Scotty's Webster

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scottyp

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So I finally have some progress on my Webster so I thought I'd start a post to keep me motivated. I built a few basic steamers and a NGEZ maybe 10 years ago with "OK" results and have had the Webster 4 stroke in mind for quite a while. The kids are older and I have since gained more milling experience and patience so I figure I should step it up a little. I have ambitions of a Tiny Inline 4 and a Demon, but let's start here right? Anyway, here are the basics so far. The valves seal up nice and the piston came out good. I had some oversize rod and milled some flats on it to hold it for the milling cuts. I'll either sleeve this cylinder (which I sort of made as practice and it fits really well) or make a new steel one, we'll see. The carb is from a .15 RC engine. More to come...
 

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scottyp

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Thanks guys, I had the day off today and my wife was working so I could do what I wanted today :) (just kidding honey) . I cranked out a crankshaft, it turned out nice and square. While I am waiting for my bushing materials I made a couple from a chunk of delrin to find out that things fit pretty well and the gears mesh nicely also.

The shaft and pin were a good and tight press. Should I pin them also?
 

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Cogsy

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I would, just for safety, although there's arguments against it also. I relied on a press fit for a single, vertical I built from Brian Rupnows design (my choice, I can't remember if the plans advise pinning) and when I had a valve retaining clip fly off the engine locked up suddenly. The quick stop bent the valve which caused the issue and also moved the crank to web in 2 axes. I corrected the crank easily enough but it wouldn't have happened if it was pinned. On the other hand, if it couldn't twist and slide where it did, it may have bent or broken something else so I really don't know if it would have helped.

Being that it's rare for an engine to just stop dead like mine did, but much more common to backfire and impart a bit extra force on the crank fits, I'd probably pin it and it'll likely never cause you any trouble.
 

a41capt

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Thanks guys, I had the day off today and my wife was working so I could do what I wanted today :) (just kidding honey) . I cranked out a crankshaft, it turned out nice and square. While I am waiting for my bushing materials I made a couple from a chunk of delrin to find out that things fit pretty well and the gears mesh nicely also.

The shaft and pin were a good and tight press. Should I pin them also?
Like Cogsy mentioned, I had a roll pinned crank on my Ford Kitchen Sink engine when it backfired (don’t ask me how such a low compression engine can develop a big backfire!), and it sheared the roll pin. I turned a tight fitting solid pin to replace the roll pin and green loctited it in!

On my Webster, I turned a one piece crank out of 1/2” HRS so I wouldn’t have that problem with my second engine. Live and learn!

John
 

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