Crankshaft

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Category: Engine Mechanical

---

Revision as of 01:07, 1 January 2015 ddgonzal (Talk | contribs) (->Counterweighted Cranks) <- Previous diff		Current revision ddgonzal (Talk | contribs) (->Identification - moved most A14 photos to A14 article)
Line 1:		Line 1:
-	The crankshaft is interchangeable between early A12, A12GX, late A12, late A13 and A12A. Only the flywheel bolts differ, after [[A-series_Engine_Changes#1974|1974]] using metric bolts.	+	{{BackTo|Engine}}
		+
		+	The crankshaft is interchangeable between early A12, A12GX, late A12, late A13 and A12A. Only the flywheel bolts differ, using metric bolts starting with the [[A-series_Engine_Changes#1974|A-engine Redesign]].
	= Overview =		= Overview =
-	Stroke comes in four sizes:	+	{{Album|17133}}
-	* 70mm (2.76 in.) stroke: A12/A12A/A13(1980)	+
-	* 77mm (3.03 in.) stroke: A13(1974)/A14	+
-	* 82mm (3.23 in.) stroke: A15	+
-	[http://datsun1200.com/modules/myalbum/photo.php?lid=17133 http://datsun1200.com/modules/myalbum/photos/thumbs/17133.jpg]	+	All Datsun A-series crankshafts are forged, and stroke comes in four sizes:
		+
		+	* 70mm (2.76 in.) stroke: A12/A12A/A13(1980)
		+	* 77mm (3.03 in.) stroke: A13(1974)/A14
		+	* 82mm (3.23 in.) stroke: A15
		+
		+	Crankshaft Stroke:
		+	<br>{{Photo|14241.jpg}}
		+
		+	Bare crank
		+	<br>{{Album|30408}}
		+
		+	Timing Chain sprocket fits over the snout
		+	<br>{{Album|30409}}
	= Flywheel Bolts =		= Flywheel Bolts =
-	* 1966-1973: crank uses english-system 3/8" x 24 UNF bolts	+	The flywheel bolts are special washerless bolts, do not use generic bolts.
-	** 12315-18000 BOLT-flywheel & drive plate 6 A10	+
-	** 12315-H1001 BOLT-FLY WHEEL 6 A12 MANUAL	+	Buy at [[Bprojects]]
-	** Will ARP 206-2802 work? For BMC A-series engines (UHL Under Head Length 0.900") $18 USD/set of 6	+	<br>{{Album|26245}}
		+
		+	* 3/8 inch bolts: 1966-1973 crank uses Imperial system 3/8" x 24 UNF bolts
		+	* 10mm bolts: 1974-up crank uses Metric M10 1.25 bolts (from '73-7)
		+
		+	12315-H1001 BOLT-FLY WHEEL 6 B110 MANUAL $4.38
		+	12315-H1000 BOLT-FLY WHEEL 6 B110 AUTOMATIC $3.51
		+	12330-20300 PILOT-CONVERTER B110 AUTOMATIC $18.66
		+	12333-20300 PLATE-CRANK CONVERTER B110 AUTOMATIC $9.44
		+
		+	Hex head: 14 mm
		+	Thread length: 20mm
		+	Head bottom length: 22mm
		+	Whole length: 29mm
		+
		+	1966-1973: crank uses english-system 3/8" x 24 UNF bolts
		+	* 12315-18001 BOLT-flywheel & drive plate 6 A10 (requires washers)
		+	** {{Ref|12314-18001|}} WASHER-flywheel for A10 only
		+	** {{Ref|12314-18002|}} WASHER-flywheel (from engine # A10-87871)
		+	* 12315-H1001 BOLT-FLYWHEEL 6 MANUAL (3/8", uses no washers)
		+	* ARP bolts - buy at [[Bprojects]]
		+	* Will [[ARP]] 206-2802 work? For BMC A-series engines
		+	(UHL Under Head Length 0.900") $18 USD/set of 6
		+	* [[Flywheel#High_Strength_Bolts|Pitroad-ARP bolts]]
		+
		+	1974-up: crank uses Metric M10 x 1.25 bolts (from '73-7)
		+	* A12,A13,A14,A12A,A15
