Lost all gear oil today, 1991 Testarossa | Page 30 | FerrariChat

Lost all gear oil today, 1991 Testarossa

Discussion in 'Boxers/TR/M' started by PA32Pilot, May 9, 2020.

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  1. Zeff

    Zeff Formula Junior

    Oct 8, 2018
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    Ok thank you for your help!
     
  2. PA32Pilot

    PA32Pilot Formula 3
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    What shims? There are 2 needed when doing the differential. RH cover and LH cover.
     
  3. Zeff

    Zeff Formula Junior

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    Yes, I need those.
     
  4. turbo-joe

    turbo-joe F1 Veteran

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    but jamie, you also know there are a lot of shims what you need when adjusting preload and backlash. you just do it an d see the problems. so the way I suggested to do all with the feeler gauge metal sheets to do all you only need shims 1 time and have then the correct size to order.
     
  5. PA32Pilot

    PA32Pilot Formula 3
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    Now that I have gone through the process I completely understand a lot of what you and I talked about.

    Before I tried to understand but I could not wrap my head around it. Now it’s like a lightbulb went off.
     
  6. turbo-joe

    turbo-joe F1 Veteran

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    you mean a light bulp went ON, not OFF? because off means for me it is dark and you see nothing - so I understand, but english is not my mother language and may be the sense is different?
     
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  7. versamil

    versamil Formula 3
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    All the care taken in machining parts, is thrown out the window, when you realize the tolerance on LENGTH for taper roller bearings. I posted about this about fifty posts ago. In measuring Jamies original housing, made in 1990 to another housing I have that was machined in 1986, the distance between the ring gear mounting surface and the bearing mounting surface is within five ten thousanths-.0005. But the Timken bearing Jamie had on his part- made in the USA is TWO thousanths longer, than the Timken Bearing I have, which was made in France. So I looked up in my Timken bearing engineering book, and low and behold, this tolerance on assembled height of this size bearing is MINUS 0 to PLUS .008 or .2032 mm. That's FOUR shim sizes!

    What this means is just in changing the taper roller bearings, you are creating more challenges in setting up your differential.If your NEW bearings don't exactly match your old bearings, even if you left ALL the parts the same, you still have issues with changing shims. Anyone doing these should really invest in some measuring tools to verify what the overall length of a taper bearing assembly is. I can't really check Jamies complete bearing length, because I never thought about having him send the cup. I have the CONE, the inner race. This is the part that is two thousanths longer. I will be checking my new bearings as I get them, and comparing the lengths to my old bearings.

    I manufacture two different cast iron machine tool housings, that use a 2.5 inch OD race, taper roller bearings. An inch smaller than the Testarossa bearings.
    I was striving to bore my housings, with about a one tenth press fit. I bought a batch of CUPS, purchased at the same time, and found that they varied in diameter by over five tenths. The NEXT batch of bearings were even larger. They were a FULL one thousanths bigger than nominal, but they STILL were in spec. And this is the OD of the bearing, something that is important to fit correctly. The LENGTH tolerance doesn't seem to be important to the bearing manufacturers, since in a LOT of applications, you adjust preload by tightening up a nut, like in the old front wheel bearings. In my cast iron housings, I use a threaded bearing retaining ring, so it's EASY to adjust preload, and also to locate my gears in relation to each other. If the bearing cups are TOO large in diameter however, I can't easily move them with my retainer. So I have to match my bore size, to the bearings I have in my hot little hands.

    The measurement I've come up with of the distance from the ring gear mounting surface, to the bottom mounting point of the taper roller bearing on the right side of the gear housing is 2.6915 or 68.3641 mm. Be interesting to know what Newman machines his housing to. Jaimie didn't send that part, but I'm sending him tools to compare his old one to the new one. May be a mute point, the bearings varying so much means they need to be measured also, before they are installed in the side covers.
     
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  8. versamil

    versamil Formula 3
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    Turbo Joe understands English better than Jamie, He's RIGHT the light goes ON, not off.
    In one of Turbo Joes posts, he mentions "somebody" claims to make shims quick and cheap. Run time for a left hand shim, complete
    is three minutes, made out of 4150 alloy steel. I have around forty of them, and more on the way, as I have to turn another spindle in a week.
    The right hand shim, I have not had laser cut yet, but will. OR I will cut them the same way I make the left hand shims, with the added complication of drilling the holes.
     
  9. turbo-joe

    turbo-joe F1 Veteran

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    so I think my english is not soooo bad ;) to understand this here. thx for clarifying brian

    I sent already several shims to the US and also to canada and will ask the receivers if I may publish there names here. then you may get in contact with them and ask how they liked my shims
     
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  10. Newman

    Newman F1 World Champ
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    Dec 26, 2001
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    Other than pointing out that the bearings vary and you might need to make adjustments, the rest is a case of making a mountain out of a mole hill. The bearings don't need to be measured and people don't need to fret about these details. In this case if backlash was checked correctly the pinion gear is on the deep side according to the pattern and he didn't take the gearbox apart or the pump screen out to properly clean out any debris but he should worry about 5/10ths variation on a roller bearing? After pieces of metal are embedded in the races those 5/10ths wont mean much. 34 years as a mechanic and 19 of those years working on Ferrari's I have never measured a bearing because it doesn't matter in this application. Its simple. Set preload then backlash, shim as required, double check pattern and button it up.

