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Discussion Starter #1
Hi All,

I'm currently rebuilding a 2L engine ('72 - AR00512) to replace the 1.6L engine in my 1975 GTj.
Would I be able to reuse my 1.6 gearbox as is? Or will it need a different bellhousing?
If possible, I would go with a 2L flywheel and ring-gear as I already have the flywheel and 2L starter.

Thanks for the input.

Wkr,
Simon
 

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I believe so. My 1975 GT Junior 1600 also had an engine swap to a 2 litre (512) at some point in its history. I don't think it required any change in the gearbox. It may be worth taking the opportunity to double check the bellhousing for any cracks around the starter motor mounting holes.
 

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It might get a little dicey on the subject of starter spacer/ flywheel teeth/starter teeth count... If you start scrambling these around there are no guarantees. Don't assume anything that you think is compatible until you check and double check. The gearbox? no prob........I would double check the tooth count on the 2L flywheel with the 1.6 flywheel and also the starters before I put it all together. The 1.6 Junior should have a flywheel ring gear of 110 teeth ... ssoooooooo... check it all out.
 

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Discussion Starter #4
It might get a little dicey on the subject of starter spacer/ flywheel teeth/starter teeth count... If you start scrambling these around there are no guarantees. Don't assume anything that you think is compatible until you check and double check. The gearbox? no prob........I would double check the tooth count on the 2L flywheel with the 1.6 flywheel and also the starters before I put it all together. The 1.6 Junior should have a flywheel ring gear of 110 teeth ... ssoooooooo... check it all out.
For some reason I already have a 2L starter on my 1600. Not sure if that's original on these late junior or if a previous owner already did some work on the flywheel for some reason. When the 1600 comes out I'll make sure everything is double-checked.
 

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Would I be able to reuse my 1.6 gearbox as is? Or will it need a different bellhousing? If possible, I would go with a 2L flywheel and ring-gear as I already have the flywheel and 2L starter.
Hmm. I've put a couple of 2L engines into 1.6 bodies, but always ran a complete 2L drivetrain: engine, thin spacer, bellhousing, transmission. But that necessitated converting to a hydraulic clutch.

To retain your mechanical clutch you will need to use the 1600 bellhousing and its corresponding thick spacer. I believe the larger, 130 or 131 tooth ring-gear won't fit inside a 1600 bellhousing, though I've never tried it. I also believe that the 2L starter won't fit the 1600 bellhousing (starter has 3 bolt holes, bellhousing has 2) and even if you attached it with only 2 bolts, it probably won't be spaced properly. My guess is that to retain the 2L flywheel, you will have to machine down its od to accept a 1600 ring-gear, use a 1600 starter, and a throw-out bearing adapter like the Classic Alfa CL033.

You might want to read the write-up at: CL033 CLUTCH TO BEARING ADAPTER FOR MECHANICAL CLUTCH
 

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Discussion Starter #6
Hmm. I've put a couple of 2L engines into 1.6 bodies, but always ran a complete 2L drivetrain: engine, thin spacer, bellhousing, transmission. But that necessitated converting to a hydraulic clutch.

To retain your mechanical clutch you need to retain the 1600 bellhousing and its corresponding thick spacer. I believe the larger, 130 or 131 tooth ring-gear won't fit inside a 1600 bellhousing, though I've never tried it. I also believe that the 2L starter won't fit the 1600 bellhousing (starter has 3 bolt holes, bellhousing has 2) and it probably won't be spaced properly. My guess is that to retain the 2L flywheel, you will have to machine down its od to accept a 1600 ring-gear, use a 1600 starter, and a throw-out bearing adapter.
Hi Jay,

My 1600 Junior is a 1975 'unificato' model, so it has hanging pedals and a hydraulic clutch like the 2L model.
 

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Discussion Starter #7
According to This post my 2L starter and ring-gear on the late 1600 are original.
That sounds like everything might just fit... :)
 

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My 1600 Junior is a 1975 'unificato' model, so it has hanging pedals and a hydraulic clutch like the 2L model.
Ah, I missed that point. So you won't need that throw-out bearing adapter I suggested. All 1600's sold in the US came with 105 tooth ring-gears and mechanical clutches, so I am unfamiliar with the 'unificato' model.

I think the key questions are:

- How many teeth are on your 1600 ring-gear? If the 'unificato' ring-gear only has 105 teeth, then a 130/131 tooth 2L ring-gear may be too large in diameter to fit inside your 1600 bellhousing.

- How many starter mounting bolts are used with your 1600 bellhousing? If only 2, and they are located to support a 105 tooth ring-gear, them I'm not sure the 2L starter will work.
 

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I would think your 1975 mouse motor version would have an 6 bolt later type crank and the same 2 liter flywheel/bell housing. If it`s a hydraulic release clutch, probably so.

In any event if its an old type mechanical bell housing the flywheel can be machined to fit the smaller diameter 105 tooth ring gear and fit in the small bell housing. Requires a 1300/100 starter to match the ringgear.
 

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Hi All

Hope you are well.

Simon
I have not seen the back of either motors but I suggest you place the two motors next to each other and take some measurements.

From my experience manufacturers don't change a lot as tooling is very expensive.
Please share your pictures.

Regards
 
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