LT1 Valvesprings?

[petryshyn]

Are the LT1 valve springs the same as the z28 ones, also what are the part number for these need a set for a pair of vortecs i want to run close to .447 lift on and i believe the stock springs won't work.

Are these the right springs i need?PN 10206040 from gm parts direct.

Thanks

 

[sled_dog]

stock springs work till .470/.480, depends where you look

 

[dyeager535]

Those are my springs specs. They are *outside* the recommended clearance from the guides when at full lift, but since I'm not running at high RPM, and the clearance isn't TOO far off, I run it as is.

There does seem to be some variance in what people will say works. Not sure if there is variance in the heads, or if some people think differently about clearance. IIRC about the thickness of a penny is min. recommended clearance at max lift. Mine was just under that.

Stock springs would not work with the above cam, (roller is part of that) but I have heard the seat pressure is something like 80lbs for the stock vortec springs, and thats not enough for anything other than very mild stock cams as I understand it.

The guy that did my heads supposedly used Z28 springs with the inner coil removed so they would fit, which gave the right seat pressure. Don't have a lot of miles on them to see how they are going to hold up, but so far so good.

 

[petryshyn]

Well just got my LT1 vavle springs now i am wondering how does a guy remove the inner coil? Does anyone know. Thanks

 

[beater_k20]

Z28s came with LT1s under the hood...

 

[4by4bygod]

Well just got my LT1 vavle springs now i am wondering how does a guy remove the inner coil? Does anyone know. Thanks

Dumb question.. why would you want to remove the inner coil? They are there to prevent valve float, If I'm not mistaken.

Tom

 

[petryshyn]

The guy that did my heads supposedly used Z28 springs with the inner coil removed so they would fit, which gave the right seat pressure. Don't have a lot of miles on them to see how they are going to hold up, but so far so good.

He said that so i was just wondering if it was possible, i will probally just end up machining were the vavle sits so it can accept these springs as we have the tools at school.

 

[dyeager535]

Dumb question.. why would you want to remove the inner coil? They are there to prevent valve float, If I'm not mistaken.

Tom

From my understanding the inner coil is (also?) a vibration/harmonics cancelling feature. Probably does help with how the springs are rated for pressure too.

Anyways, I believe he did this as a cheap way to get the springs to the exact seat pressure the cam manufacturer recommended. The more I think about it, the less I think the inner coil was removed for fit, more to get the right pressure with a spring that would fit on the Vortecs without machining. (which is one of the reasons I don't like Vortecs as much as I used to!)