Author Topic: 1600 OT replica (based coach 850)  (Read 4124 times)

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Offline Simon

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1600 OT replica (based coach 850)
« on: August 26, 2008, 04:25:46 PM »
Hello I am new to this forum, I would like first to congratulate our host for the extremely usefull material posted in this forum, particularly photo's of preparation and car repairs..thanks again really very inspiring.

A short presentattion of my activity and interest in Abarth cars.

Based in France I am regularly participating into vintage regularity rally races, my car is a fiat 850 (903 cc) sport spider, modified simply for that. To name very few simple modification done on my car
Leaf spring front beam support changed by a replica abarth model. Rocker harm cover / intake manifold and carburtor 32/32 from A112 Abarth. 4 in 1 exhaust system. A112 magnetic pick up ignition system distributor + coil. Reinforcement of the cluch cable stop holder plate in the tunnel. Shock absorber from Spax. So far so good car performs very well and is very reliable.

Regarding the subject I am  planning to build a replica 1600 OT from a 850 coach, having recuperated a 1600 OVHC engine from 1969  fiat 124 sport i have few technical point to clarify and any advice from this forum will be really welcome.
Main issue is the selection of the gear box and coupling with the engine.
Can I use a gear box from a fiat 600 that will rotate on the right direction or use a gear box from fiat 850 and therefore change the engine rotation ? in such a case what to do to change the rotation of the 1600 engine ?  is it at all possible ?
Does enyone has the production drawing/draft of the interface plate needed to adapt these gear boxes on such engine ?
Which type of cluch system  to use Fiat 850 or Fiat 124 based ?
Does anyone has the production drawing/draft of the rear support brace for 1600 OVHC engine support to fit inside the 850 engine bay ?
Photo of body works details from 1600 OT as well as rear and front wheel train details, we have seen often the photo of the 2000 OT rear train is this the same for the 1600 OT ?.And what about the front train is it a coil over shocks with unibals links lower triangle with box type cross beam like other fiat 850 Abarth upgrade ?

Well sorry was a bit long for an introduction, anywawy it is always nice to share..

Have fun be safe,

Offline trevor

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Re: 1600 OT replica (based coach 850)
« Reply #1 on: August 27, 2008, 12:59:49 AM »
Hello Simon,              Welcome.
Some first thoughts re an OT1600 berlina replica: 
Many of the issues you raise are similar to solutions adopted for 124 pushrod engines with 850 gearboxes in Fiat 850 chassis.
A range of photos in this forum under Fiat Abarth 1300 S Scorpione, and Fiat Abarth 1300/124 are very helpful. These have the engine sling, and Abarth or PBS bellhousing mating 124 motors to 850 gearboxes, front radiators etc.
For 124 twincam and 600 gearbox: if you look on this forum under car restorations "Periscope 1300OT Koos Visser" there appears to be a Fiat twincam, mated via a 131(?) bellhousing and alloy adapter plate,to a 600 gearbox (4 and 5 speed versions available plus alternate final drives), thus using clockwise rotation of motor/gearbox. Guy would know the details of the construction of the vehicle.
Ther are also Guy's photos on forum of comparison between VW beetle and Porsche 911 gearboxes for similar tasks.
For 124 twincam and 850 gearbox which requires counter-clockwise (CCW) motor rotation, this can be accomplished by reversing the rotation of the 124 motor, by reversing the rotation of the distributor (block mounted version) relative to the crankshaft, by an amended auxiliary shaft drivegear and matching distributor gear of opposite-hand/mirror image helical gears to the standard distributor drive gears. PBS used to make these many years ago using now superseded US Ford escort gears, now most only available likely by having one fabricated. I have photos of these and other detail if you wish to email me. The distributor drive gears on the camshaft and distributor from a Fiat 242E commercial benzina motor (type 132AZ2C) are the exact pattern for replicating, but can prove difficult to source.
This reverse rotation version uses twincam motor, Abarth or PBS 124/850 bellhousing and imput shaft, 1438 124 flywheel / clutch,  850 gearbox 4 speed (or Bacci 5 speed non syncro type), and usually a better final drive eg 3.9 to 1
If you can find a copy of Greg Schmidt's "Fiat and Abarth Tricks" publication, available on ebay from time to time, this has a helpful outline on the isssues.
Hope this helps.

Offline Simon

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Re: 1600 OT replica (based coach 850)
« Reply #2 on: August 27, 2008, 10:24:05 AM »
Hello Trevor,
thank you for your comments. Regarding the motor it is a Twin Cam and If I recal the distributor is on the bloc. I also have the 124 cluch housing that goes with it so maybe the easiest way is to plug a 600 gearbox. in such a case is there any preference in mouting cluch housing from 600 gear box and having the adapting plate berween cluch housing and motor, or keeping the 124 cluchousing and having the adapting plate between 124 cluchousing and 600 gearbox ?