i have a new comp cams 306 and was wondering if i can run 1.6 rockers and be better off or should i step down and stick with 1.5's as listed ?? lift's are 510/540-230/244duration and 112 lobe seperation angle ???????
i'm putting in my LT4/383 project motor ????
:confused: :chevy :confused:

 

Pop em' in you wont be disapointed. A word of caution thought, it is always a good Idea to check valve to piston clearence. Especially with a new combo.

 

I also am considering this cam over the Hot Cam. It has a slightly shorter duration than the Hot Cam but, as you pointed out, the lift with the 1.6 rockers is .540, which is more than the Hot Cam's .525 inch. One solution is to switch to the 1.5 rockers. But that is costly.

What concerns me at I am not sure this won't cause early fatigue or interference between the retainer and valve guide with the 1.6 rockers. Of course, with the 1.5 this is not a problem.

I would like to hear anyone's experience with this cam on an LT4.

 

Stock LT4 valvesprings are only good for .525 so the 306 would require a spring swap and maybe even have the guides cut(not sure on that).

Also the HOT cam can be swapped without computer reprogram where as I'm unsure about the 306 if it will throw the CE light or not.

HOT cam is just a lower cost unless you have the engine apart, other plans, etc.

 

The CC 306 is a much bigger cam that the hot cam. It does require computer tuning and heavy duty valvesprings. 1.6 RR are not a problem, but they need to be non-self aligning. With the CC306 you're also going to need a good exhaust, throttle body, CC "R" lifters and bigger rear gears. Better yet.....e-mail Chris at Speed Demon Motorsports, he give you all the info you need.

 

I had the CC306 in my '96 CE and loved it. I think you'll be very happy. ;)

 

Whoops. My mistake.

I went back to the Comp Cam web site and confirmed that it was the CC304 I was considering not the CC306. The CC306 has a longer duration and higher lift than the Hot Cam. I have to ask someone who had the CC306 would worked with OBDII and how streetable it was. Seems the idle and computer would not like it too much, but I don't know for sure. It would operate smoother in a 383 than the 350, of course.

The CC304 is about half way between the stock LT4 cam and the Hot Cam.

 

Any reasoning on this? Self aligning without the use of guide plates, non self aligning with guide plates. Hell I'm running self aligning rockers and guide plates without any troubles.

 

Which guide plates?

 

The stock motor has guideplates that are more or less useless, thus it has self aligning rockers from the factory. I didn't like the useless guideplates, so I replaced them with comp cam guide plates and hardened pushrods. I also have crane gold 1.6 self aligning rockers. It might be a little overkill, but that never hurt anybody. I got the rockers at a great price.

 

I have run the "useless" guideplates with the GMPP SA rockers. They are only useful to the factory for assembly (''guiding" the pushrods into the lifters) and as "washers" for the rocker studs. Everything I have read and guys who know much more than I about valvetrains, caution NOT to run "real" guideplates with self aligning rockers. They maintain that there's too much side loading on the tip of the valvestems and will put undue side loading on the guides. The "useless" plate's slots are about .025" wider, (it might be more or less, but I was obsessed to find out that there was a difference between the plates) and allow the thin guide washers on the roller rocker tips to do the job intended. It may take a while to trash your guides, but according to the experts, it's only a matter of time.

 

paging chris at sped demon........what are your thoughts here as for what to do with the rest of the valve-train??all i have bought so far is the cam...i will use the comp/cams next step higher press. springs also !!!!
pushrods?rockers?etc.??
thanx,chris

 

It seems like there would be a good deal less side loading on the tips of the valve stems if the guide plates keep the rockers from dancing around so much. Here's the way I picture it. Assuming the rocker dances over far enough for it to need it's self aligning feature, this would make the pushrod have to flex somewhat. The guideplates not only prevent the pushrods from flexing, but also keep them running in line, preventing the rockers from dancing as much. The result will be less wear on the actual self aligning part of the rocker than there would be without guide plates because the rockers won't move as much.

The self aligning tip will in turn decrease the wear on the guide plates because again the rockers can't dance around as much, the pushrod will be held more centered in the guide plate.

I'm sorry I just don't see it. I'm not intending to flame anybody or call anybody a liar, I just don't understand. I run my car hard and am yet to have the slightest problem. The pushrods and guide plates don't show any abnormal signs of wear, nor do the rockers or valve stems.

If somebody could draw me a picture or something highlighting exactly where the increased wear is supposed to be it would help a lot.

 

Sorry, I don't agree with you on the HOT cam swap without a computer tune. You need it. My car nearly die at lights with the stock computer and the HOT cam kit. I had to raise my idle 200rpm.

 

Actually you could probably get away with it if you let the computer play with it long enough. The latest Z-28 we built has a cam more aggressive than the stock computer and it runs just fine. It didn't want to idle at first, we had to keep revving it up for a while, but after about 10 minutes the computer started to learn the cam and it started to idle.

After we actually drove it down the road for a little ways it idled just fine. Now the problem comes in if you reset the computer, it will have to start it's learning process all over again. The computer is fairly decent at compensating, now it could do much better with a chip, but it will usually "run"

 

Nathon, you seem to always have your own view on every subject. Did it ever occur to you that your perceptions are just that? When I post on a thread on The Forum, I attempt to stick to facts. If I don't know for sure, I admit it. I also try to offer insight gleaned from knowledgeable sources if I have access to them. One thing that I really believe does a disservice to the membership is when there are myths and misconceptions that are proffered as "fact", and become perpetuated as such. Your qualifier that you don't want to "call anyone a liar" is thinly veiled as doing just that. Your basis for suggesting that someone is posting a non truth is simply your sometimes misguided perception of what YOU THINK something should be.


In this case, have you actually pulled your heads and measured the clearance between the stems and guides? How many miles of what kind of driving do you have on your real guideplates and self aligning rocker arms? Is there meaningful data to share on the subject? Hopefully one of the "Engine Mod" gurus can clarify this for us.

 

:bb :bb :bb

 

On the L98, I have. There is LOT of play, almost to the point of the rocker arm can almost fall off the valve stem tip sideways. I think this has a lot to do with why the valve guide seals wear out so soon. If rocker cahnges are wanted...definitely use aftermarket guide plates ( I like the raised lip type for even better control ).

 

First you can learn how to spell my name. Second you can re-read my post. I said that I don't understand the problem and asked somebody to try to explain it to me a little bit better. Excuse me for trying to learn. So what do you do, basically call me an butt for trying to understand what you are talking about.

Nice, real nice.

 

Sorry Nathan. I usually proof my posts, I guess I missed your name. I apparently got caught up on your "flame/liar" sentence and took undue umbrage.

As for wear and tear on your valvetrain, if there's more than about .004" on the intakes and ~.005" on the exhaust, you're on borrowed time. Especially with SA rockers. I agree that hardened pushrods, offset guide plates and non SA rockers are best. Just fyi, I believe that at least one of the authorities on heads and valvetrains that cautioned against SA's with "real" guide plates is David Vizard.

PS. BBA, if you can see movement of the valvestem tips on that L98 motor, it's no wonder that the seals are getting eaten alive. The guides have got to be gone.