Hi All,

I’ve recently fitted a punto 866 cam & matching P75 shims to my seicento sporting. Before putting it back together I started it up a few times and it all ran well. Once it was all back together properly I took it for a run and noticed it struggles to reach the higher rev range. I’ve read that the 866 cam sometimes needs adjusting by a tooth of two but thought this effected the lower revs? Any ideas why it would be struggling at the top end? I don’t want to pull it all apart again if it doesn’t improve things.

Thanks in advance.

Sounds like the timings out,
I would have thought if it was too advanced it would take away low end and have more top end,

And having to too retarded would take away top end and bring the power lower down

In my experience the 866 pulled nicely from fairly low down an still felt like it was making power to the limiter .

Also bear in mind the ecu also has to adapt to the new cam but I found both my Sei an punto ran lumpy on tick over when I first put the cam in until the ecu adapted to it

Just been out for another drive and I think you're right. It's only noticeable in 4th & 5th gear but the engine bogs down and begins to slow. I thought originally it was struggling with high revs (4k+) but now realise it hasn't got any power to pick the speed up. Have to play with it again next weekend and see if I can get it timed up better.

Thanks for the help.

Just been out for another drive and I think you're right. It's only noticeable in 4th & 5th gear but the engine bogs down and begins to slow. I thought originally it was struggling with high revs (4k+) but now realise it hasn't got any power to pick the speed up. Have to play with it again next weekend and see if I can get it timed up better.

Thanks for the help.

Did you actually check the valve clearances? Just fitting shims from a punto 75 is no good if the clearances aren't right.

Sounds like the timing is a tooth out. Redo the cam timing and that will probably sort it.

I second check the clearances and use a mixture of the shims to get as close as you can to the factory spec. Which you can find on here by searching ; )

(I can't be bothered )