Machined Valve Guide Bosses

sharplikestump
Posts: 183
Joined: January 12th, 2009, 2:28 pm

Re: Machined Valve Guide Bosses

Post by sharplikestump »

Ditto that.......I have purchased the 22mm pieces and modified them to suit, but it is time consuming. I am sure someone with the right machine (probably a screw machine) could spit them out much, much faster.

Got the only info that I have on Tech Inspection Consultants.....Don't know that this is still valid as the first publication is dated 1973, and the updated one is dated 1975, but He was located then at: 1279 Ashcroft Lane, San Jose, CA 95118
Just now found a nice bio on him, through the San Francisco Region's "Hall of Fame" record. He was inducted in 2007 with many credits to his name, but have not located contact info. I suspect I misspelled his name. Proper spelling is "Shultheis".
jphoenix
Posts: 105
Joined: July 12th, 2013, 7:41 pm

Re: Machined Valve Guide Bosses

Post by jphoenix »

sharplikestump wrote:Ditto that.......I have purchased the 22mm pieces and modified them to suit, but it is time consuming. I am sure someone with the right machine (probably a screw machine) could spit them out much, much faster.

Got the only info that I have on Tech Inspection Consultants.....Don't know that this is still valid as the first publication is dated 1973, and the updated one is dated 1975, but He was located then at: 1279 Ashcroft Lane, San Jose, CA 95118
Just now found a nice bio on him, through the San Francisco Region's "Hall of Fame" record. He was inducted in 2007 with many credits to his name, but have not located contact info. I suspect I misspelled his name. Proper spelling is "Shultheis".
Thanks for the info, the vee lines are very interesting to read.
Jim Phoenix
2016 Red Mercury FV 44
hardingfv32
Posts: 104
Joined: June 9th, 2015, 8:04 pm

Re: Machined Valve Guide Bosses

Post by hardingfv32 »

The June Fastrack Prelim states that the CRB is going to look at the subject of a minimum valve spring ID.

They are going to retain the legality of machining the valve guide bosses.

Brian
brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: Machined Valve Guide Bosses

Post by brian »

I believe the intent is to stop the trend to tiny expensive springs before it starts. Rather than disqualify a bunch of heads based on inconclusive info, setting a minimum spec for the id of the spring will take the incentive to machine the bosses away. Some may argue that it will require more expensive springs but no one likely didn't charge for machining the bosses so the total cost for upgrade is likely to remain the same either way.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
Speedsport
Posts: 170
Joined: October 20th, 2006, 7:45 pm

Re: Machined Valve Guide Bosses

Post by Speedsport »

Can someone please explain to me why machining the valve guide bosses is going to be allowed to continue and be legal based on the need to not disqualify those who had already done this, when several years ago it was no big deal to change the rules to disallow wheel covers which even more clearly fit within the rules at the time?
hardingfv32
Posts: 104
Joined: June 9th, 2015, 8:04 pm

Re: Machined Valve Guide Bosses

Post by hardingfv32 »

Politics - There is someone in the CRB system that supports (requires?) the machined valve guide solution.

Brian
cendiv37
Posts: 386
Joined: June 25th, 2006, 7:29 pm

Re: Machined Valve Guide Bosses

Post by cendiv37 »

As discussed in our last few meeting minutes, the FV Ad Hoc Committee believes that machining of the valve guide bosses to fit smaller valve springs should not be allowed because it constitutes an unauthorized modification. We disagree with the recent rules "clarification" allowing this modification and wrote a letter to the CRB to this effect. It appears others did as well.

As we have also stated in our minutes, that we think it is reasonable to set a minimum valve spring ID as an alternative to requiring unmodified bosses. This would eliminate any advantage gained by machining the bosses. Modern spring packages could be still used but the springs would have to be able to fit on an unmodified head (kind of like how our rear bodywork has to fit over a fan housing that isn't there). This would avoid the disruption that would result if modified heads themselves were disallowed. The CRB appears to be moving in this direction and is collecting data to establish this minimum spring ID. Since the committee has already collected some data to estimate valve guide boss diameter and height we have forwarded that information to the CRB to give them a start.

Bruce
Bruce
cendiv37
sharplikestump
Posts: 183
Joined: January 12th, 2009, 2:28 pm

Re: Machined Valve Guide Bosses

Post by sharplikestump »

cendiv37 wrote:As discussed in our last few meeting minutes, the FV Ad Hoc Committee believes that machining of the valve guide bosses to fit smaller valve springs should not be allowed because it constitutes an unauthorized modification. We disagree with the recent rules "clarification" allowing this modification and wrote a letter to the CRB to this effect. It appears others did as well.

