i just installed 1.6 SA roller rockers in my 97z28,it feels like i lost a little power since, is it possible to lose power if i didnt installed them correctly? my mods are cc503,ported intake,cai,MT drag radials,1.6 sa rockers,spec3,lt4 km,madz28 tune,airfoil,stock 3:42s,lca,some weight reductions, my best time was 13.2 @ 106 with a bad 2.2 ft im not concern with my 60ft but shouldnt i be trapping higher than that? temp was 88*,humidity 17% and elevation 1200,any ideas i'll aprecciate thanks?

 

Improperly set valve lash could cost you power.

 

and more lift does not always mean more power, you car may respons better to the 1.5's.. try some diffrent combos..put the 1.5 on the inake and 1.6 on ehaust and vice versa. its going to be very hard to determin anything by how it feels.. get on a dyno.

 

making sure everything is adjusted properly first is most important.

 

What valve springs are you running? If they're the stockers, that'll be your most likely problem. They can barely handle the stock cam with 1.5 rockers, let alone anything else.

 

im running comp cam springs,whats the best method of properly adjusting the rockers?

 

It all depends, i know you say your not concerned about the 60ft., are you looking for ET or MPH? thats an easy 12.7 car if you work on the 60ft. To me, that MPH isn't too bad, i'm sure it'll go 107-108 on a good run, & in this heat, thats very good, in the winter months, you'll go 110, not bad for a LT1 with your mods. In my 97 M6 i've gone best of 101 in good air, 99 in the heat & i have all the bolt-ons without a cam, my ETs were 13.7 vs 13.9 on 2.17 & 2.20 60fts., this is at a 1500ft. track, so if i could drop .7 tenths & gain 6-7 MPH from a cam swap, i would be tickled, i think your doing good IMO.

 

yea it was pretty hot last nite,hopefully next weekend i do better lol and hopefully its a bet cooler too

 

what is your preload set at??? i would set to 1/4 past zero lash and work on that 60' and i think you will be happy...
i assume that you have an m6 based on your stock gear ratio... but i definently think you should trap faster...
i trapped 13.18@103 1.90 60' with bolt ons and an a4 with 91 degrees w/ 90% humidity and 1250' above sea level...

 

maybe i dont quite get the zero lash,can anyone explain what exactly is?

 

Its when all the slack is out of the rocker & pushrod, 1st. loosen the rocker untill it has play, then just use your fingers & twist the pushrod while tightening the nut, when you feel the pushrod haveing resistance on it "STOP", then turn the nut an additional 1/4 turn tighter.

Now you do know there is a proceedure to adj. the valves don't you? Makeing sure they are on the "HEAL" base of the cam, not the lobe, you can do it with the piston at TDC on each cylinder, then adjust those valves, but there is a better method, just don't quite remember how it went Its been awhile sence i've adj. valves, i used to run a solid flat tappet. Maybe someone will chime in!!

Its like (use a remote starter button), as your looking at the rockers on that cyl., As the intake valve "starts" opening "adjust the exhaust" & as the exhaust valves "starts" to close, "adjust the intake" or something like that, i've slept sence then lol.

 

http://shbox.com/1/4th_gen_tech2.html#adjust_valves

 

I use method #1 and I set mine at 3/4 turn total.

 

^^^
I use method #1 and I set mine at 3/4 turn total.

 

with that heat its not that bad. And if your rockers are the issue everything should be fine.