Edelbrock 4.0L head soon to be available.

[SilverXJ]

Anyone know if there are any issues using screw in studs with the stock rocker arms?

Why would you do that?

[nicpaige]

Anyone know if there are any issues using screw in studs with the stock rocker arms?

Why would you do that?

I have some experience with roller rocker arms but not on this engine. I have found them to be fairly noisy compared to a stock rocker arm. Have you experienced different results on the inline 6?

[jeepxj3]

My roller rockers are quieter than stock. No problems with the bolt, no stud.

[SilverXJ]

I have some experience with roller rocker arms but not on this engine. I have found them to be fairly noisy compared to a stock rocker arm. Have you experienced different results on the inline 6?

Mine are a bit noisy. Nothing terrible.

I was asking about the studs though.

[Gristleheart]

Does installation of this head require any modifications to a stock engine? Or will this work as a bolt-on upgrade?

[rwkhaussupply]

FYI, anyone running this head. I started with the Edelbrock recommended RC12YC plugs. I have been working thru adjusting and such all kinds of things to get power out of a decently built 4.7. One thing I did was pull plugs to see color and change them. They were white as white, and then I realized that what I got from the parts store were RC12LYC.

The difference is about .23 more projection into the cyl. I tried calling Edel but it was 4:35pm pac and they were closed and I am trying everything I can to get it to a dyno tomorrow, so I just figured why not. Installed all the LYC plugs and started easier, ran smoother and I think picked up noticeable gain in power.

I called edelbrock and explained this to them and they are going to investigate the need to change recommended plugs.

Also anyone installing this head, dont be surprised if you have to open up the AC bracket lower (or the 2 upper) mounting holes. My bracket was about 1/4" to far apart and seems as though the head is manuf. with the mounting holes a tad bit lower. Easy fix, just ream out the lower mounting bolt hole some.

Another FYI, even with roller rockers and beehive springs, the Valve Train Is Noisy. I was told the valve seats were Very hard material, and I think the valve closing/hitting the seats is noticeable now in volume.

[Torqsplit]

The RC12LYC is the standard-application plug for a 4.0L. This could be tricky for you on a 4.7, especially if you get to the dyno and do some pulls. It depends greatly on your compression ration, but you may need a colder plug. That head may allow the use a hotter plug(like the RC12) by dissipating heat more efficiently, but I'd keep a close eye on them. Good luck and PLEASE post your dyno results!

[jeepxj3]

Another FYI, even with roller rockers and beehive springs, the Valve Train Is Noisy. I was told the valve seats were Very hard material, and I think the valve closing/hitting the seats is noticeable now in volume.

What cam are you using? I missed it.

[jsawduste]

Another FYI, even with roller rockers and beehive springs, the Valve Train Is Noisy. I was told the valve seats were Very hard material, and I think the valve closing/hitting the seats is noticeable now in volume.

What cam are you using? I missed it.

It was never posted. Robert or Russ can chime in if they want to divulge the specs.

[rwkhaussupply]

The cam I think is very mild.
EDIT- lift is .462/.485
Dur @ .050 206/214
113 sep.

I dont know how much other info Russ wants advertised, I know he gets this cam custom with Comp and himself liking the grind they came up with.


Now on to my pre/post dyno report.

32RH SUCKS on a dyno. No way to make a full pull and chest pounding results. No way to hold it in 2 or especially 3rd. Sure you can hold the 35mph that the dyno loads up to in 3rd at like 20% throttle. Then when you is go time and you try to pull, you have to modulate how much throttle you give it or it down shifts and then it really just goes out the winder. Or you can try to find the happy spot just before it down shifts, but then your not getting even close to Max HP #'s.

SO I used the time for what it really was for and that was for Chris to do some load test and maping and get fuel and timing better/right.

When I first installed this pretty thing I had HIGH expectations. I was extremely disappointed. Feel less than stock in power. Well it just needed alot of little "tweaks" evidently.

