Chainsaw Repair

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

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.

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

    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

Interesting 066 quads  .  Tell us more Gregg.

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