mooman10_0 wrote:
thanks for that, any way of telling by looking if a set I have are 998 or 1275, can I measure something?
Thanks,
Steve
Thanks,
Steve
If you have pressed steel rockers the 1275 have oval pads and the small bore have round pads.
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| rocker question https://www.ausmini.com/forums/viewtopic.php?f=2&t=94105 |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 4:10 pm ] |
| Post subject: | rocker question |
Do 998 rockers and 1275 rockers interchange with each other? Talking about a 12g940 head. Thanks, Steve |
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| Author: | drmini in aust [ Sun Oct 30, 2016 5:40 pm ] |
| Post subject: | Re: rocker question |
Valve spacing on all 1275 heads is greater, the exhaust guide centres were moved out. You can fit 998 rockers if you put a flat washer next to the pillar for exhaust rockers only. |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 5:46 pm ] |
| Post subject: | Re: rocker question |
thanks for that, any way of telling by looking if a set I have are 998 or 1275, can I measure something? Thanks, Steve |
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| Author: | gtogreen1969 [ Sun Oct 30, 2016 5:48 pm ] |
| Post subject: | Re: rocker question |
mooman10_0 wrote: thanks for that, any way of telling by looking if a set I have are 998 or 1275, can I measure something? Thanks, Steve If you have pressed steel rockers the 1275 have oval pads and the small bore have round pads.
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| Author: | drmini in aust [ Sun Oct 30, 2016 6:14 pm ] |
| Post subject: | Re: rocker question |
The oval pad 1275 ones have a bit more lift too, if you find some. |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 6:41 pm ] |
| Post subject: | Re: rocker question |
the ones I have are rectangular pads? |
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| Author: | drmini in aust [ Sun Oct 30, 2016 7:32 pm ] |
| Post subject: | Re: rocker question |
Are they flat on sides and curved on top? Or are the square pads wider than the body? The former are the late sintered rockers used from about 1976 on. They have no bushes in. The latter ones would probably be Cooper S/early 1275 rockers. These give less valve lift than all others. |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 7:40 pm ] |
| Post subject: | Re: rocker question |
I would say squarish pads, wider thean the arm which had a thinner ridge running along top. |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 7:43 pm ] |
| Post subject: | Re: rocker question |
junk? |
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| Author: | drmini in aust [ Sun Oct 30, 2016 8:54 pm ] |
| Post subject: | Re: rocker question |
mooman10_0 wrote: junk? I tested standard rockers a while back in 2007 using an RE13 cam, stock pushrods on a fully assembled 1275 head (12G1316) and .016" valve clearance. I measured the S forged rocker ratio at 1.16:1. You can fit offset bushes to them, this gives a bit more lift (maybe .020") Similar to this, the pressed steel ones can be done too--  Note the rocker posts need the stud holes all drilled out 1.5mm and the assembly pushed back when bolting down. Other rockers: A+ sintered rockers 1.18:1 850/998/1098 pressed steel round pad rockers 1.21:1 1275 pressed steel oval pad rockers 1.25:1 approx. |
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| Author: | mooman10_0 [ Sun Oct 30, 2016 9:09 pm ] |
| Post subject: | Re: rocker question |
Thanks, doc |
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