, sounds much better now.

I was about 5 degrees out before, sounded like a tractor in need of a valve regrind.

Its hesitating a lot on acceleration, I think that’s down to my idle jets being undersized (using Weber carbs).