Daytona tach angle drive | FerrariChat

Daytona tach angle drive

Discussion in 'Vintage (thru 365 GTC4)' started by bighitter2, Jun 3, 2018.

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  1. bighitter2

    bighitter2 Formula Junior

    May 7, 2005
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    chuck coli
    i am having some work done on my Daytona and trying to repair a leaking tach 'angle drive' i have 2 used ones and both leak.there is a small rubber seal ( almost looks like an 'O' ring except thicker)in the end where the cable come out it appears to be worn someone out there has to have had this problem and has a fix....Timo are you reading this? This is up your alley! Thank Chuck Coli Daytona 12883
     
  2. John Vardanian

    John Vardanian F1 Rookie

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    Chuck, I had a leaky driver on my 250 and assumed it was from that seal, but it wasn't, it was from the end caps. The seal is square section, but o-rings can work.

    john
     
  3. TTR

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    Chuck, that's one of very few issues I haven't had to tackle on any Daytona and therefor can't offer real advise.
     
  4. TTR

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    I'm in the middle of finishing up resealing of an engine of a car that appear to have been plagued with a variety manufacturing defects, including persistent engine oil leaks, but tach angle drive wasn't among the culprits.
    In the course of this and along with all externally exposed gaskets & seal, I replaced all seals & O-ring in the distributor angle drives, but with no apparent leaks from tach angle drive, so I left it alone.
    OTOH, it shouldn't be difficult to remedy, if need arises.
     
  5. bighitter2

    bighitter2 Formula Junior

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    Thanks John, amyone habe any dimensions on this seal?
     
  6. John Vardanian

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    Chuck, assuming the Daytona uses the same angle drive... you can get the square section seal from McMaster Carr., Part No. 1171N157, (measures: 2mmWx12mmID). However, the groove in the shaft of the drive is 3mm and you cannot find a seal that is 3x12, or at least I wasn't able. In this picture I have stuffed in the groove one seal and a half of another and the groove is filled. It's just for good measure, if you try just one seal that should do the trick as well.

    john

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  7. TTR

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    #8 TTR, Jun 5, 2018
    Last edited: Jun 5, 2018
    I'm slightly confused.
    First, all the tach angle drives I've seen in Daytonas appear different from one shown in Johns picture.
    The type I've seen/worked on have a standard shaft seal inside the distributor angle drive and a small standard O-ring set in a machined groove inside the (brass?) adapter between distributor angle drive an tach angle drive, not on the latter (like in Johns picture)
    Also, perhaps I misunderstood, but I got the impression Chucks problem was internally leaking tach angle drive(s), i.e. oil leaking/seeping through it/them, but there shouldn't be oil there anyway.

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  8. TTR

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    ..., but there shouldn't be oil there anyway, since the shaft (lip) seal inside the distributor angle drive housing, if working properly, should prevent any to get past it.
    The small O-ring inside the (brass) adapter is only for prevention of debris/dirt/dust entering into input side of tach angle drive.
    Although I've never taken a Daytona or any other Ferrari tach angle drive apart, I've serviced similar set ups on other cars and they're usually (perma-)lubed with grease, not oil.
     
  9. John Vardanian

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  10. TTR

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    John, that groove, on Daytona (brass) adapters I've seen is for the "debris/dirt/dust" prevention O-ring (2 circled in yellow, 1 new/1 used) I mentioned earlier.
    The actual oil seal (2 circled in red, 1 new/1 used) preventing engine oil coming out and in contact with the brass adapter (in your picture), tach angle drive unit or atmosphere is inside the distributor angle housing, accessible and pressed in through the hole that the adapter screws into.
    Tach angle drive or its brass adapter shouldn't be in any contact with engine oil, at least not in Daytona engines I've seen/worked on.
    Comparing parts manual drawings, 250 GT engines seem to have a different way of mounting the tach drive and seal this area than 365 GTB/4 engines.
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  11. John Vardanian

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    Timo, the motor end of the angel drive (i.e., the spade hub end) is in contact with oil. That's why the large fiber washer is there as well.

    john
     
  12. Motob

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    As Timo said, there should be no oil at the tach drive or inside the brass housing that holds it. The o-ring is only to keep dirt out. You should be able to remove the tach drive from the brass housing, run the engine and no oil should leak out. The oil is caused by a leaking lip seal inside the distributor angle drive that the slotted shaft that drives the tach goes through. The slotted end of the shaft is very sharp and it cuts the seal lip when it is installed in the seal.

