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[Datsun 1200 encyclopedia]

A-series Engine Swaps

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Categories: Engine Modifications | Engine Swaps

Revision as of 05:38, 12 September 2018
ddgonzal (Talk | contribs)
(->Swap Factors)
<- Previous diff
Current revision
racer135 (Talk | contribs)
(->Exhaust Pipe)
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* A14/A15 calls for stronger transmission. The late 1200 56A type is good, the smooth 60A is more ideal though * A14/A15 calls for stronger transmission. The late 1200 56A type is good, the smooth 60A is more ideal though
* A15 needs stronger differential than 1967-1974 [[H145]] type * A15 needs stronger differential than 1967-1974 [[H145]] type
 +* Legalities. Some states in Australia have a displacement limit for swaps (eg, more than 20% larger displacement requires certification) In that case, A14 can be swapped into 1200 as it is within 20% more displacement, but A15 requires certification as it has a 20% larger displacement. Using the A15 crank/rods/pistons in the A14 block gives you a legal 'A15' swap without needing certification.
= Exhaust Pipe = = Exhaust Pipe =
-A14/A15 use a 3-bolt exhaust flange. Datsun 1200 uses a 2-bolt exhaust pipe. So get a short section of the exhaust pipe, and have it welded to your exhaust system. Add 3/4" length so the pipe fits in the same location. If you don't have the pipe, any exhaust shop can fabricate the correct part. +The regular Datsun 1200 uses a 2-bolt exhaust pipe. A14/A15 use a 3-bolt exhaust flange. A12GX and A15E use a dual-outlet flange.
 + 
 +Tall deck engines (eg, tall deck A13/14/15) are ~20mm or 3/4" taller than their short decked counterparts (eg, A12)
 + 
 +So get a short section of the exhaust pipe, and have it welded to your exhaust system. Add 3/4" length so the pipe fits in the same location. If you don't have the pipe, any exhaust shop can fabricate the correct part.
{{Album|22852}} {{Album|22852}}
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<br>{{Album|22851}} <br>{{Album|22851}}
- +A15E [[EGI]] engine uses a twin outlet manifold similar to the A12GX/A12T, so a flange and merge setup will need to be sourced or fabricated similar to above to suit that setup
-Some models of A14/A15 (eg, A14E EGI) have a twin outlet manifold similar to the A12GX/A12T, so a flange and merge setup will need to be sourced or fabricated similar to above to suit that setup (tech wiki search for 'exhaust manifold')+<br>{{Album|4084}}
= Transmission = = Transmission =

Current revision

The A14 and A15 engines fit in the 1200 with only minor changes. 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 engine. Remember: "theres no substitute for cubic inches".

Contents

Overview

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. As they say, "There is no replacement for displacement".

A12: 68 hp, 70 lb ft torque
A14: 80 hp, 77-83 torque
A15: 80 hp

A15 in 1200
1409.jpgAlbum 1409

Note that there are 65 HP A14s and A15s too. While less powerful than an A12, they still have more torque so will be an improvement for easy driving. You can identify these by the ID plate in the engine compartment (with HP figures) or by noting if the intake manifold is round-port. Only the oval port engines are 80HP. Additionally, all 1981 and later engines are less than 80HP.

The A14 and A15 engines are "tall deck" engines, and are 3/4 inch higher than A12. However, they fit in the 1200 with a change to the exhaust pipe due to the height. This also applies to the 1974 A13 engine.

With later 1200s (1974 and newer), newer engines bolt right in. With original 1970-1973 1200s, simple changes to the motor mounts will allow the newer A12, A14 or A15 to fit in.

