Recapping the LS1 spring swap debate

[Blackrider]

well if it won't go on anymore it must be done
the spring seats I used were a set of isky seats for something or another, I lost the part number, they were a direct fit unlike the LS1 seats which alledgedly need to be ground out a little, this accounts for why yours and mine look different

Understood, It took me about 2 hours total using an Alumminum grinding stone with my dremal. 10 min per shim, but I was very carful I didnt overgrind so I was always checking lol lucky I had 3 practice ones, I fucked up 2 of them :P

I did one that way, then said "forget it" as I messed it up and found these...I'll try and post a part number or something and make everyone else's life easier.

Ehhh its not that hard, Infact the only reason I say i fucked them up is because after I had done all 12 I went and found the Lose ones and replaced them.

[AaronGTR]

I had the same problem with my 3.1T seals, they were a little tight going on. I just used a socket to push them down same as froggx did, and they fit perfectly. As for the shims I guess the shims for a '81-'87 toyota land cruiser (engine code 2F) are supposed to fit. There are probably a dozen different shims out there that will work. You just gotta find ones with the right size hole for the larger valve guides if you have the newer heads and with the right size for the bottom of the spring. I'm just glad I had the older size guides and didn't have to do that. All stock GM parts.

[AaronGTR]

Woot! cam just got here. Time to tear into the engine.

[blackbombshell95]

The valve seal will fit both inlet and exhaust valves? That is the way it looks in the pic.

[AaronGTR]

Yes, the valve stems and valves guides are the same diameter for both.

[Blackrider]

All Done, Heads are getting installed tomorrow.
For some reason 11 of the Springs where Corvette Yellow and one was Unpainted with a pink stripe. All had the same part number.

[theman3.4]

So is all of this the same when applied to a 3.4 Crate Engine in a RWD S-10 with Cast Iron Heads?

I am looking for part numbers for:

Valve Springs
Valve Seals


And will this all work with the Comp Cams Roller Tip Rocker Arms and stock Pushrods?

[TurboZ24]

Actually, the 3.4 iron head crate motor uses standard 11/32" valve stems, so any keepers/retainers for those works. Also, the stock springs are 1.25" on the iron head 3.1, so any springs that fit that dimension will work without modifications. I run 1.46" dual coil springs on mine with a 1.8" install height instead of the stock 1.7" height, but it took a few alterations too get them too fit (spring cups, .05" keepers, and a little spring seat machining)

[smilinguy99]

Here is a presentation of some springs and valves options for the Gen3:

http://www.novia.net/~sparks/heads/GEN3_HEAD_PARTS.html

Did this a long time ago and some of the links no longer work, but the part numbers do. Notice there are no ovate (LS1/LS6) springs. I actually tested them, and decided they didn't have enough pressure.

My 2 cents? My bias is towards more spring pressure on a roller cam. I have personally seen a lot of damage due to insufficent spring pressure, but no damage due to excessive spring pressure. If you are using lots of pressure and bending pushrods, get better ones. Custom pushrods are relatively cheap. Splitting the stock rockers? Do whatever you have to do to use the Cranes.

It is far cheaper to solve the problems that come with high spring pressure than to repair the problems of low spring pressure.

It makes little sense to "debate" the spring issue. Something either works or it does not. Try something. If it works or not, report it here.

If you have your heart set on ovate springs, I wouldn't trust my valves to stock LS1 springs from GM. The stock LS1 springs will obviously physically fit, but you aren't gaining much unless you use an aftermarket spring for the LS1 like a CompCams 26918 or a Crower 68155 or a Crane 144832.

sg99

[TurboZ24]

I've had some people say that about my springs. 1.46" diameter, 1.8" install height, dual coil with damper, spring rate 456. Closed pressure is 197 lbs, open is around 446 lbs. Crower said that's what I would need for the mechanical roller lifters/cam profile and the rpm I wanted. Some people have told me that is excessive, but seems too work, so..

[theman3.4]

In other words the LS1 springs dont work in the Iron Head Crate Engine?

What is a part # of a good valve spring and retainer for the 3.4 Crate Engine?

[smilinguy99]

In other words the LS1 springs dont work in the Iron Head Crate Engine?

Here's the deal. The iron head motor have valves that run parallel to one another in a straight line. Therefore, you can use fairly large OD springs without conflict.

The aluminum head has valves coming out of the head in different directions and there is a single I/E pair on this head that lean closely toward one another. If you were to use a 1.5" OD spring on these heads, the retainers would contact and interfere with one another when the valves are on the seat. So, Gen2 and Gen3 users (in other words, the aluminum head users) need a spring that provides sufficient pressure while avoiding this physical interference. One way to avoid interference is to taper the spring toward the top to keep the adjacent retainers out of each other's way. That is what the factory did with the production Gen2/3 motor.

The LS1 spring is tapered too, though I understand it is for a different reason. The LS1/6 motor has parallel and inline valves like the iron head motor so physical interference is not a factor. The reason they are tapered I've read here and elsewhere, is that the tapering gives a spring a weaker harmonic response in the vibration range of the motor. In other words, the natural frequency of the spring (and its interaction with the various vibrations that the motor normally makes throughout its RPM range) does not interfere with the spring's primary job--controlling the mass of the valvetrain.

