CALVER’S CLASS­ROOM

Our res­i­dent guru Keith looks at the pro­ce­dure for sort­ing your cam tim­ing with the en­gine still in the car.

Mini Magazine - - Contents -

If there is one ques­tion that al­ways causes a good deal of ques­tions and answers, it’s ‘what nee­dle do I need for my carb to start with?’ The cru­cial in­for­ma­tion needed to make an ed­u­cated guess at the nee­dle spec re­quired is the type of carb or carbs, cylin­der head mod­i­fi­ca­tions if any, en­gine ca­pac­ity and camshaft spec. The first three are of­ten met and an­swered with cer­tainty; though the head ques­tion of­ten leads to an ‘it’s been mod­i­fied but I don’t know how ex­ten­sively’ fol­low up. The cams ques­tion is fre­quently an­swered with an ‘ it’s not stan­dard, that’s all I know’. And of course, that al­most in­evitably means they have no idea if the camshaft was timed in cor­rectly.

The carb is easy to identity from a pic­ture. And a mod­i­fied head can be iden­ti­fied by re­mov­ing the carb and in­let should there be no give-away stamp­ings on the head top face – at least you can see if the ports have been messed with us­ing a mir­ror and a light. Ca­pac­ity is im­pos­si­ble, but in it­self is no big deal if not known. Not know­ing the cam spec is a bind, though can be rea­son­ably iden­ti­fied enough to give some work­ing idea from the way the en­gine runs at idle. But, and a big but, is – if the cam has not been timed in cor­rectly, even that can be mis­lead­ing. It is there­fore es­sen­tial to find out, and sort it if not. At least then you stand a chance of get­ting an ap­pro­pri­ate carb nee­dle spec.

This is a first for me, ex­plain­ing the pro­ce­dure of check­ing cam tim­ing while the en­gine is in the car. In over 20 years scrib­ing for the mag­a­zine, I have no idea why it has taken me this long to get around to de­scrib­ing how it’s done, es­pe­cially con­sid­er­ing the vol­ume of ques­tions that re­quire it be­ing done in or­der to ad­vise some es­sen­tial in­for­ma­tion. It may have been be­cause of the in­stru­ments and tools re­quired. But with DTI (dial test in­di­ca­tor) gauges and stands now avail­able for £20, the only other es­sen­tial piece of equip­ment is a top dead cen­tre (TDC) in­di­ca­tor. They have been hard to get a hold of, but I have man­aged to find a sup­ply and am now sell­ing them on my web­site (www.calverst.com). At £8 plus VAT it’s a cheap and very use­ful tool to have in your ar­se­nal. And with last is­sue’s cov­er­age of cam tim­ing with no gauges, this seemed the op­por­tune mo­ment to get this out there.

It is pos­si­ble to check cam tim­ing even if your en­gine is still in place!

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