Flywheel timing markings | FerrariChat
Buy

Flywheel timing markings

Discussion in 'Mondial' started by MvT, Nov 29, 2015.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #1 MvT, Nov 29, 2015
    Last edited by a moderator: Sep 7, 2017
    Ok guys, I'm driving already for over 2 years with a new flywheel that had no timing markings, which I discovered later on when checking the vavles 6 months later. I used the timing markings on the camshafts to put things on time at the time and she spurs like a kitten.

    Since I have a mandatory winter stop for the months Dec, Jan and Feb as I do not pay road tax I decided to put the timings on the new flywheel.

    I put the camshafts on the timing marks (when you look throug the oil filler hole and I have some doubts on the markings. When I only look on the flywheel I would say the red arrow would bet the TDC. However, when I put it on the camshaft timing marks it points to the leg of the P of PM. The space between the P and the stripe marking is one tooth on the cam belts.

    The question is now which of the two is TDC?
    - Leg of the P (PM)
    - Stripe between PM and 1.4
    Image Unavailable, Please Login
     
  2. Meister

    Meister F1 Veteran
    Silver Subscribed

    Apr 27, 2001
    5,516
    Duluth, MN
    Full Name:
    The Meister
    #2 Meister, Nov 29, 2015
    Last edited: Nov 29, 2015
    its been 10+ years since I did the last belt change on my ex 308, but IIRC I was never on the P, but on the hash. There are two times in which the assembly marks line up on the cam and cam caps. One it TDC on compression and the other is not. Recall also that the cam/caps marks are just assembly marks and were degreed after that point so often times the marks do not line up perfectly.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,764
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Nov 29, 2015
    Last edited: Nov 29, 2015
    The "stripe" between the PM and the 1-4 is the PM1-4 mark (so you are a little off if you are taking the cam marks as being perfect); however, you are not off "one tooth on the cam belts" - that would be a huge amount (12 degrees). The distance between the stripe of the PM1-4 mark and the stripe of the AF5* mark is 5 deg = so you are off maybe ~2.5 degrees.

    But your post seems a little confusing. You said you have an aftermarket flywheel with no marks, but your photo is a stock flywheel. Are you saying that you removed the aftermarket flywheel and put the stock one back on and this is where you are with the reinstalled stock one (and using the cam marks as perfect)? IMO, whenever you remount any flywheel, you should confirm/set the TDC position by measuring the motion of piston #1 (e.g., using a piston stop or dial indicator to do the "little low from each direction and then picking the middle" method) -- JMO.
     
  4. Alden

    Alden F1 Rookie
    Rossa Subscribed

    Apr 25, 2010
    3,596
    Central Florida
    #4 Alden, Nov 29, 2015
    What Steve says is true and very good advice for anyone trying to determine where TDC is on any engine.

    Why guess? For the price of a piston stop or dial indicator with a spark plug adapter you can find out for sure. Then mark it on your flywheel and you are certain.

    I will try to find instructions or a video on how to do this, but basically you go at #1 TDC from both directions, marking the flywheel each time the dial indicator says the piston is as far up as it will go. True TCD is exactly between the two marks.

    Here is a video with a piston stop that explains it pretty well:https://www.youtube.com/watch?v=RENhHI9n65I
    Alden
     
  5. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #5 MvT, Nov 29, 2015
    Last edited by a moderator: Sep 7, 2017
    Sorry guys I was a bit in a hurry and someone was already yellow at the stair to come down. It indeed is a bit confusing.

    This was actually a question, but put a dot instead of a Q mark :)
    The space between the P and the stripe marking is one tooth on the cam belts?

    I took of the aftermarket flywheel and put on the old one, which is useless since this has a crack from side to side. The reason for me to put it on is to determine the TDC for the new flywheel, thus I put the camshafts on the timing marks expecting to have the marking lining up on the old flywheel. Remove the old flywheel bolt on the new one again and mark it down at the yellow arrow. (There is only one way to put on any of the two flywheels else the bolt holes will not line up to fasten it, not sure what the English word is for this technic)

    To my surprise it pointed at the leg of the P, which I though would not be correct, but not entirely sure. Reason I was not sure as some pics on the internet show the TDC just before the P and had the marking there instead of between the PM and 1.4 like me.

    You are right and I did check since I had no markings, but I wanted to know what was the marking for the TDC on the OEM flywheel. It is not the first time OEM Ferrari flywheels are a bit of or way off as I seen on a Testa :) anyway here the pic that started to confuse me and I didn't see a mark in front of PM on my flywheel

    Thank you Steve for pointing out the mark.
    Image Unavailable, Please Login
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,764
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #6 Steve Magnusson, Nov 29, 2015
    There's not a good common single technical word for this in English, but something like "self-keying" or "only fits one way" or "asymmetric bolt pattern" might be how it would be described in words. But my recollection is that even though the pattern can't be shifted, there is still enough wiggle room between the bolt shanks and the thru holes that there could be some small uncertainty if TDC was not rechecked/reset (which is why the fixed pointer has a little adjustment possible).

