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Post by pitobread on Nov 16, 2018 11:16:54 GMT -5
I think malossi make a non angled spark plug head for dio's. Or used to. Would need to be cut for over ore though
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Post by oldgeek on Nov 16, 2018 21:09:24 GMT -5
Headhunting in house, I discovered my Piaggio (ET2?) has the 68mm cylinder head stud spacing I am looking for. The stock Piaggio head has a spark plug hole that does not come in at an angle like an AF16 head does. Instead it comes straight in, but off center for some reason. The two 70cc aftermarket Piaggio heads I have, the spark plug hole is in the center. They are both o ring type heads and would require decking and combustion chamber work.
Finding a 50cc Piaggio aftermarket head that has a centered spark plug hole might be the best blank canvas to start with.
Also realized the Polini corsa head I have has a combustion chamber shaped similar to 190mechs's drawing. No wonder the Corsa's are so fast! LOl
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Post by gsx600racer on Nov 16, 2018 22:07:11 GMT -5
Headhunting in house, I discovered my Piaggio (ET2?) has the 68mm cylinder head stud spacing I am looking for. The stock Piaggio head has a spark plug hole that does not come in at an angle like an AF16 head does. Instead it comes straight in, but off center for some reason. The two 70cc aftermarket Piaggio heads I have, the spark plug hole is in the center. They are both o ring type heads and would require decking and combustion chamber work. Finding a 50cc Piaggio aftermarket head that has a centered spark plug hole might be the best blank canvas to start with. Also realized the Polini corsa head I have has a combustion chamber shaped similar to 190mechs's drawing. No wonder the Corsa's are so fast! LOl I think the magic from the corsa comes from the whole package, and not just the head. lol |
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Post by 'O'Verse on Nov 16, 2018 22:38:45 GMT -5
Since you already have a very strong runner.. Are you gonna modify a different head incase the noise is still there after you successfully open one up?
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Post by oldgeek on Nov 16, 2018 22:42:07 GMT -5
Since you already have a very strong runner.. Are you gonna modify a different head incase the noise is still there after you successfully open one up? Yeah probably not gonna screw with the current one. I got other heads to mess with. |
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Post by oldgeek on Nov 18, 2018 21:20:54 GMT -5
I had to hang around the house this weekend so I was not able to work on the head. I decided today to try to do a drawing of the combustion chamber with sketchup. I failed miserably. The learning cliff is too steep for me. I was thinking I could easily get the volume of a combustion chamber from a drawing, but I could not even get the drawing done. Had a little fun though.
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Post by oldgeek on Nov 20, 2018 20:14:39 GMT -5
I am going to need to purchase an X-Y cross slide to rework the head. I have been looking at several and was wondering if anyone here has any experience with one like this Cross Slide All I need it to do is hold position after it is set, do ya think it will work for that? I could spend up to $150 for a decent one if someone has any recommendations. |
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Post by 190mech on Nov 21, 2018 4:57:22 GMT -5
It will need a table lock feature,I guess tightening the gibb screws down would do that,just need to readjust them after the job is done..
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Post by ThaiGyro on Nov 21, 2018 7:33:40 GMT -5
I had to hang around the house this weekend so I was not able to work on the head. I decided today to try to do a drawing of the combustion chamber with sketchup. I failed miserably. The learning cliff is too steep for me. I was thinking I could easily get the volume of a combustion chamber from a drawing, but I could not even get the drawing done. Had a little fun though.
I too have begun to learn drawing in "sketchup". I have used some other cad programs, but too expensive for my little use. Even though it can be scaled, somewhat, I have found that it does not like metric in mm. (It scales from cm...not cool) I like the tools, but I do not have a mouse with my Mac. Maybe I will try that. Ffffat, fffooking , sticky ffingrs?
I do very good hand renderings on graph paper...
Looks like a fun build though!
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Post by oldgeek on Nov 21, 2018 18:43:28 GMT -5
I had to hang around the house this weekend so I was not able to work on the head. I decided today to try to do a drawing of the combustion chamber with sketchup. I failed miserably. The learning cliff is too steep for me. I was thinking I could easily get the volume of a combustion chamber from a drawing, but I could not even get the drawing done. Had a little fun though. I too have begun to learn drawing in "sketchup". I have used some other cad programs, but too expensive for my little use. Even though it can be scaled, somewhat, I have found that it does not like metric in mm. (It scales from cm...not cool) I like the tools, but I do not have a mouse with my Mac. Maybe I will try that. Ffffat, fffooking , sticky ffingrs? I do very good hand renderings on graph paper...
Looks like a fun build though!
I think I am making friends with FreeCAD. It is incredibly complicated compared to sketchup, but for whatever reason I can tolerate it more. It has been a pleasing build so far, but reworking the combustion chamber on this head is driving me knuts. I just can't seem to come up with a way to get it done in a manner that is not going to result in a totally half assed looking job. 190mech I have figured out if I make the combustion chamber 10cc as it needs to be, a 12.5mm squish band will be impossible to achieve. There is just not enough room in the head for both. |
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Post by 190mech on Nov 22, 2018 5:59:41 GMT -5
I think we need to throw the text book away on this one and hog the chamber to proper volume,hopefully you'll have some squish band left...  |
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Post by 'O'Verse on Nov 22, 2018 13:17:44 GMT -5
I say don't even try to figure it out mathematically. Just take a little bit of material away the cleanest way possible and send it till your content with its performance. 👍
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Post by oldgeek on Nov 22, 2018 14:09:30 GMT -5
I say don't even try to figure it out mathematically. Just take a little bit of material away the cleanest way possible and send it till your content with its performance. 👍 Yes that is the plan. It would be done if the stupid plug hole was not at an angle. |
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Post by 190mech on Nov 22, 2018 16:18:15 GMT -5
You could dig a trench around the plug hole and make a toroidal type chamber;  Just gotta remember hogging a bunch can make a 'thin head' with little clamping and heat rejection... |
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Post by Lucass2T on Nov 23, 2018 10:50:47 GMT -5
How about adapting the stock head for a combustion chamber insert? Then you're not stuck with stock dimensions and you can use the stock cooling fins as some sort of 'crown' to clamp the combustion chamber insert to the cylinder.
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