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offset rocker bushes
https://www.ausmini.com/forums/viewtopic.php?f=5&t=35468		 Page 1 of 1
Author:  mini-dunger [ Wed Sep 05, 2007 7:56 am ]
Post subject:  offset rocker bushes
Hi all

I just got a set from the UK. Pressing the old ones out and the new ones in is simple enough, but the instructions did not mention anything about drilling oil holes? I had a look at the old ones and they have oil holes and a slit running round part of the bush. Do I have to drill em before I press them in? or just machine em so they are sloppy and hope oil makes its way in there?

Lastly how do I get the rocker pillars off the shaft? BFH?

thanks guys
Author:  drmini in aust [ Wed Sep 05, 2007 8:20 am ]
Post subject:  Re: offset rocker bushes
mini-dunger wrote:
Hi all

I just got a set from the UK. Pressing the old ones out and the new ones in is simple enough, but the instructions did not mention anything about drilling oil holes? I had a look at the old ones and they have oil holes and a slit running round part of the bush. Do I have to drill em before I press them in? or just machine em so they are sloppy and hope oil makes its way in there?

Lastly how do I get the rocker pillars off the shaft? BFH?

thanks guys


OK here we go...
The hole is primarily to lube the adjuster and pushrod socket.

It depends what rockers you have, if they are S rockers you can grind the plug off the end and then redrill through the bush. Tack weld the hole up when finished or just leave it open.
If they are pressed metal ones you have to drill the hole before pressing the bush in. That's how I did my 1.3:1 set.
There is no need for the groove. Put the hole in the same position as the old ones.
Do NOT make them sloppy or you defeat their purpose. You want no more than .0005" (1/2 a thou) clearance. I'd use a thick wall rocker shaft, the originals flex.

Finally, put them in the right orientation- the thinnest part of bush is facing the adjuster ball. Make em all the same... :lol:

Good luck, it's a PITA job to align those- I found it easier to make mine from solid bronze and then offset bore in the mill.

To get the pillars off, I just hold #2 pillar in the vice and wiggle the others off.
If they are alloy, THROW AWAY and find some later ones. The alloy ones can collapse when the head is torqued down, that's why BMC changed in the mid 60s.
Author:  mini-dunger [ Wed Sep 05, 2007 6:27 pm ]
Post subject: 
thanks doc

I have a later set of sintered metal rockers so I will pinch the posts from them. Getting everything in the right position shouldnt be to hard I will just grab a texta and mark the bush and the rocker then just line the holes and press away. (sounds easy in theory).

As long as I get the bushes machined so they are snug on the shaft I shouldnt have to worry about renewing the shaft should I? :shock:
Author:  drmini in aust [ Wed Sep 05, 2007 7:48 pm ]
Post subject: 
You will find the old shaft is worn to hell where the rockers run. Buy a new shaft or it's a waste of time. ... HD one preferred.
Author:  mini-dunger [ Thu Sep 06, 2007 8:11 am ]
Post subject: 
doc,

I was thinking about drilling a hole in an old rocker shaft adjacent the adjuster ball.
That way all I would have to do is mark the thinnest part of the bush then slide it on the end of the shaft and align the mark with the hole i drilled.

making sure the bush dosent move all I have to do is put another mark where the new oil hole in the bush should be.

the rocker is going to be moving back and forth across the shaft so providing the holes right in the centre of the bush it shouldnt matter if its a few degrees out.

On the other hand the hole that I am drilling to allign the thinnest part of the bush has to be spot on as will effect power etc etc. This part is the pain in the butt
Author:  drmini in aust [ Thu Sep 06, 2007 7:23 pm ]
Post subject: 
It's more important that the bush `thin part' is correctly positioned, than where the hole is.
Now you can see why this time I fine bored all the bush holes in the mill, after I pressed solid bushes in. So all 8 rockers & bushes are identical. :wink:
Author:  mini-dunger [ Sat Sep 08, 2007 3:03 pm ]
Post subject: 
all done, it was a bit fiddley but my home made press made it a piece of cake.
Author:  drmini in aust [ Fri Sep 14, 2007 9:35 pm ]
Post subject: 
Let us all know how much valve lift these bushes give. :wink:
Author:  mini-dunger [ Sat Sep 15, 2007 12:25 am ]
Post subject: 
probly 1.5 like the add said......NOT

Do you reakon if I set them up and find they are not 1.5 like the add said I could ring him up and bust his chops....just for a laugh?
Author:  drmini in aust [ Sat Sep 15, 2007 6:51 am ]
Post subject: 
mini-dunger wrote:
probly 1.5 like the add said......NOT

Do you reakon if I set them up and find they are not 1.5 like the add said I could ring him up and bust his chops....just for a laugh?

I doubt it! :lol:
I reckon with those bushes you will get 1.26 with an RE13 cam, maybe.
With stock pressed steel rockers I only got around 1.2:1. [better than either the S ones (1.6) or sintered A+, 1.8]
Eventually I achieved 1.31:1 with my custom bushes, but I bored the rockers slightly oversize first and my bushes have more offset than yours.

Note that the higher the cam lift is, the less rocker ratio you get. :wink:
Author:  leylandmini [ Mon Sep 17, 2007 2:31 am ]
Post subject: 
I bought some of these from jonspeed birmingham had them fitted they where ok but the wear on the valves was bad, lasted about 5000 miles. I just bought rollers now which are much better for daily use. The 1.5 bushes seem to be used for historic racing in the UK so they are stripped fequently.
Author:  drmini in aust [ Mon Sep 17, 2007 8:00 am ]
Post subject: 
A lot depends on setting the rocker height correct. I ran offset bushes in S forged rockers for years with no probs. I currently have Minispares forged rockers (1.58:1) in my 1360, valve lift is .493" and the bronze guides have done 50,000 miles. No wear yet.... and no oil leaking down the guides- I use decent Viton valve stem seals from USA, not the poxy Mini/Metro ones that all go hard.:lol:
Author:  leylandmini [ Tue Sep 18, 2007 2:04 am ]
Post subject: 
Yes i agree I have chatted to people that have had good milage use. Its a nightmare really. Minispares in the UK are now producing the 1.5 s rockers complete for Historic rallying but I would rather stick with roller ones.
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