I'm getting ready to change out my valvesprings and go to some higher lift rockers. I was wondering what the knowledgeable V6 enthusiasts would suggest as far as what type of rockers and springs would work. CAM is stock, and I'd like to be able to make some more power higher up in the band (valve float sux). Thanks
PS: what about going 1.6 on exhaust and 1.7 on intake?? or somthing like that?

 

The standard performance 3.4 GM heads have Crane Cams#99848-12 springs. This is a boltin upgrade from what you have and will handle your stock 3.1cam +1.6rockers.

 

Found my datasheet- More info for you. These are figures are percise calculations I made for the motor I am putting together. This is a setup for a high lift endurance (roadrace) motor.

It will handle .512"lift/ 228duration with 1.6rockers @ 8000rpms. 10.3:1 CR

#99838-12 springs (Height 1.688", 1.465"dia. Need to machine heads to fit.)

#99669-12 Titanium retainers (7* posi stop)
#99097-12 (7*locks)
25621-12 Chromemoly pushrods (6.163", 5/16dia w/ oil holes)

[Note: The retainers will set the combo at .040 height so the heads spring pockets need to be machined to an installed height of 1.650"]

 

what about valve seals?

I have a bookmark to a good thread about them a while back.

https://www.thirdgen.org/techbb2/sho...hreadid=215450

614street [ our resident blown v6 owner] had some good info about them. You are gonna change them while your at it?

 

I'll be doing valve seals at the same time as well. As for the springs, 99848-12 springs will be an upgrade from the stock ones in a stock 3.4 head? And for the rockers, 1.6 with the stock -3.4- cam? Just have to make sure before I buy them, a suggestion on a place to purchase the rockers would help too. I'm not even going to be jacking with them myself. I plan on dropping the car off at a buddy's shop for him to do, business is booming where I work, I don't have the time to do it myself.

 

Don't get the crane springs there over priced crap.
Out of summit there $60
There seat pressure is 105lb. @ 1.700''
Open there 296lb. @ 1.200''
They bind at 1.153''
All most the same as stock.
On stock heads your installed hight is about 1.640''.
Your limited to about .440'' of lift with those springs.
I think there a wase of $.
Not much of an up grade for $60 and the labor you will have to pay for I don't think it is worth it at all.
There very close to what the stock springs are. Nto much of an up grade at all.
When I speced my old stock springs they came out a little s#!tyer than those crane springs.
They were about 90lb at 1.640'' and only 270-280lb compressed to 1.24 , stock cam open valve.
Now get a real up grade and some real springs.
Kmotion K-700's from summit are $42
there seat pressure is 120lb. at 1.700''
there open pressue is 375lb. at 1.150''
They bind at 1.050
These will go on with other NO modification and will give you .480'' lift easy, they could give you more if you didn't care about your valve guide seals.
You are good for up to .480'' of lift or you could shim them so you could use the full open pressure of 375lb and kill your valve float.
375lb's won't hurt you lifters because there I have seen many people run all most 600lb on flat hyd lifters on V8s over at camaroZ28.com.
You can get titanium off ebay for chep.
I got Every thing (5/16'' intake valves, 16 super7 retainers, 8 super7 locks in 5/16'' and 8 in 11/32'' super7 for the exhaust) in Delwest Titanium for my Z28 except for my excylidine titanium exhaust valves, every thing was about $450 total off ebay.
I read a chevy hipro magizine about a year ago where they made 20 more hp on a 383 they had been working on just by switch ing valve spring to bigger ones.
They switched from stock like 1.25'' springs to 1.460''.
And if you can get 1.7 rockers for your 3.4 please tell me where.
You can put different rocker on the intake and exhaust sides it is a good old trick.
You can get crane gold full roller rockers from summit for like $270 and you need there rocker bolts to go with them, the stock ones won't work.
They will give you about 15 ft.lb. of torque at most through out the entire rpm range.

 

I have crane springs and retainers
Catpep 1.6 rockers
stock 3.4 cam
seals on all valves (intake and exhaust)

No problems other then I have a rocker loose

 

Oh we know that.

 

If you have 3.4 head now- then you have already the Crane 99848 valvesprings! You are fine with the stock cam and 1.6 rockers. Don't waste your money.

Alot of people don't know this but GM buy there parts in bulk from aftermarket vendors rather than manufacturing things themselves. Parts from companies like TRW, CraneCams, Federal-Moog, etc..

 

That is because they changed the bottom end and had to upgrade the springs closed pressure to handle the increased CR stroke and not loose vital CR- That is not the case with Fbodytrek, he's running stock 3.4 CR. If he goes up in valve spring pressure he will LOOSE hp and rpms.

Oilpan,
If Crane is crap, then why is every GM car I know running them and running fine without blowing motors. Every GM car stock has them (at least back in the 70's, 80's, and mid 90's)

By the way, why are you in Japan and where are you from originally?

