cagotzmann

Anyone have any advise on upgrading the ZZ383 fastburn heads with the GM spring upgrade kit. This is using the new beehive valve springs. Comes with everything except new valve seals.

New engine never been started yet.

The height of the spring when free is shorter ? .

The kit has no instructions so I would think nothing special. No shims where included as well.

Looking at the existing springs they all seam to have the same
valve spring seat & valve spring retainer. Do you usually measure install height. What else should I check.

The original valve spring seat cannot be removed unless I remove the valve seal. They look the same dimension except for the valve spring retainer, I will use the supplied retainer and clips , and leave the seal and spring seat as is.

This is the kit
http://paceperformance.com/i-1338982...rsion-kit.html

Any advise when installing the rocker arm. They seem very loose on the original springs. I usually tighten until I cannot rotate the rod with my fingers then plus 1/4 turn. Then rotate the engine 1 complete cycle and check that I can turn the rod with my fingers.

7t9l82

the spring manufacturer should have some spec on installed height, it matters a great deal that they be set right as " beehive" springs will oscilate , fatigue and break anything you can do to stack the odds in your favor are worthwhile.
personally I'm not a fan of that type of spring but i guess there are applications that you need them. good luck with your project.

cardo0

I dont understand why u want to upgrade those springs now? The ZZ383 original springs should be good enough for most cams. Did u find a cam that needs the beehive?? That ZZ383 is a designed complete package. Do u expect more power from a spring change? Replacing the vlv seals just adds more potential for problems also.

What im saying is if the ZZ383 is band new then use the springs as is until u see some power loss near 100k mi as the original springs weaken. By then u can read up on spring requirements as every major cam mfr has information to choose the correct spring and set it up. The installed height is a result of your vlv stem length. And u shim for the correct installed height which should result in the correct closed pressure if u tested your springs before installing. The open press is a result of the spring rate. But for a beehive spring i dont expect a linear spring rate like a normal wound spring though the product data will list one. But for open press what u get is what u get unless u select springs individually to match.

To adjust your lifters u need to understand the firing order and which vlvs are shut to be on the base circle of the cam. Once on the base circle tighten rocker nut until no more up or down p-rod move but still rolls in your fingers - just starts to drag. Then tighten 1 full turn. If not done correctly u can ruin your cam and or your entire engine - dont take it for granted.

cagotzmann

GM lists a specific part # for the upgrade for their zz383 base, so do I need to worry about install height. Since they don't include any shims and claim they are a direct replacement.

When I measured one bottom of spring to top of spring it measured 1.803 " and 1.846 from top of spring to head. The spring seat measured 0.43 " and I think they should be 1.8" seems like a direct replacement. ????

cagotzmann

I was planning on leaving the valve seat and seal in place and just replacing the clips and top retainer ? The seats are the same in dimenions / thinkness.



I was going to purchase the zz383 deluxe version with all installed, which includes the upgraded head's with beehive but that was a $1650 difference from base, GM dealer offered the base with the upgraded springs at a discount of $1650 to get the same unit, but I would need to install the upgrade kit.

I have only replaced cylinder #1 so far. and took some measurements they measure at 1.803 " from top of spring to bottom of spring. I dont have anything to measure spring preasure but understood this was a direct replacement GM offered.

I might call GM TECH to confirm I can just replace the springs. I dont see any special shimming of the stock / original setup so I dont know what to think.

Thanks for the input, I might do as you said, put them back and save them for another day.

cardo0

Most new enthusiasts are misled by others that have the experience to adj the vlv train correctly thinking it is easy. Well it maybe easy if u know what u are doing but the consequences of an error are terribly high. Even if u decide to replace the springs on #1 u now have to adj the lifters and done incorrectly can destroy your brand new ZZ383.

For installed height u need a vlv spring height micrometer that fits under the retainer w/o the spring on. This will tell you the distance from the spring pad to the retainer = installed height. Some will use a regular calipers for this but more difficult to use. But it not to late to just replace the original springs on #1.

BTW i have never seen a spring shim on a stock GM engine but any performance head rebuilder will use them. GM has it own ideas of requirements there.

I think u picked up a small case of OCD as most of us do but u should realize we all have to respect the technical complication of the internal combustion engine. Blue printing is a slow tedious process that can have endless details. But a crate engine has all that complicated stuff done for u already - why make it difficult now? Isnt that why u bought a GM crate to begin with?

diehrd

I just did this upgrade on my fast burn heads except I used PAC Beehive springs which allow for a 650 lift.I also put in a new cam GM 847 GM single plane .. Car screams ..

Back to the springs the PAC springs I got had seats, retainers and keepers. They are direct fit and spec the same height and pressures you need. The only issue I had was rocker studs where to short so I upgraded to AFR .

None of the original spring parts will work with the beehives so make sure you have all the items and with a spring compressor . air charging the cylinders it took me about 4 hours to do.

cagotzmann

The kits doesn't come with any seals so I cannot remove the original bottom seats. They originals look the same so I left the bottom seats in place and replaced the spring, needed to use the new top retainer its smaller than the stock and used the new split key locks.

GM ZZ383 p/n# 1915477 is pre-2013 spec Fastburn heads and in the catalog show the heads can be updated to 2013 beehive specs with P/N #19300952 converision kit which is what I bought.

I dont think the measured spring height should be a problem since the originals dont all measure the same and have no shims installed anywhere.

The documentation with the engine lists valve lash adjustment as 1/8" turn down from zero lash.

