Thanks to DrMini
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| Corolla 1.46:1 rocker conversion to fit Mini. https://www.ausmini.com/forums/viewtopic.php?f=25&t=91263 |
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| Author: | drmini in aust [ Sat Dec 12, 2015 2:38 pm ] |
| Post subject: | Corolla 1.46:1 rocker conversion to fit Mini. |
Rockers are from a Corolla 1100 or 1290 pushrod motor. 1290cc car has Hicam badges on sides. It's a bit harder to do than it looks, and takes a while. As I only have a Myford Super 7 bench lathe and a Hafco HM30 mill/drill. No CNC stuff here. Work involved: 1. Bush rockers back to suit 9/16" dia Mini shaft (use HD thick wall one). 2. Mill or turn .140" from the side of rocker hub boss which is widest. (same side as the valve pad offset is). 3. Move the shaft holes in the rocker posts back by 3.5mm. 4. Redrill the oil feed hole in #1 post at an angle to intersect the new shaft position. 5. Drill and tap a post 3/8" UNF for the relocated shaft location screw. Use the old #2 post for #3 or #4. These rockers are a PITA to hold on the mill, due to their shape. So I did the following: 1. Turn bush diaameter on end of a length of LG2 bearing bronze. Leave OD .002" oversize, drill hole 14.0mm. 2. Press rocker onto bush using tailstock. 3. Face side of rocker back by .140" approx- finished width is 0.625". 4. Bore hole in bush to have .0005" (1/2 a thou) clearance on shaft. 5. Part off bush flush with back of rocker. 6. Repeat steps for the other 7 rockers. Modifying rocker posts: I turned up some steel plugs with a chamfer on each end and also chamfered the rocker posts' old shaft holes. I tried to MIG weld one, but they appear to be sintered or cast steel, and full of oil. So NBG. Oxy saved the day! I heated them to around 700C which burned all the oil out, then brazed the plugs in with manganese bronze or nickel bronze rod and bronze welding (for cast iron) flux. Worked a treat! I milled them flat, drilled a 6mm hole, then set them up true to the hole in the lathe, and drilled them out to 14.0mm using a slot drill. Do not drill them using a twist drill, the hole will wander due to one side of hole being harder than the other. Finally I bored them to 9/16" to suit a HD thick wall rocker shaft. As said above, you want .0005" clearance- no more, no less. Note the height of the shaft in the posts is as per stock Mini. Geometry to valve looks good. There are bumps on the back of the rockers- I ground these all off so the rockers clear the side of the cover. Assemble using a HD thick wall rocker shaft. Use the Corolla adjusters- they are smaller diameter at the ball end but work fine. DrMini |
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| Author: | Mick [ Sat Dec 12, 2015 3:17 pm ] |
| Post subject: | Re: Corolla 1.46:1 rocker conversion to fit Mini. |
Thanks to DrMini
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