2CV - fitting piston barrels to crankcase
  • Help
Results 1 to 14 of 14
  1. #1
    Tadpole
    Join Date
    Jun 2013
    Location
    Dee Why
    Posts
    23

    Icon5 2CV - fitting piston barrels to crankcase

    I am a virginal 2CV owner, having just bought Bad Bertie's 56 (that's me in his photos in the Citroen appreciation thread). Two new barrels came as part of the package. However, although their ID and height seem identical with what was on the motor - it is a 425cc - the OD of their "bases" - the portion that goes into the "hole" in the crankcase - is almost a millimetre oversize. They will have to be machined to fit.

    Advertisement


    Is this normal with new barrels?

  2. #2
    Now go make me a sandwich Hotrodelectric's Avatar
    Join Date
    Nov 2010
    Location
    San Diego, California, USA
    Posts
    3,543

    Default

    There were two engines of nearly identical size- the 425cc, which your car should have, and a 435cc, which was somewhat later. I can't quote chapter and verse on the earlier 2CVs, but it seems what you have is a mis-matched set.

    And trust me- you now own a Citroen. You will not be a virgin for long.
    The measure of your character isn't what you do when people are watching- it's what you do when they aren't watching.

  3. #3
    JBN
    JBN is offline
    1000+ Posts JBN's Avatar
    Join Date
    Nov 2010
    Location
    Sydney
    Posts
    8,517

    Default

    Put the wrong barrels on the engine and the 2CV won't be a virgin either, it will be rooted.

    John

  4. #4
    Tadpole
    Join Date
    Jun 2013
    Location
    Dee Why
    Posts
    23

    Default

    Thanks for the reply, particularly the news that I will soon lose my virginity.

    I had wondered re a 435cc engine but I gather that these had a larger bore than the 425cc - 68.5mm vs 66mm. The "odd" barrels have 66mm bores. They seem identical to the ones on the engine in all respects other than the outer diameter of the lower portion that goes into the crankcase. From what you are saying, I gather that it is not the norm to have to machine new barrels.

  5. #5
    Now go make me a sandwich Hotrodelectric's Avatar
    Join Date
    Nov 2010
    Location
    San Diego, California, USA
    Posts
    3,543

    Default

    Quote Originally Posted by RichardM View Post
    Thanks for the reply, particularly the news that I will soon lose my virginity.

    I had wondered re a 435cc engine but I gather that these had a larger bore than the 425cc - 68.5mm vs 66mm. The "odd" barrels have 66mm bores. They seem identical to the ones on the engine in all respects other than the outer diameter of the lower portion that goes into the crankcase. From what you are saying, I gather that it is not the norm to have to machine new barrels.
    That is a bit of a head scratch. When I have some time, I'll look through the few A Series parts books I have and see if there are a couple different iterations. AFAIK, there was only version of the 425, and that was the 13hp. Ami or Dyane won't explain it- this is long before those two models, and they both started off with the 435 18 hp.

    A mm difference is quite a bit of material, so something stuck in the cylinder port is unlikely. I can't think that a factory liner set for a 425 would be so wildly off. What ever it winds up being, I do not recommend machining your crankcase to fit a mis-matched set.

    Just for giggles, measure the inside diameter of both ports on the crankcase, and the outside diameter of the barrel where they slip into the crankcase. Also, measure the cross section thickness and compare to your old barrels. You might have two different manufacturers. Has Bertie been able to tell you how he got the set?
    The measure of your character isn't what you do when people are watching- it's what you do when they aren't watching.

  6. #6
    JBN
    JBN is offline
    1000+ Posts JBN's Avatar
    Join Date
    Nov 2010
    Location
    Sydney
    Posts
    8,517

    Default

    I presume in all of this, you know which end is up and you are measuring the appropriate end of the barrel.

    John

  7. #7
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,748

    Default

    Wouldn't it be best just to chase up a 600cc motor and stick in there
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  8. #8
    Now go make me a sandwich Hotrodelectric's Avatar
    Join Date
    Nov 2010
    Location
    San Diego, California, USA
    Posts
    3,543

    Default

    Quote Originally Posted by DoubleChevron View Post
    Wouldn't it be best just to chase up a 600cc motor and stick in there
    He would also have to chase up the appropriate transmission, axle shafts, brakes, and all the other ancillary stuff that goes with whatever version 602 he swaps to. He may also need to clearance the fenders for the wider motor. Not difficult by any stretch of the imagination, just lots of parts and details to deal with.
    The measure of your character isn't what you do when people are watching- it's what you do when they aren't watching.

