180 Jota cam chain tension

[Tapnell]

I’m sure someone can answer this. Should the cam chain tension be consistent throughout crank rotation? Set mine as per manual at + or -5mm with inlet cam lobe on cylinder one at 3 O’clock and TDC on 1 and 3. If I then rotate until middle cylinder is at TDC on compression stroke, there is a considerable amount of chain slack between the cam sprockets

 

[The Sock]

Cam chain tension will remain fairly consistent when engine is turning at moderate to high RPM but, while turning over by hand it will vary according to valves being opened and closed.
That is why static tension is adjusted at a reference point, as indicated in the Handbook.
See attached and note correct tension is "5mm IN EACH DIRECTION UP AND DOWN" ie. 10mm TOTAL.

 

[Paul Marx]

I’m sure someone can answer this. Should the cam chain tension be consistent throughout crank rotation? Set mine as per manual at + or -5mm with inlet cam lobe on cylinder one at 3 O’clock and TDC on 1 and 3. If I then rotate until middle cylinder is at TDC on compression stroke, there is a considerable amount of chain slack between the cam sprockets

No, chain tension will not be consistent through engine rotation because the camshafts will exert a force on the chain according to whether they're lifting valves or not. Which is why there's a given position for setting free play, otherwise it wouldn't matter.
Paul

 

[Tapnell]

Cam chain tension will remain fairly consistent when engine is turning at moderate to high RPM but, while turning over by hand it will vary according to valves being opened and closed.
That is why static tension is adjusted at a reference point, as indicated in the Handbook.
See attached and note correct tension is "5mm IN EACH DIRECTION UP AND DOWN" ie. 10mm TOTAL.

View attachment 85759View attachment 85760

Yes that’s the exact same procedure I followed .