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concerned that my CR will be way to high for this 1999 4.6 stroker
Posted: February 25th, 2022, 3:10 am
by Crockodotsky
1999 4.6 stroker
3.905 bore
3.895 stroke
5.875 4.2 rods
factory 0630 head with 58 cc volume
Silvolite 2229C pistons with 11cc dish
block decked to pistons .005 in the hole
bought the pistons based on the Hughes Performance/Moses Ludel videos and most guys going zero deck. The calculator has me freaked out!
Re: concerned that my CR will be way to high for this 1999 4.6 stroker
Posted: February 25th, 2022, 9:32 am
by Randy Bobandi
Cometic has head gaskets ranging from .027" to .098" to dial in compression. You could also remove material from the chambers. Also, what camshaft are you running? Your dynamic compression or "actual compression ratio" maybe much less than you think due to valve timing.
Re: concerned that my CR will be way to high for this 1999 4.6 stroker
Posted: February 25th, 2022, 9:47 pm
by Brianj5600
There is no way a head gasket or cam is going to make a that combo run on pump gas. You need a piston with a dish much bigger, 24cc to 27cc to work with zero deck and tight quench.
Re: concerned that my CR will be way to high for this 1999 4.6 stroker
Posted: February 26th, 2022, 1:03 am
by Cheromaniac
Crockodotsky wrote: ↑February 25th, 2022, 3:10 am
1999 4.6 stroker
3.905 bore
3.895 stroke
5.875 4.2 rods
factory 0630 head with 58 cc volume
Silvolite 2229C pistons with 11cc dish
block decked to pistons .005 in the hole
bought the pistons based on the Hughes Performance/Moses Ludel videos and most guys going zero deck. The calculator has me freaked out!
Assuming a 0.043" thick head gasket, I have your static CR at 10.67:1. You could gain a few cc and lower the compression by polishing the combustion chambers and the piston dishes. The 2229 pistons have pretty thick crowns and the dishes can be machined deeper.
Re: concerned that my CR will be way to high for this 1999 4.6 stroker
Posted: February 26th, 2022, 10:37 am
by I6FAN
I believe the build video the OP has referenced is this one (correct me if I'm wrong):
https://www.youtube.com/watch?v=EcAOrbsqZBs
These videos were produced by very reputable folks. There are a lot of unknowns in this build i.e. did they open combustion chamber volume, dish pistons more, and what camshaft timing ect. They were also .010" further in the hole than OP, but that still yields very high static and dynamic ratios. They claim it's 8.7 in the video, but not sure if the piston dish is the same either. You would need a very big camshaft to net an acceptable comp ratio, and that would not be an ideal rock crawler cam. If it used the aluminum head it might work though. They really don't divulge enough information to use this as build, specification information. This is basically a 20year old build recipe; there are much better ways to do this today. You can make this work, but not as is. Piston dishing is your first biggy (but you didn't mention cam timing).