Help - Explain cam timing Please

[Richard K]

Engine is a 1700 X/flow

 

I have fitted a Venire so can adjust.

I have been told to ensure the tappets of No.1 are rocking.

Set up gauge on inlet valve and measure the ‘lift’.

 

I assume I am rotating the crank clockwise. When do I stop? When the piston is at TDC?

Then move the gauge onto the exhaust valve and measure the ‘lift’.

Again when do I stop? When the exhaust valve is closed?

 

Adding inlet and exhaust figures together then divide by 5 the X by 3 gives the max advance.

Adding inlet and exhaust figures together and divide by 2 gives max retard.

 

Take Max advance ‘add’ Max retard then divide by 2 to optimum Cam position when piston is at TDC.

 

Place gauge on inlet valve when closed and open until optimum Cam position figure is reached. Then check if piston is at TDC.

 

I think I understand the maths but can someone please correct me if I have the procedure wrong.

 

Thanks Richard

[ECR]

have you seen this, it might help ....

 

http://www.burtonpower.com/tuning-guides/tuning-guide-pages/camshaft-fitting-timing.html

 

[Richard K]

Yes - I have the Catalogue it came from.

But still not sure how to time the cam

 

The explanation above came one of 'The two Steve's', but I was not sure that I understood him at the time.

The car was only putting out 104 bhp and he said the cam was at least one tooth out.

 

I need someone to explain in step by step terms

Richard

[Grim Reaper]

Do you have a figure for 'Lift at TDC'?

If you do then you need to zero the dial gauge when the valve is closed and take the figure when the piston is at TDC.

Advance or retard the vernier pulley in relation to its centre section to make this figure match with your 'Lift at TDC' figure.

Or follow guide here

Much the same.

 

[ECR]

I added a piece on timing the cams on a VX XE engine to 7faq recently (unfortunately the photos were not added ...). it is much the same as DVA's method but if you give it a read it may also help

[Myles]

Some pages on my site here

 

Practical example based on Oily's advice and website. The only advantage I had was that I was given recommended settings and just had to achieve them.

[Richard K]

Well I have completed the timing set up.

As described in my first post.

 

Ensure tappets on No. 1 are rocking.

Place gauge on inlet valve. Zero. Rotate crank clockwise until the gauge begins to register movement.

Continue clockwise and stop when No. 1 piston is at TDC. Take reading.

Now without moving the crank, place gauge onto exhaust valve.

Rotate crank clockwise until exhaust valve is fully closed. Take reading.

Add intake and exhaust figs. together.

Divide by 5 then multiply by 3. This gives max advanced.

 

Add intake and exhaust figs. together.

Divide by 2. This gives max retard.

 

Add max advance and max retard figs. together then divide by 2.

This gives optimum fig. for cam.

 

Rotate cam around until tappets on No.1 are rocking. Set up gauge on inlet valve. Zero.

Rotate clockwise until the gauge reads 'optimum fig.' The No.1 piston should be at or very near TDC.

If not at TDC, unlock vernier, rotate engine (either direction) until TDC.

Lock vernier, then re-check.

 

Also found this You Tube Vid.

Thanks for all the advice.

Richard

 

Edited by - Richard K on 2 Jun 2014 08:10:36