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MG MGB Technical - Rolling Rockers

I'm using a fast road cam and a stage 11 head and now a set of Hi Lift Rolling Rockers 5-1 , my question is what gap should I set? is 17thou to big?
K Harris

K,

you should add clearance in relation to the OEM ~1.3 and your new roller rocker length. Just calculate how much % the new rockers give you more lift and add this to the recommandation given to for your fast road cam.

Ralph
Ralph

Right. The critical clearance is between the cam and the cam follower. Since there is no convenient place to measure this directly, we measure at the top of the valve. This IS affected by the rocker ratio, so, as Ralph says, you need to compensate for the high-lift rockers. If the cam manufacturer's recommended clearance (supersedes the factory setting) is 0.012" with the stock 1.3:1 rockers, divide by the 1.3, multiply by 1.5 and you would have 0.014" as the new setting. Preferably, since you are dealing with an after-market cam, the manufacturer would have a recommendation on their website or from their tech support that would be even better.
David "err on the side of more clearance" Lieb
David Lieb

I am running a VP-12 cam from APT with 1:5 ratio rollers.
APT recommends 0.018 on intake and exhaust.

Mike
M.A. Barrera

Cheers Mike, I using a 215 cam and the 1:5 rockers I set them at 0.017, see how I get on at that, they may be open more if needed..

As long as I'm in the Ballpark as they say:)
K Harris

Barrera- What are specs for 11, 12 VP cams please and how do they compare to Pipers, 270, 285, 300 both BP and HR? Thanx. Vic
vem myers

This thread was discussed between 26/08/2008 and 06/09/2008

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