Edelbrock head ported

[Russ Pottenger]

Just finished working over Edelbrock's 4.0 Jeep cylinder head.
At first impression to be honest I was a little disappointed. Maybe because I wasn't
realistic. I hoping the head would have my wish list of changes. Such as raised valve cover rail. Larger OD seats to help facilitate the utilizing of a larger than stock intake valve.
Lifter access holes, and the list can go on.

To be fair to Edelbrock, they didn't make this head for just me. They made it to appeal to the guy that has a bone stock 4.0, and to the guy that wants it to be better than stock and lose a few pounds off the nose of his Jeep. Lastly just as important, to be able to drive away from a smog station with a smog certificate in hand.

The good news is Edelbrock gave us foundation of what can be a very good performance head. Edelbrock has always had a good reputation of making good parts at competitive prices.





The stock port.



The stock intake port has a rather large head bolt casting boss.
Airflow at the entry of the port is greatly enhanced by blending the casting boss into the port.



The biggest upgrade Edelbrock did was to completely redesign the combustion chamber. That is what held back the potential of the Hesco head. Hesco copied the less than desirable OEM chamber.



The key factor in making the combustion chamber work is laying back wall surrounding the valve opening area. It's super critical when increasing the valve head diameter as I did in this application.



Because I was limited by the 2.000 OD seat I decided rather replacing the intake seats, I turned the Intakes down to 1.970. Chevy LS 1.550 valves were used for the exhaust.





Finally the report card. To be fair the stock head was flowed with 1.910 and 1.500 valves.
The ported head with 1.970 and 1.550
Air Flow was at 28 in of water.

Lift Intake Stock Ported Exhaust Stock Ported
.050 30.4 36.8 27.1 27.9
.100 58.1 72.5 61.2 62.1
.150 99.7 101.2 88.5 94.8
.200 132 144 104.3 117.5
.250 165 171 115.3 134.9
.300 187.5 199.5 123.9 168
.350 207 223.8 131.1 182.3
.400 225 246 152.2 191.8
.450 238.8 261.6 155.3 199.7
.500 246 274.8 156.9 204.5
.550 250.8 285 158.5 207.6
.600 243 301.7 160.1 210.8
.650 244.8 306.2 161.7 212.4

 

[Russ Pottenger]

Sorry, tried to hand type the flow numbers and is hard to understand.
I'll scan the flow sheet tomorrow and repost.

 

[Alexia]

Sorry, tried to hand type the flow numbers and is hard to understand.
I'll scan the flow sheet tomorrow and repost.

Tada!

https://docs.google.com/spreadsheets/d/1J2gHJaSqkZXlokoK1Yibz3hfFVLJl7hgxXQB-VF_ung/edit?usp=sharing

 

[Dr. Dyno]

That's a huge airflow increase by porting the head. Just shows how much Edelbrock left under the table. Awesome work Russ.

 

[cal]

What are the numbers on the Hesco head and on your top shelf 7120 head?

I think I may try and put an Edlebrock head in your hands as a Christmas present to myself this year.

 

[Russ Pottenger]

I'll go through my records and dig up those flow sheets for comparisons.

There's still some potential left in the Edelbrock head, and with the rumors swirling around that Edelbrock is considering a intake manifold, that combination put together could be a real game changer. Lets hope cylinder heads sales are good enough to incentivize them to do the project.

 

[fzsk4p]

Russ, got your message the other day and was wondering where the info was. :confused1 Dummy me I was looking in the old thread..........:laugh:

Nice work on the porting and reporting.

Rounding the numbers @ .500 you saw 12% on the intake and 30% on the exhaust which is pretty respectable especially on the exhaust side.

A comparison to a stock/massaged 7120 would bring all this together flow wise.

{Disclaimer} Written without knowing the flow numbers on YOUR bench of a 7120.

The chamber is without question a slam dunk. Wonder how much of an improvement can be attributed to the fast burn chamber on an otherwise stock engine ? IMHO not a whole lot. Start tightening up the quench and matching the dome to the chamber with some respectableable compression. Then add your porting and enough stick with lifts of .450 + and we may very well have a winner.

