Fieuw things to know about big valves

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Here's the JSM Beehive spring pressure specs with thin street bottom washers. The installed height is different than stock springs because the Beehive springs are taller and fit valves with the collets located higher on the stem. If you compare them to stock springs you'll see that they have the same pressure at full lift but about 8 lbs more pressure on the seat. This is an ideal arrangement because low lift is where valve bounce occurs but there is no cam wear at 0 lift.
Fieuw things to know about big valves

Note that Triumphs and BSAs run without insulating washers and do just fine.
 
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jseng1 said:
Here's the JSM Beehive spring pressure specs with thin street bottom washers. The installed height is different than stock springs because the Beehive springs are taller and fit valves with the collets located higher on the stem. If you compare them to stock springs you'll see that they have the same pressure at full lift but about 8 lbs more pressure on the seat. This is an ideal arrangement because low lift is where valve bounce occurs but there is no cam wear at 0 lift.
Fieuw things to know about big valves

Note that Triumphs and BSAs run without insulating washers and do just fine.
Click to expand...
Thanks Jim,
But do you think that the srings can lost pressure after a few years?
 
Yves, it was only a thought that IF it was easy to do, it would be worth doing. If it’s not, I wouldn’t bother giving it another thought...

You’ve done 50k without them, I don’t run them, i believe most trick motors don’t. I would file this idea away and get back to doing what you were doing my friend!
 
Shown with a used JSM beehive spring.

A note on that, a full race season of 24 races was enough for me to measure free length and seat pressure and convince myself to replace them, but this is racers thinking. Yours is a road bike set at a lower seat pressure! I probably wouldn't change them unless free length was seriously reduced from what I measured when I installed them.

The seal shown is designed for this spring size. Is a tight fit on a standard Norton Valve stem. It stands 16.3mm tall, steel base to rubber above the seal spring. The lower recess hole to the first rubber section is 4.5mm, the steel section hole itselfis about 16.2mm ID so probably not a tight fit around your valve guide.

The spring seat is 0.85mm thick (say 0.035"). It could be shimmed above or below. Or you could use parts similar to those you have pictured earlier in the thread to ensure good location.


Fieuw things to know about big valves
Fieuw things to know about big valves
 
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lcrken said:
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
Click to expand...
Ken, Just wondered, how do you feel about the valve guide being lower than normal relative to the stem? Do you think this can allow more lateral force onto the valve stem in operation?

I recall that Mick Hemmings used to fabricate valve guides with a flange that sat under the spring seat in his big valve conversions in the '70s. Which is another solution to Yves situation.
 
splatt said:
... 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...

These are the thicker .029" shims that I supply with the Bee springs for racing application with higher pressure. There should be enough room to add shims to find the pressure you want. The thinner .015" shims don't have the grooves. All valve springs change a little over time but I don't think you have to worry about it on a street bike.

Fieuw things to know about big valves
 
SteveA said:
Ken, Just wondered, how do you feel about the valve guide being lower than normal relative to the stem? Do you think this can allow more lateral force onto the valve stem in operation?

I recall that Mick Hemmings used to fabricate valve guides with a flange that sat under the spring seat in his big valve conversions in the '70s. Which is another solution to Yves situation.
Click to expand...

I prefer the taller guide, just because it offers a bit more support to the stem, but I don't know how significant it really is. I've never used valve guide seals on the race bikes, just a careful fit of stem to guide, so never had to choose between long and short guides. I do use seals on the intake guides on the street bikes.

Interesting comment on Mick using flanged valve guides. I didn't know that. I have one of Ron Wood's short stroke heads that was re-worked by Axtell, and the guides in it are like that. The guides are a loose fit now in their bores, and I'm planning to make new ones, but hadn't decided whether to stick with the flange design or go back to a more standard design. The choice might depend on which valve springs I end up choosing. I'm not sure I'd have enough height for the proper conical or beehive springs with a spring seat sitting on top of the flange. Guess I'll have to figure that out when I get around to building another engine to use the head on.

Ken
 
jseng1 said:
Here's the JSM Beehive spring pressure specs with thin street bottom washers. The installed height is different than stock springs because the Beehive springs are taller and fit valves with the collets located higher on the stem. If you compare them to stock springs you'll see that they have the same pressure at full lift but about 8 lbs more pressure on the seat. This is an ideal arrangement because low lift is where valve bounce occurs but there is no cam wear at 0 lift.
Fieuw things to know about big valves

Note that Triumphs and BSAs run without insulating washers and do just fine.
Click to expand...
I will go to a friend on tusday, he as the tool and we will tchek the spring pressure at 1.400, depending on that result I will try to addapt my system
Keep you posted
yves
 
yves norton seeley said:
I will go to a friend on tusday, he as the tool and we will tchek the spring pressure at 1.400, depending on that result I will try to addapt my system
Keep you posted
yves
Click to expand...

Well Yves it took you some posts to come to this conclusion but it is definitely the right way to set up spring tension by measuring pressure of each individual spring. Like I mentioned before spring height don't tell you that much, for instance I have experienced valve springs from several brands and measured remarkable differences in spring pressure at same height! Remember too low spring pressure can cause valve float, even worse too high spring pressure will cause premature wear of all parts associated.
 
lcrken said:
Interesting comment on Mick using flanged valve guides. I didn't know that. I have one of Ron Wood's short stroke heads that was re-worked by Axtell, and the guides in it are like that. The guides are a loose fit now in their bores, and I'm planning to make new ones, but hadn't decided whether to stick with the flange design or go back to a more standard design. The choice might depend on which valve springs I end up choosing. I'm not sure I'd have enough height for the proper conical or beehive springs with a spring seat sitting on top of the flange. Guess I'll have to figure that out when I get around to building another engine to use the head on.