		+	* 12315-H6900 BOLT-FLYWHEEL 6 (10mm) $4.83 USD > 12315-H6200
		+	* Will ARP 203-2802 work? For 4AGE engines
		+	(UHL Under Head Length 1.050") $22 USD/set of 8
		+
		+	26 Washer for A10 flywheel bolts only (6 needed)
		+	<br>{{Album|26242}}
		+	Imperial flywheel bolts - heads unmarked
		+	<br>{{Album|26244}}
-	* 1974-up: crank uses Metric M10 1.25 bolts (from '73-7)	+	'62' bolts for metric cranks
-	** A12,A13,A14,A12A,A15	+	<br>{{Album|26243}} {{Album|23498}}
-	** 12315-H6900 BOLT-FLYWHEEL 6 $4.83 USD	+
-	** replaced 12315-H6200	+
-	** Will ARP 203-2802 work? For 4AGE engines (UHL Under Head Length 1.050") $22 USD/set of 8	+
	= Misc =		= Misc =
	Also see: [[Bored And Stroked]] for crankshaft modifications you can perform at home.		Also see: [[Bored And Stroked]] for crankshaft modifications you can perform at home.
		+	* Twin-carb engine ([[Hitachi Twin Carb|A12GX, A12T and A14T]]) crankshafts are the same as a standard engines.
		+
		+	* 1974-up cranks use metric flywheel bolts. Early engines used British threads. See [[A Engine Redesign]]
	Apparently there are two forgings of crankshaft:		Apparently there are two forgings of crankshaft:
-	* Heavy duty
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=18244 http://datsun1200.com/uploads/thumbs/18244.jpg]
-	* Light weight: thinner straight sided counterweights that also have small scallops out of them. Late model factory crank (from B310 Sunny)
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=17135 http://datsun1200.com/uploads/thumbs/17135.jpg]
-	* Twin-carb engine ([[Hitachi Twin Carb|A12GX, A12T and A14T]]) crankshafts are the same as a standard engines.	+	Heavy duty
		+	<br>{{Album|18244}}
-	* 1974-up cranks use metric flywheel bolts. Early engines used British threads. See [[A Engine Redesign]]	+	Light weight: thinner counterweights that also have small scallops out of them. Late model factory crank (from B310 Sunny)
-	* Front bolt, that holds the front pulley on, is:	+	<br>{{Album|17135}}
-	** Part Number: 12309-78200 ($4.58)	+
-	** M16 x 1.50 (fine) pitch	+	Front bolt, that holds the front pulley on, is:
-	** 15mm diameter	+	* Part Number: 12309-78200 ($4.58)
-	** 27mm long	+	* M16 x 1.50 (fine) pitch
-	** The head is ?mm hex and about 15 mm thick.	+	* 15mm diameter
-	** Torque specification: 15-16 kg/m (108-116 ft. lb.)	+	* 27mm long
		+	* The head is ?mm hex and about 15 mm thick.
		+	* Torque specification: 15-16 kg/m (108-116 ft. lb.)
	= Identification =		= Identification =
-	* A12	+	A12: 70mm H50 & H10 straight crank throws
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=18244 http://datsun1200.com/modules/myalbum/photos/thumbs/18244.jpg]	+	<br>{{Album|18244}}
		+	A12/[[New_A13|A13]] H85 70mm scalloped crank throws
		+	<br>{{Album|17135}}
-	* A13 low deck, 70mm 9.51 kg scalloped crank throws	+	[[A14]] 77mm H62 1973-1978 straight crank throws
