Best valve guide material?

[Bill Irwin]

I'm halfway through turning up a new exhaust valve guide for my Dondolino out of LG2 – a lowish grade phosphor bronze but day to work.  A friend has just called me to say that he was reading some correspondence about Vincent guides and that phosphor bronze can 'pick-up' in the absence of enough lubrication which is certainly the case with the Dondolino.  He recommends cast iron.  I used the LG2 because it was easy to get and I read a web article that said PhB had better lubricity than cast Iron.

I won't be racing the bike but I will be riding it long distances at 60-70mph with the odd long hill or overtaking manoeuvre.

Which is the best material to use?

Bill

[Michael Moore]

Bill, Ampco 45 / 630 bronze is commonly used for aftermarket
guides. You can buy it from McMaster-Carr

http://www.mcmaster.com/#ampco-bronze/=iq1ps1

cheers,
Michael

[Pollorey]

A couple of valve guide discussions...

http://mgaguru.com/mgtech/universal/ut103.htm

http://forums.turbobricks.com/showthread.php?t=262646

All the best,

Phil

On 8/5/2012 8:13 PM, Bill Irwin wrote:

I'm halfway through turning up a new exhaust valve guide for my Dondolino out of LG2 � a lowish grade phosphor bronze but day to work. �A friend has just called me to say that he was reading some correspondence about Vincent guides and that phosphor bronze can 'pick-up' in the absence of enough lubrication which is certainly the case with the Dondolino. �He recommends cast iron. �I used the LG2 because it was easy to get and I read a web article that said PhB had better lubricity than cast Iron.

I won't be racing the bike but I will be riding it long distances at 60-70mph with the odd long hill or overtaking manoeuvre.

Which is the best material to use?

Bill

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[Jerome Kimberlin]

On 8/5/2012 5:13 PM, Bill Irwin wrote:

I'm halfway through turning up a new exhaust valve guide for my Dondolino out of LG2 � a lowish grade phosphor bronze but day to work. �A friend has just called me to say that he was reading some correspondence about Vincent guides and that phosphor bronze can 'pick-up' in the absence of enough lubrication which is certainly the case with the Dondolino. �He recommends cast iron. �I used the LG2 because it was easy to get and I read a web article that said PhB had better lubricity than cast Iron.

I won't be racing the bike but I will be riding it long distances at 60-70mph with the odd long hill or overtaking manoeuvre.

Which is the best material to use?

You have the exterior valves and rockers so the valves are not lubricated.� On an authentic Dondolino, the clearance is very large to account for the fact that there is no lubrication for the phos bronze guides.� And they wear out frequently.

On the other exterior valve/rocker Guzzi bikes such as the GTV/GTW, the valve guides are made from cast iron.� Cast iron is self-lubricating - in fact lubricating a cast iron valve guide is forbidden as that will wear it very fast.� So unless you set up some sort of lubrication system for those valves, you probably should use the cast iron.� I'm using cast iron with stainless valves having chrome plated stems.� No problems after a few thousand miles.

JerryK

[Bill Irwin]

Thanks Jerry

Looks like it's cast iron then!

What clearance and what interference do you suggest?

Cheers Bill

From: Jerome Kimberlin <kimb...@comcast.net>
Reply-To: "guzzi-...@googlegroups.com" <guzzi-...@googlegroups.com>
Date: Monday, 6 August 2012 4:49 PM6
To: "guzzi-...@googlegroups.com" <guzzi-...@googlegroups.com>
Subject: Re: [guzzi-singles] Best valve guide material?

On 8/5/2012 5:13 PM, Bill Irwin wrote:

I'm halfway through turning up a new exhaust valve guide for my Dondolino out of LG2 – a lowish grade phosphor bronze but day to work.  A friend has just called me to say that he was reading some correspondence about Vincent guides and that phosphor bronze can 'pick-up' in the absence of enough lubrication which is certainly the case with the Dondolino.  He recommends cast iron.  I used the LG2 because it was easy to get and I read a web article that said PhB had better lubricity than cast Iron.

I won't be racing the bike but I will be riding it long distances at 60-70mph with the odd long hill or overtaking manoeuvre.

Which is the best material to use?

You have the exterior valves and rockers so the valves are not lubricated.  On an authentic Dondolino, the clearance is very large to account for the fact that there is no lubrication for the phos bronze guides.  And they wear out frequently.