Ken
Click to expand...

As delivered to me my short stroke head had iron guides with large head but thin stem valves. But a guide cracked. Mick reworked it for his guides and standard stem valves. The guides used were flanged. Main concern was how little metal was left holding the guide with what were quite large ports. After time the guides were a bit loose in the head, with the flange under spring pressure they didn't move. But I always felt that there was a little oil sucked past one of the guides. Not enough to worry about, but certainly signs of it.
 
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SteveA said:
As delivered to me my short stroke head had iron guides with large head but thin stem valves. But a guide cracked. Mick reworked it for his guides and standard stem valves. The guides used were flanged. Main concern was how little metal was left holding the guide with what were quite large ports. After time the guides were a bit loose in the head, with the flange under spring pressure they didn't move. But I always felt that there was a little oil sucked past one of the guides. Not enough to worry about, but certainly signs of it.
Click to expand...
Hi Steve,
I am very intrersted in the springs seat with integral oil seal, Would you sale it to me?
Yves
 
What spring pressure will the gentlemens recommend on street bike with a re-angled big valve. Short stroke with JS1 (up to 8500 rpm)?
 
Kvinnhering said:
What spring pressure will the gentlemens recommend on street bike with a re-angled big valve. Short stroke with JS1 (up to 8500 rpm)?
Click to expand...

Why on earth do you need to go up to 8500 rpm on a street Norton? You use a JS1 so I suggest you could contact JS or one of the engine builders mentioned on his website like Yves Vanheers (Yves Norton Seeley).
As you probably know required spring pressure is determined by variables such as valve lift, weight of valve gear (valve, rocker, pushrod, tappet) and desired rpm. Personally I aim for 80 to 100 lbs (pre load) and 180 to 200 lbs full lift (street engine) or 90 to 110 lbs and 200 to 220 lbs full lift (race engine, revved up to 8500 rpm, lightened valve gear).
 
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Why on earth do you need to go up to 8500 rpm on a steet Norton?
Because my engine has the capability of 8-8500 rpm and because hearing the exhaust sound of one Norton at this rpm

Personally I aim for 80 to 100 lbs (pre load) and 180 to 200 lbs full lift (street engine) or 90 to 110 lbs and 200 to 220 lbs full lift (race engine, revved up to 8500 rpm, lightened valve

Thank you for this.
 
nortonspeed said:
Why on earth do you need to go up to 8500 rpm on a street Norton? You use a JS1 so I suggest you could contact JS or one of the engine builders mentioned on his website like Yves Vanheers (Yves Norton Seeley).
As you probably know required spring pressure is determined by variables such as valve lift, weight of valve gear (valve, rocker, pushrod, tappet) and desired rpm. Personally I aim for 80 to 100 lbs (pre load) and 180 to 200 lbs full lift (street engine) or 90 to 110 lbs and 200 to 220 lbs full lift (race engine, revved up to 8500 rpm, lightened valve gear).
Click to expand...

I have no problem with the figures you quote, but I will point out two things:

1 JSM recommends higher figures for beehive springs, assuming that by pre load you mean measured load at a given installed spring height.

2 I use a number between yours and his!

My point really is that lots of tuners use different figures based on their own particular experience and preferences.
 
SteveA said:
. After time the guides were a bit loose in the head, with the flange under spring pressure they didn't move. But I always felt that there was a little oil sucked past one of the guides. Not enough to worry about, but certainly signs of it.
Click to expand...

A clever man would allow for a good quality oring between the guide and head to help seal oil migration, the lower edges of the spring seats must get very thin when the ports get to large.
Correct me very harshly if I'm wrong but didn't they have to drop the heat insulators off the combat heads.
Agreed spring tension should be checked,, YVES is now going about it the correct way , checking tension at set height, he can now adjust or replace as required. Are those valve stem seals tight on the guides or are the like an umbrella seal
 
See the comparison of springs with recommended installation height specs for the street. Chart below shows .350" lobe lift (stock is approx .330").

Fieuw things to know about big valves


Its important that the peak pressures are not greater than stock if you want to avoid excessive wear on the street. For race cams - thicker bottom shims and higher pressures are used.

I deleted my previous chart because it showed lift up to .450" and was misleading.
 
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Kvinnhering said:
What spring pressure will the gentlemens recommend on street bike with a re-angled big valve. Short stroke with JS1 (up to 8500 rpm)?
Click to expand...

Regarding your request for guidance on spring force required to control a large-valve Norton head at high rpm (8500), IMHO the best advice you will find on this subject is to watch the Comnoz spintron videos that include a variety of cams, springs, spring force, etc. As the videos so dramatically show, results are not necessarily intuitive, and adding more spring force is certainly not always the solution and in several cases made things dramatically worse. Due to lack of stiffness in the entire system (cases, cam, pushrods, rockers, etc) adding additional spring can further exacerbate the situation by causing even more elastic deformation, which in turn further hinders the ability of the system to control valve motion.

https://www.accessnorton.com/NortonCommando/about-time-for-the-spintron.18787/

I believe Snotzo has also modeled your subject cam/engine configuration and could give you a very good idea how to achieve the solution you seek. JSM would likewise be aware of these findings and should be able to offer counsel.
 
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