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=17135 http://datsun1200.com/modules/myalbum/photos/thumbs/17135.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=17136 http://datsun1200.com/modules/myalbum/photos/thumbs/17136.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=18243 http://datsun1200.com/modules/myalbum/photos/thumbs/18243.jpg]	+	<br>{{Photo|A14CrankshaftH6240.jpg|Datsun%201200/wiki}} {{Photo|A14Crankshaft1.jpg|Datsun%201200/wiki}}
-	* A14, scalloped crank throws (H8940)	+	{{Main|A14 Crankshaft}}
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=3949 http://datsun1200.com/modules/myalbum/photos/thumbs/3950.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=3949 http://datsun1200.com/modules/myalbum/photos/thumbs/3950.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=14241 http://datsun1200.com/modules/myalbum/photos/thumbs/14241.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=14535 http://datsun1200.com/modules/myalbum/photos/thumbs/14535.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=17137 http://datsun1200.com/modules/myalbum/photos/thumbs/17137.jpg]	+
-	* A14	+	A14 77mm H89 scalloped crank throws 1979-
-	*: [http://datsun1200.com/modules/myalbum/photo.php?lid=8966 http://datsun1200.com/modules/myalbum/photos/thumbs/8966.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=8967 http://datsun1200.com/modules/myalbum/photos/thumbs/8967.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=11418 http://datsun1200.com/modules/myalbum/photos/thumbs/11418.jpg]	+	<br>{{Album|14241}} {{Photo|H89-crank.jpg|Datsun%201200/wiki}}
		+	[[A15]] 12200-G3400 MT, 12200-H9700 AT
		+	<br>{{Photo|A15crank-1.jpg|Datsun%201200/wiki}} {{Photo|A15crank-2.jpg|Datsun%201200/wiki}}
-	[http://datsun1200.com/modules/myalbum/photo.php?lid=6110 http://datsun1200.com/modules/myalbum/photos/thumbs/6110.jpg]	+	== H10 ==
		+	A12 70mm H50 & H10
		+	12200-H1000/12200-H1001 -7909
		+	12200-H5000/12200-H5001
		+	{{Album|18244}} {{Photo|crank.jpg|Datsun%201200/wiki}}
		+
		+	{{PB2.|ff245|chrislyons8||Crankshaft1.jpg}} {{PB2.|ff245|chrislyons8||Crankshaft2.jpg}} {{PB2.|ff245|chrislyons8||Crankshaft3.jpg}}
		+
		+	== H85 ==
		+	A12/A13 70mm scalloped crank throws (9.51 kg) lightweight but strong
		+
		+	12200-H8560/12200-H8500 7910- > (can replace) 12200-H5001
		+	{{Album|17135}}
		+
		+	{{Album|18243}} {{AlbumH|17136|jpg|300}}
	= Crankshaft Pulley =		= Crankshaft Pulley =
-	See [[Crankshaft Pulley]]	+	{{Main|Crankshaft Pulley}}
		+
		+	{{Album!|20598}}
	= Lightened Crankshaft =		= Lightened Crankshaft =
-	Discussion: [http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=37775&forum=1 JTS Cranks]	+	Discussion: [{{Post|234575}} JTS Cranks]
-	[http://datsun1200.com/modules/myalbum/photo.php?lid=5538 http://datsun1200.com/modules/myalbum/photos/thumbs/5538.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=7306 http://datsun1200.com/modules/myalbum/photos/thumbs/7306.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=8478 http://datsun1200.com/modules/myalbum/photos/thumbs/8478.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=8479 http://datsun1200.com/modules/myalbum/photos/thumbs/8479.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=8617 http://datsun1200.com/modules/myalbum/photos/thumbs/8617.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=9665 http://datsun1200.com/modules/myalbum/photos/thumbs/9665.jpg]	+	Race-prepped cranks are often:
