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Thread: Q4 gearbox

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    Default Q4 gearbox

    Well - meanwhile when my engine is in the engineshop, I had to use the time to something else...

    So why don't take the gearbox apart!

    Here are some pics to digest.
    Attached Images Attached Images
    Regards...

    RMB-Racing
    Ronnie Bonde
    Denmark

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    Your brave, I wouldn't trust myself to get it right putting it back together, I recently took apart a 1.8 8v gear box - sooo many components!!

    Any signs of excessive wear?

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    Are you going to put a strengthening plate in while you are at it?

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    Fletch mentioned the above mod, apparently there's a known weakness.

    wrinx
    My Q4 in the Garage

    www.alfaromeo155.co.uk ............................ □□□-V-□□□ .................................. www.ilmostro.co.uk

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    Quote Originally Posted by Evodelta View Post
    Are you going to put a strengthening plate in while you are at it?
    I?m not quite sure I know what your talking about..?
    Regards...

    RMB-Racing
    Ronnie Bonde
    Denmark

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    With more power and some spirited driving the two main shafts can force themselves apart, this cracks the gearbox casing. The SS plate goes in between the two halves of the the casings on the gearbox, it is held in place with 5 solid dowels and a couple of extra bolts which go through the casings and the plate.
    The Grp N rally cars used to use them and a couple of the UK dealers sell them for ?235.

    I can get them for ?130 delivered to you if you are interested.

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    When you have the gearbox in parts I would recommend you to to change the 5:th gear for the long one from the Delta HPE HF - that is definitely one of top three modifications I've made. at 140 km/h you lower the engine speed by ~500 rpm.

    By the way, it is easy to change the 5:th gear also with the gearbox in the car.

    /A

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    Quote Originally Posted by #84 View Post
    When you have the gearbox in parts I would recommend you to to change the 5:th gear for the long one from the Delta HPE HF - that is definitely one of top three modifications I've made. at 140 km/h you lower the engine speed by ~500 rpm.

    By the way, it is easy to change the 5:th gear also with the gearbox in the car.

    /A
    This sounds very interesting, I would like this mod in my car, can you explain it more?
    Alfa Romeo 155 Q4 Widebody - 1995 - Blue Nord Metal - See garage

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    Quote Originally Posted by Evodelta View Post
    With more power and some spirited driving the two main shafts can force themselves apart, this cracks the gearbox casing. The SS plate goes in between the two halves of the the casings on the gearbox, it is held in place with 5 solid dowels and a couple of extra bolts which go through the casings and the plate.
    The Grp N rally cars used to use them and a couple of the UK dealers sell them for ?235.

    I can get them for ?130 delivered to you if you are interested.
    Is there a chance for more information -
    1) how complex the installation is (any mods to the casings of the gearbox)
    2) what torque or HP limit such a gearbox could handle (if such info is quoted somewhere)

    Thanks

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    Okay Evodelta - your talking about three mods...

    1. Changing the fifth gear. Sounds like a great idea!

    2. Change a plate..? Is it the one on the picture..?

    3. What is the last mod..?
    Attached Images Attached Images
    Regards...

    RMB-Racing
    Ronnie Bonde
    Denmark

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    Quote Originally Posted by Evodelta View Post
    With more power and some spirited driving the two main shafts can force themselves apart, this cracks the gearbox casing. The SS plate goes in between the two halves of the the casings on the gearbox, it is held in place with 5 solid dowels and a couple of extra bolts which go through the casings and the plate.
    The Grp N rally cars used to use them and a couple of the UK dealers sell them for ?235.

    I can get them for ?130 delivered to you if you are interested.
    Hi! Where are you located? can it be paid via PAYPAL? Pls let me know, I'm interested. I'm from Buenos Aires, Argentina, but have some friends at London who can receive the parcel! Cheers.

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    No I'm talking about one mod and that is a gearbox strengthening plate, it goes where I said before (The two parts of the gearbox are at the top of your earlier pic on the right).

