MasonMcK

Hi guys, my 4.0L had 2 dead cylinders after the previous owner overheated it. I began tearing it down this week expecting the worst. Just got the engine block out today and it turns out that the short block is in perfect condition for having 165k miles. Great! I did discover that it has a blown head gasket and possibly a few problematic valves. So I'm going to send the head off the the machine shop to be resurfaced, and built up some.

With the engine out, I want to upgrade my camshaft while everything is accessible. The cam I am looking at is the 68-239-4 but Summit's site says in all caps "NOT FOR FUEL INJECTION". I've done a lot of research on it but can't find a definite answer. Half of the sites out there say that it can be run on fuel injected 4.0L's without any issues. But the other half say that it will cause the engine to not pull enough vacuum to run properly, requiring me to install a vacuum reservoir for the brake booster to function properly.

I've seen a few videos of xj's with the same cam in them but I can't find any additional information about them. So my question to you guys, is anyone here running the Comp Cams 68-239-4 cam with success? If so what was required to get it to function well, if anything? I'd rather not spend money on the cam only to have it not work. Also what is the consensus about what other valvetrain mods are required for this cam? Springs? Pushrods? Lifters? Can I run roller rockers? Anything else?

Thanks for the help,
-Mason

MoparNJeep

You can run with fuel injection but the amount of lift that cam has will not work with stock head and valve springs. The head will need machined. Also I've found its harder to find springs for the inline sixes but they are out there. If you look around on JeepStrokers.com you will see that cam is popular for strokers.

Though from my research that cam is not the best for a stock bottom end 4.0. It's not a huge torque producer.

Comp cams has a 252H (68-200-4)cam that works great and works with stock springs, pushrods, lifters, and stock head. It produces great low end torque and it also states that it doesn't work with fuel injection. Which it does as that's what I ended up running in my 4.5L stroker. https://m.summitracing.com/parts/cca-cl68-200-4

The only thing I had to do was grind the tab off the distributor at move it slightly to get the fuel timing set. There is info on jeepstrokers.com on how to do this. Also if I recall the older jeeps pre 96 xjs are the ones that didn't like aftermarket cams but I'm not 100% on that.

s346k

why does the head need machined to use that cam? you say because of valve lift...are there no stock diameter springs available to handle that lift?

CobraMarty

Here are the specs of the Comp Cams-
Comp Cams
68-115-4 240/248 192/200@0.050" 0.416"/0.416" LSA 108 Overlap 28*
68-200-4 252/252 206/206@0.050" 0.433"/0.433" LSA 110 Overlap 32*
68-201-4 260/268 212/212@0.050" 0.447"/0.476" LSA 110 Overlap 40*
68-231-4 250/258 206/214@0.050" 0.462"/0.485" LSA 111 Overlap 32*
68-232-4 250/256 206/214@0.050" 0.460"/0.476" LSA 113 Overlap 27*
68-235-4 254/262 210/218@0.050" 0.477"/0.493" LSA 111 Overlap 36*
68-239-4 262/270 218/226@0.050" 0.493"/0.512" LSA 111 Overlap 44*

As you can see the 239 is the biggest cam that they offer. I doubt if it will work with the stock fuel injection. It will produce very little vacuum and will mess up the EFI. It is more of a race cam with 4 barrel carb for like sand drags.

The suggested 200 cam will work well with a stock 4.0L and stock valve springs as stated above.
You can also use the stock cam and Harland Sharp 1.7:1 roller rockers and stock valve springs. This also works well with the EFI.

231 is a good choice if you can find valve springs that will work.