		+	* Relieved/polished to reduce chance of cracking
		+	* Lightened for quicker acceleration
		+	* Knife-edge for reduced windage friction
		+
		+	Race-prepped A-series crank:
		+	<br>{{Album|7306}} {{Album|19814}} {{Album|5538}} {{Album|8478}} {{Album|8479}} {{Album|8617}} {{Album|9665}}
		+
		+	A12 crank lightened & edged
		+	<br>{{PB2|ff245|chrislyons8|Red%20B10|3.jpg}}
	A14 knife-edged		A14 knife-edged
-	<br>[http://i297.photobucket.com/albums/mm219/ddgonzal/Datsun%201200/wiki/A14_crank-1.jpg http://i297.photobucket.com/albums/mm219/ddgonzal/Datsun%201200/wiki/th_A14_crank-1.jpg] [http://i297.photobucket.com/albums/mm219/ddgonzal/Datsun%201200/wiki/A14_crank-2.jpg http://i297.photobucket.com/albums/mm219/ddgonzal/Datsun%201200/wiki/th_A14_crank-2.jpg]	+	<br>{{Photo|A14_crank-1.jpg|Datsun%201200/wiki}} {{Photo|A14_crank-2.jpg|Datsun%201200/wiki}}
	= Counterweighted Cranks =		= Counterweighted Cranks =
	All A-series crankshafts are counterweighted and will rev smoothly to 8500+ RPM.		All A-series crankshafts are counterweighted and will rev smoothly to 8500+ RPM.
-	Here is [http://datsun1200.com/modules/newbb/viewtopic.php?post_id=130357#forumpost130357 the difference] between counterweighted and "fully counterweighted" (L/Z cranks shown):	+	Stock crank is counterweighted: there are four counterweights, one for each crank throw:
-	<br><img size=400>http://i85.photobucket.com/albums/k45/b120dat/Picture175.jpg</img>	+	<br>{{Album|17133}}
-	Fully counterweighted means each journal has it's own counterweights. Theoretically it means better torsional vibration control.	+	A12 "fully" counterweighted billet {{web|www.pitroad-ts.com/A-parts-2/engine/crankshaft-full.htm|Pitroad A12 Crankshaft}}
		+	<br>{{ExtPhoto|http://www.pitroad-ts.com/A-parts/engine|a12crank-2.jpg}}
		+
		+	Fully counterweighted means each journal has two counterweights. Theoretically it means better torsional vibration control. A regular counterweighted crank accelerates faster and has less friction, so a heavier fully counterweighted crank should only be used where torsion vibration is a known problem.
		+
		+	Here is the difference between counterweighted and "fully counterweighted" (L/Z cranks shown): [{{Post|130357}} Lseries Power Time]
		+	<br>{{PB2.|k45|b120dat||Picture175.jpg}}
	Either way, both types of Datsun cranks are precision balanced from the factory.		Either way, both types of Datsun cranks are precision balanced from the factory.
-	[http://datsun1200.com/modules/myalbum/photo.php?lid=17133 A15 crank] is fully counterweighted: there are four counterweights, one for each crank throw.	+	<blockquote>Smaller counterweights == smaller crankcase</blockquote>
