A-series Engine Swaps

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Revision as of 07:59, 14 May 2011

A-series Nissan Engines

The A14 and A15 engines are "tall deck" engines, and are 3/4 inch higher than A12s. However, they fit in the 1200 with only minor changes. This also applies to the 1974 A13 engine. The A14 and A15 are by far the most popular swapping candidates since the bigger displacement of the A14 and A15 means both more power (peak HP) and more low-speed power (torque) than the A12, A13 or A12A. Remember: "There is no replacement for displacement" (aka "theres no substitute for cubic inches").

Swap Factors

These factors are different when swapping:

• 1967-1973 motor mounts vs 1974-up mounts
• increased deck height raises exhaust pipe
• and 3-bolt vs 2-bolt exhaust flange
• A14 & A15 call for stronger transmission
• Call for stronger differential than 1967-1974 H145 type

A14 GX Engine

A15 Engine deck

A15 Engine (left side)

Like all 1974-up engines. the A14/A15 have the motor mount bosses in a different place compared to the 1971-1973 A12 engines. So the engine mounts are a bit different. This photos illustrates the difference:

Stock left-side mount in Datsun 1200, but Newer A12 engine. A better way is to move the brackets on the engine, to get the engine lower. You could also 1) use the 1974-up ute crossmember or 2) modify the crossmember.

Engine Mounts

The easiest thing to do is use a matching set:

• Late Engine
• Late Engine mounting brackets
• Late Crossmember

Or the complete set of early items if swapping an early engine into a later 1200. For more details and comparison photos, see Engine Mounts.

Early vs Late Engine crossmembers

Late Engine onto Early Crossmember

When fitting a 1974-or-newer engine into an orginal Datsun 1200, and using the original crossmber, modifications to the engine mount brackets are needed.

There is no need modify the crossmember, although that can be done. It is easy to modify the brackets.

Left Side Mount Location

Left Side (manifold side) of A-series engine

• Engine mount bolt bosses were moved back about 2" on the late blocks
• Front rubber mount fitted with roll stopper, to prevent excessive engine roll
• Rear rubber mount (transmission mount) fitted with roll stopper, which helps prevent engine from moving forward in an accident

Remove this Late LH bracket:

And fit one of these Late RH brackets to the LH side:

The mounts are also about 1" (30mm) further back. So drill two holes in a flat plate and mount it like this:

Lastly, since the mount is now up too high, slot the bolt holes for the engine bracket, and slide the mount up then tighten. This will lower the engine about 12cm (1/2 inch).

Right Side Mount

Right side (spark-plug/oil pump/starter side) engine mount bracket is practically the same Late vs Early.

Two types of right-side brackets:

The only thing you might need to do is Measure engine installed angle and if you need to lower it a little bit, slot the bracket bolt holes (where it bolts to the engine) slow you can mount it slightly higher.

Discussions and Details

The simplest way to fit the motor mounts is a flat plate:

However, this makes the engine sit about an inch too high. You could slot the bolt holes in the engine bracket so it will slide up an inch to level the engine.

• cheater_5 wrote up a detailed conversion here: Cheaters a15 into 1200 conversion
• An A14 installation Mildman undertook has been quite significantly detailed at the following web link: Mildman's A14 Installation
• There is also a technical article at the datsun1200.com site that discusses this installation too: Datsun1200.com Tech Section

HB210

B210 with A14 engine pan changed to mid-sump (USA B210 only). So if swapping this engine in, swap the pan and pickup tube with the newer B310 A14 unit (or, perhaps the A12 pan will fit).

Questions

• What's Better? A14 or A15?
• But isn't the A15 stroke to long to rev high?
• Isn't the rods too short in the A14?

For answers, see: Engine Swaps, section "A-series Nissan Engines"