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[Datsun 1200 encyclopedia]

Lowering Blocks

From Datsun 1200 Club

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Categories: Suspension Modifications | Lowering

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.

Contents

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.

12278_4f0a8f3c8a540.jpgUpload click to view

3.5" lowered, combination of reset springs (2") and 1.5" lowering blocks (see post)
4738.jpgAlbum click to view

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).

10308_4a8d15d59eaed.jpgPost click for topic

Using B210 isoclamp might lower your car 1/4" but results in quieter ride
3284_4a1de80c261c0.jpgUpload click to view

NOTE: As with any lowering, the suspension travel becomes restricted compared to the factory ride height.

9160.jpgAlbum click to view

Plain block with screw in pins
24961.jpgAlbum click to view

custom-made blocks
10816.jpgAlbum click to view 10823.jpgAlbum click to view

Modular blocks, stackable 7mm
7mm_downblocks.jpg 7mm_downblocks_.jpg

1333_56ea5571ed35b.jpgPost click for topic

SCCA racer
IMG_2982.jpgPost click for topic

 V I D E O  (click to view)
hqdefault.jpg

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

10308_4a8d1837b06f4.jpgPost click for topic

width: 50mm
a: 12mm
b: ~15mm
c: 110mm
d: 8mm
e: 13mm

5631_4afaa8686e058.jpgUpload click to view lowering_block.jpg lowering-block-1.jpg lowering-block-2.jpg

Ute needs wider bolts for larger axle housing
24959.jpgAlbum click to view

50mm wide
block.jpgPost click for topic

Datsun 1000

Datsun 1000 dimensions

50mm wide (same as 1200)
locating nubbins: 1"/25mm (1200 uses small 1/2" nubbins)

20248.jpgAlbum click to view
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.

9066.jpgAlbum click to view

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

DST9067TBa.jpg DST9067TBc.jpg DST9067TBd.jpg DST9067TBd.jpg DST9067TBf.jpg DST9067TBh.jpg

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
23850.jpgAlbum click to view

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)
pinion.png

lowered - alignment angle does not change
pinion_lowered.png

Even if the lowering is done unevenly, the important angles do not change.

lowered unevenly - alignment angle does not change
pinion_uneven.jpg

16236_5da63e0055b16.jpgPost click for topic

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

ローダウン リーフ ブロック

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).
11171.jpgAlbum click to view

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.
15983.jpgAlbum click to view

Lowering tires (lowers 1.5" from stock)
13446.jpgAlbum click to view 

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This page has been accessed 18,511 times. This page was last modified 18:21, 22 October 2019. Content is available under Datsun 1200 Club.