another cam question

[MTBracer367]

so i just got my hands on a new motor for my heep.

my jeep is a 98 4.0/ax-15/np231

the new motor is from a 2000 xj with 50k on it

my plans fo rit are to ditch the 0331 head for a 0630 or 7120 that i'm haveing the valveguies redone on it and maybe a set of roller rockers depending on cash flow
i also want to put a cam in it. i've been looking atthem since i got my jeep and think now would be the perfact time or one. i'm pretty set with lunati. and am inbetween two cams right now. the 63502 and the 63501. form what i understand i'm going to need a different timeing set being thta the motor is a 2000. is this true? if so do i need on from a 97 becaus ethe came says it's only for up to 97? or is that just for a legal thing like smog or something? i'm not to concerned about the legal end of it being one of my very good friends is a inspection mechanic.

also is this safe to run with sock displacement? being that i'm not/can't build a stroker because the motor currently in my jeep isn't gonna make it that long.

the motor is also gonna have the usual 99+ intake, header, tb, ect

i am serious about this an know thats alot of quetions but it's all stuff i need help with. this jeep is also my dd and it is wheeled but not heavily anymore

any positive input is appricated

thanks,
-Dylan

 

[Johnnie Walker]

Up til 99 they were the same, as they still used a dizzy. Wheras the 00-01 used DIS. But if you have a dizzy installed in yours then you should be alright. Lunati makes good stuff, but I dunno about those particuar cams for the 4.0L's Most on here seem to liek the mopar stage 2 cam.

 

[Dr. Dyno]

so i just got my hands on a new motor for my heep.

my jeep is a 98 4.0/ax-15/np231

the new motor is from a 2000 xj with 50k on it

my plans for it are to ditch the 0331 head for a 0630 or 7120 that i'm having the valve guides redone on it and maybe a set of roller rockers depending on cash flow
i also want to put a cam in it. i've been looking at them since i got my jeep and think now would be the perfect time for one.

Keep the stock cam for reliability and low rev torque. Aftermarket cams invariably need stiffer valve springs and with all the flat tappet cam failures that have been going on lately, you'd only increase the chances of having one yourself.
Just do the head swap (you can port the replacement head for a few more ponies) and if you still have cash to spare, you could add a set of Yella Terra 1.7 roller rockers. Valve lift would be increased to 0.433"/0.440" and you can still use the stock valve springs.
_____________________________

1992 XJ Laredo - manual - 4.6 Stroker
[email protected] - 202rwhp/258rwtq - 3620lb w/ driver

1995 Mustang GT - automatic - 5.0 V8
[email protected] - 244rwhp/284rwtq - 3480lb w/ driver

 

[Talyn]

If you are having the valve guides done you will also need a valve job done. Go with a 3 angle valve job and back cut the valves 32*.

 

[MTBracer367]

ok what do you think would be most benifical and durable?

leaveing the stock cam in the 2000 block alone, geting a 3angle valve job, valve guides resleved, magnafluxed(guy at machine shop sugested it), and a set of yellow tera roller rockers

or geting the valve guides redone, magnafluxed, roller rockers, and a cam(not yet sure of a specific one)

EDIT: cn i even use a higher ratio roller rocker with an aftermarket cam on a stock bottom end in our motors? or will i be geting into interference then? and can i use stock pushrods either way with the roller rockers?

thanks again,
-Dylan

 

[Johnnie Walker]

You will need to check and see if the valve will hit the piston with the higher ratio rocker. It is possible to use stock pushrods, but you will need to make sure everything fits properly, usually you need new pushrods with non-adj. rockers.

 

[MTBracer367]

well as of right now, from what i've been reading, i think i'm gonna leave the stock cam alone adn go with a valve job and thew 1:7 rockers but i still haven't found a deffinate awnser on weather or not i can run these on a stock bottom?

and i did read up on the push rods and i think i can use stock but i have found anything deffinate yet

any one here know anything about these things?
if you have personal experiance that would be great.

thanks again
-Dylan

 

[Talyn]

There should be no problem running the 1.7:1 rockers on a stock bottom end with the stock cam. Good plan. As for the push rods they may work, but you will have to see when everything is installed and the head work is done.

 

[MTBracer367]

yeah thats what i seem to be reading everywhere in regaurds to the pushrods but how will i beable to know if i need different pushrods? how do you figure lifter preload?

also is there any other little details anyone here would recomend for i few extra ponies? such as a thiner head gasket or anything relitively cheap?

 

[Talyn]

http://www.holley.com/data/Products/Technical/INST150.pdf Tells you how to check preload on page 2.

As I said earlier you could back cut the valves. Since you are having head work done they are probably going to mill the surface so that will increase compression. For a thinner head gasket get a the Mopar Performance P4529242 Jeep 53010587AA or a Victor Reinz 54249S. They all measure .044" compressed.

 

[MTBracer367]

my only concern with with the thiner head gasket, would i have to be concerned about any clereence issues with the extra valve lift from the roller rockers?

and between the milled head and thiner gasket would pinging be an issue? i don't care if i have to run a higher octane gas i'm just wondering if anyone new if i would have to or not?

and i'm gonna call up my machine shop again today and see about geting the valves cut back. my only quetion regaurding that is what exactrly does that do other then obviously put the valves back 32 degrees?

and that link about the lifter preload was a big help too

thanks again for all the help so far everyone

-Dylan

 

[MTBracer367]

also would anyone have any injectors to recomend me for this setup?

i was thinking lt1's but idk if they'll be enough?

 

[Talyn]

also would anyone have any injectors to recomend me for this setup?

Your stock ones will be fine. This isn't a stroker and you aren't increasing displacement.

my only concern with with the thiner head gasket, would i have to be concerned about any clereence issues with the extra valve lift from the roller rockers?

No. With the 1.7 rockers you will have .433" intake and .439" exhaust lift. I ran the Comp Cam 68-231-4 (.462" intake, .485" exhaust) with .045 deck clearance and there was plenty of room before the valve hit the piston.

and between the milled head and thiner gasket would pinging be an issue? i don't care if i have to run a higher octane gas i'm just wondering if anyone new if i would have to or not?

Hard to answer. I wouldn't bet that you won't have pinging, but if you do its nothing the premium or midgrade couldn't get rid of.

. my only quetion regaurding that is what exactrly does that do other then obviously put the valves back 32 degrees?

It buts an angle on the back of the valve which increase flow a significant amount.