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Datsun 1200 originally fitted with automatic transmission has a much larger tunnel. It makes it easier to swap in larger transmissions or larger engines.
Contents |
Overview
Comparo: Manual transmission cover vs automatic transmission cover
Manual Tunnel is very small to fit the small stock transmissions and increase space inside the passenger compartment:
The manual body has one piece lower dash panel with no joins whatsoever - the bellhousing part of tunnel is one piece with firewall.
By contrast the Auto body has separate dash panel and floor. The transmission cover is spot welded in. The welding seam is clearly noticeable on the firewall at the back of the engine.
Manual tunnel has no seam
NOTE: Unlike a B110, the B210 has the same floor auto and manual - the stick and slushbox tunnels are the same on a B210.
Swapping Tunnel panels
You can swap the larger automatic tunnel into a manual transmission car. The B210 tunnel is nearly identical to the 1200 automatic tunnel. In turn, the 610 (180B) tunnel is nearly the same as the B210 tunnel. See #Tunnel Swaps below.
Modified Tunnel
Just take a big hammer and bang the tunnel sheet metal ("massage it") to get more clearance.
Or cut part of the tunnel and weld on a bigger section
You can also move the gearbox mounts back to suit various transmissions
Maddat Tunnel
Product No TT1200SR Transmission Tunnel. Suit 1200 with SR20 or CA18 Gearbox. Comes with rubber gear stick boot. These can be installed in about half a day.
Note: fitment requires removal of heater box.
For 1200 SR conversions, it will allow the gearbox to be removed while the engine is still in the car. Very simple to install, just sit over existing tunnel, trace with texta. Then cut out inside the line by 10mm, weld the tunnel from inside the cab. From underneath now tap up that 10mm lip (can be made easier if heated up with oxy), run some seam sealer around the joint to finish off.
Custom Tunnels
Others have successfully bolted or welded in tunnels from:
- B210
- Stanza (1980 510)
- 180B (610)
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- Custom fabricated tunnels
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Tunnel Swaps
The standard B110 uses one piece lower dash. The Auto dash is two pieces (lower dash + cover).
The rear half of the tunnel is part of the floor
In actual practice when swapping, the "tunnel" is cut out of the dash and floor.
manual transmission 67300-H1000 ASS'Y-PANEL, dash, lower [manual transmission] 74300-H1010 ASS'Y-FLOOR, front [manual transmission]
automatic transmission 74306-H1020 ASS'Y-PANEL, A/T floor cover, front [automatic transmission] 67300-H1021 ASS'Y-PANEL, dash, lower [automatic transmission] 74300-H1021 ASS'Y-FLOOR, front [automatic transmission]
Auto Tunnel Swap
Auto tunnel is very large to fit the 71-series Automatic Transmission, but still fits under the heater box.
Auto Tunnel retrofit - tunnel can be cut out, then the new tunnel welded to the floor & firewall:
Shoey's diagram
B210/610 Tunnel
Includes 120Y & 180B.
Fits into 1200
Fits into a 1200 and still allows for a stock heater:
NOTE: All B210/120Y use the larger size tunnel
However the B210 floor pans differ:
- from 1200 as to where the transmissions mount points are. You can move the brackets if necessary
- B210 used eight different tunnels. See Tunnel Comparison.
A10 Tunnel
Several club members have fitted an A10 Stanza tunnel to the 1200.
unfamilia:
the satnza tunnel in- looks ok, but i wouldnt recomend it as an easy swap(my first one but piggys 3rd or 4th one). 120y was most stright forward he said, but heaps of room around this one
A10 tunnel in 1200
B310 Tunnel
B310 Sunny tunnel is same as A10, but for A-series gearboxes.
Shifter Location
Stock shifter location is well forward of the seat rail riser
Photo showing where to cut the tunnel to fit a standard "short" L-series or CA-series transmission.
Cut the hole bigger ...
Or just move the hole back and weld it back in:
1200 auto tunnel with shifter location raised and moved back | stock tunnel
71-series Modifications
71-series Transmission is used by later L-series engine, Z-series engine, FJ-series engine, CA and SR engines.
S13 gearbox clearance in manual tunnel
Rear of tunnel modification:
Reverse Lamp
To fit a 60-Series Transmission 5-speed, move the gearbox Mounts 115mm back:
To remove the brackets, drill out the spot welds
56A Modification
To clear that nasty clutch fork in the later type 56A trans
See Also
Also see: Transmission tunnel Photo Index