    What you have just shown there is a spectacle plate.

    You have to remove the thickness of the plate from the outer casing then bolt it back up again. Removal is by milling or surface grinding on a machine.

    Here is what it looks like fitted:



    Whether you need one is down to the way you drive and the power, 350bhp and 300lbs/ft torque and you should consider it before it all ends in tears.

    Also, take your differential out and check that the planetry gears are not moving about due to the stakings on the shafts working loose, not so common on the later boxes like yours, but on the early ones they made a real mess of things, see the groove they have caused here:



    And here:



    And the stakings coming loose here:


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    Quote Originally Posted by Juan ALZAGA View Post
    Hi! Where are you located? can it be paid via PAYPAL? Pls let me know, I'm interested. I'm from Buenos Aires, Argentina, but have some friends at London who can receive the parcel! Cheers.
    Yes no problem, PM me your email address and any questions you may have.

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    @ Evodelta
    great info. Should have known that quite long ago.
    What did you do for the planetary gears?

    @ #84#
    so, you have an extra ? km for the top speed! And fuel economy in cruising speed!!!

    Thanks to both of you for the info.
    Nick

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    Quote Originally Posted by #84 View Post
    When you have the gearbox in parts I would recommend you to to change the 5:th gear for the long one from the Delta HPE HF - that is definitely one of top three modifications I've made. at 140 km/h you lower the engine speed by ~500 rpm.

    By the way, it is easy to change the 5:th gear also with the gearbox in the car.

    /A
    That's cool, I never heard that one before.

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    Quote Originally Posted by arjunior45 View Post
    @ Evodelta
    great info. Should have known that quite long ago.
    What did you do for the planetary gears?

    Thanks to both of you for the info.
    Nick
    If the gears have got this bad then it is a bit too far really for repair, but if you wanted to you could and get a few more miles from it.

    Basically you push the pins back into place and make the stakings better (the staking is done not very well by a special punch in the factory which puts the star shape on the outside of the crown wheel).

    Some people weld them in place, this is 100% secure, but you have to be aware that any work you need to do another day will be difficult or impossible without destroying the parts to get them loose. Also, use TIG weld and immerse the component 90% in water so as to cut down on the chance of warping due to the heat (TIG is a cooler weld).

    Take note of what I said earlier in that this problem happens less to these later transmissions, in the pictures are 1990 integrale 8v components.

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    ok Evodelta,

    we always use TIG welding and I know what to do with this welder. As soon {hope later as possible} as I'll take apart the gearbox I'll go for the plate and the welding.

    Thanks again.

    Nick

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    Thanks for the info Evodelta.

    Have onyone any info on the mods to the gearbox needed when you have well over 350bhp and 300lbs/ft torque (and the driveing style being quite "severe"). I've heard of a "cabon" casings (or something similar) but did not find any more info on that (if its real thing and where to get it ...).

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    About the 5:th gear:

    The standard gear is calculated to result in a speed of 238 km/h @ 6500 rpm
    The gew gear is calculated to result in a speed of 274 km/h @ 6500 rpm
    At 140 km/h the difference is exactely 500 rpm with the same calculation.

    My rev limiter is set to 7200 rpm ... = 303,5 km/h .....

    The part numbers are 774 51 53 and 608 11 731.

    You just unscrew the end cover of the gearbox and you find the 5:th gear just in front of you. The gears are locked to the shafts by a nut (don't know the size) so unscrew the nut on each shaft, remove the gears and put in the new ones. No new gasket is needed since "silicon glue" is used from factory.

    Happy New Gear

    /A
    Last edited by #84; 09-01-09 at 09:17.

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    Quote Originally Posted by #84 View Post
    About the 5:th gear:

    The standard gear is calculated to result in a speed of 238 km/h @ 6500 rpm
    The gew gear is calculated to result in a speed of 274 km/h @ 6500 rpm
    At 140 km/h the difference is exactely 500 rpm with the same calculation.

