Xu10j4 rebuild
  • Register
  • Help
Page 1 of 4 1234 Last
Results 1 to 25 of 78
Like Tree18Likes

Thread: Xu10j4 rebuild

  1. #1
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default Xu10j4 rebuild

    Nothing fancy, just dropping a nice fresh xu10 into my 205. Mild cam, fresh rebuild, should be a good thing. There was a fair bit of scale in the block when I stripped down the donor motor, so
    I dropped it in the hot tank.
    Xu10j4 rebuild-imageuploadedbytapatalk1376907007.588516.jpg
    Came up quite nicely.

    Advertisement


    Unfortunately the piston to bore clearance is over .003" so she'll get new slugs. The head is reasonable - valves, guides and lifters are in top nick, but a bit of corrosion around cylinder 1 water jacket so I'll need to weld it up a bit. Crank and rods are in excellent condition.
    Xu10j4 rebuild-imageuploadedbytapatalk1376907125.671242.jpg
    Xu10j4 rebuild-imageuploadedbytapatalk1376907141.604638.jpg

    Just thought I'd share where I'm up to.
    ducksonetime likes this.
    1988 205 GTi XU10J4
    2001 406 Monaco 5sp V6

  2. #2
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    Excellent work. Posting the bump stick tomorrow. I have a part number for a Wiseco flat top if you're interested.

    '92 205 Mi16
    '90 Mi16x4

  3. #3
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Quote Originally Posted by PeterT View Post
    Excellent work. Posting the bump stick tomorrow. I have a part number for a Wiseco flat top if you're interested.
    Great, I'll ship the core out. When I pressed off the trigger arm on the inlet cam I was surprised to find no locating key/flat/dowel. The Vipec I am using has 360 degree timing offset so it's not a problem, but how do I get it in the ballpark? What do you do on a stock motor?!

    Is there any advantage to using the Wiseco pistons? I generally tend to prefer cast for NA applications due to tighter clearances and less noise. I'm interested if there's a clear benefit bearing in mind I drive it most days - what sort of coin am I looking at? I can get a set of 0.6mm oversized cast Mahle pistons with rings for about $550. These motors are already 10.4:1 with the stock pistons, right? I thought I might deck the block a little which will improve squish and bump up the static compression to somewhere around 11:1. Open to recommendations though.

  4. #4
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    The newer forged pistons run a lot closer. See attached. The main benefit is the saving in weight. XU10J4 pistons are reasonably heavy. I think I saved approx 120g per piston. Price is much the same, certainly from the link Graham Wallis posted recently.

    The window for the cam trigger on a four cylinder is very wide. It depends on the ECU, but normally needs to occur before the cylinder #1 trigger point. Motec/Autronic do it before #4 from memory. Attached is pics of a standard cam. On the std engine it occurs before the missing tooth.

    Definitely take 1mm off the deck. This gives 11.1:1 and together with the squish improvement, transforms the engine into a responsive demon!
    Attached Thumbnails Attached Thumbnails Xu10j4 rebuild-wiseco-10686-7080-small.jpg   Xu10j4 rebuild-s16-cams-2.jpg   Xu10j4 rebuild-tang-position.jpg  

    '92 205 Mi16
    '90 Mi16x4

  5. #5
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,107

    Default

    Wiseco XU10 pistons seem to be only listed for turbo applications.
    I could be interested in the Mahles if the Wisecos turn out not to be practicable.
    Graham

    Quote Originally Posted by PeterT View Post
    The newer forged pistons run a lot closer. See attached. The main benefit is the saving in weight. XU10J4 pistons are reasonably heavy. I think I saved approx 120g per piston. Price is much the same, certainly from the link Graham Wallis posted recently.

    The window for the cam trigger on a four cylinder is very wide. It depends on the ECU, but normally needs to occur before the cylinder #1 trigger point. Motec/Autronic do it before #4 from memory. Attached is pics of a standard cam. On the std engine it occurs before the missing tooth.

    Definitely take 1mm off the deck. This gives 11.1:1 and together with the squish improvement, transforms the engine into a responsive demon!

  6. #6
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    I found these after a little searching: see part number K422M865C

    http://www.importperformanceparts.net/imports/wisecopistons_citroen.html

    same compression height as the ones you're showing Peter, except 0.5mm oversize instead of 1mm.

