ratrapp Posted April 11, 2009 Share Posted April 11, 2009 my head gasket is starting to seep oil after 160k miles.i was thinking about changing to a different head while i'm at it.i've heard different stories about ho-heads and even newer heads.would it be worth my while to do this and i really don't want to change my intake just and deal with the tb issues.i'd like to hear from personal experiences.thanks Link to comment Share on other sites More sharing options...
aemsee Posted April 11, 2009 Share Posted April 11, 2009 Depends on what you want to achieve. There were some cracking issues with 2000/2001 cyl heads. With 160 you probably need at least some valve work done. I found a reman head with springs, valves for $200 a couple of years ago. Check your rocker arms and pivots really well. They tend to wear out. Link to comment Share on other sites More sharing options...
ratrapp Posted April 11, 2009 Author Share Posted April 11, 2009 umm,that really didn't answer anything.what i'm asking is it really worth changing to a ho head and are all 91-up heads the ho style. Link to comment Share on other sites More sharing options...
jpdocdave Posted April 12, 2009 Share Posted April 12, 2009 i say do it if you got a little extra money, like someone said, it probably needs valve work anyway. i have ported and polished both heads. the ho head porting is noticeably larger to start off with. if it were me i'd find a 91-96 or so head, and the latest ram style intake, and bored throttle body, there's a hot ticket right der. Link to comment Share on other sites More sharing options...
jtdesigns Posted April 12, 2009 Share Posted April 12, 2009 Head gaskets don't seep oil.... Do they??? :hmm: You mean the Valve cover gasket right?? Link to comment Share on other sites More sharing options...
jpdocdave Posted April 12, 2009 Share Posted April 12, 2009 i see a lot of them seep, you clean the oil off at the oil change, and the head gasket is damp/wet at the next one. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted April 12, 2009 Share Posted April 12, 2009 worth it. bolt-on. when you do it, you can't use the renix intake or exhaust manifolds anymore, however you can use any H.O. intake and exhaust. preferably upgrade to a 99+ 4.0 intake as well for an extra 15hp. then you'd have to either adapt the renix TB to the H.O. manifold, or adapt the renix TPS to the H.O. TB. the renix fuel rail will bolt on the H.O. manifold with no issues. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 12, 2009 Share Posted April 12, 2009 The 96-98 HO head (casting #0630) is generally regarded as the most desirable; a bit more meat, not prone to cracks, and the least troublesome. :D Link to comment Share on other sites More sharing options...
jpdocdave Posted April 12, 2009 Share Posted April 12, 2009 The 96-98 HO head (casting #0630) is generally regarded as the most desirable; a bit more meat, not prone to cracks, and the least troublesome. :D from what i've heard the 91-95 were as good, i have a casting number in the garage. i know the one i got off a 95 yj was a "desirable" one. Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 12, 2009 Share Posted April 12, 2009 from what i've heard the 91-95 were as good, i have a casting number in the garage. i know the one i got off a 95 yj was a "desirable" one. The 91-95 heads (should be casting # 7120) are also excellent. Both heads are nearly identical. Just avoid the crack-prone 99+ heads. :D Link to comment Share on other sites More sharing options...
jtdesigns Posted April 12, 2009 Share Posted April 12, 2009 from what i've heard the 91-95 were as good, i have a casting number in the garage. i know the one i got off a 95 yj was a "desirable" one. The 91-95 heads (should be casting # 7120) are also excellent. Both heads are nearly identical. Just avoid the crack-prone 99+ heads. :D What was the difference in the 96 heads from the 91-95? Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 12, 2009 Share Posted April 12, 2009 The 96-98 heads had a bit more meat for more aggresive porting, and perhaps 25% of them did not have the threaded hole for the gauge temp sensor. Other than that not too much. Link to comment Share on other sites More sharing options...
dakineJ Posted April 12, 2009 Share Posted April 12, 2009 Something I 've wanted to try is a renix block,which is supposed to have a stronger casting,use the better flowing #7120 head and the 99+ intake manifold,a 62mm throttle body,not shure which HO year.Then,as said,you have several choices for a header and intake.Of course,you don't have to stop there... ;) Link to comment Share on other sites More sharing options...
ratrapp Posted April 12, 2009 Author Share Posted April 12, 2009 i wasn't aware the bolt patterns are different for the manifolds.i just put a new exhaust manifold on and really don't want to fool with tb issue just yet.i can get a 91-95 head for less than a $100 from the local junkyard if i pull it myself.i just wanted to get a head already done and ready to swap on the same day as right now my mj is my only running vehicle as i haven't had time to put my 393 back in my mustang.i may just put up with the head gasket seeping oil.it's definitly the head gasket because i switched to the new style steel valve cover and fel-pro perma seal gasket and my valve cover has never been that dry and no more oil in air box.thanks for help,guys. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted April 12, 2009 Share Posted April 12, 2009 oh, they'll bolt on. ...but the porting is nowhere near the same between renix and H.O. intakes Link to comment Share on other sites More sharing options...
ratrapp Posted April 12, 2009 Author Share Posted April 12, 2009 as long as they'll bolt on then i'll upgrade the intake at a later time. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted April 12, 2009 Share Posted April 12, 2009 as long as they'll bolt on then i'll upgrade the intake at a later time. now is the time. you will have them off now, upgrade now. non-matching ports = absolutely SHOTTY performance. do it now and save the headache and potential leaks. I'll GIVE you a regular H.O. intake, and I'll also give you an exhaust manifold. the exhaust manifold is cracked but should be weldable. Link to comment Share on other sites More sharing options...
