Cam + 1.7

[LEN XJ]

Hi all. I am New to the form so I hope I am in the right spot for this question.
I would like to get something straight first. I know next to nothing about cams; in fact I am pretty dumb about them. All I know is this. I want the cam to come on Low and Flatting out about 5000 or so, maybe lower. The Jeep is a 1998 Xj , I run it on the street, HI-ways cursing about 2300 RPMs at 70MPH and I am crawling in the dirt/rocks a lot. I am building my motor one step at a time and one of my first steps is to add roller rockers. The question on the rockers is, should I get 1.7 or 1.6, and witch one will work better with this cam? This is the link to the speck sheet
http://www.compcams.com/Company/CC/cam- ... id=12&sb=2 .

Thank you for your help

[jsawduste]

Take the lobe lift and multiply by 1.6 or 1.7 to determine valve lift.

1.6 to 1.7 is worth ~ 2* of duration.

On a personal note, Comp is not one of my favorites. There are plenty of other to choose from.

Suspect Silver will chime in and offer up a few lessor know but highly effective grinds.

For a stock cal ed ECM keeping a lobe center in the 112-113 range will help keep the MAP sensor happy.

[SilverXJ]

I'm not very fond of Comp either. I would look into Lunati, Clay Smith Cams, Isky or a custom grind from someone like Jones Cams.

[LEN XJ]

man I had no idea; there is a lot to learn here. I am looking at all these numbers and kind of cams. Hydraulic Flat Tappet, Solid Flat Tappet, Hydraulic Rollers Cams, Solid Roller and all the other numbers with in a lot to learn.
jsawduste was saying the 1.7 roller rockers will increase valve lift more then the stock(the 1.6 is stock) . with a new cam do I want that or with the cam I pick should I have the valve lift I need leaving the rollers at the stock numbers of 1.6..
knowing that I am looking for a cam/ roller combo that will come on about 800 and sine off around 5000 or so. what kind of cam is best (Hydraulic Flat Tappet, Solid Flat Tappet, Hydraulic Rollers Cams, Solid Roller ) A brand of cam? Clay Smith was one of the company's that SilverXJ talked about. what would you pick and why?

[SilverXJ]

Hydraulic flat tappet. The 4.0L don't have a roller and there is only one aftermarket for it that isn't even worth mentioning.

[jsawduste]

I have little to offer on this reply but am hoping it provokes food for thought.

The aftermarket is famous for stating it improves performance from 800 to 5000 rpm. In other words the entire usable rev range of 99.9% of the strokers (and 4.0`s etc) on the market. Often with cam numbers that are quite a bit different then stock. I understand we can break this down to valve lift/flow/duration/LSA etc but I still find it amusing.

There is no one cam that can pull like a freight train down low and still have enough to be making power as the engine bounces off the rev limiter and vice versa.

[jeepxj3]

Who still makes the 1.7 roller rockers?

[SilverXJ]

Yella Terra does, but good luck if you ever need them serviced. I believe that Harland Sharp does, but I don't know the part number off hand and you may need to call them.

[LEN XJ]

so between the rollers 1.7 and a good cam there is no way to get a smooth idle and polling from 800 to 5000. I only seen one cam that claims that and that is the one I started this thread with. most that I have seen clam from 1000 or so to 5200 area. I tell you the more I get into this cam thing the more I get confused and I am a programmer so I don't think I am that much of a dummy.
what do you all think about putting in the 1.7 roller rockers and staying with a new stock cam. do you think that would get me the closest to where I want to go?

[LEN XJ]

I found this and I think it is good reading "camshaft 101" for those of you that are just as missed up as I am about cams this may help you. It did me (a little) http://www.svtperformance.com/forums/sh ... and-Beyond