On the other exterior valve/rocker Guzzi bikes such as the GTV/GTW, the valve guides are made from cast iron.  Cast iron is self-lubricating - in fact lubricating a cast iron valve guide is forbidden as that will wear it very fast.  So unless you set up some sort of lubrication system for those valves, you probably should use the cast iron.  I'm using cast iron with stainless valves having chrome plated stems.  No problems after a few thousand miles.

JerryK

[Pollorey]

Why is oilite not a consideration here?

All the best,

Phil

[John Mead]

too soft. John Mead Thoroughbred Motorcycles 7600 N Courthouse Rd New Kent, VA 23124-2220 USA 804.683.5615 253.484.9663-fax John...@prodigy.net --- On Mon, 8/6/12, Pollorey <phil...@nycap.rr.com> wrote:

From: Pollorey <phil...@nycap.rr.com> Subject: Re: [guzzi-singles] Best valve guide material?

To: guzzi-...@googlegroups.com Cc: "Jerome Kimberlin" <kimb...@comcast.net> Date: Monday, August 6, 2012, 9:23 AM

Why is oilite not a consideration here? All the best, Phil On 8/6/2012 12:49 AM, Jerome Kimberlin wrote:

On 8/5/2012 5:13 PM, Bill Irwin wrote:

I'm halfway through turning up a new exhaust valve guide for my Dondolino out of LG2 – a lowish grade phosphor bronze but day to work.  A friend has just called me to say that he was reading some correspondence about Vincent guides and that phosphor bronze can 'pick-up' in the absence of enough lubrication which is certainly the case with the Dondolino.  He recommends cast iron.  I used the LG2 because it was easy to get and I read a web article that said PhB had better lubricity than cast Iron.

I won't be racing the bike but I will be riding it long distances at 60-70mph with the odd long hill or overtaking manoeuvre. Which is the best material to use?

You have the exterior valves and rockers so the valves are not lubricated.  On an authentic Dondolino, the clearance is very large to account for the fact that there is no lubrication for the phos bronze guides.  And they wear out frequently. On the other exterior valve/rocker Guzzi bikes such as the GTV/GTW, the valve guides are made from cast iron.  Cast iron is self-lubricating - in fact lubricating a cast iron valve guide is forbidden as that will wear it very fast.  So unless you set up some sort of lubrication system for those valves, you probably should use the cast iron.  I'm using cast iron with stainless valves having chrome plated stems.  No problems after a few thousand miles.

JerryK -- You received this message because you are subscribed to the Google Groups "Guzzi Singles" group. To post to this group, send email to guzzi-...@googlegroups.com. To unsubscribe from this group, send email to guzzi-single...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/guzzi-singles?hl=en.

[Mike Peavey]

I forwarded the question along to Jon Andruk at Circle Machine here in the Boston area, who's done work for me.  

He deals mostly in high performance stuff, but has found working on the Airone engine, amusing, or should I say entertaining. 

Maybe more information than needed, but, for what it's worth.

Ok, here is my experience.

Cast iron works ok but I seem to need more clearance than when using Manganese bronze. If you use the Moto G. spec. it is huge compared to most other air cooled heads so probably no issues anyway unless you opt to tighten the clearance up.

There are pros and cons to all 4 major choices of materials.

Cast iron including chilled iron.
Manganese bronze, proprietary material alloy. not generic Manganese bronze
Phosphor bronze billet.
Phosphor bronze sheet metal rolled with seam or tube extruded. Inserted in a standard type guide. 

Lets use  a 911 Porsche as for reference as it has some similarities especially the valve guide and valve stem size is identical.  I have done 100's of these heads form the late 60's vintage to relatively modern stuff with huge turbos of the late 80's vintage.

The Manganese bronze always wins out.  I use WEN industries for my guides and blanks.  The only weak point this alloy has is as follows and only pertaing to the exhaust valve guide.

If the guide protruded more than about 4 mm into the exhaust port the very end can crack when used in big turbo applications.  It is simply due to the temperature. When I do a turbo, I cut the guide back so less than 4 mm is hanging in the exhaust port and everything works out well.

No doubt, there are many other bronze materials that look better by there specifications especially some of the BeCu alloys and some Be free stuff made by Moldstar but they play out real fast, like just a races or 2.

