Valve springs

[Paul Secoy]

I just mentioned it as I remembered it as a lower rate spring.

Anything at 415lb/in rate would get you exactly where you want to be as long as you shim it to the correct installed height. (assuming it doesn't put the spring closer to .060 from coil bind but I don't think you will run into that issue with any spring close to your installed height and .530 lift)

For example, a quick look turns up this spring-

http://iskycams.com/shop/index.php?main_page=product_info&products_id=2137

It's 415 lb/in 150 @ 1.875.

You want 160 lbs on the seat shim it to 1.85 (so .030 shim under this spring on your heads)

Thanks! The PSI spring was a bit more than I expected, it looked to be about $450 for a set.. $244 for the Isky springs is a bit easier to swallow. I will call Bullet and give them another go at finding one, since I goofed and gave them an incorrect installed height last time.

 

[INTMD8]

All they had to find you was a spring at 415 lb/in that can handle the amount of valve lift you will have.

You telling them a taller installed height than actual wouldn't have mattered as you can shim any spring with that rate to 160 on the seat assuming it can handle .530 lift, which most can.

 

[Paul Secoy]

All they had to find you was a spring at 415 lb/in that can handle the amount of valve lift you will have.

You telling them a taller installed height than actual wouldn't have mattered as you can shim any spring with that rate to 160 on the seat assuming it can handle .530 lift, which most can.

Opinion on Howards Cams springs? They have a couple options that are 413# rate..

 

[INTMD8]

I've not used them so have no opinion on them.

If you are talking about the 98632 it's 145lbs at 1.94 inch, so 170 at 1.88 389 over the nose.

 

[Paul Secoy]

Actually looks like only one from Howards thats close, I come about about 5# higher on both ends, not a ton, but I'd rather go a little softer if anything.

98652.. 140# @ 1.940" installed. At 1.88' installed; 164.78# seat, 383.67# open

 

[wyrmrider]

Paul
do you know how to calculate spring rates for your height from a spec?

 

[Paul Secoy]

Paul
do you know how to calculate spring rates for your height from a spec?

I believe post #18 in this thread has me headed in the right direction, I didn't know how before that.

 

[wyrmrider]

good you need to diy this yourself to compare different spec springs and your exact needs
cheers
remember you can shim or change retainers and or keepers
bvvc that retainers do not hit the rocker arms if you do this
are you using spring cups or locators?
and check your stem seal to keeper clerance
I recommend Viton seals- the center two valves run hot

 

[biomedtechguy]

I recommend Viton seals- the center two valves run hot

I had the already hand ported and performance enhanced factory iron heads on the 421 in the GTO machined for Viton valve stem seals.

 

[wyrmrider]

good luck with the goat
and I guess you know to replace the hidden oil galley plug
beep beep and then some

 

[biomedtechguy]

I guess you know to replace the hidden oil galley plug

I don't know anything about that, and the 421 was rebuilt by a local shop about 3 years ago. @wyrmrider Seems to be working fine, but I really want you to go into a detailed explanation of "the hidden oil galley plug" so I can ask the builder about that.
Thanks in advance.

 

[wyrmrider]

your builder should know
there is an oil galley plug with a hex for which you have to remove another plug to access
folks either forget to remove the inner plug and brush out the galley
or forget to put it in and just put the outer plug in forgetting the inner and wondering why no oil pressure
we did (machine work only) a Pontiac for a GMC garbage truck and their ace mechanic forgot the plug
motor was more than the usual PITA to R& R so it was my fault
from then on I put a new plug in a plastic bag and zip tied it to the appointed spot

 

[biomedtechguy]

Oil pressure has been great. Cold is higher than op temps, but even at op temp at 850 idle it's fine...
So I guess all is well??

 

[wyrmrider]

guess so
lots of motors have hidden galley pugs
then there are the oil filter diversion plugs