rocker arms

[nomaboy]

do the 96'-up 4.3 use the same rocker arms as the small block chevys? I want to put some roller rockers on it with 1.6 ratio. if they are the same, are they 3/8 stud? if not where can I find a set?
thanks

[OBI WAN]

There press in studs, not screw in and I believe if I remember right 10mm in size. 96-98 I believe use this setup. You have to rework the arrangement to use screw in studs in order to run this rollers. 98+ is semi roller allready that are fulcrum rollers with solid tips.
SLP makes a set of 1.6:1 for both arrangments!

[ZR1-S10]

Don't the guides need to be machined due to the longer ratio?

[OBI WAN]

Don't the guides need to be machined due to the longer ratio?

No thats factious info from other sites!!! The factory total lift at 1.5:1 is around .390 and the Vortec head can do .450 100% safely, and is reported to be able to take .470!

[rat]

do the 96'-up 4.3 use the same rocker arms as the small block chevys? I want to put some roller rockers on it with 1.6 ratio. if they are the same, are they 3/8 stud? if not where can I find a set?
thanks
The short answer is yes. You would have to check to make sure that you don't need to elongate the pushrod hole with the higher ratio.

What year are you talking about specificaly? If it is for your 2001, you will have some work to do. SLP makes a bolt in replacement for around $400. I have pictures of the stock rockers and head setup here:
http://www.cardomain.com/memberpage/721787/3
I also have the part numbers for almost every thing you would need if you are going to be swaping in a full roller rocker on a 2000 or newer truck. The 4.3 changed to roller trunions in 2000.
ARP has a part number for replacement studs with 3/8-24 top threads, and 8mmX1.25mm bottoms. Your stockers have a bolt that holds the rocker in, and not a stud.

[Supercharged-ZQ8]

1) I don't know for certain on the pre-98 motors -- but the '98 have full stamped rockers (no roller at all).

2) The stock stud is 10mm and is screw in -- the aftermarket rockers need 3/8", so a stud conversion is needed.

3) The '99 and up motors use a shaft roller setup -- not studs. The SLP rockers are a good bet for those -- either way, you're looking at around $400 no matter what. For the stud-mounted, it was $270 for the rockers and $180 for the stud conversion. For the shaft-mounted. the SLP set is complete and ready to install and runs $399. Either way you look to gain around about 10 hp. The best thing is that they allow the motor to rev easier and quicker -- getting you into your powerband faster.

I use the Crane Race Gold full rockers -- stud conversion was easy enough (but one stud ran through a coolant passage -- needed an oil change IMMEDIATELY) -- installing the rockers was easy enough. It's adjusting them that was the pain.

[rat]

1) I don't know for certain on the pre-98 motors -- but the '98 have full stamped rockers (no roller at all).

The cut off for the roller trunions is 2000, not '99. '99s have the same setup that your '98 had.

[Supercharged-ZQ8]

The cut off for the roller trunions is 2000, not '99. '99s have the same setup that your '98 had.
I stand corrected. . . My own experience hasn't been with a '99 truck. I knew it was either '99 or '00.

[nomaboy]

yea...i was hopin i could just bolt on a sbc set cause i really don't want to spend 400 bucks on them. but i may find an extra 400 layin around somewhere. thanks for all the responces.

[ZR1-S10]

I've got a 96' 4.3L and want to use Comp Cams self-aligning Pro Magnum rockers 1.6:1 ratio with their 3/8" stud convertion. Do I need to elongate the pushrod hole? and can I do the stud convertion with the heads on?

[Supercharged-ZQ8]

I did mine with the heads in place -- the '96 motor should be about the same.

[jharrison]

John, do you have a link or part number for the SLP rocker package for the 2001's?

[OBI WAN]

50882 (http://www.slponline.com/view_product.asp?P=50882)

http://www.slponline.com/browse_list.asp

[ZR1 S10]

No thats factious info from other sites!!! The factory total lift at 1.5:1 is around .390 and the Vortec head can do .450 100% safely, and is reported to be able to take .470!

Theres guys running .500 lift cams on the stock heads. Only one or two I beleive, I know its crazy and I'd never do it. As far as I know the limit is .480 safely.