    If this goes nowhere Graham, I'll let you know availability etc of the Mahles.

    Yep I'll deck it 1mm, thanks for the info Peter.

  7. #7
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    They look well priced too. The 86.50mm version of the one I posted is 10686-3645.

    '92 205 Mi16
    '90 Mi16x4

  8. #8
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,107

    Default

    Cheaper than my listing too!

    Quote Originally Posted by chez00 View Post
    I found these after a little searching: see part number K422M865C

    http://www.importperformanceparts.net/imports/wisecopistons_citroen.html

    same compression height as the ones you're showing Peter, except 0.5mm oversize instead of 1mm.

    If this goes nowhere Graham, I'll let you know availability etc of the Mahles.

    Yep I'll deck it 1mm, thanks for the info Peter.

  9. #9
    1000+ Posts pug-life's Avatar
    Join Date
    Nov 2010
    Location
    Geelong
    Posts
    1,226

    Default

    Quote Originally Posted by PeterT View Post

    Definitely take 1mm off the deck. This gives 11.1:1 and together with the squish improvement, transforms the engine into a responsive demon!
    Does that apply to all XU 16 valves?

  10. #10
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    No, just XU10J4.

    '92 205 Mi16
    '90 Mi16x4

  11. #11
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Didn't get a response from the above website and want to move along so I've opted for the Mahle 0.6mm oversize. 11:1 should still be pretty good.

  12. #12
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    Excellent. I'm very keen to see some pics.

    '92 205 Mi16
    '90 Mi16x4

  13. #13
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Just a quick update. There were only 3 Mahle piston assemblies Australia wide with a back order wait of 3-6 months!

    I ordered the Wiseco ones mentioned above. US$677 including rings and freight to me. They had to make them so there's a 4 week wait.

    Meanwhile I'll move ahead with the rest of the project. I'll put my rear beam back together with my cut and splined 24mm ARB and disc brakes, pull the old donk out, tidy the engine bay and work on the 16v head. No such thing as a quick project so I've found, especially owning a French car!

    Does anyone know if I will need to shorten the gti6 inlet manifold to make it fit?
    1988 205 GTi XU10J4
    2001 406 Monaco 5sp V6

  14. #14
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,107

    Default

    So which pistons did you end up ordering, size C/R?


    Quote Originally Posted by chez00 View Post
    Just a quick update. There were only 3 Mahle piston assemblies Australia wide with a back order wait of 3-6 months!

    I ordered the Wiseco ones mentioned above. US$677 including rings and freight to me. They had to make them so there's a 4 week wait.

    Meanwhile I'll move ahead with the rest of the project. I'll put my rear beam back together with my cut and splined 24mm ARB and disc brakes, pull the old donk out, tidy the engine bay and work on the 16v head. No such thing as a quick project so I've found, especially owning a French car!

    Does anyone know if I will need to shorten the gti6 inlet manifold to make it fit?

  15. #15
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    I opted for the .5mm O/S 12:1 flat tops, hopefully it's not too much compression.

  16. #16
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    Not for E85 anyway. I also recommend you adding an extra 0.5mm shim under each spring. This is usually enough to correct the seat pressure after machining and age are considered.

    '92 205 Mi16
    '90 Mi16x4

  17. #17
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Got my forged pistons today. I don't know why they say 12.5:1 cr, they are essentially a replica of the standard piston. Moreover they weigh an extra 17g per slug, so no real advantage to going this way over standard cast units aside from a supply point of view. I will cc the assembled block to verify but I'm pretty certain these will not change cr. I'll be honest and say I'm kind of relieved as I didn't really want to run e85 a or more to the point, my missus didn't!

    This is the standard original piston
    Xu10j4 rebuild-imageuploadedbytapatalk1380592943.205815.jpg

    This is the new Wiseco.
    Xu10j4 rebuild-imageuploadedbytapatalk1380592977.355089.jpg

    This is the comparison of deck heights (no difference):
    Xu10j4 rebuild-imageuploadedbytapatalk1380593036.204448.jpg
    1988 205 GTi XU10J4
    2001 406 Monaco 5sp V6

  18. #18
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    That's certainly the way I designed them, just to be a straight replica. Not sure about the weight though, maybe I didn't measure properly, or they used a different blank this time. The only change in CR will be from the extra 0.5mm bore and the 1mm you take off the block.