Me,  I would use  Cast iron or Manganese bronze for this app.  If you use the Manganese bronze, use minimum of .0025 inch press fit.  Thermal cycle the head in an oven at 250F for a few hours and let cool over night after guide installation.  Heat the head up first and the guide will press in with far less effort.  After the next day after cooling off, hone the guide to running clearance.    It will hour glass inside after thermal cycle.  No thermal cycle and you risk having the guide clearance shrink and clamp the valve when the engine thermal cycles the first time it runs and cools off.

Be in touch soon with plan on the piston.  Jon

[Jerome Kimberlin]

On 8/6/2012 7:09 AM, Mike Peavey wrote:

I forwarded the question along to Jon Andruk at Circle Machine here in the Boston area, who's done work for me.  

He deals mostly in high performance stuff, but has found working on the Airone engine, amusing, or should I say entertaining. 

Maybe more information than needed, but, for what it's worth.

Well, Jon is right in the case of a modern oiled valve stem engine.  But the Dondolino, GTV, GTW, SuperAlce have non-oiled valve guides.  Thus, his experience is not appropriate for these engines.  There is no comparison at all between a Porsche 911 engine and a Guzzi with open rockers and valve guides that you can see.  

I am of the opinion that only cast iron that is self-lubricated can stand the sand and other road grit that an open rocker engine will get during running.  In fact, it is not advised to put oil on the valve guides at all since the resulting oily road grit will eat out the guides in short order.  This would be even worse using non-ferrous bronze valve guides where the grit would embed.   Original Guzzi Dondolinos had bronze valve guides but the clearance was about 0.7 mm.  They were considered sacrificial and were changed frequently.  And this was in the relatively clean conditions of racing.  Even though Bill's engine is a Dondolino replica, he wants it to last a bit longer on the road than a race bike.  Thus, I recommend cast iron guides for his application.

SuperAlce Guzzis had cast iron valve guides and were military bikes used in Egypt and Ethiopia/Eritrea in the dirt and sand.  They seemed to last pretty well in that environment.

JerryK

[Jerome Kimberlin]

On 8/5/2012 10:49 PM, Bill Irwin wrote:

Thanks Jerry

Looks like it's cast iron then!

What clearance and what interference do you suggest?

Right out of the book......

JerryK

[Rick]

To the best of my knowledge the old open rocker Harleys run cast iron too.

 

Rick Yamane

Motion Pro Inc.

We Ride! We Wrench! We Race!

867 American St.

San Carlos, CA 94070

(650)594-9600

(650)594-9610 Fax

ri...@motionpro.com

www.motionpro.com

 

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From: guzzi-...@googlegroups.com [mailto:guzzi-...@googlegroups.com] On Behalf Of Jerome Kimberlin
Sent: Monday, August 06, 2012 8:26 AM
To: guzzi-...@googlegroups.com
Subject: Re: [guzzi-singles] Best valve guide material?

 

On 8/5/2012 10:49 PM, Bill Irwin wrote:

--

[Bill Irwin]

Thanks for all the input everyone.  What a knowledgable and helpful group this is!

Once the guide is fitted I can assemble the head and check the valve to piston clearance on the new piston.  The Falcone barrel on my bike must be shorter than the original Dondolino one as the Dondo piston protrudes from the barrel about 3mm.  I'll use a compression plate.  I'm hopeful that I'll be riding in a couple of weeks and will send some photos.

Cheers Bill

From: Jerome Kimberlin <kimb...@comcast.net>
Reply-To: "guzzi-...@googlegroups.com" <guzzi-...@googlegroups.com>

Date: Tuesday, 7 August 2012 3:25 AM7
To: "guzzi-...@googlegroups.com" <guzzi-...@googlegroups.com>
Subject: Re: [guzzi-singles] Best valve guide material?

[John Mead]

Norton Internationals and Manx run bronze guides. John Mead --- On Mon, 8/6/12, Rick <ri...@motionpro.com> wrote:

[antonio]

Bill, a few years ago I had in my possession a Dondolino that was raced
(unsuccessfully) in Daytona in 1948 by Ernie Roccio
and other venues in California and Colorado. when I got the bike, it was
in need of of urgent head work. As I recall, the 2
halves of the intake valve guide were made of bronze and the exhaust
(sodium filled) valve guide was made out of cast
iron. As by now you know the intake valve received some kind of
lubrication through that little hole that received a trickle of oil
from the rocker box.
Just a piece of trivia.
Good luck,
Antonio.

[Bill Irwin]

Thanks Antonio

That's exactly the setup I will have. Cast iron is also what Phil Irving recommends for open dry guides in Tuning for Speed.

Almost there!

Cheers Bill