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308 qv Timing gear cover

Discussion in 'Technical Q&A' started by Leif, Mar 14, 2004.

  1. Leif

    Leif Rookie

    Nov 23, 2003
    18
    Norway
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    Leif Arne Olsen
    I have a Ferrari 308 QV engine that had a breakdown on outer bearing on timing gear cover, this resulted in piston valve connection on one cylinder bank.
    I have now overhauled the cylinder head and bought 4 new piston.
    The result of this bearing breakdown was that the bearing rotated in the timing gear cover.
    Now my question, have any body been in this situation? And what did you do?
    Ferrari does not sell this cover, you have to buy an engine block, I now where I can buy a Ferrari 328 engine block, will this fit my car?
     
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  3. Verell

    Verell F1 Veteran
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    May 5, 2001
    6,997
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    A 328 block will NOT fit w/o engine mount modification. Also, It isn't clear that QV heads could be used with a 328 block.

    I'm assuming that the bearing's spinning has enlarged the bearing mounting hole so that a new bearing would be likely to spin. The best way to repair it would be to take the engine & timing cover to a machine shop. They should be able to exactly determine the center of the bearing opening, machine it out & insert a sleeve. The seal mounting surface won't be damaged, so it can be used to establish that the sleeve's center is in position.

    If the opening is just a few thousandths oversize, just enough so that the new bearing is a slip fit instead of a press fit, Loctite makes a couple of bearing mount compounds that can be used to fill the gap & ensure the new bearing won't spin:

    I've successfully used it to repair spun bearings in the past. The repairs have held up for several years w/o failures.

    The other compound is:

    It's used when the fit has become really loose (up to 0.020") oversize.

    Go to the Loctite US web site & search the Technical Data sheets for 640 and 660. I'm pretty sure that Loctite sells the same materials under the Permatex lable.

    If you use either of these, install the timing cover immediately after assembling the spun-out bearing so that the rear bearing can help align the front bearing while the retaining compound is setting up. You can then remove the cover & wipe off any uncured retaining compound. (A nice feature of anaerobic compounds like these is that the material only cures when it's away from air, thus any excess that's squeezed out won't set up & can be wiped off!)

    Unless the spunout area is way oversize, I'd be inclined to try 640 or 660 they're both used by several auto mfgs for spun bearing repairs.
     
  4. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
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    Bill Van Dyne
    You may be able to get a cover out of a wreck. although most sellers would likely want to sell the entire engine intact. Try T. Rutland, George Evans. Dennis Mc Cann, and Ferrari UK. Best of luck.
     
  5. Verell

    Verell F1 Veteran
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    There's a phrase in one of the WSM's that implies that the covers are factory matched to the engine in order to hold the necessary concentricity tolerences between the inner bearings mounted in the block, & the outer bearings in the housings.

    If this is the case, it's much better to restore your original cover than to hope a used one will match up.
     
  6. Leif

    Leif Rookie

    Nov 23, 2003
    18
    Norway
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    Leif Arne Olsen
    Tank’s for the respond!
    I think I will take the engine block and the cover with me to the local machine shop and as you mentioned hear if they can repair this for me.
    I was not thinking about replacing just the cover, if it should be anything, then I have to replace engine block with cover.
    I have a complete engine block with cover in hand, but it is for a Ferrari 328 and it is costly.
    I think I will here with the machine shop first.

    Tanks
    Leif
     
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  8. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
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    Charles
    TRutlands has lots of spares for this kind of problem.

    AS to the 328/308---the block WILL mate to the t-axle and with the bellhouse, but will NOT work with the stock injection/ignition system. Also I believe the heads are different but the 308/328 headers are the same.
     
  9. atlantaman

    atlantaman Formula 3

    Mar 31, 2002
    1,726
    Roswell, Georgia
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    Charles
    please post a pic if you can---the valve covers are interchangable 100% as are the timing belt covers--but the bearing part is confusing me---the bearing is internal and does not touch the valve cover or timing belt area---
     
  10. Verell

    Verell F1 Veteran
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    May 5, 2001
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    #8 Verell, Mar 15, 2004
    Last edited by a moderator: Sep 7, 2017
    Atlantaman,
    We're talking about the other end of the cam belts. ie: The outer bearing (#2 in the fig below) for the shaft that drives one of the cam belts spun in the timing cover(#4). The gears(#5) on the timing drive shafts are directly driven by the crankshaft.

    The issue is to maintain concentricity between the outer bearing (#2) mounted in the cover, and the inner bearing (#9) that's mounted in the block. If they aren't concentric, then one of the bearings will fail prematurely.
    Image Unavailable, Please Login
     
  11. Leif

    Leif Rookie

    Nov 23, 2003
    18
    Norway
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    Leif Arne Olsen
    I have been thinking about what’s the reason for this breakdown, as I understand it I am not the first with this problem on this engine. Can it be the shaft that is not aligned or the cover that is not in-line with the shaft? As Verell mention take the engine block and timing gear cover with me to the machine shop will be the best solution to find out this.
    But just for the future it will be nice to now if the 328 engine block and cylinder head are possible to exchange with 308 QV engine.
    Sow if anybody now anything I will be thankful for information.

