Lario valve stock spring spec's and alternatives

[IceBlue]

For a while I battled a problem where my V35C were pushing oil out of the filter/breather box oil drain. I hate oily signatures   
I went initially for what I thought to be the obvious.
Posting this, as all 2V small blocks incl. the V7 line of bikes has similar valve rocker architectures.

- Checking the filter box engine return drain and breather valve - it was OK
- Installed an engine drain return valve - no effekt. Should prevent oil being pushed back up from the sump.
- Checked the cylinder head and cylinder oil return drain all the way to the crank house - it was OK.
- The engine has 3mm oil delivery dowels in the cylinders, as per Guzzi's recommendation. - Perhaps just too much oil going to the valve/rocker assemblies...but not an issue in the right cylinder...
- Down leak checked on the cylinder in question - i discovered only the left cylinder pushed oil to the breather box - it had more that a 10% leak - replaced the cylinder and checked the valves for leaking -
  however - it still pushed oil out out to the breather box 

A Guzzi shop (Martin Hagemann) led me to the issue suggesting to check the rocker assembly. A simple rift here could be an issue.
Well - more than a rift - however not logical, as the 3mm oil dowel should prevent too much oil coming up. Well not so.

As seen on the pic's the pin holding the rockers are severely damaged due to problematical oil delivery.
The actual culprit is the sleeve between the rockers. This is some kind og soft nylon keeping the rockers suspended into their position delivering oil at the same time to the rockers, however, it gets hardened by age, and delivered no pressure any more, hense letting oil flow more freely bypassing the rockers initially. Which get over the limit to what the drain can handle in the cylinder assembly. The right cylinder didn't push oil to the breather/Filter box, and didn't have this issue either in the rocker assembly.

Replaced the complete rocker assembly incl. a new sleeve - no oil pushed out regardless of how much pressure I put on the mill. 

Hope this will help some other SB guy out there 

 

[jacksonracingcomau]

 
Well done Brian, clever bit was working out which side it was

On a completely different tack, looking at your pics reminded me of a theory I never proved relating to Larios, valve springs etc
Could you measure the rocker ratio on the 2v please,
Or even quicker , take a photo of a 2v rocker arm with a 4v one exactly on top of it, ie one up one down, a ruler underneath at 90 degrees to rocker shaft axis


My bet is the ratio is higher on the 4v (ie valve opens more for same camshaft lift)
This would completely explain what happened

[Frenchfrog]

Wow...there's an enlightement! I wouldn't have thought that was the culprit either...Thanks Brian !

[IceBlue]

Well done Brian, clever bit was working out which side it was

On a completely different tack, looking at your pics reminded me of a theory I never proved relating to Larios, valve springs etc
Could you measure the rocker ratio on the 2v please,
Or even quicker , take a photo of a 2v rocker arm with a 4v one exactly on top of it, ie one up one down, a ruler underneath at 90 degrees to rocker shaft axis


My bet is the ratio is higher on the 4v (ie valve opens more for same camshaft lift)
This would completely explain what happened

Hope this will do it for you 

We are metric here, hope this is not a problem.
Ciao

[jacksonracingcomau]

Hope this will do it for you 

We are metric here, hope this is not a problem.
Ciao

Metric no problem , we have to speak both, Australia went metric forty years ago but wheels and chains must always be measured in English, let alone anything built before the change.

But sadly not quite clear enough
I know 4v ratio is 1 to 1.4 , confirmed with dial gauge on pushrod and on valve
Trying to read pic 2 valve may be 1.3 or 1.4
If you can get another shot with rule or vernier at zero on centre of valve through centre of rocker shaft to centre on pushrod.
Picture tells a fousand words, this shows numbers I want

[IceBlue]

Metric no problem , we have to speak both, Australia went metric forty years ago but wheels and chains must always be measured in English, let alone anything built before the change.

But sadly not quite clear enough
I know 4v ratio is 1 to 1.4 , confirmed with dial gauge on pushrod and on valve
Trying to read pic 2 valve may be 1.3 or 1.4
If you can get another shot with rule or vernier at zero on centre of valve through centre of rocker shaft to centre on pushrod.
Picture tells a fousand words, this shows numbers I want

Sorry for the late reply.










Placed them om millimeter paper.
Hope this will do the trick.