17994.jpgAlbum 17994

Swap Factors

Take these factors into account when swapping:

  • 1967-1973 motor mounts vs 1974-up mounts. Simple adapters can be used.
  • increased deck height of A14/A15 raises exhaust pipe (ditto for the 1974 A13 engine)
  • 3-bolt vs 2-bolt and single outlet vs twin outlet exhaust flange
  • A14/A15 calls for stronger transmission. The late 1200 56A type is good, the smooth 60A is more ideal though
  • A15 needs stronger differential than 1967-1974 H145 type
  • Legalities. Some states in Australia have a displacement limit for swaps (eg, more than 20% larger displacement requires certification) In that case, A14 can be swapped into 1200 as it is within 20% more displacement, but A15 requires certification as it has a 20% larger displacement. Using the A15 crank/rods/pistons in the A14 block gives you a legal 'A15' swap without needing certification.

Exhaust Pipe

The regular Datsun 1200 uses a 2-bolt exhaust pipe. A14/A15 use a 3-bolt exhaust flange. A12GX and A15E use a dual-outlet flange.

Tall deck engines (eg, tall deck A13/14/15) are ~20mm or 3/4" taller than their short decked counterparts (eg, A12)

So get a short section of the exhaust pipe, and have it welded to your exhaust system. Add 3/4" length so the pipe fits in the same location. If you don't have the pipe, any exhaust shop can fabricate the correct part.

22852.jpgAlbum 22852

Exhaust Pipe: The section of pipe between the manifold and the muffler

Tri-bolt exhaust pipe
SAM_0269.jpg 22143.jpgAlbum 22143

Also See: Exhaust Manifold#Gasket

Cut this portion of the exhaust pipe off an A14/A15 vehicle, weld to the 1200 exhaust pipe
22851.jpgAlbum 22851

A15E EGI engine uses a twin outlet manifold similar to the A12GX/A12T, so a flange and merge setup will need to be sourced or fabricated similar to above to suit that setup
4084.jpgAlbum 4084

Transmission

If upgrading a 1970-1972 Datsun 1200 to an A14 or A15, use the stronger 4-speed that comes with the A14 or A15. It is a bolt-in replacement. Be sure to get the matching set: Flywheel, clutch release sleeeve, engine plate and transmission. See Gearbox Swap Notes.

The early 1200 4-speed will work fine with an A14 if you drive it smoothly. But the A15 has a bit to much torque to be reliable. It may work for a long time, but it may give out. Chipped teeth is the normal problem.

If your 1200 already has the 56A 4-speed it is strong enough for an A15.

Peek under the car, on the right side of the gearbox for the letter 56A and you are golden:
21400.jpgAlbum 21400

Or in this area (56A late ute super strong):
1680.jpgAlbum 1680

Differential

The stock H145 from a Datsun 1200 coupe/sedan/wagon is not rated for the torque of an A14 or A15. It can handle the horsepower, but not the torque.

  • An A14 or low-torque A15 will be OK in front of an H145. A15 after 1981 is low torque.
  • While some club members have had their H145 last behind an A15, many have had it break. It is the ring & pinion gears (CWP) that break, not the axles.

For upgrades you can either: 1) Fit an H150 diff center into your 1200 housing. See H150 center swap or 2) Swap an entire rear axle assembly into your 1200. See Rear Axle Swaps.

Engine Location

It is important to get the new engine in the same location as the original, so that the original driveshaft fits properly. (You can locate the engine further back if you want to customize the driveshaft.)

A14/A15 engine mounts are 35 mm further back in location than early (B110) A12. If you locate the engine like this, it will be in the correct spot
1779.jpgAlbum 1779

Note that late A12 (1974 and up) use exactly the same mounts as A14/A14.

Engine setback is approximately 2-1/2 inches from firewall to back of rocker cover
23550.jpgAlbum 23550

Engine Mounts

A14/A15 bolts directly into newer 1200 (1974 & newer utes).

When fitting to older 1200s, the easiest thing to do is use simple flat plates to adapt the motor.

The most elegant way is to swap crossmembers. If you can find the right crossmember. For example: 1975 A12 with 1974-up crossmember. Or 1972 A12 with 1970-1973 crossmember.

