Author Topic: 066 bench racing. trying to get large torque gain? (long).  (Read 1097 times)

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Offline srcarr52

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Remember to measure the bottom of the exhaust port.  If this becomes larger than the piston height + squish you'll be opening up the crankcase to the exhaust port (free port).  The more you cut out of the squish the closer you'll get and these saws (especially AM cylinders) are know to be on the ragged edge of free porting before modification.

Offline 1manband

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good catch scarr52.  i don't do this 2ST stuff anymore and its easy to forget to remember to check everything.  even checks that's need to be completed before dropping the cylinder and squish cuts are planned!

remeasured everything.  found a port width error.  then decided to use an average port roof opening height for the slightly angled down roofs of the transfers to be more accurate.

sticking with the being more accurate theme, did my best to measure millimeters down to the 0.01 mm.  note that this exceeds the accuracy of the caliper.  the degree measurements were calculated from the mm measurements, and carried over to 0.01 degree.  this in reality, would be impossible to get this kind of accuracy.  the program calculates all values out to 0.0000001.  wanted the program to not be the cause of not enough precision.
one thing to be aware of as far as the program, is concerned...  accuracy in such that 0.01 degree or 0.01 mm measurements will and do change STA's.  made the program 10x more accurate in calculation ability, than the university of belfast suggested.  this does not mean anything however, because actual physical measurements that small cannot be made.

digressed a bit.  hope if anyone got anything from that, it is to be as accurate as possible while measuring.  be as consistent with port beveling as possible as well.  both of these have a large effect on port opening timing and more importantly time-areas as i found out during this experiment.

in a nutshell....have enough room.  will show these important steps.  glad scarr brought it up.

regards
-joe

hiatus

Offline 1manband

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missed what i wanted by 0.3 mm

as only luck would have it, the base gasket will add the slack needed.

regards
-joe



hiatus

Offline KilliansRedLeo

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When I run into a situation like Joe and miss by some tiny amount 0.3mm (0.11811) and the base gasket is used to correct for the error. I will cut a custom gasket made from 110 annealed copper precision shim stock. Very large PITA and the shim stock is stupid expensive but then I am sure the the CBGT will not change.
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline 1manband

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066 stock OEM final design build.

disregard previous version.

went gasketless.

corrected a few measurements.

scaled each ports goal STA's to the smallest value possible.

one attached file broken up into 2 parts:
Part A - stock to base cut/deck cut
halfway down.......
Part B -  where the fun starts.  (not for purists).

comments appreciated.

regards
-joe
hiatus

Offline 1manband

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the aftermarket 066 big bore knockoff jug is off on the exhaust.

blunder on my part, (not checking clearance beforehand), and would cause freeporting
without an excessively thick base gasket.

i'll correct this in the future, but i my opinion, the big bore jug is not as good of a
candidate for gains when compared to the stock oem jug.

regards
-joe
hiatus

Offline srcarr52

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the aftermarket 066 big bore knockoff jug is off on the exhaust.

blunder on my part, (not checking clearance beforehand), and would cause freeporting
without an excessively thick base gasket.

i'll correct this in the future, but i my opinion, the big bore jug is not as good of a
candidate for gains when compared to the stock oem jug.

regards
-joe

That's been the general consensus. 

Offline Grande Dog

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    Howdy,
   Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg
Left Coast Supplies
1615B South Main Street
Willits CA 95490
888-995-7307   707-602-0141
www.leftcoastsupplies.com
gregg@leftcoastsupplies.com

Offline Cut4fun

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    Howdy,
   Maybe a 066 cylinder with Quad Loop porting can get you there. Should be able to carve some wide intakes, and exhausts.
Regards
Gregg

Welcome Gregg. Nice seeing you here and sharing your knowledge with us.  Thanks.

Also everything here is FREE to sell if you have a online store etc.  Just put your info in your sig and or where to buy  online board. 

All about helping folks out here freely.

Kevin

REDNECK Saw Repair

Offline Cut4fun

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REDNECK Saw Repair

 

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