O.k., here's the deal. I love my Z. I ordered it new in '97 with plans to keep it indefinately.

I'd like to put a small cam in it, but am wondering if I would stress the motor more than necessary by putting 1.6 RR's on it. I know it's done all the time, but it has to be harder on the pushrods, valves... etc.

I'm not going to rev above 6000 rpm, in fact, I want a cam that has good low end TQ and peaks the HP right around 5700-6000 RPM. I like the looks of the XE 224/230, and the CC305. I'm especially concerned about the 1.6 RR's with the XE grind, since the lobes are more severe. I may do a custom grind to get what I'm looking for though.

My concerns are that the new cam will already have higher lift, then add the 1.6's on top of that, and it seems that it might be pushing things a little bit. How much HP do the RR's get ya on a cam like those mentioned? Am I running into reliability problems with 1.6RR's? I don't want to just throw them on "because everyone else does it". I'd like good justification first.

Thanks,
Dan

 

They do put more stress on the cam,lifters,pushrods.Not enough to worry about if you use quality parts.Having had the 1.6:1 RR's on my car for a couple years,I can honestly say "dont worry about it."Depending on the set up,I am guessing a 10-20 hp difference.

 

I don't know if there is a simple answer to your question but here are some things to think about.
1) Full Roller Rockers will reduce the amount of force required to move your valve train as compared to stock stamped steel (reduced friction).
2) If you are changing to RR, most recomend changing springs, retainers and keepers also, if you are also doing a cam this becomes a must.
3) The amount of extra lift from 1.6 vs. 1.5 will result in negligable increase in required force with new springs but must be taken into consideration when ordering your new springs (make sure you have the right springs for your cam WITH the 1.6 RR)
4) If you use self aligning RR you need to change to a LT4 knock module to reduce the chance of your engine detecting false knock from the noisey RR's
5) If you go with non- self aligning (preferable since you are doing springs and cam anyway) you will need guide plates, longer studs (might as well go 7/16" thick too) and hardened push rods.

With everything done right you will have a completely practical and reliable valvetrain regardless of your choice of 1.5 or 1.6. The only time it becomes an issue is if your cam is already at the limit of practicality or you exceed your springs limit of travel (coil bind). Some people change to 1.6 SA-RR with everything else stock and risk spring failure due to compressing the old tired spring to the breaking point (I'm contemplating installing some with the knowledge that I better keep the revs below 6000)