708's and JP4 head.

1. Jackman Saxperience Addict Joined: Sep 2006 Bridgend, South Wales Posts: 11234 iTB 205 Rallye, 205 STDT.

   #1 16th December 2008, 22:41

   I've bought myself some 708's for Xmas.
   
   But im wondering how much of an advantage it would be if i was t fit them to a JP4 head rather than my standard head?
   
   Am i right in thinking they are a slightly bigger valve head as standard?
   
   Is it worth it?
   
   Thankkkk youuuuuu.
2. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #2 16th December 2008, 22:48

   JP4 has slightly large valve, however the rest of it people feel is junk.
   
   iirc its a swap over most of the J4 head (springs etc.) into the JP4
3. Jackman Saxperience Addict Joined: Sep 2006 Bridgend, South Wales Posts: 11234 iTB 205 Rallye, 205 STDT.

   #3 16th December 2008, 22:52

   Yea i believe you have to use the valve springs and stuff out of the J4 to fit the cams and stuff.
   
   Just wasnt sure if it was worth doing?
   
   Alot of people seem to be doing it, just not sure of power difference !
4. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #4 16th December 2008, 22:53

   a few seem to feel its a good mod for a few extra bhp.
   
   i remeber steve falcus on ssc banging on about JP4s back in the day and the added airflow etc..
5. pug205gti87 Frequent Poster Joined: May 2007 Birmingham, West Midlands Posts: 704 Saxo Vts

   #5 16th December 2008, 23:25

   i take it the jp4 head is the c2 vts head? i am thinking about getting one of these if i can get my hands on one
6. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #6 16th December 2008, 23:27

   JP4 is the newer engine fitted to c2s some 206s (xsi iirc) etc..
7. pug205gti87 Frequent Poster Joined: May 2007 Birmingham, West Midlands Posts: 704 Saxo Vts

   #7 16th December 2008, 23:28

   cool cool i will try and get my hands on one of those then
8. Dibz Infrequent Poster Joined: Jun 2006 Posts: 240 106 GTi

   #8 16th December 2008, 23:28

   Think the differences will be more noticed with a throttle bodied engine but theres prob a few horses to be had on standard inlet also...
9. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

   #9 16th December 2008, 23:34

   easy to just get a jp4 enine then sell the bottom end tbh for the price of head alone.
10. Ste Saxperience Post Whore Joined: Mar 2007 Yorkshire Posts: 5415 Saxo

    #10 17th December 2008, 10:18

    To say fitting larger valves on the S head would be shed loads more than buying a C2 head i suppose its not a bad mod. But if your going for silly power you'd end up doing the valves anyway.
11. leeroybrown Saxperience Hardcore! Joined: Nov 2006 Durham Posts: 16000 Clio Trophy 025/500

    #11 17th December 2008, 11:18

    Quote:

    Originally Posted by Ryan a few seem to feel its a good mod for a few extra bhp. i remeber steve falcus on ssc banging on about JP4s back in the day and the added airflow etc..

    Arrr a local lad he was Ryan
12. Nick_106 Regular Poster Joined: Apr 2008 Posts: 470 Ford Ranger Pick Up

    #12 17th December 2008, 11:24

    JP4 head and 708s fit im fitting 708s into my jp4 head and slapping it on a j4 bottom end! Where the problem lies is with the headgaskets, the j4 are 1.5mm at the smallest where as the jp4 headgasket is 0.6mm so im going to be using the j4 headgasket just incase!
13. Ryanp Super Moderator Joined: Feb 2004 Tonbridge United Kingdom (England) Posts: 38236 Vtr, 172, throttle bodied track slut

    #13 17th December 2008, 11:50

    Quote:

    Originally Posted by leeroybrown Arrr a local lad he was Ryan

    bit of a pleb at times, taking his car on track with a big oil leak lol!!!
    
    Did have some amusing conversations with alot of people back in the day though.
14. vtr130 Established Member Joined: May 2006 Posts: 2279

    #14 17th December 2008, 13:17

    Heard the valves springs are quite weak in the jp4 head though so i would change them!!
15. Jackman Saxperience Addict Joined: Sep 2006 Bridgend, South Wales Posts: 11234 iTB 205 Rallye, 205 STDT.

    #15 17th December 2008, 20:09

    I'm not looking for huge power tbh.
    
    Just after a little fun on track!
    
    I am waiting on a price for KMS Bodies though.
16. user_14757 Established Member Joined: Mar 2007 Middlesbrough Posts: 1186 mazda 3 mps

    #16 24th December 2008, 23:23

    im on my way with the jp4 head, my springs out of my old head being a 106 gti and some lovely cams gonna be inside there... il update and tell you all about it when completed, using the j4 gaskets and need to drill 5 holes a do belive for the inlet manifold.
17. katiescar Established Member Joined: Dec 2007 newport Posts: 1443 saxo vtr renault laguna v624v 3ltr manual

    #17 24th December 2008, 23:34

    jp4 head is a good budget head, but some tuners prefer the j4 head as a better port shape can be attained. Unless ur stripping engine down and complete re-build, hi-comps etc cant see the point.
18. vlatko_vts Infrequent Poster Joined: Jul 2006 Skopje Posts: 215 Citroen Saxo 1.6-16V VTS

    #18 25th December 2008, 02:33

    Quote:

    Originally Posted by katiescar jp4 head is a good budget head, but some tuners prefer the j4 head as a better port shape can be attained. Unless ur stripping engine down and complete re-build, hi-comps etc cant see the point.

    From which car is jp4 head, and from which j4?