As you have already pointed out.......Edlebrock "may" be working on an improved intake manifold. Can the late model intake come close to feeding the ported head ? Even with a 70mm BBK ?

With a 30% increase in exhaust are the typical header with ~ 1 1/2 primary's and ~2 inch collector able to flow enough to take advantage of what the head can do ? Only one I know of that comes close is the Doug Thorley HDX-634Y

Not by any means trying or wanting to throw water on the fire but just stepping back a bit and looking at the overall picture.

^^^^{Disclaimer} Written without knowing the flow numbers on YOUR bench of a 7120.^^^^

If this works out we both know a certain EMC guy and his promoter friend that would really love the power increase. :greensmok

 

[Russ Pottenger]

All good points John (fzsk4p),

Before we get started it's important to clarify Johns well made point. Not all flow benches will come up with the exact same flow numbers. The same go's for engine Dyno's.
For example Edelbrocks stock untouched flowed about 5% better on my bench that theirs. That said, if all flow work is correctly done on the same bench, flow numbers should remain consistent and be reliable so one can made accurate comparisons.

With a 2.00 Intake valve and 1.550 Exhaust valve this is my best flowing 7120 head.

 

[RWKHausSupply]

All good points John (fzsk4p),

Before we get started it's important to clarify Johns well made point. Not all flow benches will come up with the exact same flow numbers. The same go's for engine Dyno's.
For example Edelbrocks stock untouched flowed about 5% better on my bench that theirs. That said, if all flow work is correctly done on the same bench, flow numbers should remain consistent and be reliable so one can made accurate comparisons.

With a 2.00 Intake valve and 1.550 Exhaust valve this is my best flowing 7120 head.

NOW THIS IS WHAT I WANTED TO SEE :rof:

SO my Alum head you got there will out flow even your best cast 7120 head. Not that I will be doing everything else needed to get 100% of that potential with this vehicle. But its nice for piece of mind that my grand alone on the head wasn't wasted.

 

[yossarian19]

at .50 lift it's 5% difference between the 7120 and the ported Eddie. Biggest cam I can find for the 4.0 is .53 lift on intake, where its closer to 6%.
I don't see spending $1500 or so for that last few percent, myself, but it's a cool race part? Then again, with an aluminum head you can get a little more compression / ignition advance out of it without detonation. Might be a bigger upgrade than the flow numbers alone suggest.

 

[Fringeless]

Lucky bastad! Ive been wanting one of those Ebrockers since they came out. Right now in the process of installing a EFI source MS3 goldbox universal standalone in my 92 OBDI 10:1 stroker. The cool thing about it is that it can control the Jeep alternator and works off of the stock Crank and cam (distributor) sensor. Well, did you get a chance to measure the combustion chamber volume?

 

[Russ Pottenger]

After doing the chamber work I surfaced the head .019 to bring it back to 55cc
Static compression ratio will be 10.17:1

 

[fzsk4p]

Right now in the process of installing a EFI source MS3 goldbox universal standalone in my 92 OBDI 10:1 stroker. The cool thing about it is that it can control the Jeep alternator and works off of the stock Crank and cam (distributor) sensor. Well, did you get a chance to measure the combustion chamber volume?

Not to hijack Russ`s thread. Why a standalone setup when an OBD2 factory JTEC can be used with unlimited calibration ability ?

If the aftermarket system ever fails your stuck whereas with the JTEC you can get an ECM/components from anywhere.

 

[streetxj]

Just curious, how much do you charge for a ported/polished 7120 head?
Will it make much of a difference compared to the stock 0630 head on a 1996 OBD-II bolt-on jeep 4.0 engine (stock engine with newer style intake, gibson header, free flow exhaust, 62mm throttlebody, bosch 703 fuel injectors)?

 

[Boostwerks.com]

Those are fantastic exhaust gains! Great work!

