Valve holding/measuring collet.

[tonyfoale]

This is a specialised tool which will be principally of interest to engine builders, motorcycle and car. Although I can see that the basic idea could be applied in other fields as well.

The problem.

The sealing face of engine valves is not flat but is usually angled at 45 deg. (although in some cases between 30 and 55deg) and that can lead to difficulties measuring the length from face to the end of the stem, and similarly to the retaining collet groove. At times it becomes important to match these dimensions on multiple valves. This morning I decided that I needed to make a holding gadget to make valve matching easy. This post shows the result.
Don't forget to click on the images for full size view.


This sketch shows the problem and a possible solution. On the left we have two extremes of length between L1 and L2 and these can vary depending on the diameter and width of the sealing surface. in other words we have no reference surface or line for an accurate measurement. However, if we mount the valve in a block as shown on the right, which is machined at the valve seat angle and has a good fitting hole for the stem, we can see that L3 will be a stable dimension.

The solution in practice.

In addition to getting a useful length reference, another requirement is to be able to mount valves in a lathe or grinder to face off the ends to the same length and also to machine collet retaining grooves in a consistent location. In fact it is the ability to hold a valve for machining that motivated the tool. You can use a valve seat in a cylinder head together with a dial gauge and suitable bracket if measuring was all that you need to do.


Here is the physical implementation. The ring on the left is simply a spacer to ensure that a valve head which protrudes from the bottom of the block has clearance and doesn't mess up the length measurement. The other piece is the valve holding block. The large end has the 45 deg. taper which allows a large range of valve head sizes to be accommodated. The smaller end is slotted to form a collet to grip the valve stem. The last photo shows a relieving groove to allow the flexibility needed for the collet to work properly.


On the left we can see the block and a valve, on the right a valve is loaded.


A jubilee clip is an easy way to clamp the collet on to the valve stem. Note the spacer under the valve holder to ensure clearance of the valve head off the surface plate. A vernier height gauge is used to get a stable reference dimension. This tool makes it very quick and easy to check a number of valves for consistency.


Fitting the valve holder in a 3 jaw chuck. The large end is placed inside the chuck beyond the back of the jaws and closed down. Just prior to clamping on the collet the assembly is pulled forward such that the large end is located by the back of the jaws. This gives a repeatable axial location.


On the left is a clear view of the collet clamping, on the right we can see the valve retaining collet groove as machined with this holding fixture.

Thanks for viewing.

[olderdan]

This is a great idea Tony.
Interesting that you cut your own circlip seats, do you buy valve blanks to work with or modify ones that suit your needs?.
I guess that once your valves are consistent you can also check the seat depths in the head.
Its a great feeling knowing that the engine you have built is as perfect as you can make it.
Thanks for the post.

[tonyfoale]

This is a great idea Tony.

thanks.

Interesting that you cut your own circlip seats, do you buy valve blanks to work with or modify ones that suit your needs?.
I guess that once your valves are consistent you can also check the seat depths in the head.
Its a great feeling knowing that the engine you have built is as perfect as you can make it.

There are no shortcuts with race engines and as mine are far from stock there are no off the shelf parts.

Here are some links which might be of interest.

a video showing valve stem to rocker motion and the need to get the stem length correct.

Some photos of stuff.
https://goo.gl/photos/231XUHPEKKT7HYSs5
https://goo.gl/photos/hNeUaDJ2MkZcjQq9A
https://goo.gl/photos/y2qQ2FDdWESf9MsB7

[olderdan]

thanks.



There are no shortcuts with race engines and as mine are far from stock there are no off the shelf parts.

Tony I think you are the last person to be accused of taking shortcuts, I only asked about the valves because I am restoring a 1920 v twin side valve AJS engine at the moment and I could do with making some new valves, I am not sure of a suitable material and heat treatment requirements for these.
Many thanks for the picture links, what an amazing career you have had so far, that hands behind your back BMW seems to have a very interesting front end.
Also wondering about how the DOHC conversion worked out, are you back to pushrods because of regs?.
Keep it coming
Regards
Alan

[tonyfoale]

I only asked about the valves because I am restoring a 1920 v twin side valve AJS engine at the moment and I could do with making some new valves, I am not sure of a suitable material and heat treatment requirements for these.

