Some parts too look at (Valvetrain)

[Mars]

Never looked at it that way. cool.

[Guest]

Yeah the valvetrain is quite a recumbant device. There is actually very little power being robbed by the valve train, most of it comes from just the weight of the components (rotating/reciprocation mass).

[smilinguy99]

Found this on Comp Cams web site: Common Misconception:
Many people mistakenly think that using higher seat pressures causes a reduction in the horsepower delivered to the flywheel because...

Thank you for posting that. I was in a discussion on this board some time ago about spring pressures and I don't know who it was, but they were deathly afraid high pressures were going to do very bad things.

It has been my experience that high pressures are a good thing for roller tappet engines. I could not convince them of that. Oh well.

In fact LOW spring pressures do very bad things and are the cause of more damage and power loss than too much pressure. This I have experienced first hand.

[SappySE107]

I remember reading about the spring pushing on one part when its compressing another which "balances it all out'. Forgot about that but also, though I have also read that using a stiffer spring than is needed wastes power through frictional losses and also causes more wear on the cam lobes.

I will let lorenzo post his dyno sheets if he wants, but I can say that the power was building well past 5600. He is running the green LS6 springs and with .5xx lift, there is no valve float.

[torq455]

They did mention the roller lifters, but nothing on the flat tappets. Maybe no loss on the roller lifters but some on the flat tappets. Understandable, the rollers don't rely on an oil film, so they can have all the psi they can handle.

[AaronGTR]

Yeah, shouldn't be a problem with a complete roller valve train (much like I equipped my engine with ). I just know I got good results from switching springs even before the cam switch. With stock cam and heads my power peak was 5600rpm on the dyno, and after adding LS1 springs and porting (mild port job, stock valves) it shifted to 5900-6100 before drop off. That may or may not be the point at which the stock cam becomes the limiting factor. All those dyno's were with headers too... otherwise the power peak might not have shifted any higher since the stock 3400 exhaust manifolds are the most restrictive thing on the engine. lol

[geoffinbc]

Took some weight meaurements

Comp Retainer : 11.3g
LS6 Retainer : 11.5g
Comp Spring : 73.7g
LS6 Spring : 76.1g

Comp Combo : 85.0g
LS6 Combo : 87.5g

Might be of some use to someone.

[SappySE107]

well, i hope lorenzo doesn't mind:P This is his dyno sheet after tuning on the dyno for an hour. Stock intake and exhaust and heads. 3500 plenum, 4.3 TB, LS6 green springs, .23x duration .51x int lift .53x exhaust lift. It peaked at 171.1 but the print off says 169.9. Dunno why it did that but anyway, there you go.

http://60degreev6.com/Lorenzo/Lorenzo%20Dyno/3400%20Test%206.jpg

[torq455]

What is the difference between the LS6 green and the yellow springs? Just spring rate?

[SappySE107]

i have not a clue. They dont sell them anymore from what I was told.

[JMo60]

so from what i take it, the ls1/ls6 valvesprings will fit on stock 3x00 heads with stock retainers and everything?

[AaronGTR]

Um, no. The LS1/LS6 springs will fit on stock 3x00 heads using stock retainers and locks but you have to use different spring seats and valve seals. Plenty of info on this site about doing the swap, just gotta do some reading.


torq455, the green LS6 springs were the ones used on the C5 Z06 engine. At some point they switched to yellow (don't remember when but those are what I have) and those are the current springs on the LS2 motor in the new C6's. Spring rates are exactly the same, just different paint.

[Syn]

ok i have the crane 272 and lifters, i have 2000 gen III heads, i will have lift over .500, since my heads are 2000, i am thinking i won't be able to use the ls6 valve springs, or maybe i missed that i could. what do you guys recommend?

[torq455]

You can! Here's some good reading: http://www.60degreev6.com/modules.ph...rtid=34&page=1

[tejohnson]

They fit pre 2000 heads. they are copper coloured.
required no mods at all on my 1999 3400 heads.

Do they fit the valve guides snug? What is the ID? Part number please?

As a follow up, for the 99 heads and these bronze shims... An LS6 spring has a tad larger OD than these shims, to where not all of the bottom of the spring makes contact with the shim, but hangs over a tad. Wouldn't this be an issue?

Also, the ID of the shim is .520, and the top part of the valve guide on the '99 heads (where the ID id this shim is located once seated, is over the "hump") is .515. The "hump" or where the guide is larger at the bottom is .550. See this image:



I suppose I have the general question about the .005" "play". Is there any danger to this?