Heads coming out- What next?

[JeepinAudiophile]

(2000 Cherokee XJ- I6, coil on plug)
So my banks headers failed at the O2 bung so they are being replaced under warranty. That means the intake is off, and I have a leak at my head gasket so it's coming off to be replaced.

The question:
I was going to take my head to a shop to have it cleaned up and probably take it down just a tad to bring up the compression ratio... Buy an aftermarket reworked head, or take it to a shop... I really don't know who to take it to in the area.
I have been out of the Jeep modding scene for a while as my daily driver is a GMC Sierra, and my jeep stays in another state with my parents as a winter vehicle and tow vehicle behind their motorhome.

What is the best option to do? I was thinking of finding a head that has been ported, polished and reworked- but who has a good option? or just go with the path of having my head cleaned up and reworked...

My setup:
I have a clear intake path via snorkel and custom filter with a bored throttle body..
Exhaust has the Banks header, 2.5" stainless to the tail pipe with a high flow cat and Banks Monster muffler.(it's all in my signature)

ANY ideas are welcome as I the Cherokee (XJ) could use some more power and at 130,000 miles standard tuneup/replacement ideas are welcome also.

 

[Mr_Random]

Well before the head is off, do a compression test to find if the piston rings/valves are sound. If you're within spec, just try to find a local, one man engine shop; get a 3 angle valve job, possibly new valves (if not just cleaned up), have it flowbenched if you want to pay for it, and get a new cam/lifter/spring set from hesco or another reputable aftermarket supplier. Some strokers have oversized valves with roller rockers, but with the stock displacement you aren't gonna get much help (down low) from either.

Oh, the reason why I say a local, one man shop, is because you will more than likely get the best costumer service at a more reasonable price. It might take a little longer, but in the end I was VERY satisfied after avoiding the big shops to get my engine work done!

Edit: haha, forgot you said your head gasket is leaking. Find out which cylinders you have lost compression in, then do a leak down test in any that have low compression. This will determine whether it is just the head gasket, or the rings themselves (which means whole rebuild).

Oh, and I think you have the 0331 head, which has been known as a weak spot (right?), have it checked for warpage/cracks once it's off...

 

[GrimmJeeper]

do as Mr Random says, if you are keeping your old head. if you just want to outright buy a new one ready to go give Hesco a call and buy the King Dingaling head all ready to bolt on. less hassle IMO.

 

[REDXJ4FUN]

either way ditch that one , the earlier ones flow much much better.

 

[seanyb505]

the hesco ones dont make the advertised power.

 

[TheManch]

well you probably have an 0331 casting number head which is less than desirable in that it is very prone to cracking. I am currently ditching mine just for peace of mind sake. If i were in you shoes i would ditch the 0331 for an 0630 or 7120 head. They are less prone to cracking, and flow better. the 0331 head has smaller exhaust ports to help heat the pre-cats and improve catalyst light off, you could see benefit from a stock 7120 head simply due to the size of exhaust ports. Just throwing another option into the mix, if you want more info i have a thread in this form about what im currently doing with my head.
And i know its a bit of a ride but i have heard lots of good things about daves auto machine in fitchburg ma.


Mike

Also as far as taking the head down for increased compression ratio, 5-90 would be the one to talk to on that. I asked him about it in my thread and he explained to me why i wouldn't want to. It all has to do with the 4.0 having a pretty good quench height. or thats how i understand it........

 

[seanyb505]

About the quench height, I dont think its that good. The stock quench is .073"; good is somewhere in the .060-.045 range. If you shave the head to increase compression, you might get some pinging unless you want to use a higher grade fuel. I dont think it would be such a bad idea if you went for a thinner head gasket. It would bring your quench down, and raise compression. I believe some people are starting to find a .041" thick head gasket, which would raise your compression to 8.94 and lower your quench to .063. Im not sure how much power would be gained, but you would definitely have a more efficient engine.

Edit: Manch I just went back and read your thread. The reason 5-90 advised against a thinner head gasket there was you had already shaved the head. I dont know why he said the 4.0 was quench compliant, then said good quench is aroound .060-.045. Maybe just it was close enough that it had some effect?

 

[TheManch]

well that makes more sense now, since i think the guy took about .012 off my head to make it flat and true. Im still very much in a learning process with this whole thing so im trying not spread bad info.

