Hi guys was just wondering whether or not this will cause problems,ca18det inlet and oulet valve stems(5.95mm dia) and vg30dett valve stem(5.97 dia)so the reason I ask is because im looking at valve springs,retainers and seats.Springs aren't a problem just the retainers,wondering whether or not that slight difference will cause the collets to pop.

Anyone.......

Im guessing no one want's to make the call incase it goes tits up... if the collets are not a snug fit around the valve stem they will start to stretch the grove in the valve stem the spring holds the retainer in place and the tapper in the retainer suits the collet extra diameter will mean the collet will sit higher in the retainer, I would doubt enough to make any real difference as long as the spring will maintain tension what Im wondering is the grove height the same between the two and can you use the vg30dett retainer , collets with the ca18 springs or perhaps see if jun retainers/collets are better suited . To pop you need the mechanical advantage of the spring to fail,eg float,piston hitting the valve or spring binding

0.05 is 2 thou,You are talking about 0.02 difference between both of them so that is less than one thou, Guess what after 5,000 km there could easily be that much variance between any new components as they bed in, such a small amount will not be an issue, We are not talking 22,000 RPM Formulae One here where even the five axis machining centres operate as Electric discharge machining so as not to cause stress in machined components from cutting bits.

Mechanic since the seventies and as well an Engine machinist so there will be no issues as long as you buy the collets that match the valves and retainers to suit the same.