It is a 1996 350.

Just curious to see what people are using.

Hit me.....

 

Any mods that need to be done to run a ZZ4 cam with "bone stock" vortecs?

 

Comp Cams XR276HR with beehive springs in the heads to allow the higher lift.

 

im running the GM LT4 hotcam

 

Thanks.

Anyone else?

 

Stock Vortecs will take a usable max of .470" lift and it's not just a simple change of springs, valve guides must be machined down to except higher lift.

ZZ4 cam has .510" lift so valve guides need machining and new springs

You will also want to have the pressed in studs pulled and drilled for screw in studs.

If you want to run 1.6 rocker arms you will most likely have to widen the pushrod pockets

I also run LT4 hotcam and getting near 400hp out of the combo with HSR.

Check out Pace Performance for a modified set of Vortecs good to .540" lift., they clearance valve guides put in good springs and tap for screw in studs.

http://paceperformance.com/index.asp...OD&ProdID=9175

 

I use an xe262 (218/224@.050 .462/.469) I wish I had paid to mill down the valve guides and wentw ith a bigger cam, though. An xe268 or xe274... something along those lines.

But the car runs great so... no complaints... just one of those "That's nice... but I want more...." things.

 

Ive been running a Lunati Bracket Master II .480 lift 292 duration.

 

Cool, thanks for the info. I think I'll stay under .470 lift for now. The engine only has 50k on it. When the engine dies and needs a rebuild, then I'll mod the heads for a larger cam.....along with forged 383 internals.

The Trick Flow cam looks like the winner. Only $120 for a roller cam.

 

So so wrong. It IS a simple change of springs. As long as its the "beehive" style spring such as the ones from Comp.

 

https://www.thirdgen.org/forums/tech...ortec-lt4.html

 

That is a very dangerous and expensive way to press your luck and no reputable engine builder is going to put there name behind this, I know I wouldn't. I have fixed many engines where someone has used beehive springs to increase lift and it has never been pretty.

To the OP just do it the right way the first time and have the valve guides machined down.

 

Yeah even though I personally run this setup with no problems i guess I just don't know what I'm talking about.

 

even comp cams will tell you that a spring change and valve seal change will allow a bigger cam to be put in without machining. also if you email comp cams they will spec one for you for free.

 

Why?
One line statements statements like that are USELESS with no supporting information
The problem is the retainer to guide clearance; not the spring rate

Once again more info needed ; what was the problem caused directly by installing beehives?
And how does installing beehive springs contribute to engine problems any more than regular springs?

 

You guys are missing the point, just cause it works doesn't mean it's the best way to set up an engine.

If your going to spend time and money do it the BEST way you can and in this situation (my opinion) the best way is to machine the valve guides down, period.

 

Going by that logic why bother building a mild performance engine? You might as well build it the BEST you can and make 100000000+ hp. And no offence but what qualifies you to say machining the valve guides is a better approach? I personally have ran these for thousands of miles, not to mention the countless amount of money and time companies like Comp have put into these springs.

And btw, it doesn't "just work", it is an equal alternative at the least as beehive springs are a far superior design that tranditional springs.

 

No disagreement there but doesn't back up your comments above

I have fixed many engines where someone has used beehive springs to increase lift and it has never been pretty.

What problems did the beehives cause ?

 

XR276HR.
Beehive springs.
Screw in studs.
Guide plates.
1.6 rockers.
No machining.
100's of 1/4 mile passes.
Thousands of miles.

 

How much did it cost you to install those screw in studs and guide plates?

 

I have nothing against beehive springs, they are an excellent design and can add 20-40 hp in the upper rpm range and add valve stability and help an engine rev higher without valve float/bounce.

But the original converstion was just installing beehive springs without machine work.

This prompted my "dangerous and expensive way to press your luck" comment

From my experience this cause two problems, first no screw in studs, which I have seen the pressed in studs pull right out with an engine at full tilt I think the problems this would cause are obvious, my rule of thumb is lift over .480" need screw in studs (machine work). Next problem is not using locators with beehives. If you use locators(which you always should) you would almost have to machine the valve seats lower and machine the guides down, it would be different for every head, I automatically do both when installing beehives. Locators add about .060" shim so that has to be taken into account for installed height. If you don't your stack height becomes excessive and seat pressure to high which creates other problems like loss of horsepower, premature valve seat, guide, lifters and/or cam wear and left uncorrected could lead to serious engine damage, all which are not good.