Here is some info that I have for Valve Springs-
VALVE SPRINGS
**DO NOT EXCEED 225-240 lbs pressure to prevent cam lobe flattening**

Stock 60-71-80-89 lbs@1.64" varies by years bind at 1.140" safe to 0.440"lift 295-327 lbs/in
184-190-218 lbs@1.206"(0.434"lift) varies by years 209-226 lbs@1.190"(0.450"lift)
2001 Stock ?conical bind at 1.121" safe to 0.459"lift

Mopar Perf #5249464 270-271 lbs/in safe to 0.525" lift 1.418"OD install at 1.64" 90-113 lbs@1.64" 200-232 lbs@1.202-1.205"(0.438"lift) 210lbs@1.190"(0.450"lift)
220-246lbs@1.140"(0.500"lift)PERFECT to SLIGHTLY TOO HEAVY This spring is NO longer available

Scorpion 1213 conical Ford 4.6/5.4L OHC 191 lbs/in bind at 0.600" $12.49ea.
80 lbs@1.64" 166 lbs@1.190"(0.450"lift) 175 lbs@1.140"(0.500"lift) ? TOO SOFT

*Scorpion 1214 conical Ford 4.6/5.4L OHC 275 lbs/in bind at 0.600" $12.49ea.
100 lbs@1.64" 224 lbs@1.190"(0.450"lift) 237 lbs@1.140"(0.500"lift) PERFECT UPRADE nearly same as MP Springs
if install at 1.70" 83.5 lbs@1.70" 208 lbs@1.250"(0.450") 220.5 lbs@1.200"(0.500") PERFECT STOCK specs

Lunati 74813- ?same as Scorpion 1213, same specs $9.88ea
*Lunati 74814- ?same as Scorpion 1214, same specs $9.88ea Ford 3V head
Lunati 74833 300 lbs/in

PAC 1233 114 lbs@1.64" 300 lbs/in
PAC 1213 and ?1214 also same as Scorpion $11.91ea

CompCams 26113 same specs as Scorpion 1213 $15.00+

CompCams 26125 258 lbs/in 120 lbs@1.640" 236 lbs@1.190"(0.450"lift) TOO MUCH
if install at 1.70" 105 lbs@1.700" 221 lbs@1.250"(0.450"lift) 236 lbs@1.200"(0.500"lift) GOOD
if install at 1.75" 92 lbs@1.700" 208 lbs@1.250"(0.450"lift) 223 lbs@1.200"(0.500"lift) GOOD

CompCams 26981 347 lbs/in 110lbs@1.70" 249lbs@0.400" 266lbs@0.450" 283lbs@0.500"

CompCams 26995 Beehive 280 lbs/in 137 lbs@1.70" 130 lbs@1.75" 280 lbs@0.478"lift TOO MUCH

CompCams 926 (comes with 'cam kit') 415lb/in 109lbs@1.80" 317lbs@1.30" WAY TOO MUCH

Crower 68193 230 lbs/in 103 lbs@1.80" installed height, 1.30"(0.500')=218lbs
125 lbs@1.70" installed height, 220 lbs@0.450"lift $14ea $230/16

Edelbrock 5814 357 lbs/in 110 lbs@1.700" 270lbs@1.250"(0.450"lift) TOO MUCH
-this is the spring that comes with the Edelbrock Alumn 4.0L head Jegs $35/16

Edelbrock 5813 252 lbs/in 80lbs@1.70" 193lbs@1.250"(0.450"lift) LITTLE LIGHT
if install at 1.640" 95@1.640" 208lbs@1.190"(0.450"lift) PERFECT UPGRADE same as MP spring Jegs $34/16
if install at 1.700" 110@1.700" 223lbs@1.250(0.450"lift) Better choice for Edelbrock Alumn Head

Australian Ebay Spring 354 lbs/in 100lbs@1.65" 259lbs@1.20"(0.450" lift) TOO MUCH

Engle Cams #593 220lb/in 1.440"OD 1.075"ID install at 1.80"=95psi 0.450" lift=190psi
if install at 1.65"=125psi 0.450"=215psi

Engle Cams #696/697 250lb/in 1.380"OD 1.055"ID 0.805"InnerID 1.65"=105psi 0.450" lift=220psi

Engle Cams #6612/6602 280lb/in 1.250"OD 0.680"ID 1.65"=110psi 0.450" lift=235psi

cruiser54

Thanks Marty.

