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In need of a head

I have one from an 87. Not sure if there are differences.

$50, still on the motor in my garage so give me a days notice if you want it.
 
I believe the HO and renix heads are a bit different, but it should work. I think the differences are all internal (port size or chamber CCs possibly? I can't remember right now). It should bolt up the same and work though.
 
Thanks guys but they are not inter changable.My buddy has on from a late 80's and he said id wouldn't work but thanks.If all else fails I will to pick one this weekend.
 
You'll be wanting a 7120 (1991-1995) or 0630 (1996-1999) head - the 0331 (1999-2006) has reduced exhaust ports and won't breathe well for you.

Once you get the replacement, if you don't need the old one for a core, I'd like to talk to you about it. I don't have a 7120 yet, and the fact that it's cracked doesn't bother me at all (the sample 0630 I have is cracked all over - but I'm going to section them anyhow.)
 
5-90 said:
I don't have a 7120 yet, and the fact that it's cracked doesn't bother me at all (the sample 0630 I have is cracked all over - but I'm going to section them anyhow.)
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What kind of plans do you have for them? If I ever win the big one in the lottery I am gonna design a cross flow hemi head for the 4.0 with rotary valve train that will be good up to 8000 RPM. :D
 
Man,you guys in this forum know a lot about these xj's.Did you know those part numbers off the top of your head?And jeeperjohn is planning on designing a head.
 
diesel guy said:
Man,you guys in this forum know a lot about these xj's.Did you know those part numbers off the top of your head?And jeeperjohn is planning on designing a head.
Click to expand...

As a matter of fact, I did...:lecture:

And no, I'm not trying to design a new head ATM. I want to section a cylinder on each generation of head for comparison (I have a 2685, a couple of 2686, and an 0630 - need a 7120 and 0331. Preferably a 0331 and a 0331 TUPY...) and section the rest of it by cylinder for porting experiments.

I'd very much like to see a cross-draught head for the AMC six, but I don't expect that to happen anytime soon. We tossed around the idea of a signficantly-improved head on the Strokers group late 2001-early 2002, I dropped it all off with Indy Cylinder Heads about a month later, and it still took about two years before it came out (my only complaint about the head was that it was aluminum, not iron...)
 
jeeperjohn said:
What kind of plans do you have for them? If I ever win the big one in the lottery I am gonna design a cross flow hemi head for the 4.0 with rotary valve train that will be good up to 8000 RPM. :D
Click to expand...

By "rotary valve train," are you referring to the Coates Spherical Rotary Valve setup? That would be interesting - I've thought about it. But, it would be a pain to drive, since you effectively have to adapt to a DOHC timing setup...
 
jeeperjohn said:
What kind of plans do you have for them? If I ever win the big one in the lottery I am gonna design a cross flow hemi head for the 4.0 with rotary valve train that will be good up to 8000 RPM. :D
Click to expand...

Could a cross-draft head have saved the 4.0? Like hell I am gonna buy a Jeep with a minivan motor.....:flame:
 
diesel guy said:
I would love to donate my head to science lol.
Click to expand...

Cewell - let's keep an eye out for trans-California parts trains, then!

(First time I went in to see my neurologist, I walked up to the counter and said, "I'd like to make an appointment to have my head examined." Humour is alway helpful - and I did manage to say it with a straight face!

(Although, it was my head I wanted checked out anyhow...)
 
5-90 said:
By "rotary valve train," are you referring to the Coates Spherical Rotary Valve setup? That would be interesting - I've thought about it. But, it would be a pain to drive, since you effectively have to adapt to a DOHC timing setup...
Click to expand...
Yes, something like that. In many engines the valve train is the limiting factor for RPM. A rotary valve train could conceivably go 20K RPM with no issues. A cross flow hemi head with direct injection would be the shiznit! I have an idea to use air pressurized to around 30K PSI to atomize the fuel inside the cylinder as the injector sprays it for an ultra atomized mixture. This would only be a very small stream of air, the rest would be handled by a conventional twin screw type supercharger.
 
souske said:
Could a cross-draft head have saved the 4.0? Like hell I am gonna buy a Jeep with a minivan motor.....:flame:
Click to expand...
I think what killed the 4.0 was the fact that to make it fuel efficient enough for today's standards it would have cost too much even for a big automaker. A V-6 is not a bad design but just give me some reliable torque.
 
jeeperjohn said:
Yes, something like that. In many engines the valve train is the limiting factor for RPM. A rotary valve train could conceivably go 20K RPM with no issues. A cross flow hemi head with direct injection would be the shiznit! I have an idea to use air pressurized to around 30K PSI to atomize the fuel inside the cylinder as the injector sprays it for an ultra atomized mixture. This would only be a very small stream of air, the rest would be handled by a conventional twin screw type supercharger.
Click to expand...

Correct - what you're referring to is known as "valve float." This is why high-RPM engines require valve springs with much higher seat pressures (and why they wear out cams and rockers so much more quickly - even rollers.)

Enter the CSRV. http://www.coatesengine.com/. George Coates took a while to come up with this idea, and has tested it on various engines (I want to recall that his "test bed" was a BMW I6.) Advantages?
- No valve float
- No need for top oiling
- Absolutely predictable valve timing
- No valve "hot spots"
- Signficantly increased lubricating oil life (since it doesn't need to go up to the top of the head, and get overheated)
- Valves can open and close much more quickly, which means more "area under the curve" and therefore more airflow
- The idea of an "intereference" engine just became null and void!

The "tumble" would be minimised, since you don't have the valve head to cause it - but you could still get plenty of "swirl" in the air charge (it would depend on how the port opens up.)

Methinks this would complement Diesel engines very well, or even GDI (Gasoline Direct Injection) engines - since you've gotten rid of hot spots (good) and tumble (less so.)

Make one for the 6-242 in iron and have a reliable and simple drive setup for the valvetrain, and I'd be likely to buy one and put a bored/stroked block underneath it...
 
WOW,you guys sure know a lot about this stuff.But back to my original question,does anyone have a head layin around they don't need I am willing to pay.LOL thanks
 
Cal gives good head.

Check with him.
 
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