Thread: Intense Stage 2 Cam Questions

High people, first post here. Im an aussie l67 owner and you guys seem to have pretty much got these donks sussed right out so this is the place to ask my question.
I have an intense stage two cam i wanna instal but abit wary about my valve retainer/stem seal clearance. I chose the s2 after doing some research and was under the impression that with a combination of manly retainers and viton valve stem seals which i purchased,( along with crow 105s and jp double roller), i would have an extra .065 thou clearance.
This would bring available clearance to .580.
Is2 max lift is .541 at stock 1.6 rr. BUT after purchasing the cam i spoke to chris from intense and he says that i wont have clearance regardless of retainer used. However he never mentioned the extra clearance of the vitons.
So guys are running the xp hot with just milld retainers and is2 has only .005 more lift then xp. There are some guys over here running is3 with stock heads only retainers and seals.
So to cut to the chase, my heads and gaskets are in excellent condition(recent comp test showed 180-183 all cyl), and if i dont have to i dont want to lift the heads untill i have the cash for a good port and big valve. Can anyone give an opinion from experience.
I figure at this lift worst case scenario my seals are screwed in short order. thanks.
Ken
END OF LONG STORY.

Yea im thinking i should have the clearance i need.
Any other opinions?

S1X plus 1.8 rockers have more lift than IS3 cam, Id do the S1X or XP like Blue said. Not much benifit doing a S2X over the others.

I've been running an XP with YT1.61 rockers, LS1 retainers, viton seals, all stock heads for a while -- .523/.539 valve lift with no known issues. The seals don't look touched at all.

Originally Posted by bluegtp91

Your running an XP with very slightly larger than stock ratio rockers on stock springs?

Umadbro

Actually, alot less ratio.

To the OP... You probably will be fine... The IS2 cam is sorta a piece of crap when it comes to stock heads... If you can find some roller rockers in the 1.6/1.7 range you might be a bit better off as it will decrease peak lift a bit.

If you want you can probably shave a bit more off the retainers... also.. dont listen to anything intense says, I probably would never buy anything from them either.

S1X plus 1.8 rockers have more lift than IS3 cam

wrong.

depending on deflection, stock rockers have a peak lift ratio of roughly 1.75-1.78 on a NIC cam lift, and exponetialy more on bigger lift cams.

Many many people are running alot more lift than they think they are. Also answers the question why people always lose power going to a 1.6 or a 1.7 roller, they lose that variable lift function.

I have also confirmed this by seeing many beat up seals on stock rocker/xp cam cars.

ZZP figured this out a few years ago, never made it public....

Originally Posted by RegalGS98s

So when using the stock rockers instead of the roller rockers, the lifters build more pressure up and become longer so the rocker's ratio is increased? Why do the roller rocker's rated at the same or higher ratio lose this lift? I know a little about the deflection. In that running a bigger cam with a smaller ratio rocker is better than running the smaller cam with a larger ratio rocker to get the same calculated lift. What about the said deflection of the stock rockers twisting?

Lifter pump is another discussion... There is issues with lifter pump on lighter rockers, but it is not affecting peak lift.

Rollers are not losing lift, they are just static lift as the tip contact point on the valve slides across the top of the valve... a stock rocker does not roll or slide across the top, as the tip of the rocker is pointed and the ratio changes as you make lift.. the more lift, the more ratio... with enough lift you could make a stock rocker pull a 1.9 ratio, while a 1.6 roller rocker makes 1.6 ratio at that same lift (it wouldnt be on the valve at that point though.... lol).

Stock rockers deflect a bit compared to most rollers... its not that much, might kill .002-.005 on 130# springs.

Originally Posted by RegalGS98s

I get you now. So for that NIC Cam you were referring to, to maintain that 1.75-1.78 lift because it's more on the tip of the rocker, you would essentially need a 1.8 roller if you went with a roller rocker to gain just 0.02 to 0.05 lift. What kind of lifter pump issues?

Lifter pump across different rockers/pushrods is a different thread all together.....

I do not have the tools/time to do the research that needs to be done in the lifter area, but I have ran many different types of lifters to have some general idea of what happens....

Long story short, lighter rockers have more tendency to float valves due to lifter issues.