    My rev limiter is set to 7200 rpm ... = 303,5 km/h .....

    The part numbers are 7757955 and 7757956.

    You just unscrew the end cover of the gearbox and you find the 5:th gear just in front of you. The gears are locked to the shafts by a nut (don't know the size) so unscrew the nut on each shaft, remove the gears and put in the new ones. No new gasket is needed since "silicon glue" is used from factory.

    Happy New Gear

    /A
    Great Andreas

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    Good information, thanks....I have noticed the revs are a bit high when cruising in to three figures

    wrinx
    My Q4 in the Garage

    www.alfaromeo155.co.uk ............................ □□□-V-□□□ .................................. www.ilmostro.co.uk

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    If the Delta HPE gear fits then why not the Fiat Coupe, has anyone tried this? Remember the downside - you will spoil the acceleration in 5th gear and find yourself dropping down to 4th more often when you need to get serious....

    I have a friend who is working on a carbon casing (he works in the transmissions dept of Honda F1 who use this concept) I don't think it will be ready for a while yet, but when tested and for sale I'll let you know. Scara does a replacement spectacle plate, but I don't know much about it. Sadly sometimes, you just have to break your transmission and then work out how to strengthen it as the high power guys rarely give info away.

    Or drive more smoothly, as it is jerkyness which breaks things, get two wheels fighting for grip on the loose, foot to the boards, and as soon as they come back to the tarmac there is a lurch which will break something.

    Some are probably looking at my GBSP and thinking they will make their own, think again. A lot of time, money and developement went into the first one, they are all CNC Laser cut and very precise and for the price you might aswell not bother...

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    Now I have assembled the gearbox again!

    I couldn't find any excessive wear, noting in particular anyway...

    The housing has been painted, just for the look.
    Attached Images Attached Images
    Regards...

    RMB-Racing
    Ronnie Bonde
    Denmark

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    Quote Originally Posted by #84 View Post
    About the 5:th gear:

    The standard gear is calculated to result in a speed of 238 km/h @ 6500 rpm
    The gew gear is calculated to result in a speed of 274 km/h @ 6500 rpm
    At 140 km/h the difference is exactely 500 rpm with the same calculation.

    My rev limiter is set to 7200 rpm ... = 303,5 km/h .....

    The part numbers are 7757955 and 7757956.

    You just unscrew the end cover of the gearbox and you find the 5:th gear just in front of you. The gears are locked to the shafts by a nut (don't know the size) so unscrew the nut on each shaft, remove the gears and put in the new ones. No new gasket is needed since "silicon glue" is used from factory.

    Happy New Gear

    /A
    This sounds great, I am going to get in touch with my Alfa supplier tomorrow and see how much these gears are going to cost me..

    Which gear goes into what place? Would it be possible to provide pictures?
    Alfa Romeo 155 Q4 Widebody - 1995 - Blue Nord Metal - See garage

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    Quote Originally Posted by Evodelta View Post
    ...
    I have a friend who is working on a carbon casing (he works in the transmissions dept of Honda F1 who use this concept) I don't think it will be ready for a while yet, but when tested and for sale I'll let you know. Scara does a replacement spectacle plate, but I don't know much about it. Sadly sometimes, you just have to break your transmission and then work out how to strengthen it as the high power guys rarely give info away.
    ...
    Thanks for info. Saw some interesting looking (dont know if it is only painted OEM one or thats a whole casing made up from different material ... and maybe a sequential gearbox, haven't seen such from inside...) Delta Evo gearbox on this site: http://www.zica.it/galerie.php?lan=e...erie&&galid=18
    Try to get more info when I'm up to that (hopefully soon) and let you know if anything interesting there. Sadly Evo casing is a bit diferent from Q4 for it is bolted to the body/subframe in different points so there would be more work to fit it.
    Last edited by mindus; 24-08-08 at 21:01.

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