Hi Guys!

I've been offered a set of used Piper "Rally"(BP300 mech) cams for my Zetec. Piper states that I need to use mechanical lifters (I have a silver top).

Does anyone know whats involved to switch to mechanical lifters? I read somewhere that machining is needed on the head. If so, what machining are we talking about

I have asked Piper, but i haven't got any anwser yet (two weeks)

In most cases when using "wild" cam profiles,pockets have to be machined in the pistons and also the bores where the cam buckets run need dressing. That is certainly the case on Lotus twin cams and BDAs.
Checking if the cam bores need dressing is dead easy.Assuming the head is off the block, bolt in the cams (without the camfollowers)Rotate them if dressing is needed it will be obvious.

Checking for valve/piston clearance is a bit tricky not to mention time consuming. You will need some modeling plasticine and loads of patience!

Last but by no means least,finally check for coil binding. If that is out the wrong way, you will wreck your top end in seconds!.

you might find it is quite horrible to drive such an engine day to day as the valve timing will be set for very high rev’s with little low end torque. Most cam manufacturers seem to recommend not going crazy and instead selecting a mild race cam at most for the road. There's also a chance that the piston crowns may need machining to clear the valves now that they open further. Burton power should be able to help as they do know their engines.


[Edited on 24/11/07 by Mr Whippy]

I'd second what's already been said, once you get into pocketing pistons/the block you're really into a complete engine rebuild & major expense, plus the resulting engine will probably be a pig to start & will run like a bag of sh*te at low revs particularly until fully warm.
Just go BEC!

Thanks for your reply guys.

I haven't got the prirce on them yet so i decide what to do when i get it.

Right, the Piper 300 cams for a Zetec are not 300 degree cams, in fact they are 284 inlet and 280 exhaust. As such in a seven type car with correctly set throttle bodies or say bike carbs they will run a treat. With the appropriate additional work they will make a strong 200bhp.

They are a "mechanical" profile cam - that means solid lifters are required. Your standard engine is fitted with hydraulic lifters. Piper list mechanical lifters at £368 + delivery + vat per set.

In addition you'll need verniers, possibly springs and retainers. Machining work may need doing to the head and yes the pistons may need pocketing. You will certainly need to do some serious porting to unleash the potential of the upgrade.

Piper (like Kent and others) will not / cannot advise what needs doing. Your engine builder has to sort that out for himself. Piper will not get back to you.

This is an expensive route to go down - do not expect to buy a pair of cams like this off E-Bay or somewhere and transform your car for an afternoons work.

The Zetec engine is harder (read more expensive) to extract power from than say an XE or Duratec. If you have the wherewithal to upgrade the Zetec, don't, just invest in the bits for a Duratec.

Thanks Dave,

I better leave these cams and search for some milder ones.