| Gallery, Projects and General > How do I?? |
| Cylinder Bore 7/8" at a depth of 2.5" OR use DOM/CRS ? |
| << < (3/9) > >> |
| Bogstandard:
Of course not Jason, I know you are OK. But you must know the sort of people who I am on about. Stealing other peoples plans and ideas, modifying them so that they then won't work, and then calling them their own. |
| John Stevenson:
Can't be me, mine don't work before modification. John S. |
| raynerd:
Thanks for replying. I have to admit I do not know the benfits of piston rings in cast or o-rings so I was choosing o-rings as others seem to have used them on the Webster. I wouldn`t know where to start on cast piston rings having never used them (the 10V I have build just runs off a tight fitting piston with some graphited yarn). If my cylinder bore is 7/8", would the piston rings be cut from 7/8" stock as Jason has showed in his pictures and then just split. Likewise, is the groove that they lie in on the piston just a fraction shallower than the depth of the ring so that it pertrudes slightly - otherwise I guess there would be no point in the piston rings) I have to admit, piston rings are always something that have confused me despite seemingly being fundemental to most engines!!! I can`t quite understand what they offer over a good fitting piston directly in the cylinder!! Clearly I`m missing something. Thanks for your replies. With regards to cutting the bore in my original question you have convinced me that I can "try" and do this myself! I guess I need to decide what rings I am using so I can lap or hone the bore. |
| Jasonb:
There is quite a bit to making rings but its not too hard. Basically the ring is turned to an OD that is the same as the bore, split(not cut) you then spring it open, there are formula for the amount and heat the ring up so it takes on teh shape with this opening. You then put it back in teh bore and adjust until you have a small gap between the ends, in the case of my IHC it was 0.003". The base of the groove is a little less than the ID of the ring. The piston, alloy in my case is 0.005" less than the liner bore which allows for it to expand. The reason for rings is there is far less contact area than if the piston was a similar fit to teh bore, therefore less friction and you can use alloy pistons so less moving weight and also being sprung the ring will take up any slight wear. If you can get hold of the early issues of Strictly IC there is a 3 part series on making rings. Out of interest what type of ring is specified on the original webster design? I wonder weather some people take the O ring option as being a bit squidgy they allow for not being spot on with bore and piston. Jason |
| raynerd:
Jason, the plans just say the following: --- Quote ---PISTON RINGS - 3/32" X .875" SOURCE: OTTO GAS ENGINE WORKS (410)-398-7340 2167 Blue Ball Rd Elkton MD 21921-3330 http://www.dol.net/~dave.reed/otto.html 1/16" wide rings would offer less friction and probably seal just as well - simply adjust the ring grooves to accomodate --- End quote --- However on his website, under "cons" for the engine, he writes: --- Quote ---"Possibly needs thinner piston rings to reduce drag and friction (1/16" -vs- 3/32")." --- End quote --- Now I know for sure I`ve seen at least 5 or 6 on the web with O-rings and on the Webster website there are a few completed builds mentioned with O-rings. OK, I better get reading up on making piston rings as this seems the better way to go! Chris |
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