Sf2 head number of fins / valves and guides

helicopterjim said:
Cast? Stainless? Do you know anything about valve construction?

I suggest you let folks who know contribute before you add anything more. I sure as hell know little but I am thinking I know more than you.

Jim
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Standard Laverda valve guides are cast. Stainless steel valves are not a good idea.
"Cast iron guides are used mostly by OEMs due to its wear characteristics that result in longevity for high mileage applications. Cast iron is used with chrome valve stem applications as well. Cast iron cannot be used with stainless steel because of its tendency to gall."
If you want to read the article it comes from:
https://www.enginebuildermag.com/2013/04/valve-seats-guides/
This is what you are referring to, PB2?
 
helicopterjim said:
Cast? Stainless? Do you know anything about valve construction?

I suggest you let folks who know contribute before you add anything more. I sure as hell know little but I am thinking I know more than you.
Click to expand...

Hmm ? Not sure about that Jim. I suspect you still have a bit to learn.

Rather than posting a disparaging comment, why don't you share your knowledge about using stainless steel valves in cast iron guides.

I'm no expert on the subject either, but all the info I've found on the web supports PB2's comment about cast iron guides being incompatible with stainless valves. Here's another excerpt from an engine tuning specialist I found on internet. (Keith Calver of Calver Special Tuning in UK)
"DO NOT use raw EN214N (stainless steel) race valves in cast iron valve guides - they will seize in the guides."

If you google "stainless valves in cast iron guides" you'll find various car and bike forums with horror stories of them seizing and causing engine carnage.
 
Yep there was a spat of this 25 years ago when stainless valves were first used .by Eades when they were the OZ Laverda distributers $1200 for a head rebuild and $450 2 weeks later after 2 valves seazed and bent apparenty my fault for getting a fause nutral and over reving it seems there was a lot of this happening to others as well before the real cause was found I also pissed off the crap left foot change and lost the box of nutrals but it was little understood valve and guide clerance and compatability at fault0
 
I had a triple head near trashed because of stainless valves, the valves sold to me by a company that I do not wish to name because it was new technology and virtually untried, unleaded fuel was coming in etc, so I hold no grudges, it was my decision to deviate from stock, I had the choice,  the valves were hard chromed on the stems and the guides were new and stock cast iron. The work to install my new valves and guides was not done by the valve supplier but by a cylinder head specialist, who later threatened to sue me, because of what I had written, for defamation in court, which I welcomed, but they never did have the balls, all of the exhaust valves partially seized in the guides and then  completely, the guides were then moving with the valves which trashed the bores for them, in the head casting. It didn't blow up, just rattled and was running very smokey, anyone following me on the ride to the BOB museum in 99 at my own mini rally (one of three that year in addition to the big party to celebrate 25 years of ILOC) will remember the smoke filling the lanes behind me, strangely sitting level with the newly cut hedge tops)

to get going again, the same specialist head company (this is where the law suit threat originated) bored the valve guide holes, made Colsibro oversize guides, used something called nucleus centering to install new (lead free!) valve seats and prep the head for springing up. I was not a happy bunny on collection since two of the three cast iron skulls had cracked and I was told that was how the head arrived at the shop which is bollocks to use understandable technical terms. I was also told that this is common and wont affect running. I had to pay even more money than the first time.

never the less the head was fitted by a third company (I was working seven days a week at the time and employing 12 or 14 others)  only to get another failure, Paul Marx will well remember me passing his group of frogs on a Southern French motorway at about 180K two up and camping gear with his group doing about 120K, unusually high for both of us. Around thirty miles later Paul and Co came past me as I was stopped on the side of the road, with a lump of head gasket (not one of my later produced copper ones but a stock item, this was the generated enthusiasm for the copper ones which I still use) having just hit me in the right leg and the consequential loss of oil, dripping everywhere. At home the head gasket failure was obviously caused by an out of flat head, and some of the new guides were loose as well, and those that were not, were showing strong signs of the valves not seating, with ovality present on the seats, that head is now part of an off engine, valve clearance setting jig!

