Datsun Steel Crank Mod. into Ford Kent Page
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I set this page up as I get asked a lot of questions about this topic. I have now lost count on the number of Datsun crankshafts I've modified, , and custom flywheels I've made. I Know I haven't hit tripple figures yet!. These are now in a variety of cars, Escorts, Lotus Sevens, Sylvia Strikers, Single seater etc. Fitting of Datsun cranks into Ford Kent pushrod based engines has been very popular here in New Zealand for a number of years. It has also been done in Australia and South Africa. Bob Homewood told me about this alternative when the crank in my Escort Twin Cam was cracked, and all susbequent Ford/Lotus cranks subsquently found were cracked too !!.  Since then I have modified Datsun cranks to suit Lotus Twin Cams, Ford/Cosworth BDAs, and 1600 Ford Crossflows. All L16 and L18 Datsun cranks are made from a factory steel forging. It is but it is certainly a tough steel as it gives the carbide cutting tools a very hard time when being machined. These cranks are an inexpensive alternative to UK sourced  steel cranks, not as strong ultimately but certainly far stronger than the OE Ford cast iron cranks.

First step is to find a suitable crank. For Ford 1500cc precrossflow blocked engines using standadrd 72.75mm stroke then a crank from a Datsun 1600 (L16) is required (73.3mm stroke). For Ford 1600 crossflow engines using a standard stroke of 77.62mm then a crank from a Datsun 180B (L18) is required (78.0mm stroke). A Datsun 200B 2lt (L20B) can also be made to fit into a Ford 1600 crossflow blocked DOHC engine, such as the Twin Cam or BDA. The longer stroke crank (86mm) requires a lot more machining. Also the block requires some machining to allow clearance for the rods.  I've gotten it to work on a dummy build using a 'Cosworth' type rod . However Isuzu Gemini rods have been suggested as an alternative. Rod to stroke ratio is important, so the longer the rod the better.

Why do it? - Is it economical for you?, or worth the bother?. Tthe Dasun crank provides an affordable steel crank compared to the more expensive purpose made UK cranks. Access to the neccesssary machinery to modify the crank keeps costs down. I only pay for grinding and balancing  Datsun cranks do have different counterbalancing compared to the Ford and Lotus items. Miles Wilkin's quotes BRM as having modified standard cranks by adding more counter balance weight. This is a topic in itself. Personally I think the OE Ford and Lotus cast iron cranks are built too light with a flywheel that is far too heavy (standard Ford 1600 Xflow flywheel weighs 10kg). I believe the heavy flywheel on the light crank causes them to crack. Having said this it could be argued that the Datsun crank has overweight counter weights. For this reason I feel happy to machine down the counter weights to reduce the Datsun cranks' mass.

What has to be done to make it fit? If you lay the Datsun crank next to the Ford it will be self evident. The front snout has to be machined down, cut back, and drilled and tapped. The overall web diameter has to be reduced to aid clearance in the block. The rear flywheel mounting flange is shortened and the spigot bearing hole bored out to suit the Ford bearing. The webs and counter-ballances will need to be slimmed down, and some chamfered. As the Main and Big Ends are larger these can be ground down to suit standard Ford bearing sizes and strokes. Don't forget to preserve the all important fillet radii when the crank is ground. The keyway for the front pulley can be milled in. The Datsun crank is a 5 bolt not 6 like a Ford. You can make a flywheel to adapt the Ford clutch plate and starter ring gear to fit the Datsun crank. A medium tensile steel (EN8) or a high tensile steel (EN25) can be used. Or try modifying the Datsun flywheel. I have always made a flywheel as I prefer this solution. Also it is safer to  make a light weight flywheel with a steel blank. Samples shown .  A video of my Escort engine with Datsun crank running can be seen at
Escort Dyno Page. If you would like any assistance with sourcing or getting a Datsun crank modified feel free to contact me. I can also help with the manufacture of special custom made steel light weight flywheels.
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