TU5JP4S Building

1. K567 Frequent Poster Joined: Apr 2012 Bradford/Leeds Posts: 775 03 R53 Mini Cooper S with a little extra going on

   #1 6th January 2013, 17:07

   hi
   Just bought a C2 VTS JP4S the 125hp version
   
   My plan is to swap out all my current setup
   
   Jenveys
   PH3's
   4-2-1
   
   I've read alot and its said the JP4S has a stronger valve train, is it stronger than the JP4 or is it the same advice to swap out valve springs and lifters when swapping cams over
   
   Gonna swap out arp head studs, and get arp rod bolts as well
   
   Also looking at high comping it at the same time when i strip to build back
   
   With rod bolts are the jp4s rods as good as jp4 ones?
   
   What else to consider on this engine....
2. K567 Frequent Poster Joined: Apr 2012 Bradford/Leeds Posts: 775 03 R53 Mini Cooper S with a little extra going on

   #2 7th January 2013, 11:03

   Anyone?��
3. user_44357 Regular Poster Joined: May 2010 Kent Posts: 431

   #3 7th January 2013, 11:59

   The valve train is stronger than JP4 and J4. The JP4S cams are 'lairier' than the JP4 and the J4's
   I'm running 705's (the JP4/S equivalent of J4 708's) in my JP4S on standard valve springs etc and has been fine for 30k
4. K567 Frequent Poster Joined: Apr 2012 Bradford/Leeds Posts: 775 03 R53 Mini Cooper S with a little extra going on

   #4 7th January 2013, 14:35

   Are the cams different specs for aftermarket, will the PH3's i already have work?
5. user_44357 Regular Poster Joined: May 2010 Kent Posts: 431

   #5 7th January 2013, 14:41

   Valve spacings are slightly different in the J4 head and the JP4/S. that's why they make different cams. I know people have run the 708's in the JP4/S instead of the proper 705 and had no problem. But I'm not saying it will be perfect as not the whole cam lobe will not be in contact (from what I understand)