5 replies to this topic

[andys.]

Hi I'm looking at changing the cam in my 1275 spi to a kent 274, and was wondering if anyone could tell me if there is any major benifit in buying a cam from a new blank or if a regrind would be just as good as they are twice the price.
thanks Andy

[mk1leg]

why not just purchase a new cam.............Swiftune SW5-7 http://www.swiftune....duplex-kit.aspx

[andys.]

Well yeah that's what I mean but the new ones from mini spares are £150 an the regrinds are about £80. Was just wondering if there was any major benifit over the regrinds

[sledgehammer]

A regrind will wear very slightly quicker , as lobe has been reduced to get the new profile - and is old material

& bearing surface will be slightly worn - as cam bearings are nearly always std - (but shouldn't matter much as they are checked)

the new cam will be better (if quality is the same as OEM spec) as you have more lobe surface to cut a new profile on

It is almost the same as saying would you prefer a new crank - or a reground crank

When I worked for Kent (summer job) - I used to straighten shaft & brg's to 1 thou - so handle all cams carefully

on A series I used to machine off the fuel pump lobe , and the shaft , to make 'steels' as they were called

Don't idle a new cam for long , they can scuff at low speeds - ie oil has time to be squeezed out when bedding in

& use cam lube

[Guess-Works.com]

Most cams use to be reprofiled ( or reground ) but nowadays most are made from billet as there is just not the quantity of second hand cams available. Over the life of an engine I'll be surprised if you noticed the difference.

[andys.]

Thanks, so basically there's little or no massive benefit from paying the extra 70 quid?
A quick question for guessworks sorry for trading on the forum but do you do different straight cut drop gear ratio's than 1:1 ? Thanks