Also you can get conversion studs from summit or jegs. Then just pic the rockers of choice. Now the only problem is the locking nuts, on some hit the valve covers and some dont. I know my setup did thats why I have valve cover spacers.

I think it was comp that made the shorter locking nuts that will clear.

btw I'm running the Comp Cam Pro Magnum 1.52's (got the 270AHR also).

[OBI WAN]

According to GM ,the springs will bind at .470 + or -! I know I wouldnt attempt a .500 lift, they have to be binding by then!

[ZR1 S10]

According to GM ,the springs will bind at .470 + or -! I know I wouldnt attempt a .500 lift, they have to be binding by then!

Thats with different springs of course! The valve guides are what you need to worry about.

Anybody that does a cam swap and doesnt get better springs is asking for trouble :)

[nomaboy]

what do you figure is the max safe lift with stock springs?

[ZR1 S10]

NOT MUCH. No way could you run any aftermarket cam without them! I havent seen one site that doesnt show a set of springs to go with the cam.

[OBI WAN]

You can run the factory springs till around .450 without a problem and really any need for new ones since RPM levels and lift arent dramatically different. At .450-.470 the springs will bind using factory ones and need new springs. At .480 the guides will be toast if not machined!

[nomaboy]

cause the cam i ordered has a lift of.430 w/1.5 rockers think that will be cool?

[rat]

cause the cam i ordered has a lift of.430 w/1.5 rockers think that will be cool?
Call crane, and find out what the recomended valve springs are. If you put in a cam that makes power up to 5000rpm, but you get valve float at 4000, then that cam isn't going to do you much good is it? The recomended springs fit the heads with no machining from the looks of it.

It isn't like valve springs are that expensive, or hard to install. May as well do it while you have it all apart.

[jharrison]

I know I'm a little slow but thanks John!

[biglouie_underpressure]

According to GM ,the springs will bind at .470 + or -! I know I wouldnt attempt a .500 lift, they have to be binding by then!
werd....

[nomaboy]

on crane's site it lists that the valve float for that cam is 5600rpm. which i should never hit anyway.

[rat]

on crane's site it lists that the valve float for that cam is 5600rpm. which i should never hit anyway.
Yes, that is with the recomended valve springs. The maximum recomended rpm is 5000 rpm, and that I expect you would hit regularly.

[nomaboy]

i DO appriciate your advice. but the way i am thinking is that if the stock springs are good for .470 lift and the springs recommended are good for .480 lift and my cam with 1.5 rockers lift is .430 then i am not coming close to the .470. so why do i need springs that are good for 10 thousanths more lift?
the only reason that i don't want to change springs is because i can't find a spring compressor for my factory roller rockers. and i don't perticularly want to pull the heads off in fear that i may mess somthin up.

[biglouie_underpressure]

spring compressor for factory roller rockers? read the cam spec sheet and see what it tells you! all you need is an air compressor and the fitting to hold the valves in place while you check the pressure. If anything you can add a shim if springs are too light.

[rat]

i DO appriciate your advice. but the way i am thinking is that if the stock springs are good for .470 lift and the springs recommended are good for .480 lift and my cam with 1.5 rockers lift is .430 then i am not coming close to the .470. so why do i need springs that are good for 10 thousanths more lift?
the only reason that i don't want to change springs is because i can't find a spring compressor for my factory roller rockers. and i don't perticularly want to pull the heads off in fear that i may mess somthin up.
I don't think this is as hard as you are thinking. I will try to explain, i think we are misunderstanding each other.

There is more to the valve spring than how much lift it can take. The seat preasure, and the spring rate are also very important. This is what controlls the valve float characteristics, and the maximum rpm of the engine. Remember that valve float is damaging to the valve spring. If it happens one time it will happen at a lower rpm the next time. When you change the duration, lift and shape of the cam you change the acceleration rates of the valves, rockers, lifters, and pushrods. Putting in a more aggressive cam accelerates the valve quicker than the stock cam. This is why crane, and comp both recomend valve springs with all of their cams, and it is important to follow these recomendations. If you don't beleive this call, or email your camshaft manufacturer. It shouldn't cost more than $130 for the new springs. The crane springs fit without modification.

