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Anyone know or had experience with using 1.5 rockers on a overbored 1098 Orangebox ran with an MG1100 eng/box on some events, thinking of doing a 'spare' engine eventually, just toying with a 'spec'.

I ran them on my 'budget' road rally car = my mums old 1098 Clubman with rusty panels.

That was std bore and cam, but a big valve/ported 12G202 head, single HS4, MG Metro inlet and LCB/RC40. It ran well giving 47bhp at the wheels and took the car from a max 84mph to 100mph even driving uphill on the A3(M). The car did a number of 12 cars and performed well.
Ask Niall as he drove it.

1.5 should be fine to run but if your got a 12g940 head on then it be a little iffy to do as the pockets can't be done much deeper as the ring will pop out moment the piston goes up

1.3 rollers would be better IMO (cooper s on a good day) ran this spec IRRC

I ran a 1098 + 0.040" with a modified 12G 295 head, 997 Cooper cam and 1.5 rockers, very nice engine and the rockers made a difference compared to standard.

Now got a 1098 +0.060" with a big valve 12G 940 head, 285 cam and standard rockers, tried the 1.5 rockers but made no difference.

If you are using any of the BL cams up to the 731 then the 1.5 rockers should work well.

doctor jon wrote:I ran a 1098 + 0.040" with a modified 12G 295 head, 997 Cooper cam and 1.5 rockers, very nice engine and the rockers made a difference compared to standard.

Now got a 1098 +0.060" with a big valve 12G 940 head, 285 cam and standard rockers, tried the 1.5 rockers but made no difference.

If you are using any of the BL cams up to the 731 then the 1.5 rockers should work well.

You running pockets with your 940 head?