CobraMarty

No prob. Sorry for my OCD, I like numbers.

cruiser54

Please don't apologize. If you don't mind, I'd like to save it for future reference.

MoparNJeep

Yes because of valve lift. Its not the diameter but the stock springs will bind at the cam lift for the 239 cam. Head would need machined to support the valve lift.

Nice info Marty, agree 100%

CobraMarty

It's all here and more...
http://jeepm62superchargerkit.blogsp...p/misc-xj.html

CobraMarty

Last motor and head I build I used Mopar valves 2.02"/1.625" and I used the Lunati 74814 valve springs. These springe are for the Ford modular motors 4.6/5.4. These are tiny in comparison and use tiny retainers and locks, Very lightweight. And I used a Jones Cam 'Boosted Cam' 260/272 204/216@0.050" 1.6:1-0.472"/0.488" 1.7:1-0.502"/0.519" LSA 113 Overlap 40

Lunati 74814 conical Ford 4.6/5.4L OHC 275 lbs/in bind at 0.600" $12.49ea.
100 lbs@1.64" 224 lbs@1.190"(0.450"lift) 237 lbs@1.140"(0.500"lift) PERFECT UPRADE nearly same as MP Springs
if install at 1.70" 83.5 lbs@1.70" 208 lbs@1.250"(0.450") 220.5 lbs@1.200"(0.500") PERFECT STOCK specs

These springs need the head to be machined to fit. Because the springs are smaller diameter the head valve area needs to be made smaller. I did install at the 1.64" height as I have just over 0.500" lift.

s346k

what rockers and rpm range were you seeing with that jones cam, Marty? what kind of preload on the lifters? stock length and diameter pushrods?

CobraMarty

Harland Sharp 1.7:1 roller rockers, have auto AW4 so power to shift point about 4800-4900rpm, I also can shift it manually and power to 5200rpm. M90 SC fixes everything but with pulley ratio I have to keep rpm to about 5000 to keep SC speed safe. IIRC 0.030" ? preload if that's right, CM pushrods ?5/16 or 3/8" ?Trent I don't remember but they were not stock.

MasonMcK

Wow thanks for all of the replys you guys. I kind of suspected that it would be giving the stock computer some trouble by not pulling enough vacuum. Is there any way to make the computer function with the lower vacuum levels? I know I can use a vacuum canister for the brake booster but how about the computer? Also I am getting my 7120 head ported and machined so it will be no problem getting it modified for different valvetrain setups. In swapping camshafts I would like to gain a few things.
1) More mid-top end hp
2) Would like some more low end torque
3) Although not as important as the others, I would like it to have a bit of lope to it
4) And of course most important, replace my worn stock camshaft

I am aware that it's a trade off between high end power and low end torque when choosing a cam but would the 68-239-4 make my torque drop below stock levels? How about the next cam down the 68-235-4? I would like to see a little bit of increase above the stock torque level and a larger increase in the stock hp but will either cam drop me below stock levels?

Thanks again!
-Mason

s346k

I figured as much, just curious. thanks.

CobraMarty

A couple of years ago I was frustrated with the lack of information and availability of a reasonable valve spring to use in the 4.0L engine. There have been lots of cam and lifter failures and there was little to no information about valve springs. I bought a Proform digital spring compressor and bought as many springs as I could find if they were available single or cheap enough. I now have a box/collection of valve springs. I searched all over to find any information on what have been used in the past.

So most all of these numbers are from my testing and measuring of the actual valve spring.
I was especially interested in the newer lighter beehive type springs.

I wanted a light valve train. The Lunati springs for the ford 4.6 were small and light, and I used hemi retainers (8*) and locks (8*) which work with the Mopar valves.
-spring weight= 49 grams, retainer weight= 9 grams LIGHT!! (vs. stock 71 grams and 16 grams) other springs were even heavier than stock. The hemi retainers are lighter than titanium retainers for SBC springs.