Where Are The Damn Flywheel Markings? | FerrariChat

Where Are The Damn Flywheel Markings?

Discussion in 'Technical Q&A' started by donaldh2o, Nov 18, 2003.

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

  1. donaldh2o

    donaldh2o Karting

    Nov 10, 2003
    Irvine CA
    Full Name:
    Will be pulling the distributors on my 1976 308 to inspect them and to replace the small O-rings on the ends of the shafts. The car is dripping oil and I've traced it to the distributors.

    I did this years ago to stop the same leaking problem with small O-rings I bought at Ace Hardware - I'm surprised they've lasted so long. I may also replace the points and capacitors and do whatever else needs to be done while I have the distributors out.

    But my problem is setting the timing after I reinstall the distributors. Tried to time the car a few weeks ago, but could not see the flywheel markings with the timing light. I went ahead and set the timing by ear but I'm not sure that's good enough.

    Where are the markings, my shop manual is not specific. Are they on the flywheel gear teeth? If so, how do I clean the flywheel so I can see the markings without removing the bell housing -which looks like a formidable job?
  2. CraigFL

    CraigFL Formula Junior

    Jan 17, 2001
    Panama City, FL
    Full Name:
    We've had numerous, long discussions about the flywheel timing marks. If you search the old fchat you should find them...
  3. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    First of all, there seem to be numerous different flywheels, each with different markings. For example, the early US flywheels on cars with the "R2" points will have different markings than Euro flywheels w/o the "R2" points.

    The markings are, IMHO, damn near impossible to see. Get that gigantic socket (36mm??) needed for the front of the crankshaft. *Slowly* turn the engine (Important: In the direction that it runs) with someone who has a clue looking at the flywheel with a good flashlight. At each mark, put a dot of fingernail polish. This readily shows up with the timing light.

    My car had a mark at 6deg ATDC, TDC, 16deg BTDC, and 34deg BTDC. Each is labeled in some goofy way. For example, the 34deg mark was 5A34 (or was it 34A5?) meaning that is the setting for 5000rpm.
  4. gerritv

    gerritv Formula 3

    Jun 18, 2001
    St Catharines
    Full Name:
    #4 gerritv, Nov 18, 2003
    Last edited by a moderator: Sep 7, 2017
    This is what the hidden information you are looking for looks like. It's a challenge! This is from my 1976 308GT4. It was difficult to photograph let alone find in the first place.
    Image Unavailable, Please Login
  5. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    Full Name:
    Malcolm W
    The easiest way to time your car is to remove the timing inspection plate on the flywheel housing, then turn the engine over by hand (it may be easier to remove the spark plugs) remembering to turn it in the direction of rotation, until the timing marks appear then mark the spot on the flywheel with a small dob of white paint.

    You will have to do this two times for each reference because your engine has two distributers. I would mark the static mark (ie AF3) and the fully advanced mark (ie AM34), these figures will vary depending on what flywheel you have, but the theory is the same.

    When you start the engine and are checking the timing with a strobe light you will easilly be able to see the timing marks.

    Don't forget to operate the micro switch (if applicable) when checking the static timing so you can see the change of timing calibration

  6. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    Groton, MA
    Full Name:
    Verell Boaen
    To make the markings more visible, start the engine & hold the tip of a small stainless steel wire brush against the angled edge of the flywheel. It will clean the accumulated rust, clutch dust & dirt off & polish the surface.

    You may need to use some solvent on a swab or sponge brush to clean the area

    Once you've located the letters, fill them in with a yellow or white 'paint' crayon.

    Also put a dab of white paint onn the triangular pointer.
  7. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    hey guys for what its worth i have been using a dab of " WHITE OUT" for years for timing marks. something in the stuff really makes it work well with the light and once it dries its there to stay for quick tunes in the future. it also resists oil, grease, degreasers ect.
  8. donaldh2o

    donaldh2o Karting

    Nov 10, 2003
    Irvine CA
    Full Name:
    OK, spent the evening rotating and inspecting the flywheel. BTW, it rotates clockwise.

    The markings are: PM 1-4, 3'|, 7'|, 37'| and PM 5-8, 3'|, 7'|, 37'| (guessing at the 37' markings, it's not very readable). I guess PM is some Italian designation for TDC (top dead center).

    And these markings are different than those in my Workshop Manual. The car has single point distributors, so I'm assuming the flywheel is different because of this.

    To make timing the car easier, I marked the clutch housing just below the flywheel with dots of different colors of paint. Marked the PM location with a dot of white paint, 3' with pink, 7' with pastel blue and 37' with orange. Also listed the markings in the manual with a little daub of corresponding paint color.

    So now what? Set the timing to 7', is that the normal setting? What are the 3' and 37' timing marks for?
  9. Gianluca

    Gianluca Formula Junior

    May 6, 2003
    Centreville, Virgini
    Full Name:
    Gianluca Chegai
    PM= Punto Morto= Dead Point
  10. Drew Altemara

    Drew Altemara Formula 3

    Feb 11, 2002
    Tuscaloosa, AL
    Full Name:
    Drew Altemara
    I think the sequence is this:

    PM1-4 is TDC
    3' is timing at 950rpm retarded
    7' is timing at 950rpm main points (answer to your question)
    37" is timing at 3,200 or 5000rpm

    Check your operator's manual. Ferrari is very good about this.

    I would also make sure there is a smooth transition in advance as you increase rpm to make sure the weights are not sticking.

    Another note. I think the 3' and 7' refer to distributor advance which is '6 and '14 engine advance; not sure but anyhow you still set to 7'. The 37' is engine advance.

    Good luck,

  11. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    The 37deg is definitely the mark for 5000rpm. It's explained in the owners manual.

    FWIW, the 37deg mark should be your biggest concern. A few deg off at idle or mid-range won't hurt anything, but some degree (bad pun) of accuracy at high revs is important. If your advance mechanism is iffy for any reason, adjustments at low revs may not give the correct advance at 5000+.

    And, yes, there seems to be a half-zillion different flywheels. Mine doesn't agree with the manual either.

Share This Page