will the roller rocker arm from mini work in the M20?

[Coyote_ar]

http://www.amazon.com/Mini-Valve-Tim...bmw+rocker+arm

found out that while searching for rocker arms in amazon ... any ideas if that will fit in the M20?

maybe it will require a custom cam as for the roller kit from RHD engineering. but aside from that, do the dimensions match?

[stonea]

Any reason you think this would work or just the fact the BMW owns Mini?

[Coyote_ar]

well, i have never had the one from the mini in my hand (didnt even know they existed until a few hours ago), so im not sure about the dimensions. im trying to find that but no luck so far. im asking in case some BMW mechanic here is familiar with those. you can bet im betting (hoping) they are somewhat compatible since minis are also BMWs.

aside from that, what i can guesstimate from the images i got, it looks like the dimensions should be close to whats needed to make it work. asuming the diameter of the hole for the bar is the same. they have a slight bend, so that could be a problem.


the 16v SOHC head of the R50/51/52 minis has a somewhat similar layout to the M20, at least for the intake ... with the exception they have 2 valves on that side.

based on what i've read on madhatter's thread. the stock cam wont work with a roller rocker arm since the diameter of the roller wont match the one from the pad on the stock rocker. so even if all dimensions match, you still need a custom cam. its far from a plug n play thing. but i guess a custom cam is easier to get than custom roller rockers.

[itsonlygeorge]

will the roller rocker arm from mini work in the M20?

I'm pretty sure there's rockers with rollers on them already for available for the M20.

http://racehead.com.au/products-page/bmw/bmw-m20-roller-cam-conversion-kit/

E30tech thread:

http://www.e30tech.com/forum/showthread.php?t=108906

Sent from th

[SkiFree]

Concerning the rocker itself. The mini rockers ride on a different shaft diameter and the foot is too long and offset.

Had one floating around the shop. Good try though.

It may seem expensive, but given low production volume costs the RHD's are actually a pretty good bargain given the engineering and manufacturing involved.

[Coyote_ar]

I'm pretty sure there's rockers with rollers on them already for available for the M20.

http://racehead.com.au/products-page/bmw/bmw-m20-roller-cam-conversion-kit/

E30tech thread:

http://www.e30tech.com/forum/showthread.php?t=108906

Sent from th

yes, those are the ones i was referring to made by madhatter (or rama, or e21jps, or 1jzracing), many names for a single person.

his product is great, but the cost of the full kit + shipping makes it a lot of money.
so if i could get halfway of what he made, using stock rockers from a mini. that would be awesome.

the kit he sales is extremely hardcore, i think able to rev up to long nines or maybe more. i was looking into this for something quite milder, more like 8k with stiff springs reliably. plus the fact that using OEM rockers would make it easier to replace parts in case of failure.

Concerning the rocker itself. The mini rockers ride on a different shaft diameter and the foot is too long and offset.

Had one floating around the shop. Good try though.

It may seem expensive, but given low production volume costs the RHD's are actually a pretty good bargain given the engineering and manufacturing involved.

Ok, this is what i was looking for. someone who knew those rockers and the M20 and could tell if the would work. too bad they wont.

i agree that for the price, the RHD kit is great. its not much more expensive than a high end cam, and its extremely hardcore with a lot of R&D thrown at it.

but i just wanted to see if it was viable to make something less extreme using OEM parts. making a cam here is not that expensive, even getting one done from a virgin cane and then hardened. its the rockers what i wouldnt be able to make here at a reasonable price. so thats why the mini ones were interesting.

thanks for the input guys.

[digger]

Not many cam grinders can grind the roller cams with inverse radius which I believe the kit uses.

[Coyote_ar]

is that different to a cam profile used by a OHV I6/V8 with roller rockers?
and does that small depression make a huge different than a flat side?

[digger]

Inverse radius camshafts are not that uncommon on pushrod stuff with roller lifters but not everyone can grind them. Plus with a new billet cam that you can’t find cores for you need to buy the billet/blank then machine, heat treat, then grind/polish the cam etc etc to so it is a true custom cam made to the required spec rather than made cheap, not just a custom grind with existing core or regrind/ hardweld cam. part of the cost is also on the details of lobes to get correct profile

[Coyote_ar]

as you say, there are no blank cores. so the part must be custom made from billet steel. but the blank itself is not that complex and it can be made by a workshop. thats quite a normal practice for us here ... even if the blank exists ... usually its cheaper to have the core made from billet steel here.

the machines to make the custom cam profiles are there, i know many performance shops who make custom cams for different racing teams.
this is the guy i was thinking on having work with this kind of cam in case the rockers worked. he has worked on similar projects before.

https://www.facebook.com/levaspellegrini/?fref=ts

its the design of the cam lobe profile is really the biggest challenge and where the time invested by Rama really pays off. but even that is still within the experience of this guy.

but anyway ... rockers wont work. and without that, the rest is pointless.