Will it work? just making sure

[jn2630]

I have ordered my parts and the machine work is being done. I'm just doing a reality check, will this all work? Here is my recipe:

-Block Bored .030 over
-4.2 Crank rods and mains ground .010 under
-4.2 Rods
-New stock pistons and rings
-Ford 24lb injectors
-Cam? I need some advice

What should I expect in terms of horsepower? Will it run on regular fuel? Will I benefit from a performance cam? Please tell me if I'm missing anything. Thanks in advanced.

[shockcocker04]

are you building it yourself?

[jn2630]

Yes, its my first engine build.

[shockcocker04]

your specs would make it a 4.6L, your cam selection has a lot to do with the reliability of your engine as cams are the known problems of strokers. running on regular gas all depends on your compression ratio. i would select your cam on the type of driving and use of the jeep.

[jn2630]

Ok, mostly my jeep will be a daily driver, and some off road, so I need a good torque curve. If I use stock head gasket, what will my compression ratio be?

[shockcocker04]

that depends on how much the head and block are decked, if the pistons are dished, if the combustion chamber is opened up. and the thickness of the head gasket. i cant tell you the compression ration, there are to many variables that are not decided.

[jn2630]

Lets say no material is milled off the head or block, the pistons are not dished, and the head gasket is stock.

[shockcocker04]

then it would be stock, you would just have more volume in the cylinder. increased compression is were you build power. if your reusing the head and block then you should have them decked to ensure perfect flatness.

[RAPTORFAN85]

then it would be stock, you would just have more volume in the cylinder. increased compression is were you build power. if your reusing the head and block then you should have them decked to ensure perfect flatness.

not true. the compression with that setup would be about 9.7 static. Much higher then stock...

[shockcocker04]

would it be because the pistons are not dished? 8.8 is stock right?

[RAPTORFAN85]

would it be because the pistons are not dished? 8.8 is stock right?

It's because you have more volume in the cylinder. When the valve timing events are at the same position and the volume increases you have to compress the air more to fit it into the same sized chamber. Dishing the pistons would make the compression drop because it would put more room in the cylinder so you wouldn't have to compress the charge into such a small area, if that makes sense .

[shockcocker04]

i understand, i got kinda turned around

[jn2630]

how much material must be removed from the head/block total to bring the compression ratio in the 9.5 range?

[eastin82]

removing material from cumbustion chamber would help(not the bottom of head) or dishing pistons you just need to play around with cr calculator!!

[jn2630]

Ok, I've been messing with the CR calculator, but I need to know if the stock 4.0 pistons are dished already, and how much. Thanks for clearing some things up guys.