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Toyota corolla rocker accuracy
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Author:  Lindsay_Palmer [ Thu May 29, 2008 12:27 pm ]
Post subject:  Toyota corolla rocker accuracy

I'm trying to decide what rockers to run in my new project car when it is finished and the big deciding factor I think is the accuracy of the lift given by the rockers (all rockers the same lift). How accurate are the Corolla rockers compared to cooper s rockers and late model rover rockers? has anyone compared this?

Author:  spraycanmansam [ Thu May 29, 2008 12:33 pm ]
Post subject: 

http://www.ausmini.com/forums/viewtopic ... rs&start=0 :wink:

Author:  Lindsay_Palmer [ Thu May 29, 2008 2:26 pm ]
Post subject: 

Thanks for that, but not quite what I was looking for. I am looking for information about the accuracy of the rover, cooper s, and corolla rocker lift. To expand on this I want to know how accurate the lift ratio across the rocker gear set is (are all 8 rockers giving the same lift, thus giving accurate valve timing).

Author:  1310/71 [ Thu May 29, 2008 4:33 pm ]
Post subject: 

I would suggest PM DrMini direct. No doubt, he has tested it and could tell you based on his results, but of course, it uses secondhand rockers, so there may be some variation I guess.
KB

Author:  gafmo [ Thu May 29, 2008 7:19 pm ]
Post subject: 

G'day Lindsay You have my attention straight away as you have a Alfa GTV as a project in your signature so we have both somehting in commen as I have a Alfa 75 as my daily drive 8)

Regarding to prefered rockers I have alread a set of Corroler Rockers (not installed yet) but have another set waiting to be completted. I can not talk with experiance yet, but I trust those with more knoledge than myself.
The way I see it all the old rockeckers are not what they appear to be and many of the high expectations of sales hype of the new rockers are not correct.
The only way to truly get it perfect is to get it perfect by someone who knows what they are doing which is why the direction I am going :wink:

Author:  drmini in aust [ Thu May 29, 2008 8:05 pm ]
Post subject: 

I have not yet compared 8 corolla rockers for lift measurement, but Graham Russell reckons they are consistent, he has fitted many sets to race motors over the years.

With any rocker, the enemy of good valve lift is looseness on the shaft. I give mine .0005" (1/2 a thou) clearance, which Keith Calver says is optimum.

Author:  gafmo [ Thu May 29, 2008 8:23 pm ]
Post subject: 

Opps sorry I have a set of Corrolers readey to go in and the set that are being made are the pressed rockers that are being rebushed to be 1.3's for my 1152 :wink:

Author:  clubmn [ Fri May 30, 2008 6:54 am ]
Post subject:  mm1275

anyone have a set they might want to sell?

Author:  drmini in aust [ Fri May 30, 2008 8:51 am ]
Post subject:  Re: mm1275

clubmn wrote:
anyone have a set they might want to sell?

I have made 9 sets so far- I don't have any for sale right now but could make a set up, if you send me some `rolla rockers. PM me for details. :wink:

Author:  Lindsay_Palmer [ Fri May 30, 2008 9:57 am ]
Post subject: 

Thanks for the info everyone, also good to hear there are other alfa fans here. Well one at least. Someone has also told me corolla rockers are unsuitable for small bore motors, I am planning on building a 1100 that will be used for a bit of hillclimbing and sprinting, so it will have about 10:1 comp, big valves, twin SUs, ect. Are the corolla rockers unsuitable for a motor like this?, if so why? And what rockers have people been using on this sort of motor that do a good job (consistent valve lift, good durability, and don't cost a fortune).

Author:  mini-dunger [ Fri May 30, 2008 10:11 am ]
Post subject: 

I have 1.3s in my 1100.

I brought the bushes from somewhere in the UK for $120 landed.

I had to press the old bushes out and the drill the oil hole in the new bushes and press them in.

Pressing them in the right position is really important and also bloody fiddly.

I then had them reamed to fit on the rocker shaft for about $140.

Plus you really need a new thick walled rocker shaft, no point doing all this if your shafts worn. That was another $100.