  9. #9
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,748

    Default

    I assumed it would be a simple swap .... I guess it is a citroen It would certainly be a much more usable vehicle if it can cruise at the speed limit. one with a 602cc motor should be able to cruise at 70mph.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  10. #10
    1000+ Posts daffyduck's Avatar
    Join Date
    Nov 2010
    Location
    Los Angeles, CA USA
    Posts
    1,955

    Default

    Quote Originally Posted by DoubleChevron View Post
    I assumed it would be a simple swap .... I guess it is a citroen It would certainly be a much more usable vehicle if it can cruise at the speed limit. one with a 602cc motor should be able to cruise at 70mph.
    70 kph is a breeze. 70 mph is a speed range reserved for only the strongest of the 602 cars with the higher 4th gear.

  11. #11
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,748

    Default

    Quote Originally Posted by daffyduck View Post
    70 kph is a breeze. 70 mph is a speed range reserved for only the strongest of the 602 cars with the higher 4th gear.
    I thought they must have all done that... I'm pretty sure my mothers 2cv will cruise at an indicated 70mph. No idea what the "real" speed actually is though. I guess it's like an ID19 that'll do an indicated 90mph (real speed probably 75mph ).
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  12. #12
    Too many posts! JohnW's Avatar
    Join Date
    Jul 2001
    Location
    Perth, WA, Australia
    Posts
    11,301

    Default

    We all have different definitions for "cruise" Shane....
    JohnW

    Renault 4CV 1950 (R1062)
    Renault R8 1965 (R1130)
    Renault Scenic Series II 2005 (wife's)
    Renault Scenic Series II 2006 (daughter's)
    Renault Scenic Series II 2007 (mine)

    CitroŽn CX Pallas 1980 (moved on to new custodian)

    National Co-ordinator, Renault 4CV Register of Australia

  13. #13
    Tadpole
    Join Date
    Jun 2013
    Location
    Dee Why
    Posts
    23

    Default

    Thanks again.

    On the simple question - yes, I believe I know the top from the bottom. Top is not an issue, internal bore and external diameter are correct. They fit to the heads perfectly, and to the pistons. Length is also correct. Difference is only at the bottom.

    There are a couple of other differences (in addition to the oversize OD problem). The cooling fins come down almost to the bottom of the barrels whereas the ones from the original engine stop about a centimetre above the crankcase deck. All other aspects of the fins are the same, including the "wavy" profile to miss pushrod tubes, etc. The other difference is that the shoulder at the bottom - which locates in the crankcase port - is a little deeper (as well as wider, giving the OD problem) and the very bottom section of the barrels is unmachined.

    My interpretation now is that they are the correct barrels but the manufacturer did not complete the manufacturing process for whatever reason. Perhaps it emerged that they were seconds.

    I have tried ringing Bad Bertie a couple of times but so far no luck. I will continue to try.

    Re the potential for an engine swap, foolishly or not, I want the car to be essentially as it was in 1956. Not obsessively so but generally so. I plan to reverse some of the mods/upgrades it has had over its life. Cruising at 70 may be a challenge, irrespective of the units used.

    Thanks for your help.

  14. #14
    Fellow Frogger!
    Join Date
    Jul 2003
    Posts
    317

    Default

    Quote Originally Posted by RichardM View Post
    Re the potential for an engine swap, foolishly or not, I want the car to be essentially as it was in 1956. Not obsessively so but generally so. I plan to reverse some of the mods/upgrades it has had over its life. Cruising at 70 may be a challenge, irrespective of the units used.

    Thanks for your help.
    Tis a fine choice Richard.
    Try emailing 2CViking he is ex Danish/Australian now living in France and can supply the information and parts required.
    The best source of 2cv info on the net is international2cvfriends.com you will need to register but well worth it!

    All the best.
    Harley

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
  •