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[Datsun 1200 encyclopedia]

Flywheel

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Categories: Clutch | Engine Mechanical

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* To reduce vibrations, always re-balance the engine after changing rods or pistons or crank * To reduce vibrations, always re-balance the engine after changing rods or pistons or crank
* For 7000+ rpm use have the flywheel doweled. Loctite is not needed. * For 7000+ rpm use have the flywheel doweled. Loctite is not needed.
-* Make sure the flywheel-to-flange surfaces are clean. Do not let oil or Loctite get between the two, or the bolts may loosen over time. Do not oil the bolts. If using Loctite (which is not needed), apply to the crank threads using a cotton swab instead of putting it on the bolts+* Make sure the flywheel-to-flange surfaces are clean. Do not let oil or Loctite get between the two, or the bolts may loosen over time. Do not oil the bolts. Using Loctite threadlocker (red) on the bolts is recommended, apply to the crank threads using a cotton swab instead of putting it on the bolts
-* Do not get the flywheel bolt "good and tight", as overtightening weakens them. Always use a torque wrench.+* Overtightening weakens them. Always use a torque wrench.
-* Use stock Datsun flywheel bolts. If using aftermarket bolt, ensure they are 1) not too long and bottoming out 2) ensure the head face shoulder design is compatible 3) Use high strength steel like the factory bolts+* Use stock Datsun flywheel bolts. If using aftermarket bolt, ensure they are 1) not too long and bottoming out 2) ensure the head face shoulder design is compatible 3) Use high strength steel like the factory bolts 4) Ensure head size does not interfere with the clutch plate
If using high RPM, look at getting the crank flange dowelled. The flywheel is actually clamped on the head of the bolt not on the shank of the bolt (there is side-to-side play), so three dowels 120° apart should do the job. The end of the crank is soft (unlike the crank journals) and easy to drill. If using high RPM, look at getting the crank flange dowelled. The flywheel is actually clamped on the head of the bolt not on the shank of the bolt (there is side-to-side play), so three dowels 120° apart should do the job. The end of the crank is soft (unlike the crank journals) and easy to drill.

Revision as of 06:22, 29 November 2018

Datsun 1200 uses a traditional type of flywheel at the back of the engine. The face matches the Clutch while a ring gear is attached to the perimeter to let the Starting Motor turn the engine. It uses a 271mm (10.7 inch) flywheel with a 105-tooth ring gear.

Also See:
* Clutch
* Crankshaft

Contents

Overview

All flywheels for A-series engines interchange -- for rear-wheel drive vehicles. Differences are the A12 flywheel weighs 2.2 lbs (1 kg) less than the A14/15 flywheels, and is also thinner.

23641.jpgAlbum 23641 17232.jpgAlbum 17232

A10              8.0 kg (17.6 pounds)
A12 12310-H1000: 9.5 kg (20.8 pounds) 
A12 12310-H2310: 6.4 kg (14.1 pounds) GX, also sold as 'Race Option'
A14 12310-H7200: 10.7 kg (22.3 lbs)

A14/A15 flywheel is thicker than the A10/A12 flywheel. When fitting the thinner flywheel to A14, remove the Engine Plate to compensate.

A10: 25 mm thick? (does not fit A12 due to different gear angle)
A12: 28 mm thick (fits A10)
A14: 30 mm thick

15048.jpgAlbum 15048 3152.jpgAlbum 3152

In 1974 flywheel bolts changed from British Threads to Metric threads. So the bolts are not interchangeable from early to late. See Crankshaft for details.

A12 Flywheel Measurements:

thickness: 28mm
ring gear + backing: 20mm
back rim to flywheel face depth: 5mm
clutch face to inner face depth: 17mm

starter ring gear
20430.jpgAlbum 20430

Inspection

If the starter occasionally makes grinding sounds, chances are the flywheel ring gear needs replacing (or just replace the whole flywheel, which is often less expensive).

Yes, you should resurface the flywheel if it is not in good shape!!! Better to not re-grind the flywheel if it doesn't need it.

It is not indicated to turn the flywheel UNLESS cracks appear, or it is not flat (worn unevenly), or the surface is burnt (heavy glazing). Guys will tell you "it is cheap insurance" to machine the flywheel clutch surface regardless, but that's not what the Datsun factory service manual says.

Wash ... in suitable cleaning solution to remove dirt and grease ... Check friction surface of flywheel and pressure plate for scoring or roughness. Slight roughness may be smoothed by using fine emery cloth. If surface is deeply scored or grooved, the part should be replaced.

- 1980 B310 service manual

If it is warped, have it resurfaced. It is it burnt, chattered, or is grooved, resurfacing is called for. But it if still worked great, is flat, and not burnt, don't bother. The Nissan factory service manual does not recommend a resurface unless needed. Every time my Datsun flywheel did not look great, I should have resurfaced it. And everytime it looked great and I didn't resurface it, all was fine.

If the teeth are worn, replace ring gear
23497.jpgAlbum 23497

Flange damage
24122.jpgAlbum 24122 24124.jpgAlbum 24124

Removal and Reinstallation

The crankshaft needs to be locked from turning when removing or tightening the flywheel bolts.

