SO when do the pistons actually start to hit the valves?? | FerrariChat

SO when do the pistons actually start to hit the valves??

Discussion in 'California & Nevada (Northern)' started by wonkazoo, May 2, 2005.

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

  1. wonkazoo

    wonkazoo Karting

    Aug 23, 2004
    190
    Woodside/RWC
    Full Name:
    David
    Place this one under stupid questions of the month. (I chose to seek counsel from my local bretheren before engaging a wider audience of ridicule.)

    As I rev higher and higher in my '87 328 the sound becomes more and more melodious. Medusa is the name that springs to mind as I keep my right foot pinned to the floorboards, all the while savoring the scream that is my powerplant... Ships crashing upon the shore bring any images to mind?? There is a red line beginning at around 7750RPM or so on the tachometer. Presumably this line means it is time to shift, the better to keep all the moving parts in their correct places. Which brings me to my question: Purely hypothetically, where actually is the point of no return??

    Just curious if anyone has any input on how these 8 cylinder engines were designed, and how much leeway there really is in the overall scheme of things.

    Cheers,
    dce
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,105
    Cowboy Capitol of the World
    Full Name:
    Brian Crall

    In most motors the limiting factor is how fast the motor can rev before valve float and the attendant loss of power ends the climb in RPM. In a Ferrari motor the springs are strong enough you will find a mechanical strength issue limiting your RPM. If you care to explore that limit you will find that the connecting rods, will on average, fail first. It is a very expensive failure should you ever experience it and any chance of that should be avoided at all costs. It should also be known that very high RPM accelerates engine wear to a very high degree. The reciprocating weight of the piston rings wears out the ring grooves at a very high rate when the motor spends lots of time near max.

    If you really want a number, I have witnessed almost every Ferrari motor up to and including the 4 valves at 10,000 RPM but if you want to hear what that sounds like do so at your peril.

    Also we were told that the reason the 5 valve motors went to titanium rods was that they were designed for a 10k redline but that during durability testing timing belt life was unacceptably short.
     
  3. Artherd

    Artherd F1 Veteran

    Jun 19, 2002
    6,588
    Bay Area, CA
    Full Name:
    Ben Cannon
    So, hrm, if one were to say change their timing belt along with the oil every 2k or so...
     
  4. wonkazoo

    wonkazoo Karting

    Aug 23, 2004
    190
    Woodside/RWC
    Full Name:
    David
    Thanks Brian,

    I'm actually only getting to the 8500 area, which is still well past the supposed redline. All in all your reply is about what I'd expect. I.E. Push it a little if you want, not too often, and all will probably be fine. When I do occasionally se 8500RPM I won't worry too much.

    Many Thanks,
    dce
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,105
    Cowboy Capitol of the World
    Full Name:
    Brian Crall

    No, actually I strongly suggest observing Redline. The motor simply was not designed for more than that. You may get lucky and not experience a catastrophic failure but as Harry Callahan said do you feel lucky? You are not in the last lap of a race when caution is justifiably thrown to the wind and besides that the motor doesn't make any more power up there.

    And if that ain't enough for you I reserve the right to say I told you so if you blow it up.
     
  6. wonkazoo

    wonkazoo Karting

    Aug 23, 2004
    190
    Woodside/RWC
    Full Name:
    David
    Ack, you just broke my heart!! OK, I'll keep it below redline from here on out- I promise!!! And If I don't keep my promise, you know where I'll fess up to the flagellation you will be serving me on a platter!!
     
  7. gatsby

    gatsby Karting

    Apr 26, 2005
    206
    half moon bay, CA
    Full Name:
    jim
    Hi guys - i'm also a newbie and am picking up my 328 this weekend. while looking around for my f-car i actually saw a 308 engine that had catastrophic failure after high revving with an old cam belt. After the head was removed it showed that the valves actually sheared, fell into the cylinder, got pushed back up into the cylinder head, and it looked like it required a new head at the very least. It did not look good. Guess if we rev up really high we better really be confident on the integrity of the belts!
     

Share This Page