-	<br><img size=400>http://datsun1200.com/modules/myalbum/photos/17133.jpg</img>	+
-	In comparison, the E16 crank has two counterweights per crank throw, which helps reduce the overall diameter of the crank.	+	The E16 crank has a much larger stroke, so it uses two counterweights per crank throw, which helps reduce the overall diameter of the crank.
-	<br>Smaller counterweights == smaller crankcase.	+
-	A12 full counter Billet [http://www.pitroad-ts.com/A-parts-2/engine/crankshaft-full.htm Pitroad A12 Crankshaft]
-	<br><img size=400>http://www.pitroad-ts.com/A-parts/engine/a12crank-2.jpg</img>
	<blockquote>Of full counter crank benefits advantageous to the vibration reduction high-speed and high output, disadvantage weight increase and manufacturing cost. Crankshaft for race for achieving both the lightweight and stiffness UP is		<blockquote>Of full counter crank benefits advantageous to the vibration reduction high-speed and high output, disadvantage weight increase and manufacturing cost. Crankshaft for race for achieving both the lightweight and stiffness UP is
	<br>		<br>
	<br>[downside] 800 g weight increase</blockquote>		<br>[downside] 800 g weight increase</blockquote>
		+
		+	{{Album|23985}} {{Album|23984}}
	= Seals =		= Seals =
		+	{{Main|Crankshaft Seal}}
-	== Rear Main Seal ==	+	= Oil Thrower =
-	=== Installation ===	+	The thrower (oil slinger) goes over the front snout of the crank, after the [[Timing Chain]] set is placed, and before the [[Timing Cover]] is installed/
-	12279-H2301 Rear Main Seal	+
-	[http://i297.photobucket.com/albums/mm219/ddgonzal/sightings/forum/Rear_main_seal.jpg http://i297.photobucket.com/albums/mm219/ddgonzal/sightings/forum/th_Rear_main_seal.jpg]	+
-	Also apply sealant here	+	The slinger's job is to keep oil away from the crankshaft oil seal. The cupped side faces the timing chain to "throw" oil back towards the chain.
-	[http://i297.photobucket.com/albums/mm219/ddgonzal/sightings/forum/Main_bearing_cap_sealant.jpg http://i297.photobucket.com/albums/mm219/ddgonzal/sightings/forum/th_Main_bearing_cap_sealant.jpg]	+
-	=== Removal ===	+	{{searchPart|12302-18000}} THROWER-OIL CRANKSHAFT 1 A12 - $1.57
-	# Remove oil pan	+	<br>{{Album|28574}} {{Album|28575}}
-	# Remove rear main bearing	+
-	# Lift out old seal	+
		+	timing chain sprocket and OIL THROWER. The curved side goes toward the block, flat side toward the front.
		+	<br>{{Album|30407}}
-	If replacing the rear main seal when changing a clutch, you may remove it with the oil pan still in place:	+	= Specs =
-	# Puncture seal with an awl, tiny screwdriver, or similar implement. Punch through the eddge of the seal, by gently tapping through with hammer	+	from {{1973SM}} <i>Figure EM-58 Crankshaft</i>
-	# Carefully pry out slightly and work your way around the circumference until free	+	Main journal diameter 49.951-49.964 mm
		+	Main journal width 27.00-27.05 mm
		+	crankpin diameter 44.961-44.974 mm