Cheers
Brian

[jacksonracingcomau]

Sorry for the late reply.










Placed them om millimeter paper.
Hope this will do the trick.

Cheers
Brian

Thanks Brian
First one is square shot but I make it ,5mm off centre of grid
So to nearest half a mm
38.5 / 28.5 = 1 to 1,305
True test with dial gauge will probably correct that to 1 to 1,3 but academic

This is exactly what my thoughts were
Lario valve springs were selected on basis of same cam as 2valve, therefore same travel

But no one told the spring buyers that valve moved further because of new rocker ratio

So springs got coil bound, wore out the cam, the rest, as they say, is history.

Next time you’re inside your Lario valve covers, measure how far your springs can travel after max lift.
Test as for piston valve clearance on an exhaust valve, there needs to be ,1 “ but absolute min of ,04” till spring binds

I tried with  Navada springs, they were just as coil bound as factory originals, I know you try to be gentle and not over rev yours but honestly, I think nevada springs with 1 to 1.4 rockers is ticket to tears

I set my springs up for 125lb at max lift, would advise anyone with Lario to do same, BUT be sure to have safety margin before coilbind (mine have bucketloads)
Then they rev to moon safely as designed

[IceBlue]

Thanks Brian
First one is square shot but I make it ,5mm off centre of grid
So to nearest half a mm
38.5 / 28.5 = 1 to 1,305
True test with dial gauge will probably correct that to 1 to 1,3 but academic

This is exactly what my thoughts were
Lario valve springs were selected on basis of same cam as 2valve, therefore same travel

But no one told the spring buyers that valve moved further because of new rocker ratio

So springs got coil bound, wore out the cam, the rest, as they say, is history.

Next time you’re inside your Lario valve covers, measure how far your springs can travel after max lift.
Test as for piston valve clearance on an exhaust valve, there needs to be ,1 “ but absolute min of ,04” till spring binds

I tried with  Navada springs, they were just as coil bound as factory originals, I know you try to be gentle and not over rev yours but honestly, I think nevada springs with 1 to 1.4 rockers is ticket to tears

I set my springs up for 125lb at max lift, would advise anyone with Lario to do same, BUT be sure to have safety margin before coilbind (mine have bucketloads)
Then they rev to moon safely as designed

Did some checking. I have a few 4V mills sitting around with the mod.

First:
Spring length:
Stock
41mm with no load
26mm fully loaded (coil bound)

V7/Nevada spring
43mm with no load
26mm fully loaded (coil bound)

Nevada inserted:
Valve closed: 36mm
Valve fully open: 29mm

Operational play: 7mm

Leaves 3mm safety play until coil bound.

I see no issue.

Hope this is helpful 

Ciao
Brian

[IceBlue]

By the way, I have a very technical spread sheet about various springs and cam data.
If you like to have a gander at it I can send it to you via email.
Just drop me a PM. It's in German, but it should be clear enough to get the drift of it.

Ciao

[jacksonracingcomau]

Brian
Please don’t take offence, I am really trying to help
I built one 8v SB motor from 2 broken and a cam and head from third.
I had to prove I could do it and spent a huge amount of time measuring, dummy building, checking and rechecking.
That Nevada springs coil bind as oe springs exactly as I found, just less initial spring pressure. Pressure on both coil bound is massive, this is why cam and lifters wear.
There was a Mike Wren built an 8v V7 on here that was an inspiration for me getting one, if you can fund his build thread there is a good picture there of Nevada valve spring at max lift, Chuck’s comment on this pic exactly on the money.


So
Firstly
Your 7mm at valve is so far from mine, I can only take it that is with a worn cam
Use a dial gauge on valve retainer at exact same angle and check again
To mm is not a measurement, If metric go to .01 mm or better
Easier for me in inches cos that’s what my gauge reads in but you can translate I’m sure.
Take another reading at pushrod (this is cam lift)

The difference between two is rocker ratio effect.