    Leif
     
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  13. Verell

    Verell F1 Veteran
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    Hmm,
    So this is a repeat failure for the engine. I wonder if the bearing spun on the original failure, thus leaving the new bearing running off-axis. Also, it's possible that one of the timing gear shafts is slightly bent, thus cocking the inner race out of alignment. Robertgarven ran into that with his timing bearing replacement project.

    I'd have the machine shop check the timing drive shafts to make sure they're true also.

    Another possibility is that the cam belt was re-tensioned sometime after the initial tensioning, thus placing excessive tension on the bearing.

    The outer timing drive bearing position is a fairly tough application for a bearing for many reasons:

    - It's a relatively small bearing. (Compare it's size to a water pump bearing)
    - It's got a fairly heavy uni-directional radial load on it (the cam belt) with dynamic fluctions (valves).
    - It's exposed to the outside air ( thus gets splashed with water from the road, washing the car,etc. that can get inside it's seal. What's worse, it's often only used infrequently, so if it gets wet just before the car is set up for several weeks, the moisture will have plenty of time to penetrate & do some damage.) How many times does a car get driven, the road dust washed off, & put away for several weeks.
    - It's running dry (ie: depends on the lubricant that was in it when it was made)
    - It's running fairly warm (engine block temperature)

    - OLD AGE:A lot of these bearings are now well over 20 years old! Their internal lubricant is breaking down due to simple oxidation.
     
  14. Leif

    Leif Rookie

    Nov 23, 2003
    18
    Norway
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    Leif Arne Olsen
    I was not sow accurate, when I said this car, I meant in general Ferrari 308 engines.
    My car has gone 50000 miles and I have driven it 4000 miles.
    I don’t drive/start the car in long period (working at sea) sow it is standing in the garage for 3- 4 months in between each time I use it (start it up.)

    (As you maybe noticed English is not my native language)
     
  15. MarkG

    MarkG Formula Junior

    Nov 3, 2003
    369
    Colorado Springs
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    Mark
    Will be having T-belts done soon, been 3 years and am getting some noise from rear assembly, maybe bearings.

    Hlow difficult is it to replace these timing cover bearings - i.e. does it entail major disassembly or simple removal of sprockets to gain access to bearings? Thinking of pro-active replacement - '82 2V GTSi.
     
  16. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    10,328
    San Carlos, CA
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    Mitchell Le
    Verrell had done this, as did Rob Garven Jr, with the engine in the car. Bad but doable. I have done it with the engine out of the car, very easy.

    In summary, the timing cover has to come out of the car in order for you to get to the bearings. To remove the cover you have to:

    Remove dipstick and temp sensor
    remove oil pan cover
    remove oil baffle inside the pan
    remove oil pick up tube (this is the hard one requiring special ground down thin wall 10mm socket, and 6 fingers on one hand)
    remove studs from bottom of the timing cover
    remove timing cover (after you have removed the T-belts)

    My personal preference is to remove the engine and put it on the stand. But ... your mileage may differ.
     
  17. Verell

    Verell F1 Veteran
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    It's a PITA job either way.

    A LIFT makes doing it w/the engine in the car is a bit less work than pulling the engine. You can adj the height of the lift to give you the exact angle you need to get into places like the sump. Also the lift can be dropped when you need to get to the front of the engine.

    If you DON'T have a lift, then pull the engine unless you are into contortions & self abuse. IMHO, trying to get into the remote crannies of the sump while on your back with oil dripping into your face would be great for any masochist! Then there's bending over to fit inside of the wheel well to get the cover off.

    I was in Boston Sportscar recently & they'd just finished doing timing bearings on a 328 w/ the engine in the car. We compared notes & they concurred that if all the engine needs was timing drive bearings & a belt job, then in the car is less hours. However, if very much more is needed then they pull the engine.

    They were also very surprised that an amateur mechanic had actually tackled changing the timing drive bearings at all!
     
  18. Verell

    Verell F1 Veteran
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    Actually it's good enough that I hadn't noticed!
    BTW, don't change just the outer bearings, whenever an outer bearing fails it lets the cam drive shaft twist the inner bearing. Thus there's a substantial risk that the inner bearing is damaged and fails within a few thousand miles.
     
  19. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    15,203
    The Cold North
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    #16 tbakowsky, Mar 18, 2004
    Last edited by a moderator: Sep 7, 2017
  20. Verell

    Verell F1 Veteran
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    May 5, 2001
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    BTW,
    You'll need a blind bearing puller to get the inner bearings out. Harbor Freight sells a fairly nice blind bearing puller set, believe mine was $50.

    Also, a stud puller that doesn't damage the threads is a lot better for pulling the studs that tie the timing cover to the sump. These will do:
    5237-1VGA 4 PC. STUD PULLER SET $12.99

    While the descr. lists fraction sizes, they actually have a fair amount of leeway in the size stud they work with & will handle metric sizes.
     

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