Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> SOT: Valve spring woes, Next obstacle
Dr Evil
post Jan 11 2009, 09:09 PM
Post #1


Send me your transmission!
***************

Group: Members
Posts: 23,041
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region



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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
sixnotfour
post Jan 11 2009, 10:03 PM
Post #2


914 Wizard
**********

Group: Members
Posts: 11,184
Joined: 12-September 04
Member No.: 2,744
Region Association: NineFourteenerVille



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
User is online!Profile CardPM
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 2nd April 2026 - 09:28 AM
...