Secondly
Repeat check
Thirdly
Repeat again
Only when you know you have these measurements exact can you go to step 4

Measure spring pressure (gauge for this not exy, no question this was trick to my one working so well)
At installed height
At max lift

Step 5, repeat on all springs (3 times) then measuring clearance to bind on all

When happy with pressures (mine 80lb at installed, 125 max lift, ,1” to bind)

Step 6

I bought shims in .004” (.1mm) thickness to set installed height and put these under bottom spring retainer, pointless doing the above if you don’t then set the height to measured pressure.
Step 7
Check every clearance, I had to relieve rocker arm from touching each other and the pedestal , I did use elephant’s foot adjusters and would again but apart from them , the valve springs and a little lightening of bits, my “test” engine is factory std

Step 8
Clean and assemble
Thrash it mercilessly

ALL IT TAKES IS TIME

I cannot believe that I didn’t do this 35 years ago, probably only because I hated the modern space age styling, I couldn’t look through the clothes to see a glorious engine hidden in there.
Proof really in the usage, after 42 years with my  Le Mans (bought new in 78) I have owned many others but that is my bike, daily transport, touring ,everything.

No longer, the little one is now my go to bike, actually it’s nearly 2 months since I’ve ridden the BB, worse than that my wife prefers the little one too so it’s not the one for solo the other for two up that I envisaged.

With correctly set up valve springs the design is perfect for my usage, jeckel and hyde, bimble to mental.
With Nevada springs you may get the bimble part safely but not the fun bit from 7-9 k rpm.

The thing even goes as far on 18 litre tank as the BB with (modified orig) 23 litres.

RANT OVER

[Frenchfrog]

Great info jackson ...but what springs did you end up installing
 ?

[jacksonracingcomau]

Great info jackson ...but what springs did you end up installing
 ?

Springs courtesy of Pete Roper (still hasn’t sent me bill) from BB 8 v, 1400 std I think
But do not fit without checks above, less pressure might be ok , “might”not good enough for me

Real credit goes to Phil Irving, I read this then, I read it randomly almost daily, some lovely English in this book, my words above nowhere near as concise  as the original I was trying to quote

[sign216]

Springs courtesy of Pete Roper (still hasn’t sent me bill) from BB 8 v, 1400 std I think
But do not fit without checks above, less pressure might be ok , “might”not good enough for me

Real credit goes to Phil Irving, I read this then, I read it randomly almost daily, some lovely English in this book, my words above nowhere near as concise  as the original I was trying to quote

Jackson,

Phil Irving's book is a favorite of mine on engines.  Didn't he like Heron heads too?

Joe

[jacksonracingcomau]

Jackson,

Phil Irving's book is a favorite of mine on engines.  Didn't he like Heron heads too?

Joe

No Heron headed bikes in 1948 AFAIK, I have only seen Morini & Guzzi but must have been others.

But, of course, Mr Irving is as famous for his cylinder head work on Holden (GM) engines as he is for the Vincent design.

In looking for Heron head mention I found the exact words I’m trying to convey to Brian, hope google translate can do this

[IceBlue]

Brian
Please don’t take offence, I am really trying to help
I built one 8v SB motor from 2 broken and a cam and head from third.
I had to prove I could do it and spent a huge amount of time measuring, dummy building, checking and rechecking.
That Nevada springs coil bind as oe springs exactly as I found, just less initial spring pressure. Pressure on both coil bound is massive, this is why cam and lifters wear.
There was a Mike Wren built an 8v V7 on here that was an inspiration for me getting one, if you can fund his build thread there is a good picture there of Nevada valve spring at max lift, Chuck’s comment on this pic exactly on the money.


So
Firstly
Your 7mm at valve is so far from mine, I can only take it that is with a worn cam
Use a dial gauge on valve retainer at exact same angle and check again
To mm is not a measurement, If metric go to .01 mm or better
Easier for me in inches cos that’s what my gauge reads in but you can translate I’m sure.
Take another reading at pushrod (this is cam lift)

The difference between two is rocker ratio effect.

Secondly
Repeat check
Thirdly
Repeat again
Only when you know you have these measurements exact can you go to step 4

Measure spring pressure (gauge for this not exy, no question this was trick to my one working so well)
At installed height
At max lift

Step 5, repeat on all springs (3 times) then measuring clearance to bind on all

When happy with pressures (mine 80lb at installed, 125 max lift, ,1” to bind)

Step 6

I bought shims in .004” (.1mm) thickness to set installed height and put these under bottom spring retainer, pointless doing the above if you don’t then set the height to measured pressure.
Step 7
Check every clearance, I had to relieve rocker arm from touching each other and the pedestal , I did use elephant’s foot adjusters and would again but apart from them , the valve springs and a little lightening of bits, my “test” engine is factory std

Step 8
Clean and assemble
Thrash it mercilessly

ALL IT TAKES IS TIME

I cannot believe that I didn’t do this 35 years ago, probably only because I hated the modern space age styling, I couldn’t look through the clothes to see a glorious engine hidden in there.
Proof really in the usage, after 42 years with my  Le Mans (bought new in 78) I have owned many others but that is my bike, daily transport, touring ,everything.

