porting a head for a stock 4.0 ????????????

[75SV1]

Results?

It hasn't run yet. I also changed a lot of other stuff, so I couldn't point to any one thing. The 351W ran better, but the same story, I changed a lot of other stuff. I have a MB 240D to put back together, then a Ford Contour to do a few little things to sell it off, then back to the Comanche.
Tom

 

[BBeach]

Ive got the option of picking up a 0630 head from a 99TJ for a cheap price, should i get one of those or one from a 95 H.O.? Im considering milling it down a litlte bit and cleaning it up as well as porting/polishing it.

 

[j99xj]

1- You and a few others like to really wrap up the 4.0

The engine can rev quite well if its tuned up and the cat isn't clogged.

I don't know why so many people say the 4.0 sucks at revving because it most certainly does not.

Yes the engine was designed to provide good low end and mid range but it was designed for some top end too. If it wasn't it wouldn't make anything close to 190 hp stock.

 

[SCW]

The engine can rev quite well if its tuned up and the cat isn't clogged.

I don't know why so many people say the 4.0 sucks at revving because it most certainly does not.

Yes the engine was designed to provide good low end and mid range but it was designed for some top end too. If it wasn't it wouldn't make anything close to 190 hp stock.

I have a new high-flow cat & series 70 flowmaster, mine loves to run at about 3300rpm, but past 3800 is about impossible for me. I tried last week I'm sure a port/polish would do wonders but again, I'd rather have the low end any day of the week. It just suits me better. I'm shooting for a mild port and polish, easy on the intakes to keep intake velocity high and mill the head to increase compression.

I've also done an e-fan, TB bore, cold air and I was going to buy a new header, but now I'm putting that on the back burner for a while. I think a better head is the next logical improvement. Cam and cooling issues have me nervous about a stroker.

 

[Flash]

I have a new high-flow cat & series 70 flowmaster, mine loves to run at about 3300rpm, but past 3800 is about impossible for me. I tried last week I'm sure a port/polish would do wonders but again, I'd rather have the low end any day of the week. It just suits me better. I'm shooting for a mild port and polish, easy on the intakes to keep intake velocity high and mill the head to increase compression.

I've also done an e-fan, TB bore, cold air and I was going to buy a new header, but now I'm putting that on the back burner for a while. I think a better head is the next logical improvement. Cam and cooling issues have me nervous about a stroker.

So is your jeep a Renix or H.O.and what head do ya have on your bench?

Flash.

 

[seanyb505]

The engine can rev quite well if its tuned up and the cat isn't clogged.

I don't know why so many people say the 4.0 sucks at revving because it most certainly does not.

Yes the engine was designed to provide good low end and mid range but it was designed for some top end too. If it wasn't it wouldn't make anything close to 190 hp stock.

My 4.0 almost acts as if it has variable valve timing. Once it hits 3000RPM, its comes alive. I have no cat, Bullet muffler, APN headers, 99+ intake, cold air, TB spacer and electric fan. Once you feel the extra surge of power you know it was supposed to run at that level for performance.

 

[75SV1]

Ive got the option of picking up a 0630 head from a 99TJ for a cheap price, should i get one of those or one from a 95 H.O.? Im considering milling it down a litlte bit and cleaning it up as well as porting/polishing it.

Either head will do. I think the flow numbers are very simular. The 91-95 head has an extra temp port on the drivers side. You would need to plug it up. If you can get a good deal on the 96-99.5 head, then that is what I'd use. Get it checked for cracks, before any work. The price to have a head cleaned and checked can vary a bit. I think I had mine done for about $50. I've heard of twice that, though.
Tom

 

[j99xj]

My 4.0 has such a wide and flat torque curve that I can't even tell when it "comes on the cam."

My engine just runs great at all rpms. I have low end to top end.

I can actually accelerate and pass cars in overdrive at 1500 rpms and 45 mph without the aw4 kicking down to 3rd gear.

I can also make the engine scream down the highway at over 100 mph and 3000 rpm.

And this is all with a stock 4.0 with only bolt ons.

I would love a stroker but I can't see rebuilding a perfectly running engine.

 

[Dr. Dyno]

My 4.0 has such a wide and flat torque curve that I can't even tell when it "comes on the cam."

My engine just runs great at all rpms. I have low end to top end.

Same here with my 4.6 stroker. Maximum torque is 250rwtq at 3500-4000rpm and I've got at least 90% of that from 1700-4900rpm. Maximum power is 210rwhp at 4900rpm.

 

[SCW]

So is your jeep a Renix or H.O.and what head do ya have on your bench?

Flash.

Both are HO casting number 71## or something. It's the most common casting for the HO as compared to the two newer castings. Mine is a '92 and the one on the bench is from a '95 which I picked up locally for $50 last year (I'm very sloooowwww on this project).

 

[Flash]

Both are HO casting number 71## or something. It's the most common casting for the HO as compared to the two newer castings. Mine is a '92 and the one on the bench is from a '95 which I picked up locally for $50 last year (I'm very sloooowwww on this project).

Ya me to, just tring to fig out witch way to go with every thing before i start buying parts...............

Porting that one you have will be nice. You won't need to change any any thing when the head is done!

I have a spair Renix head, that i thing i will stick with so that i don't have to do all the mods that it take to put the HO head on my Renix.