    I uae a very small grinding stone on a Dremel tool or die-grinder and polish all of the sharp edges on the slotted portion of the shaft with the gear until they are smooth/beveled. This is a very common problem, and no engine builders seem to recognize what that this needs to be done, or the shaft will damage the seal when it is pushed into the angle drive. You will need to remove the distributor angle drive in order to replace this seal and polish the shaft.
     
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  13. Motob

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    This is not true. There should be no oil in contact with motor end of the tach angle drive. The fiber washer does not seal any oil. It only prevents metal to metal contact and acts a a spacer in order to properly locate the pinch bolt mounting hole.
     
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  14. John Vardanian

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    #15 John Vardanian, Jun 7, 2018
    Last edited: Jun 7, 2018
    Brian, "There should be no oil in contact with motor end of the tach angle drive", how can this be true? The tach drive penetrates the distributor angle drive and the distributor angle drive contains oil.

    john
     
  15. TTR

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    John, this will be my last reply and with all due respect, I don't know how much (hands-on) experience you have with 365 GTB/4, a.k.a. "Daytona" distributor angle drive housings and their tach drive components, but I have few under my belt, including one which I replaced the aforementioned lip seal along with all other gaskets, O-rings & seals, etc just few weeks ago and is the subject in my photos.
    I suspect Brian has much more than I and we seem to agree on this: On a 365 GTB/4 engine, the original subject model of this thread started by Chuck, there is and should be a shaft (lip) seal inside the distributor angle drive housing preventing engine oil not only to leak out but also to come in contact with tach (angle) drive or its brass adapter. If either of these appear to be in constant contact with engine oil, it is likely that the lip seal is not working properly.
     
  16. John Vardanian

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    Timo, as always, condescension is expected and appreciated. You said there should be a lip seal on the tach drive shaft. Is there?

    john
     
  17. John Vardanian

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  18. Motob

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    That is the seal and the slotted shaft that cuts the seal when it is pushed through it. It you ran the engine right now with the brass adapter removed, no oil should leak from the seal/shaft. If it does, that seal needs replacement and the sharp edges on the shaft need to be polished off.
    I have had to do this multiple times on engines that were just rebuilt.
     
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  19. John Vardanian

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    When I removed the brass adapter this is what I saw. The well was nice and dry.
    Brian, is it necessary to remove the driveshaft before replacing the the seal?

    john
     
  20. Motob

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    The distributor angle drive must be removed from the rear of the cylinder head. The shaft needs to come out, then the seal can be replaced. I recommend that all of the sharp edges ( on the slotted portion of the shaft) be polished smooth, otherwise the seal lip of the new seal will be cut when the shaft is reinstalled in the angle drive, causing it to leak oil.
    If yours is nice and dry with the brass adapter removed, then I would not mess with it. Just reinstall the adapter and tach drive and you should be good to go.
    Did you have an oil leak from this area before?
     
  21. John Vardanian

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    #22 John Vardanian, Jun 11, 2018
    Last edited: Jun 11, 2018
    Got it, Thanks. I have a newly rebuilt motor that leaks from the tach drive. I took the tach drive apart and sealed it, but I do not think that would have remedied the problem (anyway, I have not ran the motor since). But, I did not know about the lip seal until this discussion. It's possible that either the new seal was ruined during installation or the old seal was not replaced. I'll get to it this week.

    john
     
  22. John Vardanian

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    Here's the source of my tach drive leak, after pulling out the driveshaft I found the lip cut at 3 and 9 o'clock. There was fresh white sealant around it so it must be a new seal. For reference it measure 12x22x7.

    john

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  23. bighitter2

    bighitter2 Formula Junior

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    Is this the same "lip seal" you are referring to? This is one one of the Daytona angle drives i'm woring with.thanks all for the help,it sure would be nice to stop this leak ( the last one) Chuck
     

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  24. John Vardanian

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    #25 John Vardanian, Jun 24, 2018
    Last edited: Jun 24, 2018
    Chuck, no, the lip seal is inside the casting that carries the distributor itself, which is part No. 1 here. The seal is shown here as part No. 46. Look at my picture in post No. 18 and you'll see the seal nestled in its place.

    john

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