1974-up engines (including all A14/A15 engines) 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:
1779.jpgAlbum 1779
Stock left-side mount in Datsun 1200, but Newer A12 engine. All it needs is a simple flat plate with two holes drilled in it.
26378.pngAlbum 26378

Alternatively, you could 1) use the 1974-up 1200 crossmember or 2) modify the crossmember or 3) modify the engine brackets.

Crossmember Swap

Be sure to get a matched set:

  • Late Engine + Late Engine mounting brackets + Late Engine Crossmember

OR

  • Early Engine + Early Engine mounting brackets + Early Engine Crossmember

Early engines are 1967-1973, and late engines are 1974-up.

Swap the crossmember? Swapping crossmembers is fairly easy. There are two bolts on each side, plus the LCA bushing mount. But you don't have to swap crossmembers -- it's just one way of doing it. Perhaps the most elegant way. See Changing Crossmember.

23609.jpgAlbum 23609 20925.jpgAlbum 20925 20924.jpgAlbum 20924

Early vs Late Engine crossmembers
8487.jpgAlbum 8487

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: change to 1974 and newer blocks: Engine mount bolt bosses were moved back 35mm (1-3/8") on the late blocks.

154 mm: Early block front face to center of mount
19179.jpgAlbum click to view

189 mm: Revised block front face to center of mount
6109.jpgAlbum click to view

1. Remove this Late LH bracket, and discard
2564.jpgAlbum 2564

2. Obtain a duplicate late RH bracket, and then fit it to the LH side. Old A12 brackets won't fit, but new A12/A14/A15 brackets will:
20923.jpgAlbum 20923 B210 vs B310 Right Bracket
Which is best for this swap?

3. The new mounts are 35mm (1-3/8") further back. So drill two holes in a flat plate and mount it like this:
1779.jpgAlbum 1779

If the engine is centered and the plate holes drilled correctly, it will fit straight as above.

If the engine is not centered, the plate can be skewed:
Photo-0283-1.jpg

There are three different RH mounts, some allow the engine to sit higher or lower than the others. If the mount is now up too high, slot the bolt holes for the engine bracket, and slide the mount up on the block the thickness of the plate, then tighten. This will lower the engine a bit.

RH engine mount brackets (old) 55mm bolt center (new) 50 mm bolt center
Lower bolt is 5mm higher on new engine, so mounts actually bolt at the same level.
23553.jpgAlbum 23553

Perhaps a 3mm difference.
23552.jpgAlbum 23552

Alternatively, you can put the mount on the last accessory boss, which is 26mm (1") farther forward than early blocks. With this choice, you will need to redrill the lower hole on the engine mount bracket, 8mm over. And you will still need to slot the mounts and use a flat plate. Nothing gained, but it takes a little more work this way.

Alternative mount location
6109_.jpgAlbum click to view

Re-drill the lower bracket hole, and re-drill the crossmember horn hole 26mm farther forward (no plate needed). Rubber sits to one side of horn. Aircon cannot be used with this choice, as the bolt boss is for the A/C compressor.
209.jpgAlbum 209

Right Side Mount

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

2563.jpgAlbum 2563

Two types of right-side brackets: B210 vs B310 Right Bracket
20923.jpgAlbum 20923

end result with flat plate
1779.jpgAlbum 1779

The only thing you might need to do is Measure engine installed angle and if you need to lower it a little bit:

  • try the other RH side bracket (not sure which one is best), OR
  • slot the bracket bolt holes (where it bolts to the engine) so you can bolt it slightly higher on the block

Custom Brackets

For the cleanest look, instead of using adaper plates, you may cut and re-weld the brackets so they fit just so. You can fabricate the LH and RH brackets to have the 35mm offset and be a bit lower.

