pros and cons on jp4 ??

  1. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #1
    hi guys just after some info why do people do this conversion what are the advantages and disadvantages if any?? thanks
  2. Super Moderator Joined: Nov 2009 Cambridge(ish), UK. Posts: 10581 BMW 5x M50d.
    #2
    The most straightforward swap (just sensors, mounts etc) then you get a newer, lower mileage engine as a plus, but you lose some power (about 10bhp) from the softer cams.

    If you also swap the cams and springs, you get all the +ve's and keep the power.

    A downside is later on, if you want to mod the engine for more power, you can run into problems with cam choice as the clearances are tighter (valve/piston).

    If you're careful, there's basically no real drawbacks.
  3. Established Member Joined: Jan 2008 Posts: 1802
    #3
    Weaker pistons I think on the later engine
  4. Super Moderator Joined: Nov 2009 Cambridge(ish), UK. Posts: 10581 BMW 5x M50d.
    #4
    Quote:
    Originally Posted by luthor1 View Post
    Weaker pistons I think on the later engine
    Not heard this, but not sure if it's really important? TU5JP4's certainly don't have issues at standard power, so should be fine with mild mods. Anyone going bigger power (170+bhp) is generally changing pistons anyway

    Where'd you hear this anyway Andy?
  5. Saxperience Forum Bum Joined: Sep 2011 Doncaster Posts: 2627 Fabia VRS, mk1 fiesta + some others
    #5
    the 30/40K engine on the market are a big bonus!
    most vts lumps have done 100k these days
  6. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #6
    spot on cheers so basically more redlly avalible low milage engines which i prasume can be picked up fairly cheapley??
  7. Established Member Joined: Jan 2008 Posts: 1802
    #7
    Top ring is higher so weaker for boost, heard from John at GMC
    They are lighter too
    J4 engine and pistons really are extremely strong though, over engineered so no surprise the made them lighter.
  8. Super Moderator Joined: Nov 2009 Cambridge(ish), UK. Posts: 10581 BMW 5x M50d.
    #8
    Yep jump on egay and have a search for a 307 engine or some such lots and lots available. Ive paid £150 each for my last two but up to £200 is about right
  9. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #9
    ye supose but j4 engine are fairley cheap and easy to repair anyway ?? is it for ease off saving haveing to split the engine ??
  10. Saxperience Addict Joined: Sep 2008 Suffolk Posts: 11590 ITB'd Saxo VTS & Mazda 6 MPS
    #10
    Citroen over engineering something? Get out lol!
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  11. Established Member Joined: Nov 2011 Kent Posts: 1305 Daily: 2015 Juke 1.5dci Toy: 2002 106 Quiksilver
    #11
    Quote:
    Originally Posted by bigezz View Post
    spot on cheers so basically more redlly avalible low milage engines which i prasume can be picked up fairly cheapley??
    Yes mate that's it. Low mileage/non abused J4 lumps are rare as hens teeth these days IMO and there's always at least a few JP4's on eBay. The JP4's come out of cars that aren't typically ragged too - more parents taking kiddies to school and back in their 307's, C2's etc.

    One thing that's always worried me is how you can tell if the lump has done what the seller claimed the engine has done... obviously the seller could have changed/clocked the dials of the car it came out of or what if there simply are no dials and/or history that comes with the engine?
  12. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #12
    lol indeed
  13. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #13
    exactly and even things like 307 and so on also starting to see high milage
  14. Super Moderator Joined: Nov 2009 Cambridge(ish), UK. Posts: 10581 BMW 5x M50d.
    #14
    Quote:
    Originally Posted by bigezz View Post
    exactly and even things like 307 and so on also starting to see high milage
    Agree, but I bet with a week's searching I can find a JP4 with under 20,000 miles on it second hand.

    Bet you can't fine a J4 like that
  15. Infrequent Poster Joined: Jul 2012 perth Posts: 224 106 gti cheery red, 106 rallye phase 2 blaca white
    #15
    well supose your right there