Alan,

Making valves is a serious undertaking. They are subject to high loading and high temps. I am happy to modify valves but I wouldn't make them from scratch. To answer your question there are many different materials used, Titanium for high revving engines, various alloy steels, stainless and inconel are all used. I am not sure about valve manufacturers in the UK but there are a bunch in the US who can make to order or supply blanks or stock. Getting a blank of the right stem diameter and close to head diameter would be a good place to start from, but I think that in your application modifying used valves from something more modern would work out OK. Compared to modern engines yours would be considered light duty although exhaust valves in side valves engines can have a hard time.

Many thanks for the picture links, what an amazing career you have had so far, that hands behind your back BMW seems to have a very interesting front end.

That had a standard BMW front end but there was an added superstructure to set the rake angle close to 15 deg. as part of some experiments on rake angle that I did around the early 1980s. The experiments and results were featured in my books and several magazine articles. The picture that you mention was published in motorcycle magazines around the world at the time. As to my career i don't look backwards, it starts again tomorrow morning. I ain't done yet. I just try to have fun, my father said that I couldn't expect to make a career out of fun, he was wrong.

Also wondering about how the DOHC conversion worked out, are you back to pushrods because of regs?.
Alan

I prepared that engine for the Island but only got to ride it in practice, a head dropped off one of the valves (Cosworth F1 valves????) and made a pretty mess. Up to then it went really well, it had a lot more power. I never had it on a dyno. I got as far as welding the head to re-machine for new valve seats etc. but pressure of other work meant that it never got any further. I still have it and it could be made to run again but you are quite right about restrictive regs.


here are a couple of pix about those steering geometry tests.

[DIYer]

Thanks tonyfoale! We've added your Valve Holding Collet to our Motorcycle Engine category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:

Valve Holding Collet by tonyfoale

tags: valve, holder, collet

[j.bickley]

Tony, very slick. Couldn't understand it when I first looked at it, but now I do.
---Joe

[tonyfoale]

Tony, very slick. Couldn't understand it when I first looked at it, but now I do.

Joe,

The motivation for it was to be able to grind the tips of the stem to a pattern valve. The use for easy and quick measuring was an accidental bonus. I had a bunch of ex-NASCAR Titanium valves which I cut down to use in my valve train test rig to compare required spring rates and max RPM to stock steel valves. I won't use those used Ti valves in a running engine but they are fine for my testing and flow bench measurements. I have had it in mind to make this fixture for some time but the arrival of the NASCAR valves kicked me into action. The valve train test rig and flow bench will both be the subjects of future post here.
Here are some pix as teasers.

[Jon]

Congratulations tonyfoale - your Valve Holding Collet is the Homemade Tool of the Week!

Nice win. It's hard enough to build homemade tools. To build ones that we see rarely, if ever, is even more challenging.

This week was interesting in the diversity of homemade tools across various disciplines. Note the Slow Round Bale Hay Feeder by Imabass, and the Watchmaker's Press by Britannicus. We also had a nice video on Dynamic Braking on a Milling Machine by bstanga, an Improvised Fly Cutter by mklotz, a clever Hammer by tonyfoale, with center punch stored inside, and a Box Joint Jig by connan. And there was a duo of sandpaper dispensers, including one by Paul Alciatore, and one by Tim Pettigrew, accompanied by a clever comment by j.bickley to store fine grits up high to prevent contamination by coarse grits.

tonyfoale - you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, Giftrocket, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.

Congrats again and nice job!

That's win #4 for you. Here are all of your winning tools:

Horizontal Milling Machine by tonyfoale

tags: mill

Drum Brake Grinder by tonyfoale

tags: grinder, brake drums

Shock Absorber Dynamometer by tonyfoale

tags: suspension, measurement

Valve Holding Collet by tonyfoale

tags: valve, holder, collet