	= Part Numbers =		= Part Numbers =
		+	12200-H5000 CRANKSHAFT A12
	12200-H8500 CRANKSHAFT ASSY B310 A12S, A13S		12200-H8500 CRANKSHAFT ASSY B310 A12S, A13S
	12200-H8515 A12/A12A CRANKSHAFT 70mm/2.76" stroke		12200-H8515 A12/A12A CRANKSHAFT 70mm/2.76" stroke
Line 128:		Line 206:
	BEARINGS		BEARINGS
-	* See main article: [[Bearings]]	+	{{Main|Bearings}}
	SEAL, Front		SEAL, Front
-	13042-18000 SEAL-OIL CRANKSHAFT FRONT 1 A12 - superceded	+	{{Main|Crankshaft Seal}}
-	13510-H1000 SEAL-OIL CRANKSHAFT FRONT (NOK) 1 A12 0271- 2 13042-18000 $7.24	+
-	[http://www.rockauto.com/catalog/x,carcode,1208483,parttype,5604 RockAuto]	+
-	* National 223830	+
-	* Beck/Arnley 0521989	+
-	Specs	+
-	* Shaft size: 38 mm	+
-	* Housing bore: 55 mm	+
-	* Outer diameter: 55.3 mm	+
-	* Width: 7 mm	+
	SEAL, Rear		SEAL, Rear
-	12279-18000 SEAL-OIL CRANKSHAFT REAR 1 A12 - $81.18	+	{{Main|Crankshaft Seal}}
-	12279-18010 SEAL-OIL CRANKSHAFT REAR (NDK) 1 A12 0271- 2 12279-18000 NLA	+
-	12279-H2301	+
-	* supercedes 12279-H1000 SEAL-OIL CRANKSHAFT REAR (NOK) 1 A12 0271- $81.18	+
-	12279-H2311 NDK make	+
-		+
-	12279-H2301 is for all A12/A14/A14 engines.	+
-	Seal specifications	+
-	* Shaft Size 60 mm	+
-	* Housing Bore 82 mm	+
-	* Outer Diameter 82.2 mm	+
-	* Width 12 mm	+
-	[http://www.rockauto.com/catalog/x,carcode,1208483,parttype,5604 aftermarket RockAuto]	+
-	* Fel-Pro BS27493	+
-	* National 712006	+
-	* Corteco/Detroit Gasket 17209	+
	PILOT BUSHING		PILOT BUSHING
-	* see [[Pilot Bushing]]	+	{{Main|Pilot Bushing}}
		+
		+	OIL SLINGER: see [[#Oil Thrower]]
		+
		+	FLYWHEEL BOLTS: see [[#Flywheel Bolts]]
		+
		+	= Damage =
		+	== Flywheel Loosening ==
		+	The Datsun factory balanced every engine. But when parts are changed, it will get out of balance. In worst case scenario, this leads to shaking and eventual loosening of the [[flywheel]] bolts.
		+
		+	<blockquote>I started to hear a hell of a noise and shaking under acceleration and reving ... the flywheel bolts have given up the ghost.</blockquote>
		+
		+	For best practices, see [[#Flywheel Bolts]].
		+
		+	[[{{Post|395579}} Flywheel bolts failure\fix\questions]
		+	<br>{{Album|24122}} {{Album|24123}} {{Album|24124}}
		+
		+	== Cracked Crank ==
		+	All A-series crankshafts are forged, but can still crack if abused.
-	SLINGER	+	Causes:
-	12302-18000 THROWER-OIL CRANKSHAFT 1 A12 - $1.57	+	* Dropping the crank during or before engine assembly
		+	* Unbalanced engine. After replacing a piston, a rod or the crank, have the engine re-balanced
		+	* [[Pinging]] (detonation) can put massive stresses on the engine
-	FLYWHEEL BOLTS	+	The thick forging line can be seen in this photo
-	12315-H1001 BOLT-FLY WHEEL 6 A12 MANUAL - $4.38	+	<br>{{AlbumH|19917|jpg|318}} {{Album|19916}}
-	12315-H1000 BOLT-FLY WHEEL 6 A12 AUTOMATIC - $3.51	+
-	12330-20300 PILOT-CONVERTER 1 A12 AUTOMATIC - $18.66	+
-	12333-20300 PLATE-CRANK CONVERTER 1 A12 AUTOMATIC - $9.44	+
-	[[Category:Engine Mechanical]]	+	[[Category:Engine Mechanical]]{{End}}

