TECH TIP #72: Saving Worn Deutz, Continental and Wisconsin Blocks

The Continental flathead industrial engine powered literally hundreds of thousands of industrial machines including forklifts, welders, and air compressors. But because this time-tested workhorse is no longer in production, saving marginal block castings during the rebuild process became very important.  While we still offer Continental engine parts we are no longer able to provide remanufactured Continental engines.  We continue to maintain this Tech Tip for the benefit of all of you working to keep your Continental running.

Over the years the factory steadily increased the displacement of this six-cylinder Continental engine from 209 cubic inches to 245 cubic inches. They did this by enlarging the bore. As a result, the cylinder walls became thinner and prone to cracking and porosity with such failures allowing coolant to mix with, and dilute, the engine oil supply. While magnafluxing will reveal cracks, few rebuilders are able to pressure test and sonic test these blocks for porosity. As a result, problems could occur even after a thorough rebuild.

Several solutions have been tried without much success. These include sleeving a worn F245 back to its standard bore, pinning or stitching the cracked area (usually it extends into a valve seat), and circulating plastic sealant through the block. We believe a better solution was to simply to sleeve the six-cylinder F245 engine back to the F227 Continental standard bore specifications. In our remanufacturing center, we used a 1/8” wall sleeve (Nylen pn SL107) with a 3.503”OD. We then installed F227 Continental pistons and rings. The result was a much stronger block with no significant loss of power (76hp for the F245 at 2400rpm vs. 72hpfor the F227).

The four-cylinder F135, six-cylinder F209 and the F218 Continental series blocks also are problematical, but not because of porosity or cracking. The replacement pistons are simply not available for these older engines.  To solve the problem of a lack of pistons, we simply machined these blocks to a later Continental bore size. That is, we bored the F135 to an F163 standard bore and the F209 or F218 to an F227 standard bore. Fortunately, these castings were designed in an earlier age, before CAD ˜ CAM. As a result, the blocks were very beefy with thick cylinder walls.

The final flathead engine that this Tech Tip discusses is the Wisconsin V4 Series. These hardy air-cooled engines were in production for years and were frequently rebuilt. The problem was that the factory only offered slightly oversized pistons. Usually, the block was worn beyond these limits. One alternative was to purchase new cylinders (called jugs), but a better idea was to simply sleeve the block back to standard bore. Yes, a purist could argue against putting cast iron repair sleeves into an aluminum block (because of the different metal’s coefficients of expansion) however, we had successfully placed cast iron sleeves into aluminum blocks without  problem, something we would no longer be able to do today given the limited availability of parts for these engines.