I went in for a 5k major, it cost XXXX more and here's what happened" | Page 13 | FerrariChat

I went in for a 5k major, it cost XXXX more and here's what happened"

Discussion in '348/355' started by johnk..., Dec 13, 2017.

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

  1. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    34,548
    Ontario, Canada
    Full Name:
    Mike
    This describes like the P&R section
     
  2. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    I simply stand on what I have said. For timing to change some linear or angular dimension must change. That means pulley center to center distances, pulley pitch diameter, pulley eccentricity (roundness), belt skipping a tooth, or belt length, or, if you dissemble and reassemble an engine, maybe head gasket crush. As soon as you set an acceptable tolerance on timing, +/- x degrees, you can set the limits on these dimensional changes. With respect to skipping a tooth, if you set the engine to TDC with the old belt on and examine the reference marks on the cam, they are sufficiently accurate to indicate a jumped tooth.
     
  3. Dave rocks

    Dave rocks F1 World Champ
    BANNED

    Nov 23, 2012
    16,047
    Orchard Park, NY
    Full Name:
    Dave Lelonek
    What I also found interesting is that when I mount my factory degree wheel, TDC was within 1/2 degree of the "ZERO" on the wheel. I need to verify but I think that means the crank pulley key way is in line with TDC of cylinder #1 and they make the degree wheel hub accordingly.
     
  4. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,322
    Tallahassee, FL
    I'd like to pose a question based on John's point, as I've read the read and don't believe I've seen an actual answer/counterpoint to his exact question. If i missed, someone pls refer me to the post I missed which does.

    In brief, assume (yes, for the sake of argument, make this assumption) your cams are already at 1/2 degree of zero. Lock them, change belts such that the belt length is correct, and teeth are matching.

    At this point, the cams are still locked. Logic tells me they haven't moved even 1/4 degree. Now, unlock them. Certainly the cams may move NOW, but with the belts installed. Just as they will move once you start the car, no matter what procedure you used. Therefore, timing should be the same as before we started.

    From a purely mechanical standpoint, how will the timing possibly be different than the 1/2 degree we started with? If it is, what caused this?

    I'm not trying to be argumentative, nor take a side. Trying to learn something about engines that I may not be aware of.
     
  5. Dave rocks

    Dave rocks F1 World Champ
    BANNED

    Nov 23, 2012
    16,047
    Orchard Park, NY
    Full Name:
    Dave Lelonek
    That is an excellent post. I'll just say that people are getting all hell bent over precision and I'm all for being precise but take a read through the TDC method thread - I'm now very convinced most are not finding TDC with very reliable precision and therefore if the base line, starting point is not precise, the rest of the work won't be either.

    I'll also add that the 355 WSM specifies a tolerance of +/- 1 degree
     
  6. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,294
    socal
    Credibility? I am offended. I'm not here to toot my own horn. I argue with those two who propose dumb stuff that negatively effects the community under guise of doing the math. I don't get paid here. I'm not selling my products here. I just chat here. I love these cars and I hate to see them go to crap. I love it when friends and I get together and we can get their Ferraris running at their best. I'm taking a step back and will check in here from time to time. Quite frankly I'm very tired of those two johnny come lately armchair experts. I hope for the sake of the community they grow and learn . My cars will run perfectly without them.

    This is my final post on thread. 97spider yes I am sticking to my guns. Ferrari has DONE EXACTLY as you propose. These are pictures of factory timing marks and locations scribed in from the factory. These are placed by the experts who designed your car. On many models of Ferrari the factory times the cams and then scribes the back of the head for exactly what you propose. Ferrari is smart isn't it? Well, look at those exact marks scribed on the back of the heads! Those are from Stevepaa's car and the last picture is from mine. In my case my engine is still in the car. Please tell me how you are going to line up those marks within the talked about 1/2 degree with that parallax error even if the marks where "factory cast" in the head? In steve's case his engine is out of the car and you can look right at them like reading water level in a graduated cylinder. How do you align those marks within 1/2 degree? How do you make two hand scribed marks within 1/2 degree without galling metal where the 2 shafts meet? At some point theory meets practical application. Your 2 professors are clueless. Thank you and goodnight!

    Image Unavailable, Please Login

    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  7. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    Brian, it is your car. Do what you want. Once you have done that, verify it to be within 1 degree at the crankshaft. If it is, now you have one data point. When you have collected 20 data points to prove that theory is good and repeatable, you can repost the total result for all to follow. Which is infinitely better than JohnK who, from the Mountain of BS, has spewed forth various theories without any real data to back it up. He hopes that someone else can provide the data to back him up. He has a car, and a garage, he can provide his own data.

    I am now absolutely done with this thread. Happy new year to all.
     
  8. Dave rocks

    Dave rocks F1 World Champ
    BANNED

    Nov 23, 2012
    16,047
    Orchard Park, NY
    Full Name:
    Dave Lelonek
    None of these threads need to be an argument. Some just cannot have an open exchange and provide factual data.
     
  9. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    Who is talking about lining up marks? I'm not. Never have. Never even implied it. Seems you reading into things here. The only thing you might use the marks for is reference. In other works, when the old belts are still on the car you bring it to TDC and the marks should be close. Not necessarily right on because, as I think at least we all agree, those marks are necessarily dead on balls accurate. But they will serve to tell you, for example, it the belts have jumped at tooth. So, assuming they are, well, like in you picture, you know the belts have not jumped. So you can them change the belts with confidence. After the swap you can check the marks again. They may change a little due to the stretching of the old belts since they were installed, but if they are again close, you can be confident that the timing with the new belts is within +/- 1/2 degree of when the old belts were in stalled because the tolerance in belts length is such that it can not change more than that. The problem with you "experienced guys" is that you can't see past what you have been doing, or have been told to do. You read and infer things that are implied because you start with a bias. You are trapped by you preconceived notions.
     
