16 replies to this topic

[77LeylandMini]

Found this on ebay, for all the doc's out there, will I even notice a diff. if i put this in, or is it all HOOEY!!
Thanks!!
http://cgi.ebay.com/...sspagenameZWDVW

P.S. that would equal about 120 pounds..
worth it??

[The Matt]

Roller rockers can give good gains, but it does depend on other engine compnonents. They open the valve further by having a higher lift ratio to standard. I would be careful of these ones though, it may be just me, but they don't appear to have a thread in the back of the rocker, where you would adjust your valve clearance?? :erm:

What other engine modifications do you have?

Edited by mini mad me, 20 December 2005 - 07:40 AM.

[The Matt]

or is it just the small screen on my laptop combined with my tired eyes? They must be threaded for the adjusting screw!

[77LeylandMini]

becides being bored out the engine is prety much stock! Wanted to improve performance on a limited budget!!

The only thing i have done is replaced the ignition for electronic ignition with adjustable curves.
Thanks for the help!!

[The Matt]

Well, basically they will open the valves further than standard. It is an easy bolt on modification (I have a set). Valve clearances may be different to standard (not so sure on that one). The ones you posted are quite a small lift ratio so won't offer masses of improvement, but if the valves are opening a little further, they will let a little more fuel/air in and a little more exhaust out! With a better camshaft you can also alter the duration of the valve phases (286 duration camshaft etc) by combining the two you can have yourt valves open further, for a longer period of time. Another big pro with the rollers is less side load on the valves and therefore less wear.

They won't give as much of a gain as say a decent camshaft and a new exhaust manifold and carburettor, but they are an often used piece of kit. Have a look on Calvers Corner on the minimania.com website or on minispares.com. He did a review of all the different types of rockers and it makes interesting reading.

Edited by mini mad me, 20 December 2005 - 11:59 AM.

[77LeylandMini]

I was told that a camshaft wont make a bit of diff. unless you have a high flow head, is this true? And can a camshaft be changed with the engine in the car??

I have a stage 1 kit with an rc40 exhaust

[Guess-Works.com]

If you go to a high lift cam, then the increased ratio will not have much effect unless you have a worked head ( were talking stage 4/5 here ), even on a Stage 3 which is about the same valve wise as a cooper S head, once a high lift cam is installed there is very little to gain, al you start to do then is waste power by depressing the valve further than is necessary...

But they are a very good bolt on when using a std cam.. what I would do is change the valve springs though to some competition ones with fewer turns in the actual spring, because you will be pushing the valve down further you may come across the phenomenom call valve crush.

[77LeylandMini]

So leave the stock cam, do the rockers and springs? or dont bother with the rockers either?? just springs?

[Guess-Works.com]

I was told that a camshaft wont make a bit of diff. unless you have a high flow head, is this true? And can a camshaft be changed with the engine in the car??

I have a stage 1 kit with an rc40 exhaust

A cam change, will have a noticable effect, even on a std head. Not only do they increas the lift, but also the duration ( the length of time the valve is open and the point at which it opens in the 4 stroke cycle )

Even a tame road cam like the 266 is a vast improvement over the std ( and is a fair aproxomy to the addition of increased ratio of the rockers )

but, unfortunately, a solid walled 1275 unit can realy only have the cam changed with the engine out the car, it can be done in with the use of magnets on pushrods to hold the cam followers up, but one slip and a follower ends up in the gearbox, and then thats engine out and splut to retrieve that... which is what you'll have to do anyway... also you'll need to cut a hole in the inner wing to allow you to withdraw the cam... (it's all a bit too fidly for my liking and hence easier to remove the engine )

[77LeylandMini]

Gotcha! As far as the springs go, I was looking on the MiniMania website, what # spring would be appropriate for the rolloer rockers listed above? I cant find any springs called "competition" but plenty of springs from 120#'s to 350#'s
Thanks again for your time!!

[Guess-Works.com]

If you do the rockers I'd do the springs, the springs themselves will make no difference... ( may allow you to rev a little higher but not much )

but before you buy off ebay, look at the minimania websote, and see how much they can supply them for... also ask if the pedestall and rockershaft etc are in the deal ?

[neil_g]

im running 1.5's with my MD286

dont go for silly Ib springs, youll just wear the cam lobes.

[77LeylandMini]

I smell a debate coming on!! :tongue: The rockers on ebay are just the rockers, no shaft no pedistal, he claims you can re-use the stock shaft and pedistal.

Hey Neil, are you running a stock head?

[Bluemini]

If they came with the shaft and pedestals then I would say do it, but if its just for the rockers then leave them as you can buy the complete deal from minispares etc for not that much more.

If you fit new rockers, then idealy you want to fit a new shaft too.

[77LeylandMini]

Thats what i figured, thanks Rich! Work up any dates you might want to come over to the States??