Fieuw things to know about big valves

Hi there,
When you go for big valves you must re-angle the guide and you must re-angle the
places where the valve spring seats are coming, that will say take some material away from the head casting with as a result that the spring hight is more as original requested.
I am using Jim Schmidt beehive springs and the spring hight must be 1.4'
In my case there was a + 3mm spring hight, so far no problem, you make a shim from 3mm and put it under the Jim Schmidt spring seat, but then the problem arrive:
The JS spring seat as a shoulder around the guide to keep the spring centered,
This shoulder and the 3mm shim don't leave you place to fit the oil seal
Here is how to solve the problem:
On the picture below you see the original JS spring cup with his shoulder and the 3mm shim under the spring cup, you see clearly that there is no place left to fit the oilseal

On the picture below you see the JS spring cup on the left and on the right the spring cup that I designed. You can clearly see that I made the shoulder on the outside of the new spring cup, and that I made a recess in the centrer to save place for the oilseal.

On the picture below you can see the new spring cup in place with enough place for the oilseal.


On the drawing below you can see how I solve the problem of the spring hight and still save place fot the oilseal.

A very elegant solution. Over the years I've seen both types of spring seats used in Commando spring kits, so I don't think there's any drawback to using the cup style.

Ken

Yves, good solution however you are making a mistake dealing with the spring set up. Spring height doesn't tell you much. Spring tension must be set up by measured pressure not by measured height!

As I understand the solution Yves proposed, among other objectives, it replaces material lost through the machining process so installed valve spring height is within specs. The solution does not preclude measuring or adjusting spring tension.

Stephen Hill

nortonspeed said:

Yves, good solution however you are making a mistake dealing with the spring set up. Spring height doesn't tell you much. Spring tension must be set up by measured pressure not by measured height!

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I do what Jim Schmidt recomand
Yves

Stephen Hill said:

As I understand the solution Yves proposed, among other objectives, it replaces material lost through the machining process so installed valve spring height is within specs. The solution does not preclude measuring or adjusting spring tension.

Stephen Hill

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The thing is that Jim don't give any spring tension, he says to make the spring height mesurment without spring, you must do the mesurment between the under spring cup and the top collar with the valve in place, this must be 1.400, I supose that with this mesurment the spring tension must be ok, or you must have more as 50K miles with the springs, then of course you can lost some of the original spring tension
Yves

I would be a little concerned that the collar you machined on the OD looks rather thin. I'm thinking it could break of and end up going through the engine. Just me I guess.
JUG

Stephen Hill said:

As I understand the solution Yves proposed, among other objectives, it replaces material lost through the machining process so installed valve spring height is within specs. The solution does not preclude measuring or adjusting spring tension.

Stephen Hill

Click to expand...

If JS has done his homework correctly then setting the spring at the correct installed height should be good enough for new springs, yes it would be good to check tension so you know whats happening as they age.
YVES if you can take a small ball nose end mill and machine as many shallow grooves as looks practical across the bottom of the cup to cut down on heat transfer to the springs

jug said:

I would be a little concerned that the collar you machined on the OD looks rather thin. I'm thinking it could break of and end up going through the engine. Just me I guess.
JUG

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Hi Jug,
I don't use iron from a box of corned beef but high quality steel and when you look at the original collar made by the factory, the OD is also thin no?
Yves

splatt said:

If JS has done his homework correctly then setting the spring at the correct installed height should be good enough for new springs, yes it would be good to check tension so you know whats happening as they age.
YVES if you can take a small ball nose end mill and machine as many shallow grooves as looks practical across the bottom of the cup to cut down on heat transfer to the springs

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Good idee Splatt

ludwig said:

Nice work Yves , but remember springs expand when compressed , so allow some room .

Groetjes , Jan .

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There is some room, but I think the spring expand more in the middel as on the bottom
Gellukig Nieuwjaar Jan

splatt said:

If JS has done his homework correctly then setting the spring at the correct installed height should be good enough for new springs, yes it would be good to check tension so you know whats happening as they age.
YVES if you can take a small ball nose end mill and machine as many shallow grooves as looks practical across the bottom of the cup to cut down on heat transfer to the springs

Click to expand...

I will ask JS for the tension of a new spring

Remember to install washer before fitting seal, very frustrating when you discover washer wont pass over installed seal

Nice job Yves, my only comment would be that I think I’d have used some insulating material for some of that 3mm ‘gap filler’.

Fast Eddie said:

Nice job Yves, my only comment would be that I think I’d have used some insulating material for some of that 3mm ‘gap filler’.

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Hi,
It's not to late to do that, but I don't have original insulating shims close by hand, so I dont know the tickness of this shims; do you?
Yves

I don't think the insulating washers are a big issue for the inlets. but pretty important on the exhaust valves as Eddie says.

You can set your springs by length, but is better to use a guage to measure length at the required seat pressure, then shim to that length.

I don't use heat insulators on inlets.

Surely the problem of the seal fitting can be avoided by valve guide design? Making it longer in this area?

This is probably a product of mixing certain parts, e.g. valves machined atthe collet end for longer beehive springs.

Maybe it is not an issue with standard valves and springs, or conical springs that use the standard collet groove?

As a complete alternative approach, I have some spring seats that have integral oils seals! Intended for use with the same beehives that JSM supplies. They would not fit with my Fullauto standard set up, but after the valve re-angling as you show it, I think they would.

Fast Eddie said:

Nice job Yves, my only comment would be that I think I’d have used some insulating material for some of that 3mm ‘gap filler’.

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Hi, I don't know how to put the insulating washers with my system, the original insulating washers are nearly 2mm thick, so if I mill 2mm from the bottom of my system, the ID below the ressess will disapear becouse that is 2mm thick also, in that case no material any more to keep the spring cup around the valve guide....
This is only a problem for the inlets.
Putting the insulating washers under the cups from the exhaust is not a problem becouse there is no oil seal there;
on the exhaust I still use the JS cups with a washer under the cup, so if I mill the tickness from the insulating washer from the washer I made it will be fine.
Yves

SteveA said:

As a complete alternative approach, I have some spring seats that have integral oils seals! Intended for use with the same beehives that JSM supplies. They would not fit with my Fullauto standard set up, but after the valve re-angling as you show it, I think they would.

Click to expand...

Hi Steve,
Do you have some pics from the spring seats with integral oil seals?
Thanks
Yves