replace or re-use rod bolts | FerrariChat

replace or re-use rod bolts

Discussion in '348/355' started by yelcab, May 30, 2017.

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  1. yelcab

    yelcab F1 World Champ
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    For a 355, are the rod bolts replaced or reused?
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #2 Rifledriver, May 30, 2017
    Last edited: May 30, 2017
    Ferrari says to replace them every time. Their safe life is very finite. By now, many have been on and off, maybe more than once. And even in a single engine repair the bolts may be installed and torqued more than one time for trial assembly, measuring rods etc. Most times when a 20 year old exotic engine is opened there are a great many unknowns. They have been tested to failure and like I said, their safe life is very finite.

    And the type and method of thread/bolt head lubrication is very important. Titanium is not forgiving like steel.
     
  3. SoCal1

    SoCal1 F1 Veteran
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    A very good friends works for Ford engine development. He and the other engineers spent 1.5 years on testing threads alone. What I learned from him ragging at me day after day, replace them.

    :)
     
  4. Dave rocks

    Dave rocks F1 World Champ
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    I agree but I'm guessing the rod bolts have not been touched more than the first time at the factory - maybe one other time???

    They are not torque to yield, Mitch so I would reuse them (I believe they are bat **** crazy expensive - $103.00 each :eek:). Of course, inspect them visually.
     
  5. m.stojanovic

    m.stojanovic F1 Rookie
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    I think another factor to consider is the mileage of the engine, i.e. through how many load cycles (engine strokes) the bolts have gone.
     
  6. dm_n_stuff

    dm_n_stuff Four Time F1 World Champ
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    #6 dm_n_stuff, May 30, 2017
    Last edited by a moderator: Sep 7, 2017
    $115.00 each.

    Dave, serious question for a non-mechanical guy like me.

    How would I visually inspect this part to determine how many times it's been torqued and then determine if the saving was worth the risk vs. simply replacing them as Brian suggests?

    They're $116 each (approx) on Ricambi America and you need 16.
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  7. Rifledriver

    Rifledriver Three Time F1 World Champ

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    I don't guess. I build motors that don't make big windows in the side.

    If you don't like the prices buy a Miata.
     
  8. INTMD8

    INTMD8 F1 Veteran
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    To see if they are stretched you measure their length vs a new bolt.

    At that price I would be tempted to have some made.

    But yeah, one of these breaking is a bad day!

    :D
     
  9. Dave rocks

    Dave rocks F1 World Champ
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    You can't visually inspect for how many times they been torqued but you can look for obvious defects. I suppose you might even be able to send them for analysis but I've never done this nor have I ever seen such an expensive fastener. My point was, it's reasonably safe to assume the rods on most of these cars are coming out once, maybe twice??

    As always - I just about spit my sandwich up - :) :)

    I think this thread is about to cost me $1600 on my motor rebuild or I need to start making rod bolts :)
     
  10. Dave rocks

    Dave rocks F1 World Champ
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    #10 Dave rocks, May 30, 2017
    Last edited by a moderator: Sep 7, 2017
    For my own curiosity (yes Brian - I did believe you) I just scanned the WSM's. I could find nothing in the 355 manual but in RED on the 360 - they are only to be used once.

    Crap - Fchat just cost me more money :)

    (I know - just saved me more as taking the motor apart twice would suck)....

    I'm seriously going to look into making these or perhaps aftermarket already exist?

    Even though they are not classified as torque to yield, seeing the turned down section, I would speculate they are - are they Brian??
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  11. Dave rocks

    Dave rocks F1 World Champ
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    #11 Dave rocks, May 30, 2017
    Last edited by a moderator: Sep 7, 2017
  12. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #12 Rifledriver, May 30, 2017
    Last edited: May 30, 2017
    I don't recall that but I do remember his head bolt group buy. He wanted to make a dumb design change and people responded accordingly. Besides, he doesn't get it, in this business we are not looking for ways to put expensive, slow moving parts in inventory .

    355 manual was written before the cars were built. 360 reflects that which was learned.

    Ferrari does not make bolts, there are many companies here that already do.
     
  13. Dave rocks

    Dave rocks F1 World Champ
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    This is one reason we aborted our project to produce new rubber R and Auto buttons for 430 and 599's...

    I already have $$$$$ in slow moving inventory so I get it.

    Who?
     
  14. ferraridriver

    ferraridriver F1 Rookie

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    It is important to understand that while the manual may not call out a "Torque to yield" spec the bolt may well, and most probably is, stretched to near the same length as if it were torqued to a measured length.

    It really doesn't make any difference to the bolt how the torque is measured or expressed,
    torque to angle, Ft/lbs, or torque to a measured length, as long as the same tightening pressure is applied to the bolt.

    In any case I have never re-used rod bolts in any engine I have built. Main bolts, depending on the main cap configuration is another matter.
     
  15. itsablurr

    itsablurr Formula 3

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    Starting to bring back nightmares of BMW rod bolt debates on the old S54 M3 motors... single-use, vs risk-based justifications of 2nd or 3rd use... cost vs ARP alternative... cost of putting a hole through your block... torque method; torque to spec value per ARP rec or torque angle per factory manual? relative material properties and subsequent data interpretation... ugh. All for the sake of a few hundo/laziness $

    The safe (and least headachy) bet? Unless there's a demonstrated problem with the factory bolt spec, follow the factory part/single-use rec. Short money and intact confidence on an expensive motor.
     
  16. Rifledriver

    Rifledriver Three Time F1 World Champ

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    ARP is the logical choice. The rods were made by Pankle. They might sell bolts but as I recall they didn't make the bolts either.
     
  17. mike32

    mike32 F1 Veteran

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    Not strictly true, i get the point you are making but they are never going to be exactly the same-especially from different batches.
    An acceptable method in industrial diesels is to measure the length, install them and torque to the recommended setting. Then remove them and check the length against your original length, if it is the same then it is good as it has returned to its original length without permanent set.
    If it is longer it is scrap as it is failing.
     
  18. Rifledriver

    Rifledriver Three Time F1 World Champ

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    See what you've started?
     
  19. Rifledriver

    Rifledriver Three Time F1 World Champ

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    One reason I really like the older design with nut and bolt. It could be measured installed. Many motors with that design torque to specific stretch inside a torque window. Hard to do with a cap screw.
     
  20. Dave rocks

    Dave rocks F1 World Champ
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    ARP does not have any Ferrari stuff listed on there website...I'll email them
     
  21. yelcab

    yelcab F1 World Champ
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    I asked a simple question !

    I got bitten in the butt with the E30 M3 stretch head bolts once. Never again.

    That necked down bolt does look like a one time use to me on the 355.
     
  22. Dave rocks

    Dave rocks F1 World Champ
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    I'm glad you started this thread except for the $1600 part :)
     
  23. Rifledriver

    Rifledriver Three Time F1 World Champ

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    They make anything you want.
     
  24. INTMD8

    INTMD8 F1 Veteran
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    True, I guess you would need a new/baseline measurement.
     
  25. mike32

    mike32 F1 Veteran

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    And they say engines are better designed these days.

    We had a Paxman Generator which the managers decided not to change the big end bolts- 2 stage stretch bolt with a fine longitudinal splined nut. Specifically have a max number of running hours.

    After doing some work on it, they loaded it to about 500kws and a big bang as 2 of the 12 rods punched holes in the engine side as the heads broke off the bolts. 10 cylinders firing and 2 rods distroying the engine block, liner blocks and crank.

    Chief engineers comment to the managers- thats a pity as we just changed the oil in the sump.
    Not far off a new engine, althrough we had to strip it into bits as could not crane the old wreck out.
     

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