    Dave rocks likes this.
  10. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    You see, again you haven't been paying attention. The point has not been how accurately the car was timed prior to the belt swap. The point was that a belt swap doesn't change the timing. It was stated from the start that you must be confident that the car was correctly time to start with, and mechanically sound.

    Now, if you find that the majority of the cars that you work on are off after you install new belts then, 1) either you are timing the car incorrectly, or 2) everyone else who worked on those cars before you timed the cars incorrectly. Assuming you get cars from a wide variety of people and those cars have been serviced by a wide variety of individual, professional and DIY, and you find the majority of them off, I'm going with number 1.
     
  11. Dave rocks

    Dave rocks F1 World Champ
    BANNED

    Nov 23, 2012
    16,047
    Orchard Park, NY
    Full Name:
    Dave Lelonek
    Right. The comments about marking stuff was based on the dowel pin in the pulley / cam shaft and marking belts, etc.
     
  12. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    Correction: "those marks are not necessarily dead on balls accurate.
     
  13. 97 Spider

    97 Spider Formula 3
    Rossa Subscribed

    Dec 15, 2012
    2,241
    Texas
    Full Name:
    Brian
    I never said anything about using Ferrari factory marks and I’m not sure anyone else did. I’d have to reread the entire quagmire again. I wouldn’t try to use someone else’s crooked ars marks. It doesn’t even have to be a Ferrari engine we are talking about.

    Back off all the other BS and the emotional distortion of the question and answer.
    The real question is if I have an engine that I or someone I trust has degreed before and made competent marks, the engine is running great. For some reason I have to dismantle this engine. When I reassemble the engine if I put the #1 piston at TDC and put my cams in according to my marks. I slide my belt or belts or chain or whatever on. I turn the engine over a couple times and see that all my marks are lining up correctly. My timing will be... HAS to be exactly the same as when I tore the engine apart. I can do this 20 times or 100 times the timing will always be the same as when I originally set and marked it. It’s a piece of steel, the cam lobes down just move.
     
    Dave rocks likes this.
  14. 97 Spider

    97 Spider Formula 3
    Rossa Subscribed

    Dec 15, 2012
    2,241
    Texas
    Full Name:
    Brian
    I don’t really understand what your saying about doing it 20 times. I don’t have to... trained mechanics have made and used timing marks since the invention of the internal combustion engine. It has been proven literally BILLIONS..BILLIONS of times.
     
    Dave rocks likes this.
  15. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    He is implying that until someone actually gives you a dollar for 4 quarters 20 times you can not conclude that 4 quarter equals a dollar.

     
    Dave rocks likes this.
  16. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
    668
    Vermont
    Full Name:
    john truskowski
    Hey guys,
    I do a lot more reading than talking on here, but I'm going to just jump in for a bit. I am no longer a chevrolet or ASE master tech, but used to be for 10 yrs. So again, I'm not here to expect people to marvel on my expertise or lack of. But in my days, I have replaced countless timing belts on american, japanese, korean, and european vehicles. But none of these engines were going to be run in the indy 500 or any other prestigious race. If someone who drives these vehicles on the public highways cant live with their cams being within 1/2 of a degree out, than perfectionists they are. I believe ferrari put +/- 1 degree on the WSM because they probably assumed that their clients were going to be just as happy with the performance of their new ferrari just the way it left the factory.
    But I guess if you talk to the crew chief of the SF race team, he will insist that his engine builders get those cams to 1/4 degree or else. Because after all, that could be the difference of 1st or 3rd place! Hmm, I wonder if there ever was a winning engine with its cams out 1 degree? (just kidding).
    I guess it all relates to who it matters.
     
    Pangea likes this.
  17. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,629
    CT
    Full Name:
    John Kreskovsky
    I agree with what you are saying and would also point out than when tuning a race engine it is quite possible that the cam timing will be set differently depending on the track. For example, on a track with lots of turns and short straights it may be desirable to time the cam to provide higher torque at lower RPM to give better acceleration out of the corners. On the other hand, on a track with long straights the cams may be timed to give max power at higher RPM to achieve higher straightaway speeds.

    Some may find the following summary interesting:

    Image Unavailable, Please Login

    The above assumes the lobe separation angle remains constant. That is but intake and exhaust cams are advanced or retarded the same amount, and generally changing timing by more than a fraction of a degree.
     
  18. Dave rocks

    Dave rocks F1 World Champ
    BANNED

    Nov 23, 2012
    16,047
    Orchard Park, NY
    Full Name:
    Dave Lelonek
    I agree. But let's also remember: There is accuracy and the perception of accuracy when the method or tools just are not very accurate.
     
  19. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
    668
    Vermont
    Full Name:
    john truskowski
    Yes, I agree. Behold, the skill of the talented automotive technician would not come to fruition without his tools and the ability to use them properly. But I have been guilty of using my screwdriver as a prybar more than once though.....o_O
     
  20. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
    668
    Vermont
    Full Name:
    john truskowski
    Yes and as the world of racing goes, every tuning technique for a given track is usually a closely guarded secret. But for a production vehicle, which the 355 is, I think that factory methods and specifications should be considered a standard. Of course means and methods for achieving the same goal can and should be left to the performing technician or DIYer. With the emphasis being that the factory intended specs are met.
    Of course if someone wants to pay a shop a premium to reblueprint the entire engine at each service, then that is his right. And after all, it makes great conversation at the wine tasting at the club.
     

Share This Page