Offset rockers
Turbo Mini Forums

Hi folks,

I'm just messing about with some old mini bits that I have laying around in my shed and I have found a spare set of later type rockers (standard lift) and I remember seeing that you can get a offset bush kit for the early pressed style rocker assembly, has anybody ever given it some thought about machining the later type to give higher lift? Please don't shoot me down too much here as I'm only doing at as a engineering excercise and not going to use it on a engine....I do have access to mills, lathes etc so no problems there....any help or measurements for machining will be great.

Thanks

Paul

I maybe wrong but surely offsetting them would put the pushrods at a weird angle?

Also don't think it's worth the hassle. Just get the right cam for the engine build.

I have a set of the forged rockers with offset bushes in my engine that has now done over 7K.

Received wisdom from Vizard is that you drill out the rocker posts to move them to align everything.

The tricky bit is getting the offset bush in exactly the right place in the rocker. I broached mine rather than reaming them.

TBH, although they have given me no problems, I doubt if I would bother again.

IIRC they dont exactly give much more ratio do they? somthing like 1.3 to 1.35

I did some once with pressed steel. Didnt have a problem. Just aligned the bushes by eye. Marked each rocker and marked a line across the offset bushes before I parted them off to align when pressing them in, then honed to size. The tolerances are poor in the first place I think so you never going to get it spot on..

No, they don,t Joe, but at the time I was scratching around for anything. I was a turbo virgin and had no ideas except what was given to me on here.

Not much better now !

To go from 1.23 ish to 1.40 I estimate that you'd have to move the pivot 2mm back. If you're talking about later sintered (non-bushed) rockers, you'd now need to allow for a bushing too. I can't see there would be much metal left on the rocker's underside for any half decent change in ratio.

I never use the sintered ones.

I have two sets of forged ones and some of the pressed steel ones,which can be reinforced with weld, a la Vizard.

Both I suspect are lighter than the sintered ones which were just a cheaper production alternative.