Eggplant Jeff

In case anyone is considering this... Don't waste your money.

I dropped 1.6 (stamped steel, $64 at Scoggin-Dickey) rocker arms on yesterday. I've got a cat-back, ultimate TBI mods, open element air cleaner, gears. But stock L03 intake and exhaust manifolds, cam, and heads. I was hoping for some more top end, nothing dramatic but at least for it to pull a little higher.

Nothing dramatic is what I got. At WOT the difference was BARELY noticable (maybe even just wishful thinking on my part). I should have saved my money, that's half of a new intake manifold.
<sigh> nothing I do makes my car fast. Well, the gears made it fast from 0-25 mph. javascript:smilie('')

ImportsRsloths

LOL i cant really tell why your so SLLLOOOWWW but id imagine its one of these?????!!!!??

Stock exhaust manifolds!!!!!
Stock TBI manifold!!!!!!
Stock TBI cam!!!!!
Stock TBI!!!!!!
Stock TBI heads!!!!!

YOU ARE A STOCK TBI GUY!!!!

1989camarorsrs

iTrader: (-1)

what gears u got ?

v8powr

i thought that 1.6 rockers on the LO3 was a bad thing to do? Maybe i read that wrong. Could I buy 1.6 full roller rockers and they work good with say and Lt1 cam?

Chuck!

No, the lift with 1.6 rockers and the stock cam is still well under .400 lift intake and just over .400 exhaust, as compared to the LT1 cam which is .447 intake and .459 exhaust.

CAMp3RO

would have to change anything if you did put the 1.6 in with an LT1 cam? when i do the cam change, i bought stock l03 replacement springs and gonna get a new set of valve seals. shoudl i get anything different if i were to change from 1.5 to 1.6?

v8powr

So whats the best to do? Get an LT1 cam and retain 1.5 rockers or keep the stock cam and get 1.6? If the answer is the first I could get the LT1 cam and full roller rockers right? I would think that would make the valvetrain alot more effiecent. And what about springs? Stock or something else. With a descent intake and ported heads(prolly just gonna port the stock lo3 heads and get rid of as much of the swirl port as possible) and a good exhaust...i should be able to turn around 5500 to 6000 rpms right? just tryin to get a ballpark estimate.

NJ SPEEDER

the 1.6 rockers need to be done in conjuction with a little mroe timing advance and a touch more fuel pressure to be felt. since they make the cam "bigger" they will make the motor want a little more timing. once you put 2-3 more degrees of base timing in it you will feel it a lot more of a difference.
although i will admit they are no replacement for a cam swap, they are a cheaper and much easier alternative if someone doesn't want to do the whole cam swap ordeal.

later
tim

Eggplant Jeff

Just FYI, the specs on the LT1 cam are given assuming 1.6 ratio rockers, which the LT1s came stock with. If you run the LT1 cam with 1.5 rockers, you'll get 1.5/1.6 as much lift and some calculatable-if-you-know-way-too-much-math-geometry-and-cam-lobe-profiles amount less duration.

I believe that the LT1 cam even with 1.5 rockers is still a dramatic step up from the stock cam.
Stock cam 1.5 rockers I/E: .351 / .385
Stock cam 1.6 rockers I/E: .374 / .411
LT1 cam 1.5 rockers I/E: .419 / .430
LT1 cam 1.6 rockers I/E: .447 / .459
Duration changes too since the duration everyone compares is duration at .050... When you add 1.6 rockers .050 comes earlier (and later on the down side) since it is now what used to be .047. And no one reports duration at .047 :-).

NJ Speeder, thanks for your response. I can try more timing, currently it's set at 4 degrees advanced (been there for a while). I did adjust the fuel pressure until I had the O2 sensor reading average about .900 mv at WOT.

Nitroburn

Actually, it doesn't change the during at all. Duration is measured at LOBE (or lifter) lift, not vavle lift. The rocket ratio will only change vavle lift...nothing else. To modify the duration, you have to change the cam.

Later,
Mike

NJ SPEEDER

changine th erockers does change the duration at .050 of the cam. the total duration from open to close will stay the same.
since it is opening the valve faster it will reach .050 lift sooner and stay above that lift fro longer.

later
tim

Nitroburn

Tim.. you're are going with VAVLE lift. Remember, duration is measure are the LOBE of the cam, not at the lift of the valve.

When one degree's their cam in, the lift is measured by the dial indicator with the lifter installed and the dial indicator pin directly on the lifter (and sometimes with the pushrod installed and the pin on the pushrod) but NOT THE ROCKER.

To measure .050 lift AT THE VALVE, you would have to have the rockers installed and measure from the valve-side of the rocker, which would be incorrect.

Thus, .050 lift is LOBE lift and the rockers have nothing to do with the duration.

If you don't think this is correct, read this doc...
http://64.90.9.168/cranecams/pdf/803.pdf

Later,
Mike

brodyscamaro

what you put down as the LT1 cam with 1.6 rockers is really the LT1 cam with 1.5 rockers

vjo90RS8

iTrader: (1)

LT1 with 1.5 rockers : .447/.459
1.6 rockers: .477/.490

poncho9789

[QUOTE]Originally posted by Eggplant Jeff
Just FYI, the specs on the LT1 cam are given assuming 1.6 ratio rockers, which the LT1s came stock with. If you run the LT1 cam with 1.5 rockers, you'll get 1.5/1.6 as much lift and some calculatable-if-you-know-way-too-much-math-geometry-and-cam-lobe-profiles amount less duration.[/QUOTE

Actually the lt1 came from the factory with 1.5:1 rockers the exact same most of you guys have on your cars the part numbers on the rockers are the exact same. They reccomend that when you put 1.6:1 rockers on a LT1 you should change the valve springs there have been several guys brake valve springs from putting a set of 1.6:1 rockers on a LT1.

The LT4 hot cam and the standard LT4 cams are the only gm small block cams that are calculated at a 1.6:1 ratio.

poncho9789

I didn't have any problems with my springs when putting 1.6:1 rockers on my 97 LT1 formula.