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The A12 engine of the Datsun 1200 features a modern lightweight cast-iron cylinder block.
Also see Block Comparison
Contents |
Identification
A12 - see main article: Engine ID Mark
Ventilation
Under the block breather pipe, this steel mesh separates out the oil vapor from crankcase ventilation air.
Block Height
A10 Deck Height: 179.1mm A12/A12A Deck Height: 189.1mm A14/A15 Deck Height: A12 height 204.1mm
Head Locating Dowels
Starting with A12 engine for B210
11053-73400 DOWEL-BLOCK TO HEAD 2
Cylinder Blocks
A12 Deck Height: 189.1mm (?)
~2.5 liter coolant capacity
The A10 block is 10mm shorter than A12 block, while A14/A15 block is 15mm taller than A12 block. Length is the same for a A-series engine blocks.
Also see: Block Comparison
Original Block
H10 block castings
11010-H2300 A12 BARE BLOCK 73mm/2.87" bore size
* USA 11010-H2300 0570- ALL <> 11010-H1000
* USA 11010-H1000 -0470
* JPN 11010-H2300 GX, running change replaced <2,0> 11010-H1000
* JPN 11010-H1000 except GX
M08 block from 1970-1973 E10 Nissan Cherry X-1R A12T
M15 E10 Cherry A12 single-carb
Redesigned Block
- 11010-H5000 A12 73mm bore size
- 11010-G1600 A12 From June 1975 (?)
- 11010-G1618 A12 B120 7908-8503
- 11010-G1619 A12 B120 8504-
- M79 casting
-
- 11010-H9960 A12A BARE BLOCK B310 75mm/2.95" bore size
- 11010-H8500 Sedan, Coupe B310 -8010
- 11010-H9463 Van B310 8011-8109, 8110-
M79 casting, from late 1200 Sunny Truck
Tall Block
Deck height: 204.1mm (?), or 15mm taller than an A12/A12A block. Length is the same.
- 11010-H6200 [1974] A13 BARE BLOCK 73mm/2.87" bore size
- A14 cast "A14" above fuel pump
- H72 or G30
- 11010-H9700 A14/A15 BARE BLOCK 76mm/2.99" bore size
- G34
Overbore
The 1971-1973 A12, the one with the front distributor, can usually be bored to 76mm. This is the same as a stock A14. There are probably some dud blocks around, but generally 76mm is fine. Pistons of 76.5 mm size and larger were offered through the Datsun competition department and others back in the 70's, so it's a factory approved bore size.
A14 pistons use a 19mm wrist pin while the A12 rods have a 17.5mm hole, so you have choices:
- Bore the original rod to 19mm. This is most commonly done
- Find a set of late A12 rods. There seems to have been a change in the later rods and these forgings look like they are the ones that were used for the A12A & A13 engines. [more on this later]. These rods have more 'meat' around the pin hole & would be stronger than a 1200 rod after the pin hole was bored to 19mm.
- Find a set of A12A or 1980's A13 rods as these have the right length and the correct wrist pin hole for the A14 pins
73mm bore piston used the 17.5mm piston pin diameter:
- A10
- 1971-1973 A12 (1200)
- 1974-up A12
- 1974 A13 (tall block engine)
A series pistons for engines with 75mm bore used a 19mm pin:
- A12A - USA & Japan only
76mm bore size also used the 19mm pin:
- A14
- A15
- 1979-'81 (Asia only)
A12A and late A13s were just bored out A12s, so they had the shorter A12 length rods, but with the bigger pin size. The crankshaft is interchangeable between early A12, late A12, late A13 and A12A.
Crankshafts
Stroke:
- 70mm (2.76 in.) stroke: A12/A12A/A13(1980)
- 77mm (3.03 in.) stroke: A13(1974)/A14
- 82mm (3.23 in.) stroke: A15
For more details and part numbers, see Crankshaft
Connecting Rods
See main article: Connecting Rods
Weight
For maximum performance, use the lightest rod that will hold up to the intended usage. Stock A-series rods are forged, and will last a lifetime in a stock or moderately upgraded performance engine. There is no need to use a heavier duty rod unless you are using a high boost turbo or supercharger, or revving higher than 8500 RPM.
For road racing engines with sustained high-RPM loads, a heavier duty rod may be required.
The weight of a stock A15 rod with ARP rod bolts and nuts installed, no bearings is:
Approximately 514 grams
Pistons
A12 engine came with dished pistons for approximately 9.0:1 compression ration. Standard bore size for the A12 or A13 block is 73mm/2.874". Pistons are cast. Nissan Competition does not recommend forged pistons for street use.
See main article: Piston
Main Bearing Caps
Also see: ARP
12293-18001 BOLT-MAIN BEARING CAP (10) L=72.5 <> 12293-01M00 * A12/A14/A15 engine (quantity 10) * L16, L18 and L20B engine (10) * 720,D21,S110 with Z20/Z22/Z24E/Z24I (10) * 910,S130 with L24/L28E (14) * B11, N10/N12 with E15/E16 (10) * D21 PICKUP with KA24E engine (10)