    Yes, they weren't always very consistent with where the stripe was located relative to the identifying text, but the stripe is always the true location mark (for any of flywheel position marks).

    Now you are left with the usual conundrum as to whether the cam marks should be trusted or not ;)
     
  7. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #7 MvT, Nov 29, 2015
    Last edited: Nov 29, 2015
    So I see now once again :)

    Thanks Alden! I'm pretty sure mine is good as I used a piston stop tool. However only on the pulley on the other side at the time, since I had no markings on the new flywheel and things already were put together 7000 miles back :). After using a piston stop tool or cam belt change I always manually rotate for two full rotations for the reason you mentioned and for my own sanity as I still do this only for a hobby :D

    thanks for looking up this video still! Appreciated!
     
  8. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #8 MvT, Nov 29, 2015
    haha! :) let me say I do not trust this flywheel. (for the moment) Things will be out as one cam seal is leaking and now that all is open I will redo the whole thing and come back on this how it turned out.
     
  9. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
    1,839
    UK
    #9 Bell Bloke, Nov 29, 2015
    Last edited: Nov 29, 2015
    Hey MvT, why didn't you mark it against the old flywheel?
    Also did you put the TDC marks on the new flywheel?
     
  10. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #10 MvT, Nov 29, 2015
    The day I bought her I couldn't shift anymore due to a cracked flywheel, wrong slave clutch cylinder, shortened rod and movement in the rear silent block of the shift shaft.

    I got a new flywheel and just bolted it on and, my mistake, didn't look for the timing marks hence didn't know it wasn't on it. Also a time issue as I had an appointed for MOT and import into NL since I was driving with German plates.

    First valve clearance check was ok that was the first week I had her. After 10,000km I did a check again and 4 where a bit tight so took out the cams. Discovered the smileys on the cams and when putting back the lot together I found out I didn't had the marking. After putting it on the correct timing I didn't want to paint marking on through the inspection whole onto the new flywheel as it was dirty and some oil. Also the lot worked so I didn't really care.

    My idea was to mark it against the old flywheel now and I thought why not be more accurate an bolt on the old one put it on time.. Take of the old one.. put on the new one and mark it. Then I discovered this, which surprised me really.

    Another thing that surprised me was the s**t collected inside the bell housing... Dirt, sand, grass :eek: that after 20,000km.. It's really time to make your flat floor pan :)
     
  11. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
    1,839
    UK
    #11 Bell Bloke, Nov 29, 2015
    Ah ok MvT well I must take my engine floor pan off and measure it up for you asap....it really is fantastic! ;-)
     
  12. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #12 MvT, Dec 3, 2015
    Last edited by a moderator: Sep 7, 2017
    Thx Bell!

    Ok an update on this one. Needed to put in a new crankshaft seal first as it was leaking now.The old flywheel is incorrect for sure. The markings on the cams perfectly line up after determining the TDC on the new flywheel with a cylinder stopper. Added a pic for folks who are curious how this tool looks like. This one is a bit too long for this engine.

    Steve you are right that there is some wiggle room left when bolted it on, but not fastened. wiggled it left and right and put it in the middle. However the wiggle does not compensate the distance from the P to the marking. The farest I get is the first leg of the M.
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  13. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
    1,839
    UK
    #13 Bell Bloke, Dec 3, 2015
    The old flywheel markings are wrong? Really? That has to be a first....
    Anyway I use a dial guage down the bore to find TDC on an engine without marks.
    Regards Bell.

    Ps If your cam markings are correct but your crank marks are off then maybe your cam wheels have been adjusted incorrectly in the past (they are adjustable)
     
  14. MvT

    MvT F1 Rookie

    May 25, 2013
    4,261
    The Netherlands - NH
    Full Name:
    Tijn
    #14 MvT, Dec 4, 2015
    hmmm... I never took of the cam wheels hence didn't know they were adjustable. Perhaps that is the case. Perhaps I can see if the were taken off. thanks for the tip! I never used a dial gauge actually. Perhaps I should start using it :)
     
  15. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,764
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #15 Steve Magnusson, Dec 4, 2015
    The position of the fixed pointer is also adjustable so one can't be sure that that was never mucked with after the car left the factory (although there are humans involved at the factory so errors can happen there ;)).
     

Share This Page