SOT: Valve spring woes, Next obstacle Options

[Dr Evil]

About corvair heads:
I went to the machine shop on Fri to get my heads that were finally done now that I located the rare valve locks. Of course it could not be that easy. The machinist tells me that the springs are too tight. Understand that these heads originally had smaller springs on them as they were the older model. The spring pockets were widened for the later style springs. I am using standard size valves, retainers, and locks. Here are the numbers:
Recommended
- Installed spring height 1.660"
- Closed tension 78-86#
- Open spring height 1.260"
- Open tension 170-180#

Actual
- Installed spring height 1.450"
- Closed tension 130-140#
- Open tension Just above 300#

So you see a difference in height of .200 and almost 2x the closed tension. However, research has shown some interesting things.
There are options for springs; stock, Iskey, and HP. The stock are known to be crap as they lose their tension and are unpredictable in such. Here are the interesting numbers regarding the 3 options:

Stock: Closed- 100, open- 205, coil bind- .096
Iskey: Closed- 130, open- 230, bind- .379
HP: Closed- 140, open- 265, bind- .093

So, you can see that the stockers are not even as low as is prescribed in the service manual and the aftermarket ones are all where I am now at 130-140#. That is still more pressure than I want.

Here are the questions:

1- I need valves that have an install height of 1.450 and allows for .400 movement. Looking at these parameters I shopped for springs, are these likely what I would need?
http://www.compperformancegroupstores.com/...ory_Code=SPRNGC

2- Provided I have enough material in the seating surface, would it be a bad idea to have them mill .200 out of the pockets? The machinist is not wanting to do this, and I have a spare head we can inspect to see if it will work, but woudl it not be easier to find shorter springs?


This is my first time getting deep into the valve spring thing so if I am missing something, let me know. I am thinking that finding shorter springs should be the best bet, though.

[orange914]

corvair (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/icon8.gif)
(IMG:style_emoticons/default/shades.gif) (IMG:style_emoticons/default/biggrin.gif)

[sixnotfour]

call john barnes ,206-365-3900 , 30 plus year, hp corvair engine guy.
west coast , but he is a night owl ,so I am sure hes up.
http://www.corvairkid.com/190cid_01.htm

[VaccaRabite]

Could you have custom springs made?
Since you have the stats on what you need it seems like you might be able to have a small run of springs made. Probably more expensive, and you would want to have extras in case you needed them again in the future.

By any chance did you surf McMaster Carr to see if they had a spring that was more to your liking? Its a long shot, but I have usually had good luck there.

Zach

[r_towle]

cutting the spring seat is a viable option.
It will force you to use springs of the same dimensions forever, unless you weld up the seat.
If you do it that way, buy a few extra springs for your stash...just in case yo break one.

I would seek advice from a corvair pro...if the heads are aluminum you will need solid experience to let you know how these heads behave with the higher spring rate...do they deform? do the seats hold up?

rich

[Dr Evil]

After removing the inner dampener and changing all to the springs over to the solid retainers (exhaust were rotary), the closed is 120# and open is 260# which is just fine for the head and within limits for the spring design. So, this problem is solved as far as we are concerned (IMG:style_emoticons/default/smile.gif)