From Datsun 1200 Wiki

Datsun 1200's A12 engine uses a roller chain-driven camshaft. The camshaft is located on the right side of the engine block, and drives the valves via pushrods and rocker arms. The camshaft also drives the Oil pump and distributor. Camshafts are physically different starting with 1974 model year engines, because the newer engines have the distributor in a different location.

Replacement camshafts don't have to come from Nissan. You can get them from most cam grinders.

Also see: Camshaft replacement

Table of contents

1 Cam Interchange 2 Valve Timing Specifications 3 New Camshaft Break-in 4 Installation 4.1 Timing 1 Adjustable Cam Gear 2 Part Numbers 2.1 Nissan Competition Parts 3 Parts Suppliers

Cam Interchange

Datsun A10 & 1200 engines, with the distributor at the front, use a single drive gear to drive both the oil pump as well as the distributor.

From 1974 ALL Datsun A series engines used a second drive gear as the distributor was now re-located back where the earlier fuel pump once was.

Strict interchange

• 1966-1973 cams interchange
• 1974-up cams interchange

Loose Interchange

• Late cam [two gears] = can be used in all engines, but conditions apply for early blocks
• Early cam [one gear] = Can be used only in early engines, if you want to use a standard type distributor ignition system.

You can use the later cam in the earlier block as long as you block off the fuel pump mounting & run a different pump [electric?], but if you wish to use the distributor in a later engine, then the earlier cam will not work as you get a fuel pump eccentric instead of a drive gear at that point.

Valve Timing Specifications

Also see: A12GX Engine

Here are the specs used in the standard B110 camshaft (from 1973 USA factory manual):

• Exhaust open duration: 248 degrees
• Intake open duration: 248 degrees
• Intake opens at: 14 degrees BTDC
• Intake closes at: 54 degrees ABDC
• Exhaust opens at: 56 degrees BBDC
• Exhaust closes at: 12 degrees ATDC

NOTE: It is unclear at which valve lift specifications this is measured at. So be wary of comparing other camshaft specs.

• Lift: ???

B = before

A = after

TDC = Top Dead Center

New Camshaft Break-in

• Discussion:

IMPORTANT

• Always use new lifters with a new or rebuilt camshaft
• Coat the cam lobes with break-in lube
• When you first start the motor, run it at 2000rpm for 20 minutes to break in the cam. Set the timing as best you can, fill the carbs with gasoline THEN start the motor and don't shut it down for minor leaks or problems until the 20 minutes are up. Otherwise the camshaft will soon wear out from improper break-in.

Installation

Go to the public library and check out a Repair manual. You can either get a 1200-specific book or one of those that covers many kinds of cars -- they all have timing chain installation information.

Timing

 (http://datsun1200.com/modules/myalbum/photo.php?lid=5767)  (http://datsun1200.com/modules/myalbum/photo.php?lid=16844)

1. Make sure engine front pulley is on the mark (0 or Top)

   

   When lined up, the engine will be at TDC or BDC

2. Check distributor to confirm TDC -- if the rotor is not pointing at spark lead #1, rotate the engine 1/2 turn to line up the mark again
3. Install the pulleys and chain such that the cam dowl hole lines up with the key groove

NOTE: Only for first-time install will the "match marks" line up. Once the engine is rotated, or if double-checking previous work, the match marks *will not* line up. This doesn't indicate a problem as the match marks are only used when putting the chain on, just check that the centers line up.

Be very careful, even if off by one tooth the engine won't work exactly right. If it doesn't look perfect, re-do it. If you are careful, you can tell if it is a tooth off, or not. Use a level or a t-square or some other precision straightedge as an tool to make sure they line up -- exactly.

