- Location
- Hammertown, USA
I always thought quench should be 'less than .040'. Ours is in the .020 range.
Edelbrock aluminum head in the works
- Thread starter Talyn
- Start date
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
Yes. That said, with all else being equal you could run a half to a full point more compression using an aluminum head so Edelbrock were being conservative.
You could zero deck the block to tighten up the quench to the thickness of the head gasket, add the aluminum head, and still run regular pump gas.
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
.044" quench will be fine. Anything over ~.60" is useless. .040" to .035" is a safe area.
The combustion chamber CC could be lower to increase compression, yes. However, I think they produced this head with the idea of being able to run a stroker as well as a stock engine. I'd bet that the majority of these heads end up on strokers.
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
double
Root Moose
NAXJA Forum User
- Location
- ON, Canada
So how do you get quench under the thickness of the head gasket?
Negative block milling and making sure the piston doesn't stand proud of the gasket at TDC?
Negative block milling and making sure the piston doesn't stand proud of the gasket at TDC?
- Location
- Hammertown, USA
Thats exactly it. Have the piston come up out of the hole 10-15 thou
offroadordnance
NAXJA Forum User
- Location
- Florida
My guess is they kept CR low to keep NOX at acceptable levels in order to get their EO exemption. They might of left the exhaust ports a little restricted for the same reason. For lack of an EGR system, they need to keep combustion temp around or below 1,300C, that magical temp where NOX is formed. An external EGR system would of allowed them to bump up the CR and maybe increase exhaust flow, but it would have had to tie into OBD2 which isn't practical.
streetxj
NAXJA Forum User
- Location
- Pembroke Pines, FL
I found a couple of more pics.
Russ Pottenger
NAXJA Forum User
- Location
- West Covina, California
Jeep Porno.
Can't wait to get my hands on one.
Can't wait to get my hands on one.
hot_rod_hooligans
NAXJA Forum User
- Location
- Indianapolis
https://www.facebook.com/video.php?v=762881130416204
Dyno time....
Dyno time....
streetxj
NAXJA Forum User
- Location
- Pembroke Pines, FL
As you can see, it's an OBD-1 4.0 HO. Usually, the OBD-1 version is more responsive to modifications. I wonder if the gains they were advertising are from a 91-95' HO. If that's the case, will it be less for the OBD-2 4.0's?
I've just posted a comment regarding the gain comparison of the 91'-95' HO vs the 96'-04' HO on the edelbrock facebook page. I just don't think the gains they posted for their advertisement would cover both OBD-1 and OBD 2 versions of the 4.0 HO since the cams and ECU's are different.
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GrimmJeeper
NAXJA Forum User
- Location
- Gardena, CA
wtf is the washer tank doing there? it should be on the passenger side if its an OBD1. i see a dual diaphragm booster, makes me think this might be a 96?
- Location
- Torrance, CA
Sbec ecu says pre-96, so maybe a 95?
GrimmJeeper
NAXJA Forum User
- Location
- Gardena, CA
my 95 had it on the passenger side firewall
Root Moose
NAXJA Forum User
- Location
- ON, Canada
It's a Jeep... the washer reservoir has probably been in a dozen different locations over the course of the Jeep's life.
streetxj
NAXJA Forum User
- Location
- Pembroke Pines, FL
^lol I agree. My friends old 91' XJ had the reservoir on the drivers side if I remembered correctly. My 96' has it on the passenger side.
alex22
NAXJA Forum User
- Location
- CT: waterbury area
Too bad it has the lower exhaust ports. Is there a way to run the 99+ pre-cats with this setup and not have a nasty port overhang and not require welding on a brand new head?
One of these might just find its way onto my next money pit of an engine build.
One of these might just find its way onto my next money pit of an engine build.
streetxj
NAXJA Forum User
- Location
- Pembroke Pines, FL
You could do something about your pre-cat issue, but I can't mention it in the forum. Lets just say it involves spark plug anti-foulers. :eyes: :shhh: Worst case scenario, you can get a high quality port and polished thicker cast 0331 head. The intake and exhaust port shape of the 0331 head is more ideal for the 4.0 scavenging-wise compared to the 7120/0630 head based on what I've read. The exhaust ports are much smaller, but they have higher velocity compared to the larger exhaust port of the older HO head. Not sure why edelbrock didn't go with the 0331-port style/design if it was supposedly better.
alex22
NAXJA Forum User
- Location
- CT: waterbury area
I've ran one of the aftermarket 0331 heads, they need porting to be as good as a factory casting due to the casting flash inside of the ports. A quick clean up and the exhausts will flow plenty, there is no real reason to go town on them.
The raised ports of the 0331 heads are better than the lower ports on the 'HO' heads. I've ported and flowed 0331 castings and the 0630 heads.
Mine will be going into a 96 so I'm not worried about it, I'm wondering about the claim of 50 state legal in the Edelbrock catalog and whether or not it will work with the required pre-cats.
:cheers:
~Alex
The raised ports of the 0331 heads are better than the lower ports on the 'HO' heads. I've ported and flowed 0331 castings and the 0630 heads.
Mine will be going into a 96 so I'm not worried about it, I'm wondering about the claim of 50 state legal in the Edelbrock catalog and whether or not it will work with the required pre-cats.
:cheers:
~Alex
streetxj
NAXJA Forum User
- Location
- Pembroke Pines, FL
Oh okay. You can try contacting Edelbrock. I personally think it will be a pain in the a$$ since you'll need to use headers made for the older 7120/0630 exhaust port locations.
Just wondering, what was the difference between the 0331 and 0630 flow-wise based on your tests?