Front Engine Parts, Counterweights, Pulleys

Return to Main Engine Parts Page

Front Engine Assembly
See images above/below	Description	All-85	86-92	93-95
(1)	Thrust Plate	11-5040-1011	11-5040-1011	11-D520-N390
(2)	Thrust Bearing	11-505B-0813	11-505B-0813	11-D540-NF01
(2)	Thrust Bearing (competition)	78-1840-0822	78-1840-0822	xxx
(3)	End Spacers	(see chart below)
(4)	Bearing Plate	11-5010-1011	11-5010-1011	11-D510-N3H1
(5)	Thrust Washer	11-5070-1011	11-5070-1011	11-D530-NF01
(6)	Oil Pump Drive Gear	11-551A-0839	11-D750-N326	11-D750-N326
(7)	Drive Gear	11-5310-0839	11-5310-0839	11-5310-0839
.....	Key Way (front)	60-5710-9923	60-5710-9923	60-5710-9923
....	Key Way (rear/flywheel)	11-7050-0820	11-7050-0820	11-7050-0820
(8)	Front Pulley Bolt Washer	22-8000-9956	22-8000-9956	Not Used
(9)	Front Pulley Bolt	11-611B-0820	11-420B-N318	11-4060-N3C1
	Description	All-85	86-92	93-95
(10)	Front Bolt "O-ring"	not used	10-1105-9954	10-1105-9954
(11)	Front Eccentric Thermostat	not used	11-D150-N326	11-D150-N326
Replacement for above thermostat, if you choose to not use it			11-PLUG (for 86-95)
(12)	Eccentric Thermostat Spring	not used	11-D170-N326	11-D170-N326
......	Oil Pump Gear	14-141A-0839	14-1430-N326	14-1430-N326
.....	Oil Pump Chain	14-1420-0839	14-1510-N326	14-1510-N326

Important note on counterweights: The front and rear (or flywheel) counterweights PLUS the rotors make a balanced assembly. The years / rotors we list in the following charts are for PRODUCTION years of the rotors / counterweights! A lot of mixing can be done when building engines, providing the rotors and counterweights match. By this we mean 89-92 non-turbo rotors (lighter weight, higher compression) can be used in an 84-85 13B engine as long as the matching front and rear counterweights are used also, for instance.

Balancing of the assembly is normally not needed, as long as the components are matched.

Front Counterweights
Engine/Rotors	Year/Rotors	Part Number
12A	76-80	No Longer Available New- call to ask for used part
	81-82	No Longer Available New- call to ask for used part
	83-85	11-511A-N226
13B	74-85	11-5110-N304
	86-88	11-D61A-N326
	89-92	11-D610-N350
	93-95 A/T	11-D610-N3A8
	93-95 M/T	11-D610-N3A7

Eccentric and Alternator Pulleys
These are "underdrive" pulleys - meaning the water pump and alternator will turn slower. This reduces horsepower loss from the drag of those units, and reduces the chance of water pump cavitation at higher rpm's.
Pulley	Part Number	Image
Single Belt Eccentric Pulley 3.25" OD	11473
Dual Belt Alternator Pulley 3" OD Fits all Mazda RX Alternators -92	11479
Dual Belt Alternator Pulley 2 5/16" OD Fits 93-95 Alternator when swapped into an earlier car.	11480-V Silver
	11480-VP Purple
	11480-VB Blue
74-92 Underdrive Eccentric Pulley 4" OD Timing marks at -10 (ATDC) 0, 10 (BTDC) and 20 (BTDC)	11469
Single Belt Eccentric Pulley 3.5" OD 6 Bolt 5mm x.8 (same as 10-32) This does not fit any other pulleys we know of.	01-7201-0000
Single Belt Alternator Pulley Larger diameter than stock pulley. Slows down alternator for racing purposes.	78-153A-0833
Water Pump Pulley 5" OD Slows down water pump for racing applications Fits 79-85 water pumps	01-7211-0000
Water Pump Pulley 5" OD Slows down water pump for racing applications Fits 86-88 water pumps	01-7212-0000
Water Pump Pulley 5" OD Slows down water pump for racing applications Fits 89-92 water pumps	01-7213-0000
Note: If you have removed the air pump, the remaining belt does not wrap very far around the water pump pulley. This lack of belt contact area area can lead to slippage of the water pump at high rpm's/high load conditions. The "high load" can be caused by the fan itself, or by the fan clutch being too stiff and/or frozen. We strongly recommend using at least the dual belt alternator pulley to double the water pump pulley belt contact area.
Please read FAQ at:Front Pulley / Thrust Bearings to help prevent problems when changing front pully.

Stock OEM have the "counterweight" built into the flywheels. The rear counterweights listed here are needed when using aftermarket light flywheels that bolt to the counterweight. All of our light flywheels are supplied with the correct counterweight to match the engine you are using.
See our FAQ Identifying Flywheels if you are not sure what year of flywheel you have.

Rear Counterweights
Engine/Rotors	Year/Rotors	Part Number
12A	79-82	11-751A-1883
	83-85	No Longer Available
13B	76-85	11-751A-1029
	86-88	11-521A-N327
	89-95	11-5210-N351
You may want to read our FAQ on Identifying Rear Counterweights
All Rotary - Flywheel Nut		11-711C-0810

Front Cover Gaskets and "O" Ring / Sealing Washer
It is mandatory that you read our: '86-92 "O-Ring Problem" FAQ Page
	Front Cover Gasket 74-85 and Some 86-92 (For O-ring only type) For 86-92, Do not order without reading FAQ above!!	10-5020-N2Y0
	Front Cover Gasket (For O-ring AND Teflon Seal type) Do not order without reading FAQ above!!	10-5020-N386
	Front Cover Gasket (93-95)	10-5020-N3A1
	0Front Cover Gasket (13B-RE) This metal gasket works on all front covers. Upper most bolt hole on the right side will not be utilized on some front covers.	10-5020-N390
	Front Cover O-ring (All)	10-1740-N231
	White Nylon/Teflon sealing washer that goes around the O-ring (Be sure you have read the FAQ)	10-C150-N326

Engine Front Covers
Year & Engine	Part Number	Generic Pictures
79-85 12A	No Longer Available
84-85 13B GSLSE	10-A600-N304
86-88 NON-TURBO	No Longer Available
86-88 TURBO	No Longer Available
93-95	10-500B-N3A1
RX-8	10-500G-N3H1

Dowel Pins - 4 used in each engine	12A	10-111B-0839
	13B	10-1110-1757

Tension Bolts
	12A	Long	10-452A-1015
		Short	10-451B-1015
	13B	Long	10-E520-N326
		Short	10-E510-N326
		Long Ribbed	10-E61A-N350
		Short Ribbed	10-E51B-N350
		Seal for any of the above tension bolts (each) 74-95	10-4550-0839

Main Engine Parts Page