---

Current revision

<-- back to Engine

The crankshaft is interchangeable between early A12, A12GX, late A12, late A13 and A12A. Only the flywheel bolts differ, using metric bolts starting with the A-engine Redesign.

Contents 1 Overview 2 Flywheel Bolts 3 Misc 4 Identification 4.1 H10 4.2 H85 5 Crankshaft Pulley 6 Lightened Crankshaft 7 Counterweighted Cranks 8 Seals 9 Oil Thrower 10 Specs 11 Part Numbers 12 Damage 12.1 Flywheel Loosening 12.2 Cracked Crank

Overview

Album 17133

All Datsun A-series crankshafts are forged, and stroke comes in four sizes:

* 70mm (2.76 in.) stroke: A12/A12A/A13(1980)
* 77mm (3.03 in.) stroke: A13(1974)/A14
* 82mm (3.23 in.) stroke: A15 

Crankshaft Stroke:

Bare crank
Album 30408

Timing Chain sprocket fits over the snout
Album 30409

Flywheel Bolts

The flywheel bolts are special washerless bolts, do not use generic bolts.

Buy at Bprojects
Album 26245

* 3/8 inch bolts: 1966-1973 crank uses Imperial system 3/8" x 24 UNF bolts
* 10mm bolts: 1974-up crank uses Metric M10 1.25 bolts (from '73-7)

12315-H1001 BOLT-FLY WHEEL 6 B110 MANUAL $4.38 
12315-H1000 BOLT-FLY WHEEL 6 B110 AUTOMATIC $3.51 
12330-20300 PILOT-CONVERTER B110 AUTOMATIC $18.66 
12333-20300 PLATE-CRANK CONVERTER B110 AUTOMATIC $9.44

Hex head: 14 mm
Thread length: 20mm
Head bottom length: 22mm
Whole length: 29mm

1966-1973: crank uses english-system 3/8" x 24 UNF bolts 
* 12315-18001 BOLT-flywheel & drive plate 6 A10 (requires washers)
** 12314-18001 WASHER-flywheel for A10 only
** 12314-18002 WASHER-flywheel (from engine # A10-87871)
* 12315-H1001 BOLT-FLYWHEEL 6 MANUAL (3/8", uses no washers)
* ARP bolts - buy at Bprojects
* Will ARP 206-2802 work? For BMC A-series engines
  (UHL Under Head Length 0.900") $18 USD/set of 6
* Pitroad-ARP bolts

1974-up: crank uses Metric M10 x 1.25 bolts (from '73-7)
* A12,A13,A14,A12A,A15
* 12315-H6900 BOLT-FLYWHEEL 6 (10mm) $4.83 USD > 12315-H6200
* Will ARP 203-2802 work? For 4AGE engines 
  (UHL Under Head Length 1.050") $22 USD/set of 8

26 Washer for A10 flywheel bolts only (6 needed)
Album 26242

Imperial flywheel bolts - heads unmarked
Album 26244

'62' bolts for metric cranks
Album 26243 Album 23498

Misc

Also see: Bored And Stroked for crankshaft modifications you can perform at home.

• Twin-carb engine (A12GX, A12T and A14T) crankshafts are the same as a standard engines.

• 1974-up cranks use metric flywheel bolts. Early engines used British threads. See A Engine Redesign

Apparently there are two forgings of crankshaft:

Heavy duty
Album 18244

Light weight: thinner counterweights that also have small scallops out of them. Late model factory crank (from B310 Sunny)
Album 17135

Front bolt, that holds the front pulley on, is: 
* Part Number: 12309-78200 ($4.58) 
* M16 x 1.50 (fine) pitch 
* 15mm diameter 
* 27mm long 
* The head is ?mm hex and about 15 mm thick. 
* Torque specification: 15-16 kg/m (108-116 ft. lb.)

Identification

A12: 70mm H50 & H10 straight crank throws
Album 18244

A12/A13 H85 70mm scalloped crank throws
Album 17135

A14 77mm H62 1973-1978 straight crank throws

A14 77mm H89 scalloped crank throws 1979-
Album 14241

A15 12200-G3400 MT, 12200-H9700 AT

H10

A12 70mm H50 & H10

12200-H1000/12200-H1001 -7909
12200-H5000/12200-H5001

Album 18244

H85

A12/A13 70mm scalloped crank throws (9.51 kg) lightweight but strong

12200-H8560/12200-H8500 7910- > (can replace) 12200-H5001

Album 17135

Album 18243 Album 17136

Crankshaft Pulley

Lightened Crankshaft

Discussion: ^POST JTS Cranks

Race-prepped cranks are often:

• Relieved/polished to reduce chance of cracking
• Lightened for quicker acceleration
• Knife-edge for reduced windage friction

Race-prepped A-series crank:
Album 7306 Album 19814 Album 5538 Album 8478 Album 8479 Album 8617 Album 9665

A12 crank lightened & edged

A14 knife-edged

Counterweighted Cranks

All A-series crankshafts are counterweighted and will rev smoothly to 8500+ RPM.