    '92 205 Mi16
    '90 Mi16x4

  19. #19
    1000+ Posts schlitzaugen's Avatar
    Join Date
    Nov 2010
    Location
    loneliness capital of the world
    Posts
    8,775

    Default

    chez, can you check the piston weights (alone, i.e. without pin) again? The weight difference might be explained by the density of forged vs cast.
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

  20. #20
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Xu10j4 rebuild-imageuploadedbytapatalk1382062052.277746.jpg

    Fresh metal. Just need to set the ring gap and check conrods and the bottom end is ready.
    ducksonetime likes this.
    1988 205 GTi XU10J4
    2001 406 Monaco 5sp V6

  21. #21
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Just a quick heads up for anyone interested in these Wiseco pistons. They need a channel milled into the skirt to clear the piston crown oil jet that protrudes into the bore. This is an 8x8.75 cut and works perfectly.

    It's a bit of a pain but it came up fine.

    Xu10j4 rebuild-imageuploadedbytapatalk1382603590.837226.jpg
    ducksonetime likes this.
    1988 205 GTi XU10J4
    2001 406 Monaco 5sp V6

  22. #22
    1000+ Posts schlitzaugen's Avatar
    Join Date
    Nov 2010
    Location
    loneliness capital of the world
    Posts
    8,775

    Default

    Where is the oil jet coming from?

    In your picture above where pistons are compared side by side it seems the original pistons don't have that channel.
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

  23. #23
    Fellow Frogger! chez00's Avatar
    Join Date
    Nov 2010
    Location
    Adelaide
    Posts
    567

    Default

    Yeah sorry a little more info is required:

    The picture is a "before and after" of the Wiseco pistons - I hadn't yet milled the bottom one. Where I've milled is not really the skirt but the webbing of the piston (it does not run against the cylinder wall).

    The jets are a bolt in die cast aluminium item that came on the xu10j4 standard, and are there to cool the piston crown. They feed off the same oil gallery as the main bearings and point a squirter up the bore, protruding from the base of the cylinder into the bore about 7.5mm, aimed towards the underside of the piston crown.

    The OEM pistons do not have the webbing and thus the oil jet just squirts straight onto the piston crown inside the piston skirt. The web of the Wiseco pistons, however, is exactly where the jets are and hit against it before reaching BDC. I have actually lightly die-grinded the inner edge of the channel (the side towards the conrod) to guide the oil towards the piston crown rather that squirting into the oil control ring.

  24. #24
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,415

    Default

    They must have forgot to do yours, as mine are notched.

    '92 205 Mi16
    '90 Mi16x4

  25. #25
    1000+ Posts schlitzaugen's Avatar
    Join Date
    Nov 2010
    Location
    loneliness capital of the world
    Posts
    8,775

    Default

    Quote Originally Posted by chez00 View Post
    Yeah sorry a little more info is required:

    The picture is a "before and after" of the Wiseco pistons - I hadn't yet milled the bottom one. Where I've milled is not really the skirt but the webbing of the piston (it does not run against the cylinder wall).

    The jets are a bolt in die cast aluminium item that came on the xu10j4 standard, and are there to cool the piston crown. They feed off the same oil gallery as the main bearings and point a squirter up the bore, protruding from the base of the cylinder into the bore about 7.5mm, aimed towards the underside of the piston crown.

    The OEM pistons do not have the webbing and thus the oil jet just squirts straight onto the piston crown inside the piston skirt. The web of the Wiseco pistons, however, is exactly where the jets are and hit against it before reaching BDC. I have actually lightly die-grinded the inner edge of the channel (the side towards the conrod) to guide the oil towards the piston crown rather that squirting into the oil control ring.
    Thank you, chez. Makes sense.

    I was talking about the picture where you have the two pistons on the same wristpin.

    The extra webbing then explains why the Wiseco is heavier too.
    ACHTUNG ALLES LOOKENPEEPERS

    Das computermachine is nicht fur gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitssparken. Ist nicht fur gewerken bei das dummkopfen. Das rubbernecken sightseeren keepen hands in das pockets-relaxen und watch das blinkenlights.

Page 1 of 4 1234 Last

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •