807 engine balance.
  • Register
  • Help
Results 1 to 11 of 11
Like Tree5Likes
  • 1 Post By Bustamif
  • 1 Post By PeterT
  • 1 Post By alan moore
  • 1 Post By 59 Floride
  • 1 Post By Shoji

Thread: 807 engine balance.

  1. #1
    Fellow Frogger!
    Join Date
    Nov 2010
    Location
    sydney
    Posts
    479

    Default 807 engine balance.

    Can 807 gurus please comment.

    I have a few periods of vibration in my engine.

    Mild at 2000, harsher at 3100.

    Yes I made my engine brackets and everything else is modded to the max etc etc. I admit there is more parts on it than in the space shuttle.

    My pistons, wrist pins and rods were all within a gram.

    I didn't balance the crank balanced because 2 I got checked in the past were good from the factory.

    I'm using a different flywheel than the one that came with this crank.

    Did the factory balance as a set?

    Advertisement


    I didn't balance the flywheel or press plate either.

    It's costing me $10 a day in super glue to keep gluing my fillings back in.

    Any 807 guru comments?


    Sent from my E5823 using Tapatalk
    BR

    Building a race car is easy - building a race car that can be road registered is hard.

    For any custom fabrication call Precision One Off Engineering - Sydney 02 4587 8666

  2. #2
    Simon's Avatar
    Join Date
    Jul 2000
    Location
    Adelaide
    Posts
    5,835

    Default

    Buffeting as the car just starts hitting the sound barrier?

    Otherwise the crank and fly (along with the clutch) were balanced as a set from the factory.
    1963 Renault R4 Van
    1964 Renault R4
    1967 Volkswagen 1300 Deluxe
    1969 Renault 8 Gordini 1300
    2005 Renaultsport Clio 182 Cup

  3. #3
    Fellow Frogger!
    Join Date
    Oct 2014
    Location
    Windsor 2756 NSW Australia
    Posts
    327

    Default

    Considering the revs you have reached on that motor I would definitely balance the clutch and flywheel as an assembly and not assume the factory spent the time and effort necessary for an engine with your mods. Same goes for the crank. I have seen the result of a wobbly flywheel coming out of a bellhousing on a Porsche then through the rear parcel shelf at 8k rpm (not mine). It may be worth checking to see if the flywheel bolts are all tight, from what I have seen with other people’s engines, if there is a balance problem. the flywheel bolts usually loosen up before letting the flywheel escape.
    Roland likes this.

  4. #4
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,004

    Default

    I concur. The harmonic balancer, crank, flywheel and pressure plate need to be balanced as a set and marked for assembly.
    Roland likes this.

    '92 205 Mi16
    '90 Mi16x4

  5. #5
    Fellow Frogger! driven's Avatar
    Join Date
    Apr 2005
    Location
    Melbourne
    Posts
    951

    Default

    Had issues with rough 807 engine. Maybe not as bad as you have
    After rebuild never put back the two large weights on each side of engine at the front.
    Forget what they were called, DePhasers?
    Refitted with new rubbers and all good.
    Never used a front pulley either, aka R16,
    I recall flywheel only fits one way by bolt hole pattern. Need locktite so they don't come loose. May be loose bolt here
    French would have never balanced the assembly as a whole. They were into saving money!
    Just bolt up the individual balanced components at assembly.
    Pressure plates are balanced by manufacturer. Look closely.
    Always use new bolts on pressure plate. Old ones stretch and break on old Renaults
    Ensure they are all the same with the same washer type

    You can change these bolts one at a time

  6. #6
    1000+ Posts alan moore's Avatar
    Join Date
    Oct 2001
    Location
    Ipswich, Queensland.
    Posts
    1,737

    Default

    The 807 cranks I have had balanced have been very close from the factory. If getting balancing done yourself, the flywheel would then be fitted to the balanced crank, and then the pressure plate and balanced in turn. I don't know what the factory did, but I doubt they would have done this. Given I expect you lightened the flywheel it would have been prudent to have balanced it on your crank.

    Renault went to a lot of trouble on the R15/17 with the 807 motor to fit a large crossmember with "Dephasers" as Driven has mentioned to try and deal with harmonics. I do remember my 15 having a harmonic vibration at 2700 -2900 Rpm. I changed a lot of parts including the engine, fitting a flex section to the exhaust, engine mounts, and so forth and never did get rid of it.
    Roland likes this.
    '56 Renault 750 (16TS Power)
    '62 Renault Dauphine Gordini
    '89 Renault Alpine GTA V6 Turbo
    '08 Renault Megane sedan

  7. #7
    Fellow Frogger! Shoji's Avatar
    Join Date
    Jan 2012
    Location
    Mandurah WA
    Posts
    519

    Default

    Very interesting reading.
    Geko Engineering had picked up on a drive, that my 17 maybe has this similar issue. At around 3000rpm it has a vibration. Ray mentioned harmonic balance.
    On the new engine we will be talking balancing.
    Good luck with finding the issue Brett.
    Cheers. John
    “Listen very carefully, I shall say this only once.”

  8. #8
    VIP Sponsor 59 Floride's Avatar
    Join Date
    Oct 2010
    Location
    It's how I roll...Brisbane
    Posts
    31,255

    Default

    ...is the family cat accounted for?

  9. #9
    Too many posts! JohnW's Avatar
    Join Date
    Jul 2001
    Location
    Perth, WA, Australia
    Posts
    8,754

    Default

    Quote Originally Posted by Shoji View Post
    Very interesting reading. Geko Engineering had picked up on a drive, that my 17 maybe has this similar issue. At around 3000rpm it has a vibration. Ray mentioned harmonic balance. On the new engine we will be talking balancing.
    Good luck with finding the issue Brett.
    I'd more than talk. When I last did the R8 I had it fully balanced, clutch included. But then you will be doing it, I'm sure.
    JohnW

    Renault 4CV 1951
    Renault R8 1965
    Renault Scenic 2005 (wife's)
    Renault Scenic 2007 (mine)
    Peugeot 306 XT 1995 (daughter's)
    Citroën CX Pallas 1980

    National Co-ordinator, Renault 4CV Register of Australia

  10. #10
    Fellow Frogger! Shoji's Avatar
    Join Date
    Jan 2012
    Location
    Mandurah WA
    Posts
    519

    Default

    Quote Originally Posted by JohnW View Post
    I'd more than talk. When I last did the R8 I had it fully balanced, clutch included. But then you will be doing it, I'm sure.
    Absolutley JohnW. Fully balanced, got it!
    That includes weighing certain items, yes? Pistons, rods, etc.
    I'm sure Geko Engineering will sort it out for me.
    JohnW likes this.
    Cheers. John
    “Listen very carefully, I shall say this only once.”

  11. #11
    1000+ Posts schlitzaugen's Avatar
    Join Date
    Nov 2010
    Location
    loneliness capital of the world
    Posts
    7,395

    Default

    You don't need to weigh pistons rods, etc, other than making sure they are the same weight, which you can do at home with a kitchen scale (you don't need more precision than .1g). I rebuilt my engine with Bretille pistons from Mecaparts and they were all the exact same weight. Conrods and pins were reused and they were all within the .1 gram accuracy of the scales I used.

    The shop where you take your bits will require a piston, a pin and a conrod to factor them in the balancing exercise (based on the assumption they are all the same weight), together with anything that is bolted to the c'shaft for dynamic balancing.
    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.

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
  •