Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: BlackYJ on November 03, 2008, 08:10:30 AM
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How involved is it to change out the lifters in the '94 4.0L. Does the head have to come off?
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Yes
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Also if the lifters are shot they might have taken the am with them as well it should be look at and measured.
If you want to do it your self Scott I will give you a hand.
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Might as well do the cam when you are in there bud. Do Corey's comp cam and mopar spring combo for a nice easy recipe and serious increase to bottom end.
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Thanks for the offer Aaron, I will definitely keep that in mind. My dad and I were talking about maybe tackling it over the winter here one weekend. Are there any special tools that are needed?
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Thanks for the offer Aaron, I will definitely keep that in mind. My dad and I were talking about maybe tackling it over the winter here one weekend. Are there any special tools that are needed?
Harmonic balancer puller / installer , let me know when you are ready for this . NO POUNDING !
My stroker ate a balancer very quickly ( old / used one ), replaced it with new , it's good now , inspect yours , they don't last forever .Look closely at the lamination between the inner and outer hub . When the two separate ( fail ), the results can be dramatic :'( .
Valve spring compressor & possibly freshening up the valve seats not a bad idea , can discuss this as well.
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being so close to a jeep parts department i found that mopar has 4.0L performance camshafts and lifter kits, along with what springs to run with each. has anyone heard much about the mopar cams?
sorry for jumping on your question scott... :(
but, ya, if you're changing the lifter, throw a funky cam in to help that YJ out!
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being so close to a jeep parts department i found that mopar has 4.0L performance camshafts and lifter kits, along with what springs to run with each. has anyone heard much about the mopar cams?
sorry for jumping on your question scott... :(
but, ya, if you're changing the lifter, throw a funky cam in to help that YJ out!
The last time I checked , those cam/kits were discontinued , has that changed ?
They offered three choices / phase 1 , 2 & 3 , each with slightly more lift and duration. A couple of valve spring selections too , which are still available. There's not a lot of room under a 4.0 valve cover though , adding Mopar roller rockers and the required Hesco valve cover spacer severly limits what little room there is below the valve cover. The valves are tilted to the left , the left side of the valve cover is profiled to clear the springs and retainers , all of that changes when a spacer is added . Smaller diameter springs or conical springs clear valve covers well . Bill has mentioned more than once , using the Mopar performance 360 springs , check clearances carefully with this spring , they are larger in diameter than stock , are straight wound , undeniably a quality spring , but , clearance can be an issue.
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Here's why the head has to come off to remove the lifters , this sacrificial 4.0 head was bucked in half in the interest of science. What it shows...........
The verticle passage where the pushrod passes through is narrrow , bored just large enough to do the intended job. Observant viewers may see some other stuff too .
(http://img.photobucket.com/albums/v29/JeffH/40HEAD-CROSSSECTION.jpg)
I'd like to enlarge the passage to enable lifter removal on my next cylinderhead build. The existing pushrod bore is 9/16" + (.5625") , the diameter of a lifter is .904". It would appear , based on the cross sectional view that there is sufficient material to enlarge the bore , allowing the lifters to be removed without having to disturb the cylinder head.
Some trivia , 4.0 lifter , same part as small block Mopar ( flat tappet versions )
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I think that the 4.0L mopar cams might still be available but i know for sure they discontinued the 2.5L cams
Thanks Jeff for all the help. If and when I decide to go this I will definitely be giving you a call
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being so close to a jeep parts department i found that mopar has 4.0L performance camshafts and lifter kits, along with what springs to run with each. has anyone heard much about the mopar cams?
I just called and I guess these cams are still available. Would one of these mopar cams be a good alternative to a comp cam? Gearhead / Bnine?
Here are the specs
(http://i94.photobucket.com/albums/l99/srelliot/chart2.gif)
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Well , since you had to ask..........................................
The specs shown are an abrieviated version , what's missing is the timing of events , intake closing , exhaust opening etc. Not a big deal though , that information is not often shown in a catalog. Let's compare the three cams with the Comp cam that is so popular.First let's look at what they do show us.
The advertised duration
#P4529228AB = 240 / 240 degress
#P4529229AB = 248 / 248 degrees
#P4529230AB = 256 / 256 degrees
Comp Cams #68-232-4 = 250 / 256 degrees
All three Mopar cams have the same duration and are known as single pattern , meaning the intake and exhaust duration #'s are the same for each cam.