Plus depending on what valves you are using you will have to put packing underneith the rocker pillars to bring everything back inline.

Plus you have to enlarge the holes in the rocker post and push the whole lot over so the rocker pads are right over the valves.

If I did it again I would use corolla rockers. I would keep the valves standardish and keep the compression up otherwise it run like a pig down low. you probly wouldnt want to mill to much off the head either (depending on cam) incase your valves smash things.

This is just my opinion, Making 1.3 yourself is a crap job. The doc makes these himself and they are better than the ones I brought from the UK.

either way PM the doc he will help ya.

Author:  drmini in aust [ Fri May 30, 2008 12:04 pm ]
Post subject: 

Corolla rockers are too big for a smallbore- unless it's a racecar, 1.3 ones is the way to go.

Fitting and reaming offset bushes is a PITA- I did it years ago.
It's very hard to get the offset in the same place on each rocker.

I'm doing some 1.31:1 rockers right now for Wombat-
I press solid LG2 bushes into pressed steel rockers, then offset bore them by 1.1mm to finished size in the mill.
This way, they are all offset identical and I don't need to ream them, either.
I fine bore them to have 1/2 a thou (.0005") clearance on the shaft.
Then I drill out the stud holes in the standard rocker posts as Vizard says, you then push the rockers back when bolting down.

Wombat's are the 3rd set I've done.

Pics of my 1st set with 1275 head (going on the 1132 Moke)-
Image
Image

<edit> Here are the results I obtained from different rockers last year.

22/7/07 Checked valve lift- 12G1316 head fully assembled.
RE13 cam, stock pushrod, valve clearance .016”:
Lift at #1 inlet valve-
S forged rockers 0.321” lift
A+ sintered rockers 0.327” lift
998 Deluxe rockers, cast iron posts 0.337” lift
998 Deluxe rockers, A+ sintered posts 0.339” lift
998 Deluxe rockers, cast posts lowered 0.6mm, rockers offset bushed 1.0mm, 0.359” lift
998 Deluxe rockers, cast posts lowered 0.6mm, rocckers offset bushed 1.1mm, 0.365” lift (1.31:1)
Corolla rockers, late `sintered rocker’ type posts with shaft offset 3.9mm, 0.402” lift (1.44:1)

There is probably a few thou more valve lift hiding there if I play with pushrod length- these figures were using a stock height 998 block and pushrods.

Author:  9YaTaH [ Fri May 30, 2008 5:16 pm ]
Post subject:  Meat

drmini in aust wrote:
Image


Doc...there isn't much meat on that back side....then again, there ain't much movement, there is a lot of oil getting splashed around and the heat would be a little lower down. Ever seen any evidence of burnishing :?:

Author:  drmini in aust [ Fri May 30, 2008 7:19 pm ]
Post subject: 

Mick they don't get any hotter than the oil, and there's nothing new about doing this- offset bushes were used in the UK for yonks until they started selling cheap hi-lift forged rockers.
I see some people there and in US are now fitting these bushes and claiming to get a 1.5:1 ratio- it just isn't so. Not enough metal there to do it. :lol:

If you are worried about whether they can move, I pressed one out once because I overbored it- they are just as hard to press out as the solid ones were to press in.

I bore all the rockers to clean up first, then make the bushes to have .001" interference fit.

Author:  9YaTaH [ Fri May 30, 2008 9:04 pm ]
Post subject:  Offset

drmini in aust wrote:
Mick they don't get any hotter than the oil, and there's nothing new about doing this- offset bushes were used in the UK for yonks until they started selling cheap hi-lift forged rockers.
I see some people there and in US are now fitting these bushes and claiming to get a 1.5:1 ratio- it just isn't so. Not enough metal there to do it. :lol:

If you are worried about whether they can move, I pressed one out once because I overbored it- they are just as hard to press out as the solid ones were to press in.

I bore all the rockers to clean up first, then make the bushes to have .001" interference fit.


Thanks...just showing my ignorance...I was not thinking the inserts would move and therefore run....just thought the thin side could overheat and burnish :oops:

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