Double check my engine builder please 340 stroke
3) the pistons have (8) .4 cubic inch or 6.44cc gap between the cylinder wall and piston that is .015 wide and .222 deep down to the first compression ring that adds cylinder Volume. (See pictures and the calculation tool allows for this measurement)
4) the cams advertised duration 253/266@20 deg or 276/294@6 deg. The intake closes at 76 degrees (actual zero). I used the 76 degree number in the calculator. Note: asked to install the cam with 4 degrees of advance.
5) the engine builder says the Static compression ratio will be 11.57:1 and the dynamic between 8.1 @ 1160 elevation or 8.4 at sea level.
6) I asked him about crank pressure. He said 225psi. I asked him if that was high. He said he has other engines out there with aluminum heads st 225psi and it is no problem. He said if my heads were iron he would have stopped at 180psi.
Good for the added info. Good caliper pix!
Very real PROBLEMS that I found in your numbers:
1) The info that there is 6.44 cc in that gap is incorrect and is off by an order of magnitude. It is about 0.042 CI or about 0.64 CC.... I just computed it directly twice.
2) I used 278 as an estimation on the advertised already. Intake closing at .006" is 68 degrees, not 76 degrees, for 4 degrees of cam advance. It appears that you made a mistake in entering the cam advance and
it has been entered as cam retard. With that mistake THEN the ICA will be 76 degrees. With that cam at 4 degrees advanced, there is no way that DCR will be low 8's.
3) In no way, shape or form will the cranking pressure will be 225 psi at sea level! You would need some sort to pressurized air to get there!
- Adding in the 0.64 cc's
- using a 278 advertised duration
- using a thicker head gasket than before at .051" thick
- 018" deck height
- 4 degrees of cam advance
.... then I get an SCR of 10.95 and DCR of 8.65. Those relative number compare as I expect; the builder's relative SCR and DCR number do not make sense with this cam. Cranking pressure is gonna by around 170 to 180 psi. That is not all that awful for 93 octane and AL heads. I suspect total timing will have to be limited some, but that is not any disaster IMHO.
BTW, if you tune it with 110 octane, then it'll run good with a lot of timing but you had better pull back total timing before putting in 93 octane Premium.
And I have to question the deck being as tall as .018 over those pistons. ICON's and SCAT rods and such decks are not usally that far off. So be careful; as R. Reagan said: "Trust but verify"....