The Comp Cam is a dual pattern , simply put , the additional exhaust duration is to promote scavenging. Towards the end of the exhaust stroke , when the piston is on the way up and near the top , the intake valve opens , the exhaust valve is open as well and has been for some time , this , in terms of valve timing events , is known as overlap. The amount of overlap is one of the most critical of events in valve timing , in particular , the point where the intake valve opens , critical to throttle response , vacuum , fuel economy and emissions.
Confused ? you shouldn't be , yet , often the confusion begins when trying to understand the difference between intake centerline and lobe separation angle.
Lobe separation angle is the number of degrees separating the peak lift point of the intake and exhaust lobe , established when the cam is ground at the time of manufacture. This can not be changed.
Intake centerline can be described as the position of peak lift of the intake lobe in relation to piston top dead center. This can be changed , if desired by the installer , using a timing chain / sprocket set that has a crank sprocket which is machined to provide three positions for the woodruff key. The procedure used to mess with this is called "degreeing the cam " , enabling the installer to advance or retard timing events . As mentioned multiple keyway sprockets or offset keys are used to adjust valve timing from a straight up install. An example of a timing chain / sprocket set that allows timing changes ( degreeing the cam ) is Mopar #P5249519 , a well built double roller chain , high quality kit that includes detailed instructions.
For the purpose of what you are doing , the above is not all that important , these cams are usually installed straight up , the installer would not bother with advancing or retarding the valve timing. Just cuz I know you might ask about altering timing , here's the deal on that.
Advancing valve timing increases bottom end torque , while retarding valve timing boosts top end horsepower. There are trade offs to altering timing , advancing timing causes overlap to occur earlier , the result of that ? , the engine is not as efficient.
I like knowing the point of intake closing , this affects compression ratio , nice to know , when messing around with altered reciprocating parts like strokers or high compression pistons.
The lift of the cams being discussed are as follows
The three Mopar cams............
.430" / .430" , .440' / .440" , .450" / .450"
Comp cam
.460" / .476"
Obviously the comp cam is more aggressive than any of the Mopar #'s , there's no denying that it works well in a 4.0 l six, so to answer your question , yes the Mopar cam ( hottest one ) would be a good choice. Looking through some catalogs today , I realized not all of the information is listed , there is enough data to make an intelligent choice. My choice would be the Comp cam 68-232-4 .
You will need to do the springs with either cam , remember this , the Mopar P5249464 spring ( 318 / 360 ) spring is a quality chrome silicon spring , it is .110" larger in diameter and will need the corect retainers & locks , not to mention the limited room under some valve covers.
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:o
I didn't mean to make this into a science project ! , you initially asked a very simple question .
Um , ooops
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i saw the same page in the mopar catalog at work. the middle of the line cam was listed as the "4x4" cam to go with and the bottom one was listed as the "hot rod" ca mto go with. but if thecomp cam is even wilder and still has some good low end torque then maybe thats the way to go. personally i was curious just cause i get a good deal onthese parts. but then again, cams arent expensive either. so go with what works.
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I understood all of it.
I also in reading this realized another resin I like Heavy Diesels more. I can change one from 100hp to 500hp gust by changing some things on the computer. Also I think this is so cool A Cat engine in a highway truck pulls 300hp take the same engine and put it in stationary generator set you can get 600hp our of it. Agene take the same engine and place in a boat and you can get 1200 plus hp out of it. The difference is other then a few small things is the cooling systems. The killer of a diesel is heat. I gust think that is so cool.
Sorry about side tracking. It just got me excited. :D
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Good info here.
http://www.jeep4.0performance.4mg.com/index.html
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Thanks for the response Jeff. I am kind of understanding what you are saying but I need to read it again, but it is some great info
Now my next question, how does fuel economy play into the picture of more aggressive cams? I know jeep are not ever bound to be fuel efficient but it is nice to get some decent mileage for a jeep
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Thanks for the response Jeff. I am kind of understanding what you are saying but I need to read it again, but it is some great info
Now my next question, how does fuel economy play into the picture of more aggressive cams? I know jeep are not ever bound to be fuel efficient but it is nice to get some decent mileage for a jeep
You'll have to forgive me for even mentioning fuel economy . When discussing / planning a high performance engine , fuel economy is often sacrificed for increased power , there are exceptions though , often an "RV" cam used in a larger , heavier RV type vehicle can get you a slight increase in power as well as an improvement in fuel economy if used with a combination of other parts , like exhaust , cold air kit , n' stuff. RV cams generally aren't all that aggressive , just a step up from a stock , emissions friendly cam. My 4.7 isn't all that hard on fuel on the highway , around town with the varying speeds and rpms , stopping and starting , it's a bit thirsty.