Flywheel Stop:
23604.jpgAlbum 23604

Less effective type of stop, can be used in a pinch using a scrap of metal. The bolt will bend while bolting or unbolting the flywheel
23490.jpgAlbum 23490

Installation - torque the bolts in a star pattern
23498.jpgAlbum 23498

When installing the Clutch, use a spline-aligner so the transmission will slide on
23560.jpgAlbum 23560

Lightening

For race cars, a light flywheel allows the engine to rev faster according to this principle:

The more weight, the more time it takes to accelerate

23496.jpgAlbum 23496 16998.jpgAlbum 16998

Now a street car wants a heavier flywheel, so that it will:

  • smooth out the combustion pulses
  • smooth out the drivetrain

19041.jpgAlbum 19041

These are the factory specs for flywheel weight reduction:
1014.jpgAlbum 1014 3913.jpgAlbum 3913

Finished wheight is about 6.5 kgs --a total of 2 kgs removal

Reference: Datsun B110 Competition Tune-Up Manual, Nissan Motor Co. Ltd., Tokyo Japan 1974
6209.jpgAlbum 6209

1280.jpgAlbum 1280 13202.jpgAlbum 13202 13203.jpgAlbum 13203 13308.jpgAlbum 13308 11151.jpgAlbum 11151 11152.jpgAlbum 11152 10428.jpgAlbum 10428 11108.jpgAlbum 11108 5509.jpgAlbum 5509 5510.jpgAlbum 5510 5511.jpgAlbum 5511 5512.jpgAlbum 5512 6208.jpgAlbum 6208 6209.jpgAlbum 6209 7979.jpgAlbum 7979 8003.jpgAlbum 8003 3507.jpgAlbum 3507 3923.jpgAlbum 3923 5428.jpgAlbum 5428 5429.jpgAlbum 5429 5430.jpgAlbum 5430 2513.jpgAlbum 2513 1268.jpgAlbum 1268 1481.jpgAlbum 1481 1487.jpgAlbum 1487

Bolts

Nissan flywheel bolts are very strong. Just clean the threads and use a torque wrench to install. ARP does not make A-series flywheel bolts (though some use non-A-series ARP bolts on the A-series). In any case the stock bolts are plenty strong.

For bolt part numbers, see Flywheel Bolts

Best practices:

  • Reusing the flywheel bolts is acceptable. Even new bolts will come loose due to shaking. Even ARP bolts will snap!
  • To reduce vibrations, always re-balance the engine after changing rods or pistons or crank
  • For 7000+ rpm use have the flywheel doweled. Loctite is not needed.
  • Make sure the flywheel-to-flange surfaces are clean. Do not let oil or Loctite get between the two, or the bolts may loosen over time. Do not oil the bolts. Using Loctite threadlocker (red) on the bolts is recommended, apply to the crank threads using a cotton swab instead of putting it on the bolts
  • Overtightening weakens them. Always use a torque wrench.
  • Use stock Datsun flywheel bolts. If using aftermarket bolt, ensure they are 1) not too long and bottoming out 2) ensure the head face shoulder design is compatible 3) Use high strength steel like the factory bolts 4) Ensure head size does not interfere with the clutch plate

If using high RPM, look at getting the crank flange dowelled. The flywheel is actually clamped on the head of the bolt not on the shank of the bolt (there is side-to-side play), so three dowels 120° apart should do the job. The end of the crank is soft (unlike the crank journals) and easy to drill.

Also see: Harmonic Balancer

For 7000+ rpm use have the flywheel doweled
7372.jpgAlbum 7372

A10 Flywheel

A10 engine flywheel is lighter than A12 flywheel, so will not smooth out the power pulses as well.

On the other hand it has less mass, so aids acceleration. You can lighten the A12 flywheel (by machining) or use the already light A10 flywheel (after machining). Unfortunately the A10 flywheel requires machining to use with an A12.

160 mm clutch area (vs 180mm for all other A-engines)
26653.jpgAlbum 26653

* Machine step out of the A10 surface
* Drill new holes for the larger clutch
* Use a longer Release Bearing Sleeve
  Some say you can shim it

See main forum discussion

FWD

Front-wheel-drive flywheel from E10 Cherry/120A, F10 Cherry/F-II or N10 (310/Pulsar) is smaller diameter and the clutch fits down inside the FWD flywheel.

13801.jpgAlbum 13801 13802.jpgAlbum 13802 13803.jpgAlbum 13803

Interchangeability with Datsun 1200: none

Part Numbers

* 12310-18001 ASS'Y-FLYWHEEL B10
* 12310-18002 ASS'Y-FLYWHEEL B10 (from E/# A10-87871)
* 12310-H1000 FLYWHEEL ASS'Y A12, A12S, A12A, A13S
* 12310-H6200 ASSY-FLYWHEEL A13
* 12310-H7200 FLYWHEEL ASS'Y A14 -7909
* 12310-H7201 FLYWHEEL ASS'Y A14 7910-8010
* 12310-H8900 FLYWHEEL ASS'Y V A14S, A15 8011-
* 12310-H8910 FLYWHEEL ASS'Y A14S, A15 8011-
BOLTS - See Flywheel Bolts
* 12313-10600 DOWEL (3) all A-series A10-A15
* 12312-18000 GEAR-ring, flywheel A10/A12/A14
* 12312-18010 GEAR-ring, flywheel A14S 8110-
BUSHING-pilot: see Pilot Bushing
The flywheel "Assembly" includes these parts:
* 12312 GEAR-ring, flywheel
* 12313 DOWEL-flywheel

RockAuto.com

ATP ZA543 Flywheel Ring Gear $22.79
* Outer Diameter=10.655"
* Inner Diameter 9.451"
* Pitch=10/12 Width=.400"
* Teeth=105
* Chamfer=FRONT #1231218000

VW Conversion

9259.jpgAlbum 9259 9260.jpgAlbum 9260

MT conversion

9372.jpgAlbum 9372

Aluminum Flywheel

16767.jpgAlbum 16767 16768.jpgAlbum 16768 14582.jpgAlbum 14582 

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