I have a set of these corolla rockers for sale.

$330. neg

PM me

Hey guys,
Been reading this thread with interest and thought I'd share my experiences with 1.5 rockers.
I inported a MiniSport Stg 3 head from pom land to NZ for a new motor-very flash and very expensive....VERY!
On my old cylinder head I was constantly finding the valves were elongating the guides-they werent wearing at an alarming rate, but wear was there all the same. It was a moderate cam, and the engine was in moderate condition-nothing to point to any defect in particular. This lead me to carefully examine the action of the rocker tip on the valve stem head. If you set up a head with a unsprung valve and rocker/shaft, and then approximate the cam lift, you'll see the extent the rocker first pushes the valve down and forward, and after mid lift, pushes the valve further down and rearwards....This is ofcourse natural as the tip of the rocker needs to slip forward and backwards over the tip of the valve stem duriing its operation. After spending an untold amount of cash on this new cylinder head, i decided I needed roller tip rockers to compensate for this rocker slip action and allow the roller to do its job and roll across the tip of the valve stem. As the funds were all dried up, I decide to have a crack at making my own.
I had access to a CNC mill and drawing software so put it to use, and at this point I thought i may as well go the extra mile and increase the valve lift by increasing the standard 1.3 to 1.5 ratio.
The rockers were made from a grade of alloy that was T6 , 6084, that illuded itself to hardening-more specific age hardening-the alloy is held at ah elevated temp for a sustained period and then gradually cooled. They were then anodise a sexy green colour. The bearing surface or bush were made from oversized DU bushes-or teflon coated cintered bronze. The rollers were made from S1 - shock resist tool steel, heat treated and full ground, The roller pin were made from tooling dowels. As well as this, new pedistals were made from MS and a new heavy duty rocker shaft was used.
One thing that aftermarket rockers employ and one that Mr. Vizard alludes to is the apparent HP loss in using the springs to separate the rockers. It might be common knowledge but incase its not-the springs force the rockers against the pedistals and increase rubbing friciton therefore taking HP-a small amount, but for the simple conversion itself of putting in alloy spaces and disgarding the springs should not be overlooked.
Once set on the cylinder head, minus springs, the roller action can clearly be seen.
Wear was all but eliminated in the guides and the rollers remain free from flat spots.
I think at the end of the day, I suceeded in fabricating roller tip rockers, but on a price comparison basis, I'd say I broke even with the commercially available ones.
Even tho guide wear might be accelerated with 1.5 or 1.7 ratio rockers, I do like this Corolla conversion you blokes have cracked onto-fully worth while.

Glenno

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If you idiot proof the world, only idiots there shall be!!!!!

I've had 1.5 forged Minispares rockers in my 1310 now 1360 for about 7 years. Valve guides are Minispares bronze. I've had no probs with guide wear at all. Cams I've had in there are Camtech VP3, then RE13, now RE282. My valve lift is 0.493".
Rocker faces are not wearing either.
BTW the rockers and guides have done about 45,000 miles now.

On the other hand, I've seen Mini***** 1.5:1 roller rockers get flats on em in 10,000km. Makes them worse than useless then.

Corolla rockers (and 1.5:1 forged ones) are used in many race Minis here in Oz.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I to did run bronze guides-but they weren't typical mini ones-were a replacement from a local engine recond. outfit. New but perhaps something was amiss with them?
Anyway, got roller tip rockers now-and original guides....

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If you idiot proof the world, only idiots there shall be!!!!!

That set is new, willy never ever used them. Bargain.
My current cost to make them (I've just made and costed some for my 1412 stroker) is lots more than that.

Here's some pics of willy's set-

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

how much of an advantage does this mod give? i dont particularly understand lift and stuff so in leymens terms what good is it, and is it worth it for me ill be having one of grs cams i forget what he called it but not the re13 on an 1100s 1275 bored out to +60thou e.t.c. e.t.c. is it worth it for me is the main quesstion.

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I have a problem.. apparently

(guess) It's probably worth 4 or 5HP on a 1275, above 5000 rpm. More on a race motor. My 1310 and 1360 motors went much harder from 5000-7500+.

For a smallbore, forget it, too much lift- get some 1.3 roller rockers, or offset bush some 998/1098 pressed steel ones.

<edit> These had a 1.31:1 ratio when tested with an RE13 cam.
The 1275 oval pad ones I got a 1.35:1 ratio.
Both rockers using a .044" offset bush.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

cheers mate might leave it for now i think...although if ive got the cash i might as well. decisions decisions. haha

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I have a problem.. apparently

I've been looking at this conversion and noticed the corolla rocker shaft is quite a bit bigger than the mini one. So i was thinking offset bushes could work on these rockers to bring the ratio up to around 1.6, maybe even 1.7:1

Would this be worth doing?

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Mini - The Wizardry on Wheels!

Really, anything much over 1.5:1 in a Mini motor is a waste of time. Particularly in a road car.

re the bushes, the Corolla shaft is 16.0mm, the Mini one is 14.3mm (9/16")
so, these bushes I make are only 1.7mm/2 = 0.85mm thick. No room here for any offset.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

doc, what do you charge to make a set of these rockers? if you make them that is.

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I have a problem.. apparently

PM sent.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Getting back to Rupert's original post about Corolla rockers, he said you can simply turn the original rocker posts around then redrill the small hole (to 10.0mm) to fit over the head studs.
This is true, but with the following provisos-
1.
They must be the early type CAST IRON posts with both ends radiused.
2.
They then need the front face machined severely to clear the springs.

Note the earlier alloy ones are too weak, they will collapse before you get 40lb/ft torque on the head nuts and give gasket leaks.

Here's pics of a set of alloy ones I fixed up- the PO made them, but the springs and caps were chewing up the posts (because he never filed enough off them) so I milled them to just clear.
Pretty flimsy with that big old head stud hole there, eh.. and the back end where the headstud is is now too thin.
When we bolted these back on the S head, we could not even get 40lb/ft on the head nuts, when we took them of you could see the alloy post was being compressed by the load... The alloy posts are rubbish.




So, it is now getting a set of the later style sintered/iron posts- I bronze weld steel plugs in, then bore them offset to move the shaft back 4.0mm.
Like these-

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Read my above post again, it has now been severely edited...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi Kev

Got the rockers back from my engineer today

I have to still set them up etc but they are basically done

Did you drill the little oil holes in the rocker


Thanks
Bernard