Now if a wanted to full race engine and wanted to sqeeze out every bit of HP I would need to check spring heights / pressure, and as someone else stated and a little OCD , (he may be right and just return to stock) but I would just like it to perform very close as designed (2013 design) with reliable results on not worry about every last bit of power.

I am starting to figure out that the after market car industry agree's on nothing. I wish the manufacturer's would just provide reliable information that we can base our judgments on. I never get the same answer to the same question and last guy states the other guy is wrong. My problem is when it go's full circle and still dont know what to do. Thats why I like this forum. You do get many answers to the same questions, but you start to thrust some idea's.

Should I worry about the bottom seats that I wont replace. I dont want to remove the origial valve seals. ?

cagotzmann

That's is what I thought I was getting with the Spring conversion kit. I simple remove and replace. GM supplies the parts that just work. I am ok with the install procedure.

I am using compressed air the hold the valves in place, I am using a dial gauge to find the lowest point on the lob to get 0 lash for each spring, then as my GM supplied documentation 1/8 turn and lock the retainer in place. I am not using a quick method of doing multiple cylinders at a time. Its much slower but I feel better this way. I am also measuring the spring heights with a digital caliper. Not the best, but if something doesn't seat properly I should notice. The 2 I did measured at 1.803 and 1.814.

Any other thoughts as how I should proceed, but I think I will more forward and contiunue.

scottyp99

Beehive springs are yesterday's news. All the cool kids are using the new conical springs, now! Jeez, get with it, square!

Scott

diehrd

The bottoms are thicker on the oem ones the Beehives are thinner. How this can affect you is in height and pressure. Will it cause issues i bet not .. So why did you change your springs ? I did it so I could run a 595/595 lift cam

cagotzmann

I measured the OEM bottoms and the new bottoms, both are about 0.043" so I didn't think there would be a problem to leave them as is.

I was going to purchase the GM ZZ383 deluxe which was the current version, GM dealer offered a base model + the spring kit which makes the specs the same at a $1650 savings. The $1650 savings was used to purchase the extra items required to complete the build.

63mako

Spring installed height on those should be 1.800. Get some thin shims.

cardo0

As far as 1/8 turn on the rocker myself i have never seen GM instructions use less than 1/2 to 1 full turn. But if your crate instructions say 1/8 then ok use 1/8. Myself i feel 1/8 leaves more room in the lifter for aerated oil to reduce lift but dont let that confuse u now - go with your instruction set. Something that is a common problem with roller rockers (im reading the ZZ383 has) is the poly lock get loose and the rocker arms fall off the p-rods. Do a google on this as the cure is just an additional nudge on the nut once lifter preload is set - learn this to your satisfaction as error here can be a disaster.

Not trying to criticize u but just hoping u take a sober look at where u are (going). Any experienced mech can verify #1 vlvs on base circle by just looking at #6 vlvs are part open in overlap. That dial indicator is way to much work and even error prone compared to a timing order visual verification.

A $5,000 crate engine is not really a place for the learning curve. And unless u are changing cams i dont expect u to gain even 1hp with those beehives.

I wish success but advice caution.




BTW summit will sell u parts all day long whether u need them or they are simple to install or not.

cagotzmann

The stock originals where all different as well ?

Is it worth the effort for 14 / 1000 " what would this calculate to in pressure variance ? Would this change anything in reliability ?

Since I cannot check each spring pressure I am not sure each spring is close enough in tolerence that shimming will have any effect ?

Maybe someone else can shed some light on this ?

If they are not a perfect 1.8" what symptoms could I expect ?

cagotzmann

After doing 3 cylinders I noticed that the crank has markers for TDC for the others (never seen this before) and also by looking in the spark plug holes I can read the stamp numbers on the piston so finding the base of the circle was not that hard. The dial gauge confirmed the positions. I would rotate the crank until I would get the compression stroke for each cylinder, watch the piston come up and verify tdc for each cylinder. I did this for each and only would change out 1 cylinder at a time.

I also thought 1/8 turn was very little but this is what they have in the manual.




As for the poly lock I know what you mean. When removing some of the rockers they seemed to take very little effort to remove the poly lock. I would have never thought to check them if I was not changing the springs. I didn't know what to think about this, but now I will pay extra attention to this detail.

cardo0

google it and learn how others failed and what others have done to correct it.

63mako

I would get as close to 1.800 as possible. Shims are available in .015, .030, .060. A .015 on your 1.814 gets you to 1.799. The beehives are an smart upgrade. Better valvetrain stability at higher RPM. I worked with Pauldana figuring out a beehive for his 383. It would quit pulling @ 52-5500 with the dual springs speced for the cam. After the beehive swap it pulled to 6500 and he was shifting @ 7000 with a hydraulic roller. Think he ended up busting his cast crank.

diehrd

LS7 lifters which are used in all GM roller SBC are all 1/8 turn after zero lash. Supposedly it allows for greater RPM. I know with mine I did 1/8 and 63mako is right I can rev this motor until it explodes 7k no problem .. So I set trans to auto shift at 6500 even though my cam is good to 7200

cagotzmann

Thats good to hear that the springs have a purpose. I bought them because it was part of the sale with the motor. Now I need to get it installed and running.

I already tested my new ignition system on the original motor. Purchased a MSD 6AL2- programable with a locked dist. I figured I needed to learn how this worked before trying on the new motor. All went well with this test.

The first startup I feel will be stressful. I was planning on a 2 week project, but I decided to take more time and check and double check what I need to make a clean swap.