Mike

 

[JeepinAudiophile]

Thanks for the quick replies and information... I had just started reading about the 0331 head and based on the size of my exhaust ports I'd say i have it. I am only in town for a few days before flying back to Florida so my father is going to be doing all the work. He told me he'd like to keep the iron block and just have the head rebuilt, valves, etc...
He was just planning to get our head done, but I will advise him that we should get the older style head instead. He also said hes not interested in doing a cam and going that route... and I don't blame him, down the road I want to build a stroker but thats another plan for another day.

So as far as power adders- I guess the tuneup and older style heads are all its going to get. Thanks for all the information.

What would be the differences between the 0630 and 7120 head? Will either be fine- or should I look for a specific one?

 

[TheManch]

from what i have read the 0630 and 7120 heads flow pretty close to the same numbers, with the 7120 just barely beating the 0630. I saw a flow chart somewhere but dont have the link. Also bear in mind that when you swap to this style head there are other changes to be made, you will need to make a bracket for your coil on plug setup. You said that you have a banks header too, from what i have read the ports on that should be big enough to cover the exhaust ports on the head, just a thought as i would hate for you to have to get a new header. for mine im just using an APN header for a 94 because thats what year my head is. I think there might be a difference in the location of a port for the cooling temp sensor but i dont remember for sure at the moment,


Mike

 

[Talyn]

Ditch your current 0331 head. Find a good used 0630/7120 head and if you want you can port and polish it your self. After that get a 3 angle valve job and back cut the valves 32*. Or just get an Alabama Cylinder Head revised 0331 head and slap that on.

 

[JeepinAudiophile]

The biggest problem for me is that I am not doing the work. My father is doing the swap on the jeep as I am out of town and I would hate for him to have to do a bunch of extra work. When I ordered the headers from banks, it was a part number specific to the 00-01... should I be concerned about the headers not fitting the exhaust ports? I am sending the headers in for replacement- perhaps they would swap styles for me?
We got snow and freezing rain yesterday so my mom is freaking out about having the jeep back and getting her convertible off the road... my dad does not need any snags during the re-installation as he is working 50-60 hours a week and really doesn't have the time to be messing around.

I got a price of around 400 for the older style head, all reworked... this is a good price for my parents as they are not so concerned with rebuilding it to get more power, they just want it back together.

I checked out the Alabama Cylinder Heads 0331 head, I didn't see anything that mentioned "revised" but the cost was $495 which is reasonable if thats the right one.

 

[Talyn]

I am not an expert on what after market headers fit what head ports, but I have heard from several people that after market headers have ports large enough to accommodate both head's port sizes and locations. I can't guarantee it though.

As far as swapping to the earlier design it depends on which emissions package you have. Do you have the cali or federal?

If you already have the 0331 header, and you aren't looking for a better flowing head at the moment, but you need 100% bolt together then I would go with the Alabama cylinder head.. just ask them if it is the reinforced one... another option is finding a late model stock 0331 head. I have heard that they revised the design in 2003 or 2004 to fix the cracking issue. Most of the cracked heads I have seen have been from 00 and 01, but that could also be due to the fact that I frequent XJ sites and they only had two years of that head. I think the $495 is a bit high for the Alabama head as you should be able to find a good late model 0331 (when was the last TJ made? 05?) and have a 3 angle valve job and reworked for $300 by a machine shop. If you NEED it NOW, then pay the extra for the Alabama head.

 

[JeepinAudiophile]

Thanks for the quick help everyone, I think we have everything in order for a trouble free tune up.

 

[johnnyc]

This is where I got my 7120 for $239.

http://cgi.ebay.com/ebaymotors/REBU...62QQcategoryZ33617QQihZ017QQitemZ270309968754

They also have a new 0331 head for $489.

Whichever route you go, tell your dad to mount the intake and header to the head while on the bench. Then drop the entire unit into the Jeep.

Of course, he'll need a cherry picker to do it. But it makes life so much easier.

 

[JeepinAudiophile]

Damn that's a good idea... That is such a pita to work on... And an engine hoist we have... Thank you for the very very helpful suggestion. I was trying to figure out how he was going to get the head in there by hmself as it was without damaging the head, gasket, etc... That should work perfectly.

 

[Talyn]

Whichever route you go, tell your dad to mount the intake and header to the head while on the bench. Then drop the entire unit into the Jeep.

Of course, he'll need a cherry picker to do it. But it makes life so much easier.

x2 he will thank you later. I did it separately the first time. Last time I did that. It all goes in as an assembly now.

 

[johnnyc]

It just so happens that right before I took that picture, the rearmost stud snapped off in the head.

That would've been a PITA if the head was in the Jeep. But since it was on the bench, it was very easy to get the broken stud out.