But then again i seam to change my mind every day. AAAhhh I'M BECOMING A WOMAN!:twak: :laugh3:


Flash.

 

[SCW]

I wouldn't waste the time and effort on the RENIX head. Just the HO conversion is worth quite a few ponies, and the P&P on top of it is as much or more work than the conversion. Do it right once. You will also notice that there are a lot more header options for the HO, further increasing possible output.

Then again, that's why mine isn't done either. I didn't want to put it all back together with the original downpipe and header, but I can't afford the header I want and new downpipe. So it sits...and sits.

 

[Flash]

Ya and i still might..........I just HATE wiring and even tho its just lengthen wires on some of the sensor and, throttle body, manifold, head exc.

I truly think that i can port the Renix head to out perform the HO head.....in stock form of course! I think it will out perform HO, in the lower rpm range especially! the hi port OR razed port design (H.O) would be hard to compete with in the 3000+ range. I know that all the HO's out perform the Renix head but, i have two Renix head, throttle body's, Intake and.......no header yet, to play with, with out costing me a dime but 50 buck for a HO head would be sweet tho

If i could come up with the head and every thing cheap, i would go with the HO head.

Flash

 

[Flash]

as fare as headers go, and if i do go with the HO head i will be going with the APN header!!!!!!

 

[streetpirate]

im a bit fond of the clifford header myself

 

[XJING]

I run a ported/polished Renix head, Chevy valves, Never flowed it when I did it, and had the tools to flow to. It made a difference, will make more of one when I go stroker this summer.

 

[Flash]

Finally some one ho has done a Renix........Info Info!!!!:wave1:

so did it loose any bottom end, top end, yours and auto or standard


Flash.

 

[XJING]

No I didn't lose any bottom end, It gained a lot in the "torque band" 2200-4500" still very linear, but much, much stronger...I did the "port and polish, basically, port matched the intake, smoothed out everything I could get to on the intake side, short side radius, ect...polished it up nice, On the exhaust side, just port matched and cleaned it up. Had chevy valves put in it, and they did a 3 angle valve job. (http://www.cylinder-heads.com) Clearwater cylinder heads is in my town

If I was to do it again, I might get adventurous and clean up the combustion chamber but am happy the way it is. You also have to understand my motor has almost 400,000 miles on it. Yes I have had it for 19years, and my sons are convinced it wont ever blow up. I have everything to make it a stroker and will do it this summer, no one uses the Xj on a daily basis anymore, but it gets out and about a few times a month and when the boys are home from school they are always out in it. The XJ will stay in my family forever....

 

[Flash]

No I didn't lose any bottom end, It gained a lot in the "torque band" 2200-4500" still very linear, but much, much stronger...I did the "port and polish, basically, port matched the intake, smoothed out everything I could get to on the intake side, short side radius, ect...polished it up nice, On the exhaust side, just port matched and cleaned it up. Had chevy valves put in it, and they did a 3 angle valve job. (http://www.cylinder-heads.com) Clearwater cylinder heads is in my town

If I was to do it again, I might get adventurous and clean up the combustion chamber but am happy the way it is. You also have to understand my motor has almost 400,000 miles on it. Yes I have had it for 19years, and my sons are convinced it wont ever blow up. I have everything to make it a stroker and will do it this summer, no one uses the Xj on a daily basis anymore, but it gets out and about a few times a month and when the boys are home from school they are always out in it. The XJ will stay in my family forever....

So you are running a 2.02/1.60 Chevy valves?

Is it an auto or standard transmission

how long ago did you port the head?

did you have to un shroud the valves in the combustion chamber (if ya put the over sized valve in it?)

what about ext.......did you buy a header and if so what brand?


Flash.

 

[XJING]

So you are running a 2.02/1.60 Chevy valves?

Is it an auto or standard transmission

how long ago did you port the head?

did you have to un shroud the valves in the combustion chamber (if ya put the over sized valve in it?)

what about ext.......did you buy a header and if so what brand?


Flash.

On the valves, I am not sure because its been awhile and I can't find the paperwork, But I seem to remember 2.02 and 1.60 for exhaust, Because of a family friend at the shop, I didn't unshroud the valves, they did when they did the valve job(should have noted that) The head's been ported for at least 3 years, maybe about 15,000 miles, The XJ just gets used to go camping, to the motocross park and grocery getting, the last few years,
As for Tranny, I put in a AX-15 5 speed many years back.
As for header, I have a borla with the downpipe and a mandrel bent 2.5" exhaust from there back with a 40 Flowmaster and high-flow cat. exiting in the stock location.
Going to tear into the motor in June to build the stroker, The motor still runs great, leaks oil but very little burn.

Its been well maintained. I hate recomending anything on the boards anymore, as someone always calls B.S on it, But my motor has had its oil changed everytime using gunk engine flush since the first time. My dad owned a machine shop specializing in high performance and I leaned the cleanliness is Godliness thing early. I can tell you this, I have never had to do a rear main in it. Although that is where it is leaking now. (last year,) so the rear main lasted 18years. My guess is because it never had build up on it. Some people use Seafoam in the crankcase, I would rather use it down the TB, thats the only two things out of ordinary maintenance that has kept my XJ alive. Preventive maintenance goes along way.