I bought a new (RGS) head still in the wrapping at a very good price, this came with guides etc all fitted, and partially cut seats, just requiring individual lapping of the new valves and away we went. I have never had a head repaired since, and I have a strong belief that as with K series Leylend/Rover cylinder heads , if they overheat or need heating for maintenance eg guides or welding, that the temper is lost and cannot easily be replaced.

CLEM
ps that was a longun wasn't it!
 
I remember well Clem.

I have stainless valves fitted to my S by Phil Todd in 1999. I've done about 500 km to date plus quite a bit of tuning in the garage. All's well.
Will need to check tappets soon since seats are new.

Paul
 
FFS Jim, think before you post, mate. It was Red who told me I'd have to use bronze alloy guides with the stainless valves HE supplied for my head. He even supplied me the raw material I made the guides out of. End of story.
 
Paul Marx said:
I remember well Clem.

I have stainless valves fitted to my S by Phil Todd in 1999. I've done about 500 km to date plus quite a bit of tuning in the garage. All's well.
Will need to check tappets soon since seats are new.

Paul
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Also innaresting. I was in contact with Phil when working on my small valve head project and he put me on to the correct grade of cast if I wanted to use steel guides - he mentioned that he has stainless stems hard chromed IIRC.

In fact here is a cut and paste of what he wrote (hope you don't mind Phil!): 'I had my stainless valves made with chrome plated stems - so no problems with C.I.  guides.'

Highly likely Phil was on the case with your bike, Paul.
 
It was Quentin.
Hard chromed stems.
A special set with provision for the early wide collets. Rivet counter or what? I'm even using the wheel type primary tensioner.

Paul
 
Paul Marx said:
I remember well Clem.

I have stainless valves fitted to my S by Phil Todd in 1999. I've done about 500 km to date plus quite a bit of tuning in the garage. All's well.
Will need to check tappets soon since seats are new.

Paul
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They have rather a neat stellite wedge in the tip - does mean a lot less hollowing with the std tappets -  have used them for over 30 years now ! regards - Phil
 
Piranha Brother 2 said:
FFS Jim, think before you post, mate. It was Red who told me I'd have to use bronze alloy guides with the stainless valves HE supplied for my head. He even supplied me the raw material I made the guides out of. End of story.
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Hahahahaha ...... that was worth the shit taking! I didn't even have to delve into sodium cooled valves!

I actually know very little but the responses definitely enlightened me quite a bit.

Jim
 
>>>>>>
Cast? Stainless? Do you know anything about valve construction?

I suggest you let folks who know contribute before you add anything more. I sure as hell know little but I am thinking I know more than you.
>>>>>>


Just to remind you what you posted in your beer-addled state, Jim. I personally didn't find it one bit amusing. Time to move on ... got more pressing things to worry about - like Stage 4 lockdown.
 
Dellortoman said:
Are you able to go to work? If not, then the silver lining to that cloud would be more time to work on SFQ. Stay safe and healthy mate.
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Thanks Cam. No, all bicycle mech work in-shop is off for now. Plenty keeping me busy here domestically (the other half working full-time from home), running the show, but I am making progress on the SFQ ... ticking off the jobs ever so slowly! Need to access my welding guy but pretty sure I'm not allowed do that under St 4. Waiting for warmer weather to start on some fibreglassing.

Also looking at a house extension we've tried to start for the last 15 years - hoping to get the homebuilder subsidy. Four people in a 2BR house at the mo.
 
Piranha Brother 2 said:
Just to remind you what you posted in your beer-addled state, Jim. I personally didn't find it one bit amusing. Time to move on ... got more pressing things to worry about - like Stage 4 lockdown.
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Well I hate to disappoint you ....... but I still find it amusing. I doubt that I will move on ..... I am in a non-lockdown zone so I will just carry on being an asshole.

I do appreciate that where you are and your situation is likely much different than mine so I will make allowances for that ...... but I'm not really certain what those allowances will really mean as we are in different parts of the world.

I do hope all will be well with you though ..... please be safe and healthy!

Jim
 
Ok the 7mm guides are cast iron, we can?t use stainless valves, can we bore out the guides and install ?k? line inserts in bronze alloy to accept the new valves? If that?s the case can you bore them out  and go back to 8mm valves?  Is that an advantage or a backward step?
 
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