Thank you. So, just to be clear, you think a 10.0:1 DCR/7.9 SCR, 0.059" quench distance combo would be more prone to detonate than a 10.45:1 DCR/8.25 SCR, 0.039": quench distance combo with modern aluminum heads?
Thank you very much. That's exactly what I was trying to discern. I wonder if there's any truth to that.
Thank you. Which cam did you have in the 10.17/ 0.085" quench distance combo that never knocked? Do you recall the advertised intake duration and LSA? Just trying to get an idea of where your SCR would've been with that combo.
Quench was definitely not an afterthought. However, right after I had the rotating assembly balanced, I came across a set of trick flow heads for basically free (minus some manual labor and minor machining costs). That changed my plan from using my RHS heads (68cc), to a set of 59cc heads. Now I'm trying to figure out the best method to make this combo work and not ping. I'm not looking at all for max horsepower. I'm just looking for a combo that won't knock with CA's 91 octane pump gas.
Worst case is I buy the Autotec 408 pistons that have a 24.5 cc dish and .008" lower compression height than the Icon's 20.5cc dish, and have the crank re-balanced. I'm hoping that's not necessary though. That would results in 10.05 DCR and 7.94 SCR.
What head gasket thickness did you use in your 5.9? If the block surface was just skim cut to clean it up but not actually checked, there's a good chance the pistons are 0.005" - 0.010" in the hole. Also, what pistons are they? Icon 745? Lastly, what is the cam's advertised intake duration?
What was the compression ratio of the 440 measured? Sounds like that one is right on the cusp of detonation. I'm curious where the DCR is on that one.
That's definitely another option. Although, that would put me at 10.49 DCR/8.27 SCR (highest of all other options. w/ .037" quench.