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Blocks may be used for lowering leaf-spring cars like the Datsun 1200. This is the traditional easy, time-tested and inexpensive method for lowering the rear. See Lowering for other methods.
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Overview
Datsun 1200 use a straight axle mounted on top of the leaf springs, so by fitting blocks between it and the spring, the rear of the car is lowered.
3.5" lowered, combination of reset springs (2") and 1.5" lowering blocks (see post)
Block are available in different heights such a 1.5", 2" , 3" for differing amounts of lowering.
Buy a 1200-specific block, or a "universal" 2.0 inch wide block. "Kits" come with block and U-bolts, so make sure the u-bolt fits a 1200 (M10 bolts, ute needs wider u-bolts than sedan/coupe/wagon). Ute may use 66mm internal width u-bolts (approx. 2.6").
Width: 2.0" (narrower 46mm may be used) Height: whatever you want Pin: 12.75 mm Hole: 12.75 mm U-bolts: M10 diameter (approx. 3/8" -- will the common but larger 7/16" work?) * M10 x ?2-1/4" ??? (1200 sedan/coupe + 1974 B210) * M10 x 2.5"??? or 2.6"??? (1200 ute)
Larger Datsuns use 2.5" wide blocks, so they will not fit the 1200. B10/B110/B210 all use 2.0" wide leaf springs, although the block specifications vary.
Sources:
Bprojects South Yokohama Dellow Lovells 50mm LBNIS5065 1000/1200/120Y Lovells 75mm LBNIS7565 Universal: * JC Whitney * any race shop such as * Jegs * Summit
U-bolts * local truck spring shop custom made (about $40 per set of 4 in USA)
Bprojects sells long u-bolts which can be used with blocks or without blocks (cut to fit length needed).
Using B210 isoclamp might lower your car 1/4" but results in quieter ride
NOTE: As with any lowering, the suspension travel becomes restricted compared to the factory ride height.
Plain block with screw in pins
custom-made blocks
Modular blocks, stackable 7mm
SCCA racer
Legality
See discussion: POST Lowering blocks...... Legal??? * NSW Yes * VIC Yes * SA Yes * QLD Yes
In Australia, the main requirements are:
- keep a minimum of 100 mm ground clearance
- keep 2/3 of original travel (so no lowering onto the bump stops)
- Lowering blocks must be steel or aluminium (not wood or cast iron)
Dimensions
width: 50mm a: 12mm b: ~15mm c: 110mm d: 8mm e: 13mm
Ute needs wider bolts for larger axle housing
50mm wide
Datsun 1000
Datsun 1000 dimensions
50mm wide (same as 1200) locating nubbins: 1"/25mm (1200 uses small 1/2" nubbins)
Regular Datsun blocks can be used on 1000 by creating a larger sleeve to fit the locator on top and boring out underneath.
Truck Lowering Blocks
Sunny Truck/ute lowering blocks are the same as coupe/sedan/wagon but the u-bolts are a wider U — to go around the larger axle housing.
Moon lowering blocks in 1", 2", 3" sizes - buy at Bprojects
2" Moon DST 9067TB Width: 45mm Length: 120mm Height: 50mm/2" Pin Size: 12mm
U-bolts Stainless Steel Internal width: 66mm Length: 245mm
Suspension Travel
- Trim the bump stop rubber by 1" to gain more travel
- Fit more compressible shocks
- Stiffen the effective spring constant to make bottoming out less likely, e.g. add leafs or add an overtravel leaf from a ute
Pinion Angle
Correct and Incorrect Angles
From top to bottom: OK 1 stock 2 lowered with straight blocks 3 angled diff. Transmission must be angled to match 4 lowered with angled blocks NOTE: transmission must be angled to match NOT OK 5 only diff angled 6 only gearbox angled
NOTE that lowering the car properly will not change the alignment angle. Although the driveshaft angle changes, the pinion-to-transmission angle does not change. Hence, no angle blocks are necessary. Howerver, if you choose to use angle-blocks then the transmission must also be angled the same amount.
stock alignment angle (black lines)
lowered - alignment angle does not change
Even if the lowering is done unevenly, the important angles do not change.
lowered unevenly - alignment angle does not change
Notes
- Lowering blocks are legal in most countries, including most Australian states (where usually 100 mm of ground clearance is required)
- New Zealand reportedly allows max of 50mm lowering blocks
- Square blocks will lift the diff squarely and will not change pinion angle
- Angle-ground blocks will change pinion angle so are NOT recommended. These are normally used with extreme lowering and require the diff angle to be modified or the transmission angle modified
- Handbrake cable will need to be re-adjusted after lowering
- On a BW68-equipped sedan, the blocks make for less access to the brake adjuster and brake bleeder. This is because the BW axle has in bottom-mounted brake cylinders
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Limits
2mm suspension travel left. The bump stops can be cut about 1" to increase the travel, but after that the shock will bottom out (see Lowering Shocks).
The limit for lowering, using any means is when the axle is against the chassis rail. To get the car lower than this, you can use 1) smaller diameter tires or 2) modify the chassis (tubbed, etc). In this photo the bump stop has already been shortened.
Lowering tires (lowers 1.5" from stock)