Now, for the messing things up part. I don't think you will mess any thing up. If you are willing to change a cam, then you can change the springs, piece of cake. Your rockers will have to be removed, you have to remove them anyways to pull the pushrods, and lifters to get the new cam in. It is just one bolt per rocker to remove the rockers. Now that the rocker is off you have to get the springs off. There are several ways to do this. I bought a valve spring compressor for $13 at murrays(a local parts chain). Before you compress the spring, you need to prevent the valve from falling into the cylinder. Bring the given cylinder to topdead center. Get a 14mm air fitting at your local autoparts store for the spark plug hole. Turn on the air, the air will keep the valves closed. If you don't have an aircompressor, take a bit of nylon rope, and tie a large washer to the end. Now feed the rope into the plug hole, and bring the cylinder up, this will also keep the valves from dropping. Then you just pull the locks, and take the springs off. The new springs go on like stock. Easy. Make sure you have a magnet on hand. The locks are a tricky, because they are small and easy to drop. Cover the lifter valley as well while you do this. Don't forget to get the locks, and retainers for the new springs.

Did that make sense?

[nomaboy]

yea that made sense. i wasn't thinking about the faster acceleration of the valves. i found the springs for 60 bucks so price isn't an issue. once i find the spring compressor i should be set.
thanks for explaining it to me.

[rat]

yea that made sense. i wasn't thinking about the faster acceleration of the valves. i found the springs for 60 bucks so price isn't an issue. once i find the spring compressor i should be set.
thanks for explaining it to me.
Don't forget the retainers and locks.

[ZR1 S10]

Trust me just get new springs and retainers, you will not regret it!!! I dont care what anyone says about stock springs handling .470 lift, its just a bad idea.

[bvr775]

I use the stock springs for break in then change to a stiffer spring.

[nomaboy]

roller cams don't require much of a break in though do they?
and yea i plan on new springs and retaners
thanks guys

[rat]

roller cams don't require much of a break in though do they?
and yea i plan on new springs and retaners
thanks guys
No, when i did my cam i ran with the new stiffer springs right off the bat. I took it easy on the cam for the first couple hundred miles. You are suposed to break in the springs though, by getting the engine up to operating temp, and then letting them cool to room temp.

[nomaboy]

k. just got on summit and ordered timing chain #CLO-9-3154. springs/retainer set #11308-1 and locks #99097-1.
so hopefully these parts will work. I'll find out in about 3 weeks.

[ZR1 S10]

No break in needed with roller cams.

Have you thought about lifters?

The comp cam High energys are a great replacment.

[nomaboy]

i am not pulling the head so i don't want to put lifters in that would cause me to have to get the heads machined. also being an 01 they have the roller rocker arms and i would have to get a stud mount kit as well. either way it is like 400 bucks. i have spent enough money already.

[ZR1 S10]

You have roller trunions not full roller rocker arms. Also you dont have to pull the head to do lifters.

[rat]

I did not replace my lifters when i did my cam last year. Now i have a little bit of rocker arm noise. I am going back and replacing my lifters, since the stockers have 95K miles on them. The lifters don't change the lift of the cam, and you wouldn't have to pull the heads to change them. You have to take them out to get the cam out anyways. If your lifters have less than 60K miles you might be fine, it is easy enough to get in there to change them if you have problems later. You have roller trunions by the way. They look like this:

http://memimage.cardomain.net/member_images/1/web/721000-721999/721787_14_full.jpg
http://memimage.cardomain.net/member_images/1/web/721000-721999/721787_15_full.jpg
http://memimage.cardomain.net/member_images/1/web/721000-721999/721787_16_full.jpg

[nomaboy]

yea. for some reason when ZR1 said lifters i was thinking of rocker arms, don't ask why. my lifters have 45000 on them so i would think they would be fine.

[ZR1 S10]

Just saying there was a guy on another forum that did the cam swap and a few days later lifter noise. I personaly think one of his lifters went bad. Either way its up to you but it sure would be a pain to pull everything apart (right after you just did) again because a lifter died!