Edelbrock 4.0L head soon to be available.

[Cheromaniac]

Has anyone worked out the CR for this new head on a stroker with 4.0 rods, KB 944 pistons at zero deck height?

Same as a typical iron head.

Depends. If the Edelbrock head has a slightly smaller 55cc chamber, the CR will be 10.0:1 in a zero deck engine with IC944 pistons. However since the head is aluminum, the engine would be about as prone to detonate as the same engine with an iron head and a full point less compression.

[shawnxj]

being an aluminium head shouldn't they be able to push an 11;1 cr?

[jsawduste]

Keep another factors in mind. Not just a compression number.

That is the efficiency of the combustion chamber. How well the mix is dispersed and what the swirl might be. Then how the flame front is controlled by the squish.......quench.....

[b2carpen]

As it was mentioned before (and relating to jsawduste's comment about the ignition control) I am curious how the new chamber design will work with our piston dish being shaped to match the original chamber design. I'm interested to hear if edelbrock tested different piston dish shapes to match their modern design (similar to chevy) chambers. I imagine it will also chamber air flow characteristics slightly as well.

[b2carpen]

*change air flow characteristics...

[Russ Pottenger]

I hope Edelbrock incorporates some of the most obvious changes/upgrades in their 4.0 cylinder head the first release.

Designing the head that is a simple direct bolt on is probably best for Edelbrocks bottom line, but with
a little thought they should be able to appease most of us that want to take it to the next level.

A few thoughts.
Raising the valve cover rail. Opening the pushrod hole for lifter access. Putting OD valve seats and valve guide diameters
that allow off the shelf Chevy LS valves, retainers. With a 1.700 installed height we would have a bunch of choices in
valve springs in the 28 to 40lbs spring rate range.

[sly-jeeper]

For the stroker would I'm not so sure its worth it, because of the smaller 55cc chamber's and the stock valve sizes

[jsawduste]

For the stroker would I'm not so sure its worth it, because of the smaller 55cc chamber's and the stock valve sizes :huh:

Ahh, but your underestimating the importance of chamber design and thermal efficiencies.

The reason quench (squish) is so important is because the chamber design on the stock head is so poor. Add to the chamber`s flow design and the importance of a tight squish will go away.......To a degree.......Add aluminum to the mix and you rise another notch.....Another jump.

[sly-jeeper]

So with my near 0 deck and Keith black ic944's pre ignition shouldn't be a problem?

[sly-jeeper]

And what about valve diameter? How hard would it be for them to have put 2.02 and 1.60's???

[jsawduste]

So with my near 0 deck and Keith black ic944's pre ignition shouldn't be a problem?

Quite possibly a fact.

Ever wonder why the atypical stroker with a tremendous amount of quench (squish) and a low compression often needs a higher octane fuel then an engine with a tighter squish and more compression ? Even when keeping the same IVC event as part of the equation. At the very least if detonation is not an issue the overall performance is not as heightened as a tight squish engine ?

Why a cam company says "for use with X amount of compression and above"......Because of squish getting tightened up as part of raising the compression. Sometimes planned or by default.

Do a little homework and you will soon learn a few facts about our beloved 4.0 based strokers and combustion.

Cliff Notes.........The typical chamber is based on a design that is almost old as dirt. With the changing of the fuels we have to burn, emissions and advancements in camshaft technology that old chamber NEEDS a tight squish to avoid detonation. This is a very brief, lightly touched explanation.

Encourage anyone considering the new head to understand what they are buying and why it is better. At the same time those building an iron head stroker to understand why squish is so important. Most folks just recognize a term or a number and don`t really understand what they mean or the effects.

On the strokers I personally get involved with. If I cannot get at least .050 squish I don`t build it.

Personal opinion 101 ? The new chamber of the Edlebrock head will allow 4.0 based engines to reach the next level and to an even heightened state when combined with modern piston design.

[b2carpen]

Ever wonder why the atypical stroker with a tremendous amount of quench (squish) and a low compression often needs a higher octane...
Cliff Notes.........The typical chamber is based on a design that is almost old as dirt. With the changing of the fuels we have to burn, emissions and advancements in camshaft technology that old chamber NEEDS a tight squish to avoid detonation. This is a very brief, lightly touched explanation.

Encourage anyone considering the new head to understand what they are buying and why it is better. At the same time those building an iron head stroker to understand why squish is so important. Most folks just recognize a term or a number and don`t really understand what they mean or the effects.

On the strokers I personally get involved with. If I cannot get at least .050 squish I don`t build it.

Personal opinion 101 ? The new chamber of the Edlebrock head will allow 4.0 based engines to reach the next level and to an even heightened state when combined with modern piston design.

Most also don't understand or address the condition of the stock chambers and the imperfections that lead to early detonation... such as the ridiculously rough casting marks and bumps, huge ledges and sharp edges all over the place, ect... these are the areas I've spent most of my time addressing as I find it unacceptable to leave the stock chambers in those conditions.

[jsawduste]

All fine examples of how an engine should go together.

Mean no harm but the descriptive terminology, "poormans" build is a great disservice to 4.0 based strokers in particular and engine builds in general. Understandbly folks jump to the thought of getting something for little to nothing. All tbe while missing the basic nuance of engine builds and available performance. Sure they are out there and running but what if they had been built in a better way to begin with ? Perhaps the bad rap strokers get for lackluster performance and poor reliability might be less.

Sorry Dino, no harm intended but things are what they are.

[Root Moose]

All fine examples of how an engine should go together.

Mean no harm but the descriptive terminology, "poormans" build is a great disservice to 4.0 based strokers in particular and engine builds in general. Understandbly folks jump to the thought of getting something for little to nothing. All tbe while missing the basic nuance of engine builds and available performance. Sure they are out there and running but what if they had been built in a better way to begin with ? Perhaps the bad rap strokers get for lackluster performance and poor reliability might be less.

Sorry Dino, no harm intended but things are what they are.

This terminology is a pet peeve of mine also. "Economy work horse for those willing to do the work" doesn't exactly roll off the tongue though.

[BADASYJ]

It doesn't matter if they kept the stock designed chamber or not on the head.I would bet 8 out of ten heads will never see the track anyway. If it's for a poser jeep the stock design chambers will be fine. If it's going on a race jeep it's going to the machine shop first for some massaging. Remember it's aluminum, it can be welded and machined to any design you want, same as the valve cover rail weld it up n machine it down. I'm not sure a new chamber design would even be noticeable on these motors. At the most they might spin around 7000rpms at that point I would be more concerned with the bottom end then flame travel.