    As for my diffs we reverse engineered it using a good diff out of a Testarossa.
     
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  11. turbo-joe

    turbo-joe F1 Veteran

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    absolutely right
    but there are always people who make out of a mouse an elephant
     
  12. Zeff

    Zeff Formula Junior

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    Thanks Paul for the informative phone call today with me and Juan. Your a great help. Very much appreciative of all that you do!
     
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  13. versamil

    versamil Formula 3
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    When one of the variables in setting up the differential can be different by almost half the shim range, one would think it needs to be taken into account. I rebuilt my first Ferrari engine in 1978, worked on them full time until 2000, and then discovered what real precision is when I bought two machine tool manufacturers. I've bought over five hundred Timken roller bearings, machined the housings for them. Twenty years making parts that you measure to the tenths, makes me somewhat knowledgeable about bearing fits.

    When someone gets a part that needs accurate assembly, and doesn't get, nor can they find shims to adjust with, what are they supposed to do? Maybe some shops like yours has some. Maybe someone supplying the main component, should supply a shim pack as just a courtesy to whomever they sell a $2500 part.
    Why expect your customers to hunt down machine shops to make shims, when they're so easily mass produced. People DO need to fret about the details, when details like bearing dimensions that people take for granted, can wildly vary.
     
  14. EZORED

    EZORED Formula 3
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    #739 EZORED, Jun 4, 2020
    Last edited: Jun 4, 2020
    Turbo Joe sent me 3 blanks and my mechanic had then ground to spec. I have one blank left over, if anyone needs one.
     
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  15. PA32Pilot

    PA32Pilot Formula 3
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    Ok so you said I need roughly 1.8-1.2kg of force to turn the differential with the correct preload?

    I rigged up a string and a pull scale and not counting the pressure when you start rotating it but after it is already rotating I get a reading of 1.4kg.


    Sent from my iPad using Tapatalk
     
  16. PA32Pilot

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    Here is my current preload video.



    I also tried to test side to side movement. I think I only got movement when I accidentally tapped the dial gauge.

     
  17. turbo-joe

    turbo-joe F1 Veteran

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    #742 turbo-joe, Jun 5, 2020
    Last edited: Jun 5, 2020
    I said 1,8 to 2,0 kg

    1,4 is not bad, but a little more would be better. remember that the aluminum gearbox housing is increasing when getting warm, more than the diff. there is oil on the bearings and no dirt and the diff is rotating without feeling any hard way sometimes?
    I wonder a little now because you have written that you will send all to brian to let him check why you now ask?

    just have seen this after I posted:
    when you did the last turn the diff turns a little more even you not touched it. so you need a little more preload

    side to side? this you never can do with your hands only, also it seems that you try to turn the diff and not to try to move from right to left side or otherwise.
    when I see how the diff turns then you not have sideways play, but it needs a little more preload

    how much it needed to start turning?
     
  18. PA32Pilot

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    Your up! Man do you ever sleep lol. I was thinking I’d hear from ya later this evening.

    Sent it to Brian so we could measure any differences between the new TR cover and the old cover.

    The differential will not rotate without me rotating it. If I try to spin the differential it will not spin and come to an almost sudden stop.
     
  19. PA32Pilot

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    Ok going one less shim on the RH cover. Give me a few minutes to remove and replace.
     
  20. turbo-joe

    turbo-joe F1 Veteran

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    #745 turbo-joe, Jun 5, 2020
    Last edited: Jun 5, 2020
    when you look at your last preload video you see clearly that sometimes when you turn and put your hand away that the diff still turns on a very little. hard to see. but this is a sign of less preload. so reduce right side 5/100 ( I talk in mm, not in inch size ) to see how much the preload will increase. F offers the shims with 1/10 distance, but when I meassure and adjust I grind down to about 1/100 mm, so what I would need
    hopefully you have a shim 5/100 less? I think 1/10 would be too much


    I just called with germany, there it is 22:35, here in thailand just now 3:35, but will go sleep soon again
     
  21. PA32Pilot

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    Here it is with a shim .12mm thinner.

     
  22. turbo-joe

    turbo-joe F1 Veteran

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    that looks now much better
    1/100 less is about 0,15 kg, so now you have 12/100 less, this means about 1,8 kg more, and that is then too much.
    but before you try other shim test again with your scale. I think now you will have a little more than 3 kg
    better a little more than less, and when you use good gearbox oil a little more preload is not so bad
    when you turn now the diff you feel a big difference or only a smal difference instead before? it looks not so that you have to use much power to start rotating
     
  23. PA32Pilot

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    I’m limited on shims I have. I have a 1.55mm and a 1.67mm.

    1.67mm was the one where you said it needed a little more preload.

    1.55mm is what I have now.

    To me the resistance feels the same. I can have the 1.67mm ground down to 1.61 but I want to make sure I don’t need to make adjustments to backlash.

    If I need to move differential left I need to put a smaller shim on LH cover and a larger shim on RH cover to keep preload the same.
     
  24. PA32Pilot

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    I feel a big difference now. I think it feels better.

    When I use my handy test scale I made it shows 3.2kg.

    I think a perfect shim will be 1.62mm which I can make out of the 1.67. But I want to make sure about backlash first right?
     
  25. PA32Pilot

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    Right now I have a 3.0mm on LH cover under racer.

    I have a 2.97mm and 2.9mm shim for the LH as well.
     

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