I’ve been working on some diesel conversions of four stroke glow engines. I have several successful conversions. The engines start easily and run well. Power is on par with the original glow version or better. The engines run quietly and are tolerant of needle settings. Fuel consumption is typical of diesels. Compression adjustment is accomplished via the glow plug hole by an adjustable volume chamber.

The conversion process consists of increasing the compression ratio to what is required by the fuel. I make adjustements to components affected by milling the head and case, like pushrods, pushrod covers, and intake manifold. I also modify the carb slightly to improve fuel draw and throttle response. The “lanova cell” is what we are calling the adjustable compression device is made to suit the engine size.

To date, the following engines have been successfully converted:

OS FS-25 (an OS FS-20 stroked with an FS-26 crankshaft)
OS FS-26 Surpass
OS FS-30 Surpass
OS FS-40 The old 1981 version
OS FS-48 Surpass
Magnum XL52AR

These engines are in progress and should make acceptable conversions:

OS FS-40 Surpass
OS FS-52 Surpass 2
OS FS-70 Surpass
OS FS-91 Surpass
Magnum XL-91RFS

OS FS-40 diesel conversion

One Response to “Home”

  1. mrpipe Says:

    What was the head profile and of the .74 conversion…I am currently trying to convert a norvell .15 to diesel.
    would like to comunicate with you. Also have some input on your Walbro carb set up on your .91…..I have over 100 walbro carbs at my shop with different pop off presure and intake velocity calibrations.



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