If/when I ever build a stoker I will definitely be hitting you up.

 

[Johnnie Walker]

Just curious, how much do you charge for a ported/polished 7120 head?
Will it make much of a difference compared to the stock 0630 head on a 1996 OBD-II bolt-on jeep 4.0 engine (stock engine with newer style intake, gibson header, free flow exhaust, 62mm throttlebody, bosch 703 fuel injectors)?

Simple answer: Yes.

 

[Russ Pottenger]

Just curious, how much do you charge for a ported/polished 7120 head?
Will it make much of a difference compared to the stock 0630 head on a 1996 OBD-II bolt-on jeep 4.0 engine (stock engine with newer style intake, gibson header, free flow exhaust, 62mm throttlebody, bosch 703 fuel injectors)?

PM sent.

Increasing airflow in a engine is critical in making more power.
It's much like running up a flight of stairs with asthma with any sense of efficiency.

Lets try to put this in more perspective and make come comparisons.
Many of you might be familiar of making a stroker out of a 350 Chevy.
Much like dropping in a 258 crankshaft in one of our 4.0's to make a 4.6 or 4.7,
Chevy's version of this is very similar. Drop in a 400 stroke crank to 350 block bored
.030 over you get 383 cubic inches.

Now lets take a fresh look at our 4.6 stroker. Each one of cylinders is measuring about
47 cubic inches. If we wanted to make a rough comparison to our Chevy 383 stroker we would add two more cylinders at the value of 47 C.I. each and we would have a engine that measures 376 cubic inches, not far off from our 383 Chevy engine.

My point in all of this is if we want our Jeep strokers to make more power, we need to
cure the asthma.

 

[Fringeless]

Not to hijack Russ`s thread. Why a standalone setup when an OBD2 factory JTEC can be used with unlimited calibration ability ?

If the aftermarket system ever fails your stuck whereas with the JTEC you can get an ECM/components from anywhere.

For me it is about control. Basically, the Goldbox is the same thing as a megasquirt 3 pro. The only difference is that it is larger (room for addition of an internal transmission controller and it lacks an internal clock circuit). It and the ms3/ms3x/ms3pro are the only standalones that I know of that work with the stock jeep cps (1 window) and cpk (forgot format). It is easy to install hook up to stock ecu power and engine /alternator circuits, trunk map/tps/vss to transcontrol unit (under dash for 92 obdi) then go play. I like the system because I have the ability to analyze and modify my engine when ever I want (wirelessly) through my cell phone, laptop, or tablet. I can view VE tables/af/timing/vacuum/view fuel consumption/run e85 (or any alcohol blend) with automatic ecu compensation and so on. I like to travel the less traveled road. In all reality, installing something like a goldbox or ms3 pro would be easier and less time consuming than doing a full-on obdii conversion, yet would yeild better results as far as tuning is concerned. Note, I said easier not less expensive considering jtec and ancillaries are pulled from a yard.

Steve-Oiratefla

 

[Fringeless]

I forgot to mention that I am making a homemade patch cable using a female connector from an old ecu and a male from an old harness. The splices are in a weatherproof box, not in the factory harness. What does this mean? It means that if my aftermarket ecu ever fails, then I unplug the aftermarket ecu and just plug the factory harness back into the factory ecu (which is left in its stock location). Cheers.
Steve-O

 

[sidewaysstarion]

I forgot to mention that I am making a homemade patch cable using a female connector from an old ecu and a male from an old harness. The splices are in a weatherproof box, not in the factory harness. What does this mean? It means that if my aftermarket ecu ever fails, then I unplug the aftermarket ecu and just plug the factory harness back into the factory ecu (which is left in its stock location). Cheers.
Steve-O

You can do the same thing with a jtec and the only sensor you really need is a battery temp sensor. What is nice about running stock parts is you have the reliability and availability of a factory ECU. Let say I brick my ecu, I can go grab one out of the junkyard for ~$40 and be up and running after a quick reflash. Plus they are cheap enough to have a spare or two sitting around just in case.