As we have also stated in our minutes, that we think it is reasonable to set a minimum valve spring ID as an alternative to requiring unmodified bosses. This would eliminate any advantage gained by machining the bosses. Modern spring packages could be still used but the springs would have to be able to fit on an unmodified head (kind of like how our rear bodywork has to fit over a fan housing that isn't there). This would avoid the disruption that would result if modified heads themselves were disallowed. The CRB appears to be moving in this direction and is collecting data to establish this minimum spring ID. Since the committee has already collected some data to estimate valve guide boss diameter and height we have forwarded that information to the CRB to give them a start.

Bruce
As the saying goes: Be careful what you wish for.
After testing a "modern spring package" that has the same i.d. as the original straight spring AT THE BASE, not only does that spring have an undesirable spring rate, (and/or length) but the real problem is that in order to incorporate the advantage of the bee hive design, they are a more radical cone (large dia. at the base, same dia. as the smaller spring on top). The problem this creates is that as the spring is compressed, on SOME of the heads, the much smaller coils now collide with the top of the spring boss. Not the ideal way to dampen harmonics!
W/O going back through all of the posts, I remember that the sampling of heads that were measured was extremely small. I am thinking between 4 and 6 sets. All that was stated was the spread of guide boss DIAMETERS. There was ZERO data on boss ECCENTRICITY. I have measured several dozen sets of heads, and as previously stated, have found bosses so far out of concentricity (from the C/L of the valve) that the STRAIGHT springs were rubbing on the bosses. What I am finding is that regardless of spring diameter, if we want the advantages of any bee hive spring, at least some of the bosses must be reduced for clearance, and at this time I have yet to see a full diameter spring that is right for our engines. I welcome anyone who doubts me on this to prove me wrong by producing such a spring.
Even, should that happen, to each his own but I strongly suggest that all bosses be checked for location and machined for clearance as needed.
Mike P.
cendiv37
Posts: 386
Joined: June 25th, 2006, 7:29 pm

Re: Machined Valve Guide Bosses

Post by cendiv37 »

So what you're saying is that because it works better it's legal.

Interesting perspective.

Hmmmm, just think of all the things I can do to my Vee now!!!
Bruce
cendiv37
jferreira
Posts: 19
Joined: November 2nd, 2011, 1:12 pm

Re: Machined Valve Guide Bosses

Post by jferreira »

This is the decision – I wish I knew what it meant….

The CRB and the FSRAC will be looking at defining a minimum ID for the bottom of valve springs in FV. Many heads came from VW with this area of the valve guide already machined. The clarification about machining this area was issued to prevent misunderstandings and confusion in tech, and will not be withdrawn.
John
satterley_sr
Posts: 237
Joined: June 27th, 2006, 3:27 pm

Re: Machined Valve Guide Bosses

Post by satterley_sr »

I have looked at a lot of heads but don't believe I have ever seen one from the factory with the boss machined. I would like to see evidence. But then how would we ever know it was from the VW factory?
hardingfv32
Posts: 104
Joined: June 9th, 2015, 8:04 pm

Re: Machined Valve Guide Bosses

Post by hardingfv32 »

Most of the head is un-techable as there are no stated dimensions for most of the machined surfaces. Practically speaking we can only set new dimensions after someone is 'discovered' to have done something creative.

From what I sampled... all the bosses are machined. I would venture to say one cutter forms the boss and valve spring seat/pocket possible along with the valve guide bore.

I got a number of new heads from SR a few years back and the bosses actually have a tapper machined on the top half of the bosses.

Brian
hardingfv32
Posts: 104
Joined: June 9th, 2015, 8:04 pm

Re: Machined Valve Guide Bosses

Post by hardingfv32 »

jferreira wrote:This is the decision – I wish I knew what it meant….
It has been pretty well explained in previous posts. If you missed it... the CRB has stated in Fastrack that it is legal to machine the bosses to any dimension. They intend to standby that opinion/interpretation.

Brian
cendiv37
Posts: 386
Joined: June 25th, 2006, 7:29 pm

Re: Machined Valve Guide Bosses

Post by cendiv37 »

The question remaining is what dimension they will set for the minimum ID of the base of the valve spring.
Bruce
cendiv37
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