Eagle Posted April 12, 2009 Share Posted April 12, 2009 i wasn't aware the bolt patterns are different for the manifolds.i just put a new exhaust manifold on and really don't want to fool with tb issue just yet.i can get a 91-95 head for less than a $100 from the local junkyard if i pull it myself.i just wanted to get a head already done and ready to swap on the same day as right now my mj is my only running vehicle as i haven't had time to put my 393 back in my mustang.i may just put up with the head gasket seeping oil.it's definitly the head gasket because i switched to the new style steel valve cover and fel-pro perma seal gasket and my valve cover has never been that dry and no more oil in air box.thanks for help,guys. JeepcoMJ is correct. The bolt pattern isn't the issue. The issue is that the ports on the HO heads are higher up, and shaped differently, and the position of the locating dowels is different. You can mate Renix manifolds to an HO head (or vice versa, I guess), but with the turbulence created by the mismatched port shapes I have always wondered if there's any gain at all, or really a new loss. Personally, if I had a Renix (which, in fact, I do) I would use a Renix head, clean up and polish the ports a bit, maybe do a light polish on the combustion chambers, and go with it. One thing to consider, gents: Most of you know that I'm a certified Olde Pharte. I've been playing with these things for a loooong time. It has always been considered accepted knowledge that doing a valve job without also doing the lower end of the motor accelerates and increases blow-by, because the new valve job seals great but the old rings don't. Way back when I was married to my first wife in the early 1970s one of the heads on her car (which I had bought used -- a 1969 AMX 390 4-speed) needed work. We were newly-weds, on a tight budget AND trying to help support her recently-widowed mother, so a complete engine rebuild was out of the question. I pulled the heads, cleaned up the valve seats using a manual cutter (basically just removed old carbon), did some very mild polishing, installed new valve seals, and slapped the heads back on. Oil consumption increased by a factor of about two+. Before the head work it used a quart in maybe 1500 miles. Within a couple of weeks after, we were using a quart in about 750 miles. Which just demonstrates the wisdom of the old adage: "If it ain't broke ... don't fix it." BTW -- I've never heard of a head gasket seeping oil. If it's oil, I would look elsewhere for the source. Link to comment Share on other sites More sharing options...
ratrapp Posted April 12, 2009 Author Share Posted April 12, 2009 you've never seen a first gen. dodge neon head then.trust me it's the head gasket seeping as others will testify too as well. Link to comment Share on other sites More sharing options...
jpdocdave Posted April 13, 2009 Share Posted April 13, 2009 4.0 heads leak and or seep oil, i've owned and repaired them and repaired them for customer's Link to comment Share on other sites More sharing options...
JeepcoMJ Posted April 13, 2009 Share Posted April 13, 2009 I agree about the heads seeping...my H.O. that i just swapped in the MJ has a seeping head gasket. I'm not worried much about it at the moment. kicking myself in the @$$ though...the motor has only 3k miles so I didn't pull the head, but now wish I had. also, eagle is correct it is somewhat pointless to do a head rebuild and valve job if you're not doing rings. -Pat Link to comment Share on other sites More sharing options...
Comanche County Posted April 13, 2009 Share Posted April 13, 2009 I had my 89 renix head rebuilt because my head gasket and rear main seal were both leaking oil like crazy. I put in a new rear main, oil pressure returned to something acceptable, but then the head started blowing oil worse than the RMS and oil pressure was low again, below 20 lbs. The head gasket can leak badly on the passenger side where the lifters are without losing compression. This is what mine was doing. It was running great, compression was fine, but it was leaking some'in fierce. The rebuild cost me 300 bucks, maybe I could have gone with an HO head, but I didn't want to mess with swapping any of the fuel stuff. Got it magged, 3 angle valve job, new seals, valves and springs all checked by a high performance engine shop. (Rigde Reamer in Arvada, CO). I'm happy with it, the truck starts great, runs as smooth as a baby's bottom, and it runs even cooler now. I was going to switch to an open cooling system, but not now. It doesn't even think about getting hot, even with a 195 degree t-stat. I'm going to leave it like it is and run it another 50K. Also, when I pulled the head, I could still see the factory cylinder wall honing, EVEN AFTER 196K! These really are great motors. (Working on a stroker in the garage now, for a future install in the far future) Link to comment Share on other sites More sharing options...
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