Autosprint Reprofiled Cams

[matt_vaughan]

Right, might be a silly question, but why stay away? I've heard so many people say dont use reprofiled cams, but no-one explains why.....are they not as accurate or something?

[Paul]

they rattle a bit

[djbrowney]

The way i look at it, if you put an old crank back in you put new bearings in, when putting a re-profiled cam it its like fitting a old crank with old bearings !

[brucer]

i had autosprint reprofile my cam on my e16se. did the job as my build was on a budget, i would have prefered a new one though. cant he make a new cam from a new blank for like 50quid more?

[dumpycorsa]

I've had 3 pairs of Autosprint re-profiled cams and I've never had an issue. There is a write up on the sbd website as to why you should steer clear -


http://www.sbdev.co.uk/Camshafts/cams_2.0L&1.6L_intro.htm



I think QED use them for their mild profiles though.

Give Autosprint a ring I'm sure he'll happily explain advantages and disadvantages.:thumb:

[Stuart]

for a mild tweak on a twin cam engine they are 'ok' but for a serious profile or single cam engine you cant beat a blank.

[alan b]

if you run solid lifters and shims theyd be ok wouldnt they?

[mowgli]

if a cam shaft is removed from an engine & is in good condition, then i can't see how it would suddenly become a problem item just because the lobes have been reground.. a used camshaft will have all its stress lines sorted out and it will fit straight back in where it came from...

[alan b]

if a cam shaft is removed from an engine & is in good condition, then i can't see how it would suddenly become a problem item just because the lobes have been reground.. a used camshaft will have all its stress lines sorted out and it will fit straight back in where it came from...
because theres metal taken from the whole way around the lobe. even the round bit. so when the cam is in rotation the lifters can have a gap between them and the cam, making them tappy.

[Stuart]

its the fact that to get more lift/duration the base circle is ground down so the lifter has to jack up to it...... Old/tired/cheap and nasty new Lifters might not enjoy that experience.

To convert to solids requires a cam profile suited to it (ideally) and if you are going down that route anyway you might aswell spend out on a blank cam with the exact profile you want on it :)

[mowgli]

because theres metal taken from the whole way around the lobe. even the round bit. so when the cam is in rotation the lifters can have a gap between them and the cam, making them tappy.

the lifters make up the gap hydraulically.... that is their job..

you see the whole concept of hi lift cams is that the top of the egg is no higher than the std one, but the rest of the lobe is smaller & shimmed up

[MK999]

you see the whole concept of hi lift cams is that the top of the egg is no higher than the std one, but the rest of the lobe is smaller & shimmed up

only on a regrind, on a blanked one they'd move the profile to within normal operation of hydraulics lifters i believe

[mowgli]

where do you think they get the blanks from???

they are std cam blanks. they don't have huge amounts of metal on them to start off with.

if camshafts had enormous lobes, then the engine would need harmonic balancers to stop it pulling itself apart.

[Stuart]

cam shafts are largely balanced by themselves and in the grand scheme of things the weight isnt that far from the point of rotation (plus its very light, not like a piston on a rod lol)

Blanks have a much taller top of the egg profile and a wider shoulder to let you machine what you want... hence for some uber high lifters you need to mod the head and valve guides.

[alan b]

the lifters make up the gap hydraulically.... that is their job..

i no but the problem is as far as ive heard is that xe lifters dont go high enough on anything over a very mild cam(reground)

[dumpycorsa]

To be fair if your looking at cams on a standard XE bottom end you'll be looking at a fairly mild profile anyway.To warrent the use of solid lifters I'd be expecting lots of lift and duration thus meaning not being able to use them with standard piston pockets.

I'd say re-profiles are "ok" for standard bottom ends (mild profile) and to go blanks thus decent lift/duration you'll need to step up to the next level of budget (solids,piston mods,valve spring upgrade etc etc).

[nova 2L 16V]

Im regreting re profiling my cams now lol.