Yes, yes I do post alot!
Posted 20 August 2012 - 09:59 AM
Green Eggs and Spam
Posted 20 August 2012 - 10:33 AM
Yes, yes I do post alot!
Posted 20 August 2012 - 11:09 AM
Edited by orangeLJ, 20 August 2012 - 11:10 AM.
Green Eggs and Spam
Posted 20 August 2012 - 11:20 AM
Edited by wot179, 20 August 2012 - 11:26 AM.
_Ned Loh_
Posted 20 August 2012 - 11:57 AM
G'day Grant ,I 'll try to answer your concerns ,The torsional forces against the cylinder walls actually change with the rod to stroke ratio.(std 202 rod/stroke ratio is 1.61) If you build the old falcon crank 234 stroker with short holden rods the (rod/stroke ratio 1.45) greater rod angles place much more force on the cyl walls and the resulting quick piston acceleration from tdc does not work well with the restricted breathing.
The long rod stroker has a rod to stroke ratio of 1.68 which is better than a std 202 .The lesser rod angles actually place less stress and friction on the cylinder walls than a std stroke/rod 202 engine.Also the piston moves slower from tdc due to the longer rod meaning the intake valve is open further before the piston starts moving quickly down which helps with cylinder filling.Mick
_Ned Loh_
Posted 20 August 2012 - 12:00 PM
Wow! I should start more threads!
I cant comment on the discussion too much,
BUT!
I do know have a 12 port header plate in CAD format, so will be getting some cut in the near future to make more pipes.
Will confirm a price soon, but around $35-$40 should cover them? 12-14mm mild steel, laser cut.
Can also do 9 porters for about the same I think
_STRAIGHTLINEMICK_
Posted 20 August 2012 - 07:35 PM
I use .035 ,.055 or .075 overbores without any problems in 186 or 202 blocks in n/a applications, I wouldnt use .120" overbore in my engine but some people do in speedway applications without problems.the trick is to sonic test the wall thickness to verify a good casting before deciding bore size.capacity increases roughly 9ci from stroke increase and 7ci from the bore increase,it costs roughly the same to grind the crank to either stroke.IMHO - the change in forces on the cylinder walls is the least of concerns, I can't get over the .100"+ over bore mentioned earlier in the thread...
Also, just to clarify, we really are talking about (roughly) equal capacity gains for the crank and overbore aren't we?
_Ned Loh_
Posted 21 August 2012 - 07:15 AM
I use .035 ,.055 or .075 overbores without any problems in 186 or 202 blocks in n/a applications, I wouldnt use .120" overbore in my engine but some people do in speedway applications without problems.the trick is to sonic test the wall thickness to verify a good casting before deciding bore size.capacity increases roughly 9ci from stroke increase and 7ci from the bore increase,it costs roughly the same to grind the crank to either stroke.
_CHOPPER_
Posted 21 August 2012 - 02:10 PM
Wow! I should start more threads!
I cant comment on the discussion too much,
BUT!
I do know have a 12 port header plate in CAD format, so will be getting some cut in the near future to make more pipes.
Will confirm a price soon, but around $35-$40 should cover them? 12-14mm mild steel, laser cut.
Can also do 9 porters for about the same I think
_STRAIGHTLINEMICK_
Posted 21 August 2012 - 06:57 PM
Probably no less than .120" for n/a enginesHi Mick,
Agree regarding the importance of sonic testing (for high HP applications). What wall thickness do you like to see (after overbore) on the 202?
Cheers.
Yes, yes I do post alot!
Posted 21 August 2012 - 08:24 PM
Yes, yes I do post alot!
Posted 27 August 2012 - 02:01 PM
_Bomber Watson_
Posted 27 August 2012 - 06:39 PM
Yes, yes I do post alot!
Posted 27 August 2012 - 09:57 PM
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