Stock crank is counterweighted: there are four counterweights, one for each crank throw:
Album 17133

A12 "fully" counterweighted billet Pitroad A12 Crankshaft☁
☁

Fully counterweighted means each journal has two counterweights. Theoretically it means better torsional vibration control. A regular counterweighted crank accelerates faster and has less friction, so a heavier fully counterweighted crank should only be used where torsion vibration is a known problem.

Here is the difference between counterweighted and "fully counterweighted" (L/Z cranks shown): ^POST Lseries Power Time

Either way, both types of Datsun cranks are precision balanced from the factory.

Smaller counterweights == smaller crankcase

The E16 crank has a much larger stroke, so it uses two counterweights per crank throw, which helps reduce the overall diameter of the crank.

Of full counter crank benefits advantageous to the vibration reduction high-speed and high output, disadvantage weight increase and manufacturing cost. Crankshaft for race for achieving both the lightweight and stiffness UP is

[downside] 800 g weight increase

Album 23985 Album 23984

Seals

Oil Thrower

The thrower (oil slinger) goes over the front snout of the crank, after the Timing Chain set is placed, and before the Timing Cover is installed/

The slinger's job is to keep oil away from the crankshaft oil seal. The cupped side faces the timing chain to "throw" oil back towards the chain.

12302-18000ᴳ THROWER-OIL CRANKSHAFT 1 A12 - $1.57
Album 28574 Album 28575

timing chain sprocket and OIL THROWER. The curved side goes toward the block, flat side toward the front.
Album 30407

Specs

from 1973 Datsun 1200 Service Manual Figure EM-58 Crankshaft
Main journal diameter  49.951-49.964 mm
Main journal width     27.00-27.05 mm
crankpin diameter      44.961-44.974 mm

Part Numbers

12200-H5000 CRANKSHAFT A12
12200-H8500 CRANKSHAFT ASSY B310 A12S, A13S 
12200-H8515 A12/A12A CRANKSHAFT 70mm/2.76" stroke
12200-H5720 A12 COMPETITION CRANKSHAFT 70mm/2.76" stroke
12200-H8915 A13/A14 CRANKSHAFT 77mm/3.03" stroke
* Weight 26.2 lbs
12200-G3400 A15 CRANKSHAFT 82mm/3.23" stroke

Old Numbers:
12200-H1000 ASSY-CRANKSHAFT 1 A12 MANUAL - $624.02 
12200-H1001 CRANKSHAFT 1 A12 -671 12 12200-H1000 superceded 
12200-H1000 CRANKSHAFT 1 A12 0671- 2 12200-H1001 superceded 
12200-H5000 CRANKSHAFT 1 A12 0572- 2 12200-H1000 $624.02 

BEARINGS

SEAL, Front

SEAL, Rear

PILOT BUSHING 

OIL SLINGER: see #Oil Thrower

FLYWHEEL BOLTS: see #Flywheel Bolts

Damage

Flywheel Loosening

The Datsun factory balanced every engine. But when parts are changed, it will get out of balance. In worst case scenario, this leads to shaking and eventual loosening of the flywheel bolts.

I started to hear a hell of a noise and shaking under acceleration and reving ... the flywheel bolts have given up the ghost.

For best practices, see #Flywheel Bolts.

[^POST Flywheel bolts failure\fix\questions
Album 24122 Album 24123 Album 24124

Cracked Crank

All A-series crankshafts are forged, but can still crack if abused.

Causes:

• Dropping the crank during or before engine assembly
• Unbalanced engine. After replacing a piston, a rod or the crank, have the engine re-balanced
• Pinging (detonation) can put massive stresses on the engine

The thick forging line can be seen in this photo
Album 19917 Album 19916 

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