Oil cap
The stock Datsun 1200 Rocker cover uses a push-and-twist oil cap. It is a classic all-chrome cap and seals with a simple round gasket. Some other Datsuns use a threaded cap that will not work in a 1200. By the way, this is where you add oil to the engine.
Overview
All A-series engine rocker covers uses a cam-twist (push-and-turn) oil filler cap.
Datsun 1000 vented cap Datsun 1200 sealed cap
- All A-series engines from 1970-on use a sealed cap including all A12/A13/A14 and A15
- Other Datsun engine types use a threaded cap that will not work in a 1200
- Alloy rocker covers invariably use a different type of oil cap
Original
The original 1200 cap Part Number is Nissan 15255-15953. However if you order this part number you are likely to get one of the superseded styles instead of the plain silver version.
The timeless style of the original B110 cap looks good with customized engines
1200 from intro to 1978 March (Japan) or to circa 1973 (USA) * superseded by #B34 'NISSAN MOTOR OIL' cap 15255-15953 CAP-OIL FILLER 15270-11200 PACKING-OIL FILLER CAP
2-3/4" Oil Filler Cap (1-13/32" x 1-19/64" Cam Twist) RockAuto.com * STANT Part # 10102 * GATES Part # 31088 
* NOT BECK/ARNLEY Part # 0160048 screw-in cap (fits L-series)
Aluminum Version
Machined aluminum version of original 1200 style oil cap
VENDOR: Bprojects Product: Billet Hollow Oil Filler Cap RAW☁ Aluminum A6063 Hollow structure, very lightweight 100g
May be finished with Elephant applique from Bprojects
Or a Nissan applique
Color varieties from Bprojects
Datsun 1000
The earliest A-series engine, the B10 Datsun 1000 A10 engine, uses a vented oil cap, so it doesn't work with the 1200 (Datsun 1200 caps are sealed). Vented cap is also known as a "blowby cap" because fumes will come out of it -- visibly so when the engine is worn. 1200 uses a sealed cap for happy motoring.
USED BY * R16 engine (Datsun Roadster) * J13 engine (Bluebird 411, Datsun Trucks 521, 620) * H engine (Datsun Roadster?)
Datsun 1000 used one of three varieties of oil cap
* plain blue * plain blue with Nissan text overlay applied * Elephant cap
The regular 1000 oil cap is plain blue with a little arrow sticker.
Datsun B10 Elephant Cap was used in some markets. Apparently the elephant oil cap is a JDM OPTION cap
15255-10651 CAP-oil filler (op.) ALL
Subtle difference between original and repro caps. The cap on the right has no arrow:
The following is reportedly from 1000 coupe brochure, but looks very much like an A12. Did they make an updated A10, or is this a prototype Elephant Oil cap for an A12?
B10 Japan 15255-15852 CAP-oil filler <> 15255-15853 15255-15853 CAP-oil filler (from E/E A10-1550971) 15255-10651 CAP-oil filler (？？地仕様) (op.) ALL 15270-11200 PACKING-oil filler cap
Nissan
Later Nissan replacement caps differ stylistically from the original but work on all 1200 engines.
B34
Circa 1973 they updated the cap by putting writing on it, and used it for the USA market. Japan did not switch over until April 1978. This replaced the #original plain silver cap.
15255-B3430 CAP-OIL FILLER $12.12 * supersedes 15255-15853/15255-15903/5255-15952/15255-15953 * A-series engine, R16, J13, E-series Engine 15270-B3400ᴳ PACKING-OIL FILLER CAP $1.40
ニッサン モーター オイルを NISSAN MOTOR OIL 注入して下さい
For Nissan Motor Oil Fill Occasionally
1980s
1980s Nissan stamped-steel cap
1990s
The 80s cap was eventually replaced with a stylish sculpted version
G82
I bought a brand new oil cap last year from Nissan Parts Business (Japan) for about $15 USD. It was the gold finish kind. The original plain silver type has been replaced by the gold type.
15255-G8250 - latest version drops the text in favor of an international oil symbol
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