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cat cams 428,gutted



  clio sport 182
well been down to gdi today spent the day there was all going well until we fund out my cylinder head has been skimmed meaning the valves are hitting the piston head,im gutted,more money lol but gota say these guys know there stuff
 
  e92 + E46 M3 + Cup
Shitter mate :dapprove: ... thats the thing with buying a second hand motor, you never know what the previous got upto
 
  ITB'd MK1
Unlucky, could you not hear it knocking or any other symptoms?

wasn't doing it until we put the higher lift cams in. nothing apparent at idle but at soon as the phase shifter was activated when the engine was revved a little there was a properly odd noise. Changed the pulley, the plunger and spent ages trying to work it out, then remembered renault had rebuilt it under warranty. The head's clearly been skimmed :(
 
M

mini-valver

How much have they taken off??? Thats a big old lift to be having valves munching pistons....
 
  clio sport 182
i couldnt tell ya how much,but danny im coming down on thursday with it and ill be leaving it with you until saturday,im going to go ahead with the piston head skim,i mite as well,i tryed fonin u after leaving,so ill give you guys a ring tomoz after iv spoken to renault and arrange something,cheers for today bud

the car was fine when i bought it pre owned the engine went when i had it,and was a horrid noise at about 2k i think
 
M

mini-valver

May be cheaper to buy a new head?? OR, fit a thicker HG.
 
http://www.ferriday.co.uk/cnc/decompression_plates.shtml

DSC03796.jpg


This guy used one as his pistons were like this-

DSC04191.jpg
 
  ITB'd MK1
enlargen the valve cut-outs in the piston is the plan. thicker gasket would drop the compression, this way the drop is minimal may even get a benefit of a higher than stock CR
 
  LY 182
is that not pistons out to mill them???

heads got to come off anyway,, cut the valve seat a few thou further down?

i dont even think you'd have to remove anything of them stem as the lash adjusters would take it up
 
  clio sport 182
yeah true,like i said dan ill come down on thursday morning mate,and plus tbh if this thicker gasket is an option i think id rather go that way as said earlier funds are tight
 
  2005 Nissan Navara
Would take more than cutting the seats back by a couple of thou....more like 0.010-20!

Good excuse for forged pistons if you ask me...pistons are gonna have to come out either way, may cost an extra say £350-400 compared to milling the cut-outs in the std pistons, but on a bill which is going to be reasonably high anyway, this may be worth considering.

Other logical thing you could is knock the inlet timing back a fraction.
 
The head skim must of been massive to cause those issues, i've deliberately skimmed over half a mill off stock heads with 428's and and stock pistons. Sure its not something else, like a slip or a mistake? Its happened to me before. Have you checked the actual clearance running the 428's?

I'd of also said it would be more than £400 ontop as there would be substantial extra labour involved with stripping the block bare to rebuild up with new pistons.
 
  ITB'd MK1
Mystery solved. The head had indeed been skimmed, but that wasn't the issue.
The engine was rebuilt by a renault dealer under warranty. Not very well it seems, all 4 pistons are the wrong way round, so the larger pockets for the inlet valves are on the exhaust side and vice versa. Looks like it's being paid for and the dealer seems to be being reasonable which is a relief
 


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