Can I just put a set of 1.6" rockers on stock heads without changing the valve springs? Looking to get a little bit more without doing a cam swap right now.

 

Reliably, no.

Stock springs will be marginally close to coil-bind - not good.

 

Even if you did do it you probably wouldn't be able to feel any difference with a stock engine.

 

As long as you swap the springs. Take stock lift and divide it by 1.5, then multiply by 1.6 that's your new lift which stock springs can not reliably handle at higher rpm.

If you swap the springs along with it, then yes you can run 1.6 rockers. You don't have to modify the head or anything like that. Depending on the rocker you get, you may need new valve covers or have to modify yours.

I modified my valve covers and they have never sealed to my liking since. I get leaks out of the top of my valve covers.

 

I've done it. My engine is still holding together.

With a completely stock set-up, you have about 0.060" of clearance before coil bind (varies slightly depending on year). With 1.6 rockers and all else stock, you have about 0.030" clearance before coil bind.

Pretty much all cam and spring manufacturers recommend a minimum of 0.060" ...

I'm not recommending whether you should do it or not, just saying what the numbers are. If you have an engine with lots of miles, I personally wouldn't risk it. With only 35K on mine (at the time) I did risk it. But with stock air intake and stock exhaust you might not see much difference in power.

 

Factory springs are cutting it a little close to coil bind with 1.6 rockers. And thats assuming all the installed heights are 1.780, sometimes they are more/less.

Toss in some Isky 235D's and you're good to ~.550, that or some LT4 valve springs. Valve springs are important, these arent steering wheel covers...

-Dustin-

 

I happen to agree with Bob. It can be done reliably and leaves more than .025" of spring clearance before coil bind. That clearance is cumulative...the total of all gaps. The result is thT it will work. It might be too close for comfort for many guys....

 

The more you close the gap to coil bind the more it shortens the life of the spring. On higher mileage 15 year old LT1 springs it might be worth the $50-100 investment to save your motor.

-Dustin-

 

$50 springs are more of a problem than putting 1.6 rockers on....

 

lol yeah you're going to want to spend at least 150 on a good set of springs.

If you're interested I have some dual coil comp 978 springs that I've never used, they're good to a .600 lift. I went with beehives so these have been sitting in the box since 2006.

$75 shipped if you want them, OP, I paid $130 for them.

 

If you're willing/able to put in new springs, then you won't have to worry about this. I went back-and-forth on this a lot before I decided to do it.

BTW, if you go with 1.6 rocker arms with the stock springs, I would NEVER exceed the factory red line. (I personally would never exceed the factory red line unless the entire engine was built up for it... my viewpoint is very conservative on this.)


EDIT: @OP, what mods (if any) do you have now? Depending on what they are, there may be better things you can do to get more power, than adding 1.6 rocker arms.

 

I'm running Isky springs I bought for $40 new that utilize stock hardware. They are good to .550 lift when installed @ 1.750, .580 @ 1.780, and .630 lift if you feel like running them to coil bind at stock height. Anymore they can be had for under $100 if you look hard enough. They are far better than $36 LT4 springs. But let's not discredit the LT4 springs. They are a great bang for the buck, good to .525 lift, and readily available. Not to mention the fact that LT4 springs have reliably seen more miles than any of us will combined. 1/2 of them doing it with a more aggressive than stock Hotcam. Hell I put 70,000 on a set of LT4 springs when I had 1.6's as a bolt on.

So I suppose I'm forced respectfully disagree that buying $36 springs is more of a problem than smashing crusty old LT1 springs crotch hair close to coil bind.

PS: Anyone who is buying $150 springs for a factory cam has no business opening the motor up.

Sorry the truth hurts.

-Dustin-

 

You respectfully disagree and then state things like crotch hair close, etc. That's anything but respectful. In addition, what you say is your opinion, not fact.

While your OPINION is the accepted norm, in actuality many people have used 1.6 rockers and stock springs without a catastrophic failure. In fact, find a post where an engine grenades due to this combo and I'll shut up and will never voice this OPINION again.

 

I was with you - right up until you got to this point in your post...

 

You got me, it is just my opinion, but you better call these guys and tell them the difference between their opinion vs fact as well.

Each lists .050-.060 MINIMUM clearance.

http://www.iskycams.com/camshaft.php

http://www.cpgnation.com/forum/comp-...tech-2047.html

http://www.cranecams.com/faqview.php?s_id=21

http://www.lunatipower.com/Tech/Valv...pringTech.aspx

http://www.kmotion.biz/instht.htm

A valve spring doesn't have to break and/or drop a valve and/or blow the engine to fail. When it stops effectively control the valve it's already failing. The point of adding 1.6 rockers as a bolt on is better performance. But if you over stress the spring and it loses its ability to control the valve what's the point?

Get mad guys, but no one who actually knows motors is going to advise abuse of a factory spring like this for a "performance" gain. I'd do it if the car was my DD, I was flat *** broke, and I had no other way of keeping my job if I didn't go to work the next day. But I'd toss springs on it the next payday.

-Dustin-