I have a renix head and a h.o 4l to put together. I understand they bolt up. But what head set should i use? One for the renix or the h.o??

Also how much can i shave the head. I'd like to get the cr up and gain some torque. Im not opposed to decking the block. Id like to take it down to just a touch more than the rod stretch if i can.

So thats what i am up too. Also any links would be handy also looking to go with a better than factory oil pump.

Thanks for any help

 

if you have a hi output motor use a high output head you can port and polish have the head bored out for bigger intake and exhaust valve a high volume melling oil pump build a budget stroker get a 4.2 motor put the parts in the 4.0 block and you got a 4.5 stroker use the search to find other things and im sure someone else will chime in

 

I'd go with the HO head on the old block. Check out the Advanced Tech forum, someone posted some very informative links in there (though maybe it was here actually) about a budget stroker. Basically assemble your 4.0 but use the rods and crank from a 4.2 and... 4.5! Just like that. (well almost)

 

i'll check it out, but i'm not after a stroker. a small port head with high cr makes great torque. i dont get much over 2000 rpm when i am wheeling so i dont need a head thats more efficient above my target rpm, because big ports are going to slow my air speed and that will make for a dogy low end. now if i was stroking it would make sense tho. more displacement more cfm higher air speed ='s need for bigger ports.

i was looking thru my manual but un-like my bmw book . it don't list the piston to valve clearance. maybe thats what i should have asked for. oh and i'll try searching it too

main reason i dont want to build a stoker is. if i keep my jeep i'm putting a little diesel in it. but it will be like 9 months from now and my current engine is starting to tick or knock a little on start up and on decel. the recipe i am after i found on a few other forums months ago but. i was searching up something completely different when i stumbled upon it. i just never caught what head gasket was choice.

 

so the stoker thread is in the how too section, also hers engine data from this forum.

the renix has a better low end and peaks torque sooner even tho it makes a little less. so thats my main reason for staying with it and using ho manifolds .

4.0L performance Mods.....and Stats..
4.0L Engine revisions *********

'87-'90: 177hp at 4500rpm, 224lbft at 2400rpm, redline 5000rpm
The '87-'90 engines had Renix electronic multipoint fuel injection, electronic ignition, a 52mm throttle body, and an inefficient "low port" cylinder head similar to the old 4.2L/258. They have a water temp port in the back of the head. (Use a '91-'95 HO head for a head swap to replace these most easily.)

'91-'95: 190hp at 4750rpm, 225lbft at 3950rpm, redline 5250rpm
In 1991 engines received Chrysler sequential MPFI, a larger 60mm throttle body, revised intake and exhaust manifolds, and a more efficient high port cylinder head. As a result, these engines produced 13hp more than their predecessors and gained the "High Output" designation.

'96-'99: 190hp at 4600rpm, 225lbft at 3000rpm, redline 5300rpm
In 1996 engines received noise, vibration, and harshness fixes. The blocks were stiffened with extra ribbing, a main bearing brace was added, and lighter cast aluminium pistons were introduced to improve efficiency and reduce cold start piston slap. Engines also received revised camshaft timing for more low rev torque. Heads are similar except that they have no water temp port. (The OBD II system drives the guages and, only requires one port, these can be drilled and tapped for the sender used in earlier models if you're doing a head swap.)

'99.5-'01: 193hp at 4600rpm, 231lbft at 3000rpm, redline 5300rpm
In 2000 a distributorless coil-on-plug ignition system was installed, intake and exhaust manifolds were revised, and a more efficient water pump was included. These heads are quite different. They have smaller exhaust ports and, mounting bosses for the coil pack used with the distributorless ignition. There are different accessory mounting hole locations on these as well.

 

Renix head will be fine for what you're after. Mill it a bit if you like.

 

Oh, just some specks. Maybe not really too much help, but you can decide on that! http://www.jeep4.0performance.4mg.com/tech_specs.html

 

Thanks for the link.

Any one know of a roker arm upgrade. Like on the ls1 forum they use different ratio roker arms to get a little more lift. I searched but found only long arm upgrades for my front end lol