8131.jpgAlbum 8131

210.JPGAlbum 210 21058.jpgAlbum 21058 21059.jpgAlbum 21059 21060.jpgAlbum 21060 21061.jpgAlbum 21061 21062.jpgAlbum 21062 21063.jpgAlbum 21063 21064.jpgAlbum 21064 21065.jpgAlbum 21065

Discussions and Details

The simplest way to fit the motor mounts is a flat plate:
26378.pngAlbum 26378

Photo-0283-1.jpg

If you use the correct engine bracket it will be very close to level, maybe about 4mm higher.

Three different Right Side engine brackets. Which is best for a swap?
20945.jpgAlbum 20945

Early Engine onto Late Crossmember

To fit an early (1970-1973) engine into a later 1200, you can either swap crossmembers, OR just use simple adapter plates on each side as explained below.

Use Newer Mounts

Or use newer engine mounts? You can modify the engine mount brackets to fit an early A12 engine (GX, anyone?) into your later 1200. The only trick is to drill a flat plate to bridge the 35mm difference in back-to-front location.

  1. Use Datsun 1200 RH mount
  2. Use 120Y A12 or B210 A14, or any B310 LH mount with a longer bolt
  3. Drill two holes in 4mm flat plates

4mm thick plates. The mount bracket overlaps the insulator so it is partially supported by it -- in other words, it is plenty strong and doesn't stress the rubber insulator.

Right Side
23572.jpgAlbum 23572

Left Side
23573.jpgAlbum 23573

Use the B110 lower radiator hose to clear the alternator. The new A12 places the alternator on the other side of the engine compared to the original A12. You'll also need to extend the alternator wires to go to the other side. 23597.jpgAlbum 23597

Right Mount Bracket

The original A12 RH bracket is very similar to the newer bracket -- but the newer RH bracket doesn't fit the original A12 engine. So use the RH bracket that matches the engine.

Left Mount Bracket

On the LH side, use a LH engine bracket from a late engine. The newer LH bracket will match the newer or older LH crossmember horn. The height is perfect and no adjustment is needed.

Old A12 uses stepped bracket (upper boss is set back). To fit New A12 bracket, remove the stud and use a longer stud, or a bolt.
23554.jpgAlbum 23554

To fit the new A12 bracket, use 19mm worth of washers and a longer bolt or stud. Bolt centers are the same for the original A12 stepped bracket and the revised A12 flat bracket, so it fits just right
23555.jpgAlbum 23555

Swap Notes

  • 1200 wiring will reach either Distributor (under #1 or under #3)
  • Alternator fits on opposites sides. Late engines have right-side alternator.
    • Can refit alternator to other side, but not necessary
    • use extension wires to reach across (Ground, Battery, and FN/LS wires). Be sure to use the same thickness (gauge) wire as original.
    • Newer engine may have an alternator marked S-L. If so, simple wiring mods can be done.
  • Radiator hoses are different for the original 1200 low-mount alternator.

Datsun 1000

When fitting an A12 into Datsun 1000, use 3mm spacer on the engine mounts so that the deeper pan will clear the 1000 crossmember. Reference: POST 1000 vs 1200 oil pans

174_57a000cf5cbb0.jpgPost 480296 174_57a000efe74f3.jpgPost 480296

When fitting late A-series (1974-up) you can unpick the crossmember uprights, then weld on the late-model uprights
16210.jpgAlbum 16210 16211.jpgAlbum 16211 16209.jpgAlbum 16209 16208.jpgAlbum 16208

HB210

North American B210 came with A14 fitted with mid-sump engine pan.

  • if swapping this HB210 engine into 1200, swap the pan and pickup tube with the newer B310 A14 pan and pickup tube.
  • If swapping an engine into a North America B210, see B210 Engine Swaps#North America

B310

B310 fits all A-series engines from 1974 on. There is no bolt-in crossmember for the early A-series engine.

B310-crossmember-3.jpg B310-crossmember-1.jpg B310-crossmember-2.jpg

Questions

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

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

¤