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Spitfire gearbox removal


PeaTear
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Guys I'm trying to remove the gearbox to change the clutch but I can seem to get any movement on the prop shaft to move the gearbox back. I've tried jacking the engine up a bit but the whole car starts to lift. Is there something I should be doing. I've followed the steps in both workshop and Haynes manual

 

 

20200202_122453.jpg

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That prop looks clear of the flange to me. You should be able to lift the rear of the gearbox (NOT the engine - don't jack the engine) from there, as long as you've undone the mounting rubbers properly. However, you'll find it very tight when it comes to putting it back in, so I'd probably remove the prop as YS suggests.

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From the position shown in your photo youve got to lift the gearbox a little so the gearbox mounting rubber's threaded stems lift out of the mounting bracket. By the time youve done this the flanges should just about clear. Id do it by jacking the rear of the engine (between sump and backplate?) so that when the gearbox comes away the engine will be supported rather than just relying on the engine mounts....

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guess you have a prop without a telescopic  so would also recommend removing it to give some space to work rearwards but yes you must lift 

the box high enough to disengage the rubber cotton reel mounts , you could unscrew them as well to aid more wiggle

you will probably have to rotate the assy to clear the clutch housing to clear under the heater outlets

get two long 5/16unf studs in the top engine plate to aid refitting, old trick to gauge you have the engine and box  ][  not [/   odd piece of wood 

to fit the gap and eye up  /gauge that  both are parallel   and jack and lift to get it in line 

dont forget to check the oil level when finished 

Pete

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I’ve never had to remove the prop on my GT or more recently on my brother’s Spitfire. You have to lift, pull, then rotate and pull at an angle to clear the heater and the bulk head hole. You need to be a big strong lad, or failing that have a helper.

Doug

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if its unfortunate to have a strap drive prop its got no means to shorten its fixed length makes things more interesting (not)

when disengaging the couplings to play at box out 

and on refit you need to get fingers in to turn the coupling when in gear to  align the clutch disc splines 

so less blood if its ....removed  ha !

pete

 

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The good news is it's out. Loosening off the front engine mounts gave enough wiggle room to clear the box from the prop flange. 

Also discovered the pin for the clutch lever was missing. I'm glad I had ordered one.  

Now just to clean it all up and rebuild

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Did you go for the uprated version? I've been supplied, in the last month, with one that's just a metal cylinder, and while it's a good fit now, any wear will see it drop straight out the bottom. You can get versions that are like a nail, with a larger head (£2.95), and Chic Doig sells a really heavy duty version that's going nowhere for years.

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The pin I was sold has a circlip round the top and looks good for as long as it takes the circlip to rust through; which in normal road use in the UK won't be too long! I didn't risk it, but went for one with a visible top like a nail; there's little chance of it dropping through for the next few years. The Chic Doig version is in the other photo along with the bronze bushes and the head on it is huge, so it will probably outlast the car; it's in my other Herald which has an alloy bellhousing, so might wear more quickly than the cast version.

DSCF7752.jpg.56527f27dbd1dc56228fc0c882506a33.jpg  DSCF0934.jpg.343f38c1138a785140b11661e6f5abcd.jpg

 

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So I thought I've gotten this far. Why not have a look inside a gearbox. 

The teeth look fairly decent although a few are chipped on the reverse gear

As I hadn't planned on opening this up I dont have gaskets. Would it be ok to use a silicone gasket maker?

IMG-20200202-WA0003.jpeg

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Ouch! Is there that much of a rush you cant wait for the proper gaskets to turn up? Why not change the front and rear oil seals at the same time, its easy to do and can save a lot of hassle later. Also have a look at the gaps between the bronze synchro rings and the gears they engage with. You can push them with your finger and the smaller the gap the more worn they are with second usually being the worst. If theres minimal gap the synchronisation wont work very well and you get crunchy gear changes but unfortunately changing them involves dismantling the internals.... 

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you dont have to have gaskets on solid faces  being involved with many trials on production  the use loctite 574  set a standard that solved many leaks , not a fan of silicon as its slippery and any faces that can  'pant'  will end up leaking 

the loctite really bonds once air is excluded 

it wont set in its nozzle like other sealers  which tend to block 

Pete

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Maybe he means the cover wont go down flush onto the flywheel by hand which I think is normal (as long as the friction plate is in the right way round of course (smooth side to flywheel?)). You have to use the fixing bolts to draw it down the last little bit because thats what ensures the friction plate is clamped tight and wont slip in use.

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Just reread my post. I could have made it a bit clearer 😔.  THe locating holes on the cover are slightly further away from the locating dowels by nearly. I did think about trying to tighten it down a bit with the bolts but I'm worried that something might get damaged.  The old cover goes on easily.  I'll phone canleys in the morning to see what they suggest. 

I really dont want to reuse the old part

20200203_204402.jpg

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You should see how much wear is on those fingers. Could the missing pivot pin for the clutch release arm have attributed to this wear.   

I've spoken to canleys and was advised that the dowels can get bent so best course of action is to remove the 3 dowels from the flywheel, loosely bolt the  clutch cover on and reinsert the dowels 

I'll give this a go tonight

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