Datsun 240Z L24 Front/Timing Cover Hardware Sizes and Specs

As said in How to Rebuild your NISSAN/DATSUN OHC Engine — a very often recommended book for good reason — it seems like the Nissan engineers attempted to come up with as many different unique bolt sizes as possible. Couple that with the fact that some auxiliary hardware that was optional across even one engine (potentially related to optional air conditioning), these bolts are truly different sizes across the board.

If you’re following that book as I did, the author instructs to keep the bolts in one bag. I would advise against that. This is one of the most important components for which you need to keep your bolts perfectly well organized. Take the extra time to tag/bag each bolt and note where it came from. I have included a chart for you to use that I will refer to in this article moving forward.

Apologies for the odd lettering scheme — I had to switch things around and then avoid confusing myself! Here is a chart with the sizes for these, some caveats for installation, and the torque specs. The sizes are approximate when it comes to length, but should be accurate within a millimeter.

M6 bolts get torqued to 2.9 – 7.2 ft-lb (0.4 – 1.0 kg-m) and M8 bolts get torqued to 7.2 – 12 ft-lb (1.0 – 1.6 kg-m).

BoltName (if applicable)SizeHex SizeHardware NotesTorque to:
T1Left Cylinder Head to Front Cover BoltM6 x 1.0 x 19mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
T2Right Cylinder Head to Front Cover BoltM6 x 1.0. x 19mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
AM8 x 1.25 x 80mm (25mm of threads)13mmIncludes a Lock Washer and Regular Washer, Secures Alternator Bracket 7.2 – 12 ft-lb
BM8 x 1.25 x 95mm (25mm of threads)13mmIncludes a Lock Washer and Large Spacer* 7.2 – 12 ft-lb
CM6 x 1.0 x 41mm (22mm of threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
DM8 x 1.25 x 45mm (23mm of threads)13mmIncludes a Lock Washer and Regular Washer 7.2 – 12 ft-lb
EM8 x 1.25 x 83mm (25mm of threads)13mmIncludes a Lock Washer 7.2 – 12 ft-lb
FTop Timing Indicator Tab BoltM6 x 1.0 x 19mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
GBottom Timing Indicator Tab Bolt M6 x 1.0 x 19mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
HM6 x 1.0 x 21mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
IM6 x 1.0 x 21mm (full threads)10mmIncludes a Lock Washer 2.9 – 7.2 ft-lb
* When I disassembled the engine, there was a large spacer, approximately 12mm thick. I would assume that this left optionality for some form of bracket or other hardware that would support something optional like air conditioning. Without this, and this allowing the 95mm bolt to fit somewhere, I actually couldn’t find a way to insert these bolts that made sense. If anyone has a better explanation for this, please email me at [email protected].

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