8 replies to this topic

[racingbob]

mate has just ordered some offset rocker bushes for his mpi

 

I assume there ok for the sintered rocker gear

 

are they easy to fit looks like they give 25 - 30 thou more lift

 

all helps bit here bit there

[ACDodd]

Nope, they are for the older pressed steel rockers.

Ac

[racingbob]

Nope, they are for the older pressed steel rockers.

Ac

ah! I thought that might be the case

[carbon]

If you do manage to fit the offset bushes to a set of rockers, then you shoud also either modify the pillars or find a set of the correct offset pillars which are like hens teeth...

[racingbob]

If you do manage to fit the offset bushes to a set of rockers, then you shoud also either modify the pillars or find a set of the correct offset pillars which are like hens teeth...

why do you have to modify the pillars after fitting bushes

[Swift_General]

As otherwise the rocker will not sit where it should over the valve and pushrod.

[racingbob]

As otherwise the rocker will not sit where it should over the valve and pushrod.

how

 

As otherwise the rocker will not sit where it should over the valve and pushrod.

 hows that done, modify pillar

[Swift_General]

As otherwise the rocker will not sit where it should over the valve and pushrod.

how
 

As otherwise the rocker will not sit where it should over the valve and pushrod.

 hows that done, modify pillar

If you us offset bushes then the centre of the bush is offset towards the pushrod end of the rocker. Moving it this way increases the lift to the valve end. Moving the centre of the bush that way means the rocker moves the other (i.e. towards the valve). The contact patch on the top of the valve moves and the pushrods are now leaning towards the valve unless the shaft is moved towards the pushrods by the same amount the bushes are offset to bring the rockers back to their original locations, hence the need for modified pillars. You may get away without - I don't know as I've never tried it but it would be ideal in any case. Not sure if you could modify standard pillars yourself or where currently sells them I'm afraid.

Edited by Swift_General, 08 March 2015 - 09:44 PM.

[carbon]

The old 'workaround' here was to open out the stud holes in the pillars with a larger drill size, so the pillars could all then be moved so the rocker tips are centralised over the valve ends.