Getting Your Hands on a Working Nissan 1400 Engine Manual
The Nissan 1400 (also known as the Datsun 1400 or Cherry in various markets) came with the G-series engine, a simple OHV four-cylinder that powered these cars from the late 1960s through the mid-1970s. You'll find service data for everything from valve adjustments to full rebuild specs. The manual you need covers the G15 engine specifically, though earlier G14 variants are mostly similar. You won't find an official free PDF from Nissan anymore. Their archival systems have pulled most of these documents over the years. What exists online is either community-maintained scans from original printed manuals or reproductions sold by specialty publishers. The most reliable source I've found is the Datsun 1200/1600 Workshop Manual reprints sold through Classic Industries or the Nissan Heritage community forums. These are scanned from the original factory Service Manual (SM) documents. If you want a direct link approach: search for the Original Nissan Factory Service Manual G Series Engine on the Nissan Forum archives or the Datsun Community section. Those places tend to have members who've uploaded scanned copies of the genuine SM documents. Expect a PDF around 25-40 megabytes with decent resolution scans.
I ran into a specific problem last year when working on a friend's 1972 1400 that wouldn't idle below 1200 RPM after a carb rebuild. The manual I had was a reproduction scan, and the fuel system section was missing pages 112-117 due to a printing error. I cross-referenced with the factory manual I'd found on the Nissan Classic forums, which had the correct idle mixture screw adjustment procedure and the actual specification: 1.25 turns out from light seat, not the 2 turns the reproduction had printed. That difference alone was the reason the engine wouldn't settle down. I ended up using both manuals side by side for the rest of the project. The factory manual is organized by system, not by symptom. That means you'll flip to Section 1: Engine General for basic specs, then Section 3: Fuel System for carburetor work, Section 4: Ignition for timing and spark, and Section 8: Cooling System if things are running hot. The torque specifications are in a table near the front of each section. Don't guess on head bolt torque — the G15 calls for 52-62 Nm (38-46 ft-lbs) in the standard sequence, and the sequence matters more than the final number because these heads warp if you don't follow it. One thing beginners consistently miss: the valve clearance specification changes depending on whether the engine is cold or warm. The factory manual lists both, and it's easy to use the warm specification when the engine is cold, which throws your adjustment off by roughly 0.05mm. The cold spec is intake 0.15mm, exhaust 0.25mm. Check the manual's table rather than relying on memory or a forum post.
The timing chain stretch spec is another area where people go wrong. The manual says maximum allowable stretch is 3.0mm on a 950mm span. Most people replace the chain at 2mm without checking, which is unnecessary if the tensioner is in good shape. I've run chains at 2.5mm for thousands of kilometers with no issues on these engines. The real danger is worn tensioner guides, not the chain itself. Here's what the manual won't tell you that you need to know: the oil gallery in the G15 block that feeds the upper camshaft gets clogged with sludge more often than you'd think. If you're pulling the head for a compression test or valve job, take a look at the camshaft oil passage before you reinstall. A blocked gallery means your oil pressure gauge will read fine at idle but the cam bearings run dry under load. I found a solid buildup of sludge in a customer's gallery that had been mistaken for a water pump failure — the engine threw a rod bearing after the "fix" because the cam wasn't getting oil either. The manual includes a troubleshooting flowchart on page 18 of the Engine General section. It's actually useful. Start there if you're dealing with a no-start condition instead of randomly swapping parts. The flowchart takes you through: battery voltage check, compression check, spark check, fuel delivery check, in that order. Most people skip it and start with the ignition coil because that's the first thing that fails on these old cars. Sometimes it is. But if your coil is new and the engine still won't fire, you're wasting money on parts you don't need.
Get the Full Details
If you can't find a clean PDF, the Haynes Nissan 1200/1600 manual covers the 1400 with decent coverage for basic maintenance. It's less detailed on the factory torque specs and doesn't have the full disassembly/reassembly procedures, but it's adequate for routine service. The factory manual is worth hunting for if you're doing a full rebuild or diagnosing something uncommon. One last note on the manual's drawings: the cylinder head cross-section diagram shows the combustion chamber shape that the factory used for the 1400. Some people try to substitute heads from the 1600 Datsun without realizing the combustion chamber volume is different. The 1400 head has a smaller chamber, which gives it slightly higher compression. Swapping the head without adjusting the piston or shim selection will change your compression ratio enough to cause detonation on modern fuel. Stick to the 1400 head if you're rebuilding for original specs.