The reason the LS1 spring seems attractive to the Gen2/3 users is that it provides a relatively inexpensive way to get more spring pressure within the clearance limitations of the motor.

Clear as mud? Here's what it boils down to: You have a lot more options for valve springs with the crate motor than the Gen2/3 motor.

You need not fixate on the LS1 spring just because there are a lot of folks talking about it on this site. Pay attention to the engine they are talking about. Are they talking about the Gen2/3? If so, keep their unique situation in mind.

Curtis mentioned he uses 1.460" springs. That's a good place to start. In the 1.460" diameter there are a lot of springs in a lot of pressure ranges. Find out what your cam manufacturer recommends in terms of open pressure, closed pressure and then find out what kind of installed height you currently have and then calculate how the various spring options work within the total lift/installed height parameters. If you don't have the necessary spring height for your spring of choice, you may need to sink the spring seats a bit. The process sounds complicated, but it's really pretty simple. Many of the spring mfg. sites have this process spelled out for you.

If after doing this work, you find a combination that works, let the world know right here. I know you are simply looking for part numbers, but you may have to find the part numbers the way many folks on this site have found them--by doing the basic research in vendor catalogs and by measuring various aspects of their motors. It's not that hard, and I think you'll be rewarded with a pretty good result.

Here's some good places to start looking for springs, retainers, keepers, seals and other valvetrain parts:

http://www.crower.com/misc/m_cat.shtml

http://www.cranecams.com/catalogs/PP0203B.pdf

http://www.compcams.com/Technical/CurrentCatalog/HTML/324-339.asp

sg99

[ikessky]

It makes little sense to "debate" the spring issue. Something either works or it does not. Try something. If it works or not, report it here.

If you have your heart set on ovate springs, I wouldn't trust my valves to stock LS1 springs from GM. The stock LS1 springs will obviously physically fit, but you aren't gaining much unless you use an aftermarket spring for the LS1 like a CompCams 26918 or a Crower 68155 or a Crane 144832.

sg99

The only reason I used the word "debate" is because there seemed to be a few different opinions on what parts were needed for the different model year heads. It had more to do with the seals than the springs themselves though.

As far as I'm concerned, I was always thinking aftermarket LS1 springs rather than stock GM LS1 components.

The write-up/webpage that you posted earlier was very informative. Did you do all those mods on a Gen 3 head? If so, that opens my options for springs over the standard LS1 replacements (although sticking with the beehive design would be my first choice).

[RacerX11]

SG99,
You are slightly misinformed on the conical spring topic. The gen2 engines came stock with straight valvesprings, not conical. The conical springs did not debut until the gen3 engines. They used the conical springs on the gen3 for the same reason the LS1/6 uses them...lighter valvetrain mass and better spring harmonics. With the gen2/3 splayed valve heads, clearance is not an issue when using the stock 1.25" OD springs. There may be clearance issues when trying to use 1.5" OD springs, but there are plenty of 1.25" OD small block chevy springs/retainers that can be used without problems that provide plenty of pressure, making the 1.5? springs unnecessary.

Compared to a stock 3X00 spring, the stock LS1 spring offers slightly more seat pressure, but a lower rate, so open pressure is close to stock. I agree this is not much of an upgrade. The LS6/LS2 springs, however, have more seat pressure and a higher rate. Combine this with the ability to use the stock gen3 retainers, and it is a worthwhile upgrade. No need to spend more money on the aftermarket conical springs if they aren?t needed.

Two drawbacks I see to running obscene spring rates on aluminum heads are increased power loss, and head robustness. If the lower pressure spring is capable of controlling the valvetrain movement without float at the maximum rpm you operate the engine, any extra pressure on top of this is wasted power. You are robbing power to move the valvetrain with no benefit, and adding extra stress to the pushrods, rockers, and valve guides. High spring pressure puts more strain on the rocker studs. How much pressure can they handle before the stud is physically pulled out of the head? This is more of an issue if you are using gen1 adjustable rocker studs with the pushrod guideplates (as shown in your pictures), as they have fewer threads engaged in the head.

Marty

[AaronGTR]

I agree with RacerX11. There is no reason to run excessively higher spring rates than is necessary. It uses up more HP and can cause other wear issues. Like he said the LS1 springs have just slightly more seat pressure and about the same open pressure as a stock 3x00 spring. Since the stock springs can have float issues at higher than stock rpm, this is a cheap upgrade that can somewhat help with that issue. They are fine at least if you are running a stock cam. Otherwise you'll obviously need something more. I think the LS6 spring should have plenty of pressure for most aftermarket cam profiles that someone would run on a street engine. It's significantly stiffer than the LS1 springs. I'm using them on my engine and I'm running slightly less total valve lift than a stock LS6 cam. The comp cams 26915 spring is similar. It has 15lbs more seat pressure but about the same open pressure... not a big difference. The 26918 springs are stiffer, but they are about the limit I would go unless you are running a really radical cam and know you need more pressure, otherwise it's just overkill. I have the crane rockers and custom chromoly pushrods as well, so I know they'd handle it, but I don't think I'll need the stiffer 26918's because I don't plan on running too high an rpm. I'd only switch to them if I find some issue with the LS6's I'm using or plan to rev it higher, in which case I'd be building up the rest of the engine anyway.