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MG Midget and Sprite Technical - Valve clearance: Kent 276 / 1.5 rockers

Oil running down the LHS of my block tells me I'm changing a head gasket over Christmas.

I run a Kent 276 which has a recommended valve clearance of 16 thou. However I also run Minispares 1.5:1 roller tipped rockers. I have always set the clearance to 16 x 1.5/1.3 = 19 thou. Is this correct, I'd love to hear any opinions.

Thanks.

Jeremy Cogman

aren't the standard rockers 1.3 to 1? IIRC you just need to allow for the %age difference between 1.3 and 1.5
David Smith

Standard 1275 pressed rockers are 1.25:1, although Kent quote 1.3 in their literature, for some reason.

You math(s) is/are good!
Dave O'Neill 2

David vizard covers the simple math formula I dont recall what that is

I run .16 on my swiftune with 1.5 ratio roller rockers

Id think .19 would be way to wide....but thats just me, got ear plugs?

Prop and the Blackhole Midget

Btw... you might try just retorquing the head before re gasketing

If its a payen gasket its probably just that brass crush oil ring in the corner has gotten a little loose...it happens

Prop
Prop and the Blackhole Midget

16 on the inlets and 18 on the exhausts with an APT scatter cam (similar openings to a 286) on 1.5 rockers - as advised to me by the cam manufacturer.

Daniel Stapleton

That's not such a silly idea Prop.

(Oh god, my reality just wobbled a bit).

Thanks for your input everyone, it's always been a bit tappety on 19, I might experiment with Daniels figures.
Jeremy Cogman

Jeremy,

I had the same Kent 276 and 1.5 rockers and set them to 0.019", using the same arithmetic as you. The tappets were audible, but not particularly noisy.

More recently I have been using a Piper 270 (276°) and their standard tappet setting is 0.012", instead of the Kent 0.016", so 0.014" for the same 1.5 rockers. I also run the exhausts 0.002" wider (0.021" with the Kent 276) to make sure that they get the maximum seat time to avoid previous problems with sticking valves in the bronze guides (unleaded conversion).

The Piper cam is definitely quieter as far as tappet noise is concerned.

Richard
Richard Wale

I run an RE130T cam (Recommended tappets .016") and 1.5:1 rockers. so I used .019".
On Pete Burgess' rolling road we experimented with closing the gaps by a couple of thou, because it sounded a bit tappety. We lost several horsepower, so Pete put them back to where they were.
They don't sound particularly loud, although I don't think the posh rocker box cover helps much. Even after I'd fettled it for clearance.

Mark
M Crossley

This thread was discussed between 17/12/2015 and 18/12/2015

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