 

So what you're saying (vsixtoy) is that the springs I have will be fine with the 1.6 rockers, and that going any higher in spring pressure won't help me higher in the rpm band??? I always thought valve float was when you stopped making power . To alieviate that you upped the spring pressure a bit to compensate. now, where do I find me some 1.6 rockers, i don't want roller unlesss they are worth it. 250 bux is WAYYY too much for a set of 12 rockers.

 

I only think those springs are a crappy upgrade for the money.
I dont think crane as a hole is crap just those those spintgs in the appication.
My cam is a crane cam (one for my V6), I plain to get crane gold roller rockers for the V6 and crane has a retro fit roller lifter kit and they make the exact cam I want for my Z28.
You wont see me buy springs form them any time soon, every thing else maybe.

 

Yes, the stock 3.4 springs can handle .500"lift @6000rpms no problem. Your cam with 1.6 rockers will have a total of .484"lift. You'll be fine. Installed hieght is 1.70" and the open height is 1.20"= .500" travel with a open pressure of 296#. Again, that plenty for what duration and lift you have, they will not float. Valve float causes piston damage- so yes, you do lose power and you'd know it real fast.

This is anther reason why the very best valvetrain mod would be to spend the extra money on the aluminium rockers- they are expensive, but they are worth it. They are much lighter so 1)will rev faster and higher, 2) will return faster without "float' and piston contact over the steel type rockers- another safety margin if you over rev.

Budget motors always blow up-why?- they never focus on reliability. Gold rockers are reliability.

 

What I want are aluminum roller 1.6 rockers huh? 250 sounds steep, but what kind of gains would the aluminum roller give me over the stamped 1.6? Just weighing my options, you understand

 

Personally, I have them on every car I own except the V6. I just never got around to it because I would have to pull the heads to do the work I want, then fit the 1.6's on there with the Fiero covers I have (But again I'm not wasting my time with this 2.8). I do have steel 1.52 rockers on it now and am ok with those combined with the stock 2.8 valvesprings I have.

They will definitely be going on the new motor- This is "in my opinion" the best modification that can be added to any motor. It lightens the valvetrain bigtime and helps with topend power. They also do add duration at .050"lift readings and lightness allows them to shutdown quick on the steeper ramp.

How do you feel about your car? Meaning, if you could afford to someday, would you sh*tcan it and buy a better "dreamcar" or do you intend on keeping it around a long time. Personally, not trying to sound arrogant, I could easily afford a new vette or such, don't what one. I like the cars I have and I love driving this V6 because it handle better than anything I have ever driven (and I have driven more exotic cars, and full race vehilcles than mosst anyone you know)- cost me alot of money and TIME to get it that way and I did it to keep it for many years to come. So, parts like the above are worth it to me.

 

I plan on keeping my car personally. I've put in alot of wrenchtime and have a sentimental attachment to it. I want the best personally, but sometimes the best is beyond means... I want this motor to last though. I have heard stories of the life expectancy of aluminum rockers is 30 thousand. I will take your advice though.

 

Cheap off brands like Summits own Aluminium rockers have terrible roller bearings. Crane Gold rockers are top notch quality and will last.

Its just like running crappy 2pc steel rodends compared to the Aurora or QA1 3pc Aircraft Chormemoly rodends. I can junk a crappy rodend in one day on my suspension, the goodones will last about two years the way I drive.

 

You can not run .500'' of lift on stock springs. You will break some thing if you run .500'' lift.
The Stock springs WILL bind at .475 lift. You will most likey bend push rods untill your engine dies. if your lucky thats all that will break.
The springs are not installed at 1.700'' they are installed at 1.625'' in real life on our heads.
1.625'' - .400'' lift (stock) = 1.225 (the max recomended open hight)
I have pictures if you don't belive me.
The stock springs bind at 1.150''
You can add spring hight and change ( find a way to add .075'' of installed hight with different retainer, locks or machining)the installed hight to 1.700'' and then you will be good for .500'' lift.
It would be cheaper to spend $42 on kmoting springs, a $20 tool from sears and $6 for new velve cover gaskets.
All most every case of valve traine damage not enough spring is all most all ways the cause.
This is what I found on my 85 and up 2.8 heads, and the 3.4L are the same.
Your heads might be a little different only way to know is to take them apart.
At the factory they put there heads together at 1.625'' to take adventage of the open pressure, like shiming but there cut that way so no shims.
I have a pair of bare V6 heads and I still have the original retainers, locks and valves.
I took measurements my self, I found out the easy way that these heads will not take .500'' of lift insted of breaking some thing.

 

I have catpep.com 1.6 stamped steel rockers. About 50 bux I think??

I used the stock 10mm pivot ball, and nut.
I had to grind a bit on the tip to clear the new retainers I have, but when I tested them on my stock 3.1 heads/retainers, they were fine.

 

Oilpan, Ther heads you measured are 2.8/3.1 heads. The springs in those heads are only good to .420"

The 3.4 heads are .500" (edit: I just check again to verify coil bind and thats actually at .547"- so they still have much accidental overrev protection.)