Started with new O2 just cause. Seemed to help a tad bit.
Tried to move dist/cam sensor over one tooth each way to see if that was the issue, nada.
Then found that one plug wire was arcing out and figured just new wires and plugs. Bought the rc12Lyc projected tip (stock basically) plugs. Pulled out White as white can be plugs and installed the new longer tip and good new set of wires. This was significant improvement.
But, still lugged and bogged and would not down shit in to 1st. Adjusted the trans detent cable. This was the single most impact-full thing, besides tuning on dyno. Now it was drive-able without mentally just thinking lets pull this out and LS swap it.
At this point I was now about double the power It felt like then when I first drove it 2 days prior with the new 4.7.
Then I had one of my 3 mufflers removed. I had/have, 2.25 all manderal bent tube with 2 tiny lil (like 4x6x4) spintech true track race type mufflers and a 10" glass pack, as well as a magnaflow CA legal high flow cat. Hard to explain, but if you have a TJ imagine a rear triangulated susp setup and nice over sized belly skid. And my prime concern when I had it done, was for quiet and compact. SO I had the one glasspack removed from the rear most position to open it up a bit. It got louder and sounds alot like an older SBC in say a chevelle or such. But, again picked up a tad more power I think.
Then since it would run lean(15.2-15.4) at idle with a long term fuel trim of -14 to -17, and then Very fat at WOT in the low 11's), I bought a set of FiveO 24.5lbs inj. Just incase my 30lbs were just too much.

Went to dyno last night. As mentioned above, no way to do real pulls. Just pieces here and there it seemed. I think the highest it reached was like 120HP and 201tq on different occasions and the majority of the graphs were so up down and one even went around in a circle almost. SO I dont think the HP ever even got close to max, and I doubt th etorque was maxed either, but Everything I read on the 32RH TJ and larger tires etc. The typical loos is about 35-40%. SO if the 201tq was maxed even then I would be sitting about 280TQ, and it was almost perfectly flat from 2k up to like 5200. SO I am sure it has more TQ even. But this is all guessing.

Chris flashed a few times after doing some partial pulls here and there. I was lost mostly as to what he was really doing.

But after about 3 hours, we wrapped it up. On my way to MOTOIQ to use their Dyno about 40 miles away, it drove ok. As chris first said when he was just reving, it to cal the dyno engine speed, it just didnt seem like it wanted to rev, it was rough. On my way home, it was a whole other creature. Very responsive now. It does want to rev now, I feel. The A/F were in the high 14's cruising on the Fwy. And the few times on the way home I WOT'd, it was high 12's maybe 13.1. Much better. It has more power still again.

The MPG registered at 14.9 for my 40mile drive home. The long term fuel trim was only at -2.5 to -3.

I feel this engine now has the power of my race jeep that had also a russ built engine, but the fully worked over iron head and I think more comp, but over a point more, but cant say for sure. I also had the AW4 with lower first, 5.38 gears and a 35" tire. SO if this is on par with that engine now, as I really think it is. I am very happy. And the rings still might seat in a tad bit more. Only maybe 300-400 miles on it as of now.

What I like:
Very flat power "curve"
Idles very nice
Should be very smog legal, as everything is CARB legal (maybe cam tech. is not, but thats niether here nor there).
Decent gas mileage
Trans is very nice as a street driver, shifts at perfect RPM now and downshifts perfectly I feel. Will add a transgo kit soon though.
Bling parts, matters when you went from race jeep to family jeep lol.

What I dont like so much:
How loud it is now. Not very bad but not my quiet lil 4.0 thats for sure.
Cant spin the tires (but 4.11 gears and 35's on an auto).
How mild the cam is I THINK. Maybe this is for the better though. I run 17-18in vac at idle, get 15MPG, and idle purrs.
The 3 sp trans, but not willing at this point to AW4 swap it. maybe next year.

Would I do it all over with the Engine and head I have, maybe not. The extra cost of the head I dont think is justified if you have the 7120 option from Russ also avail at I would guess $1000 less. Maybe if you are building a track style engine, but its still Just a 4.0 block with long weak cam stick.

Would I recommend Tuning. HIGHLY! I cant do what Chris or I guess any one with the right knowledge and equipment can. And I did Not feel comfortable with the fuel in the 11's at WOT (washes the cyl bad and bad for O2 etc), and then daily driving and semi loads on engine were in the 14.8-15's. Not to mention the drive-ability and smooth rev's now. And I am sure the timing he added had to have helped.

Sorry about the long post. but just hope to get all the info, facts, and my opinion in there.

[jeepxj3]

Cam seems very mild, lift wise, for that head. Maybe try a set of 1.7:1 roller rockers would add some lift to 0.491"/0.515"?