For a competition camshaft, use the manufacturer's recommended procedure, usually something like this:

 (http://datsun1200.com/modules/myalbum/photo.php?lid=3639)

Adjustable Cam Gear

Fitting an adjustable Camshaft gear lets you fine tune the timing. The cam vendor's recommendations are usually best, but retarding the cam a degree or two will generall shift the torque curve higher up in the RPM range. Advancing the cam will (usually) lower the power curve a few RPM. Adjustable gears come in a few basic kinds:

• Multi-key. Rollmaster had one with nine adjustible keys in the crank sprocket
• Multi-hole. Using different holes
• Variable: Slotted holes allow a continuously variable range

 (http://datsun1200.com/modules/myalbum/photo.php?lid=682) Tomei  (http://datsun1200.com/modules/myalbum/photo.php?lid=3639)  (http://datsun1200.com/modules/myalbum/photo.php?lid=3640)

 (http://datsun1200.com/modules/myalbum/photo.php?lid=7339) Rollermaster

Part Numbers

LIFTER-VALVE

13231-H1000 A12
13231-H1001 1970-1983 A12, A14, A15 

B110 ASSY-CAMSHAFT

13001-H1000 USA, JDM
13001-H2300 GX
13001-H7000 USA 0772- °13001-H2300

This indicates USA models starting June 1972 have the GX cam fitted.

B10 ASSY-CAMSHAFT

13001-18000
13001-H0100

B120

13001-H5000 A12S JDM 7510-

B210 ASSY-CAMSHAFT

13001-H5000 A12S JDM
13001-H5700 A12T, A14T JDM
13001-H6200 A13 USA, A14S JDM, USA, Datsun F10 USA

B310

13001-H5000 A12A 0879-0780 USA, CAN ALL, A12S,A13S JDM
13001-H9800 A12A 0880- USA °13001-H5000
13001-H6200 A14,A15 -0780 USA, N10 A14S USA
13001-H9800 A14,A15 0880- USA °13001-H6200
13001-H5700 A14E,A15E JDM
13001-H6200 A14S,A15S JDM, N10 A15S USA

• Crane cams for the A-series engines. No Longer Available. Part# F-22/280-2-10-NC. This cam has [In] .420" and [Ex] .441" of lift.

Also see:

• Pushrods
• Roller rockers
• Rocker arms

Nissan Competition Parts

CAMSHAFTS & RELATED COMPONENTS (A-SERIES)

PART NO. DESCRIPTION QTY REQ.

• 13001-H2300 GX CAMSHAFT (.331"/256°)
  • For use in A-series engines built up to 6/73. Requires only new lifters for installation. 1
• 13001-H5700 GX CAMSHAFT (.331 "/256°)
  • For use in A-series engines built from 7/73. Requires only new lifters for installation. 1
• 99996-H1031 ELECTRAMOTIVE RACE CAMSHAFT #1 .468"/300°
  • cam is ground on 104° lobe centers. Requires use of competition valve springs, retainers and new 13231-78201 lifters. 1
• 99996-H1032 ELECTRAMOTIVE RACE CAMSHAFT #2
  • Except for 310° duration all specifications and installation requirements are the same as 99996-H1031. 1
• 13001-H5741 CAMSHAFT BILLET 1
• 13231-H1001 STOCK CAM FOLLOWER
  • New lifters must be used with any new cam installation. 8
• 13231-MO821 LIGHTWEIGHT CAM FOLLOWER
  • A high-performance alternative to the stock unit. 24 grams lighter than 13231-H1001. 8
• 13231-78201 OVERSIZE CAM FOLLOWER
  • Required when installing either of the Electra-motive race camshafts. 8
• 13203-H2300 GX VALVE SPRING/OUTER 8
• 13204-H2301 GX VALVE SPRING/INNER 8
• 13203-M0820 HIGH-PERFORMANCE VALVE SPRING/INNER 8
• 99996-H1132 COMPETITION VALVE SPRING
  • This inner and outer spring assy should have an installed height of 1.61" and a seat pressure of 130 lbs/in. Requires the use of 99996-H1131. 8
• 99996-H1131 ALUMINUM VALVE SPRING RETAINER
  • Requires use of 99996-H1132. 8

Reference: 1984 Nissan Competition catalog

Parts Suppliers

See: Parts Sources for current details and contact information for these vendors.

• Tomei: lifters, cams, sprockets, etc
• Iskenderian - legendary California hot rod Cam Grinder - mperdue has an Isky cam (http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=22314&forum=1)
• Crane: cams, springs, lifters
• Datrats
• APT
• Malvern Racing
• Yella Terra, roller pushrods