No longer, the little one is now my go to bike, actually it’s nearly 2 months since I’ve ridden the BB, worse than that my wife prefers the little one too so it’s not the one for solo the other for two up that I envisaged.

With correctly set up valve springs the design is perfect for my usage, jeckel and hyde, bimble to mental.
With Nevada springs you may get the bimble part safely but not the fun bit from 7-9 k rpm.

The thing even goes as far on 18 litre tank as the BB with (modified orig) 23 litres.

RANT OVER

No offence taken by any means.
I think it's great to get everything on the table.
The very reason for me to dive into the 4V mills were the challenge to get them safer or safe.
The Lario is one great fun generator.

Your info has rekindled my plan to build a 8V mill up all from mostly old new stock parts -

New virgin crank house - (no play in the bear rings for the cam)
New virgin cam shaft
New virgin lifters
New V7C/Nevada springs
New heads
etc etc

Then retest the spring tolerance - as you know the stiff stock springs are coil bound at the same length as the Nevada springs -

This would in my opinion be a conclusive test to the validity of the Nevada springs in that perspective.

[jacksonracingcomau]

No offence taken by any means.


Then retest the spring tolerance - as you know the stiff stock springs are coil bound at the same length as the Nevada springs -

This would in my opinion be a conclusive test to the validity of the Nevada springs in that perspective.

Do the measuring, opinion is pointless, conclusive testing proves the invalidity of both springs, share the knowledge when you have it, internet is full of  this kind of Lario misinformation, such a shame,

First thing you need to know is actual exact valve travel, measure on any assembled 8v you have
Measuring 4 , in and ex both sides, will tell you any cam wear you have already
This 1948 drawing explains it well

[IceBlue]

Do the measuring, opinion is pointless, conclusive testing proves the invalidity of both springs, share the knowledge when you have it, internet is full of  this kind of Lario misinformation, such a shame,

First thing you need to know is actual exact valve travel, measure on any assembled 8v you have
Measuring 4 , in and ex both sides, will tell you any cam wear you have already
This 1948 drawing explains it well

Well, I like to do a check of a virgin setup. I find it hard to believe that Guzzi would use a spring for so many years that was improper in dimension. I’ll address the issue again as soon as I have made a conclusive test.
Ciao

[jacksonracingcomau]

Well, I like to do a check of a virgin setup. I find it hard to believe that Guzzi would use a spring for so many years that was improper in dimension. I’ll address the issue again as soon as I have made a conclusive test.
Ciao

Sorry Brian
I failed to give you method for establishing installed spring height measurement
Difficulty in believing is like assumption or opinion, not relevant.

That Lario valve springs were miss-specced is not in question, the hows and whys can be debated but if I were lucky enough to have virgin bits, I’d  correct installed height and use oe springs, wish I’d done it back then, bleedin’ obvious now.

You could change thread title to “Lario valve springs” , might be easier for search

[Chuck in Indiana]

I find it hard to believe that Guzzi would use a spring for so many years that was improper in dimension.

Uhh, for a while, I think Luigi was promoted to design.  The V11 sport transmission pawl spring is a fine example. When I looked into it, they were over driving the spring by several degrees.  No wonder they broke. Many made different springs, but they never really did the math, apparently. <shrug> I've never heard of *any* new design springs having a problem.. and they are all over the world, now.
I'll try not to break my arm patting myself on the back..

[IceBlue]

Getting all the virgin stock parts together.
Should be simple to check.

A new unused cam shaft has 27mm cams.
They can wear as low a a bit over 24mm under the pressure of the Lario stock stock springs.
 
As mention, I'll build a mill with all new parts and adjust for factory settings and do the check on the spring.
The Lario stock spring and the V7C/Nevada spring coil binds at the same length totally compressed and fit the same base spring plate/retainer.
So the stock spring test will define the fate of the V7C/Nevada spring.