When engines come to my shop the person who just installed beehives springs and did nothing else usually fall into one or both the problems listed above and have ranged from bent vavles to locked up engines.

These are just my experiences with beehives without machine work, not saying it can't be done different sucessfully as you guys have proven here.

For those that do not know I build high performance marine engines and have used beehive springs since 2005 very successfully. These engines range from small to big blocks, mild to wild 572 with blowers running 1250 hp. These engines live at wide open throttle most if not all the time which qualifies as severe duty so my wins and failures have been numerous over the years as can be expected with anything high performance. So I try to figure where I failed and correct the problem and through experience I have very few problems today and try to pass along what I have learned with others so they don't make the same mistakes I did.


Hope this helps answer some of my previous comments.

 

That was the info required to back up your statement.
It is not the beehive springs themselves but a lack of good engine building knowledge that causes the problems

 

So, is it a problem with the valve guide being so tall it hits the retainer? Or is it a problem with it being so big you cant fit a good valve spring in there?

 

In stock configuration ;Yes
The beehive springs and retainers solve the problem so long as you take into account the potential problems mentioned above by TransAM Joe

 

I suppose my comments should be qualified as well.
ANY performance oriented engine should have screw in studs. I can see how if you were to say that installng a beehive style spring solves all your problems is misleading.
Also consider that if any upgrade to a more substantial spring is made, modifications will have to be performed accordingly.
Further to that, you have to decide between a self guiding rocker and a more traditional guide plate setup.
In summary, when upgrading a Vortec cylinder head, it safe to say that there is machine work invloved to bring it to specs that are over and above what's invloved in simply dropping in the new springs.
Point well made.

 

I dont understand.

I thought the point of beehives was to get more spring travel before you ran into coil bind? How is the retainer any higher when you have the same valves? The retainer's gonna sit on the same spot on the valve, right?

 

Bee hive springs are made of ovate wire which allows greater spacing between coils. Also because of the reduced spring i.d., the retainers are smaller which as well as reducing overall mass, provide more room between the guide and the retainer itself.

 

This is what I have, stock ZZ4, I am upgrading my valve train.
Comp Cams push rods, Lunati 1.6 Roller rockers, LS6 bee hive valve springs.
I measured my stock ZZ4 clearances, Installed height of my springs is 1.74, not 1.78 as my book states, height when retainer hits valve seal 1.175, that leaves .565 lift, with stock springs that is not happening since coil bind is 1.21. So if you want to run 1.6 rockers with the ZZ4 cam you have at .544 lift you will have 0.021 clearance to the valve seals, thats according to my stock ZZ4 engine.

 

Im building a 383 with vortec heads. Im going to be running the lt4 hotcam with 1.6RA. .525 lift

The solution is not the springs. The beehives are not what actually solves the issue. The fix is the clearanced retainers.

I have not built my motor completely so i can not confirm this first hand, but take a look at this:


This is the vortec bible. 49pages takes a while to read. Some people even grind there stock retainers and get away with it.
http://www.nastyz28.com/forum/showthread.php?t=56505

and

http://www.carcraft.com/techarticles...ade/index.html

 

well you are half right.

the .480 lift max is caused by the retainer hitting the seal on top of the guide.

So yes, smaller retainers give you more clearance. But you have to watch out at that point for coil bind. If you machine the guide/or use shorter retainers, you will achieve a higher max lift. But if you try to run that higher lift without changing to a proper spring, you will be in just as much trouble.

 

I am putting in com cams 08-414-8, @.050 is 230-234, .474 .474 with 1.5 rockers, I am putting 1.6 lunati full roller rockers that will put me up to .506-506, Am also putting beehive springs with comp cams push rods, is going in my ZZ4.

 

Bump for back on topic. I am doing a 383 vortec motor now and I am looking well matched cam for the setup.

Also, when you use the guide plates/screw in studs, do you have to machine down where the screw in studs go so the guide plates will fit. I am worried the stud will stick up to high.

Thanks.

 

Yes, you will have to machine the rocker stud boss to provide a flat register and to allow for the thickness of the guide plate and/or stud base.
As far a picking a well matched cam, there are several variables that must be considered.
Providing all the requisite data to a company like Comp will result in several choices.
I picked up the Cam Quest program from Comp and picked a cam based on the results (more or less).