installing valve guides question

pete.v · May 29, 2011

rvich said:
T95 said:

Vary interesting post! I haven't touched my head yet so I have to ask, does the removal and pressing take place from the combustion chamber side of the head?

Click to expand...

The go from indside toward the outside for removal. A double diamter drift is the common tool you see in texts for this job. They would look something like this:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... OTORS:1123

Russ

This tool is nothing but a piece of aluminum cut to fit inside of a guide. Any kind of force ,which is needed to remove these guide, will destroy it. Go with the threading the id, screw in a bolt from the rocker side and punch through from the combustion side with a hardened drift against the bolt. The force applied in this manner is quite positive and the shock of the hammer has a much truer feel.

Hobot · May 29, 2011

I ain't yet found the alloy designation of Norton Heads but do know they can take more heat than needed to expand just to work on safely. By and large heating short of melting is used to harden various alloys not soften them - usually followed by fairly fast cooling in under boiling temp hot water or room temp aged after heating beyond just thermal interference fit ease-safety, as sure don't want to gall and ruin bores or inserts forcing things.

The cylinder head and barrel are cast in a new aluminium alloy which was developed for Grand Prix racing car engines. This alloy does not require heat treatment for maximum strength, thus obviating the risk of fin warping. The cylinder head is fitted with sintered iron valve seats, so can be used with lead-free petrol.

http://members.shaw.ca/elrojo/motorcycl ... anxman.htm

hobot writes on 10-18-2001:-

> >The note on the loss of temper in welding 6061 T6 has my attention
> >now. I need to weld a 6061 T6 bolt on to 6061 T6 engine plates at
> >the rear most edge is there anything to be aware of other than just
> >small tacking and letting area cool so heat stays localized and low as
> >possible. Can someone review me on the structure asspects of T0 vs T6
> >and effects of the local welding on of some little stuff.

Welding heat treatable aluminium alloys results in the weld area being
bought to T4 condition, i.e. Weld T6 to T6 and the result is T4. Weld T4 to T4 and the result is T4.
Welding non heat treatable alloys renders the area to T0 i.e. Fully
annealed. Both of these situations apply only to the heat affected zone.
6061 is not listed as being available here in UK in plate or sheet form.
Someone mentioned about salt bath heat treatment... I think he might be
referring to solution heat treatment. Not right, Solution heat treatment
is where the material is heated to a certain temperature and then cooled
rapidly , usually by quenching in water. The process uses different
temperatures for different alloy specs. The solution referred to is the
solution of the molecules of the material.. Age hardening is another way of
achieving strength. This is achieved by either leaving in normal air temps,
or by heating to 100-200 degrees C for a suitable period, this can be as
little as 2 hours or thirty , depending on spec. This is artificial
hardening.
By the way there is no such thing as T0 Heat treatment scale goes from T1
to T9 . The spec for T6 is Solution treat and artificially age.
0 is for the completely annealed state.
Trevor Southwell UK

HEAT TREATMENT

STRENGTH AT ELEVATED TEMPERATURES

The tensile properties of LM25 alloy at elevated temperatures are influenced by the condition (heat treatment) of the castings and the duration at the elevated temperature. On short term testing e.g., 30 minutes at temperature, the properties fall only slowly and uniformly up to about 200°C, at which temperature the strength of LM25-TF is reduced by about 20%. Very prolonged heating e.g., 10,000 hours, results in a sharp loss of strength at about 135°C. At 200°C the strength of LM25-TF is less than half of that at room temperature. There is therefore no advantage to be gained by heat treatment, if the component is to be used at temperatures above about 130°C,for extended periods of time.

There are three heat treated conditions commonly used for this alloy:-LM25-TE ( precipitation treated ) - heat for 8-12 hours at 155-175°C and air cool.

LM25-TB7 ( solution treated and stabilized ) - heat for 4-12 hours at 525-545°C and quench in hot water, then stabilize at 250°C for 2-4 hours. The time at temperature must be enough to ensure a reasonable stability of the properties, prior to mechanical testing.

LM25-TF (fully heat treated ) - heat for 4-12 hours at 525-545°C and quench in hot water, then precipitation treat of 8-12 hours at 155-175°C.

http://www.nortal.co.uk/alloys/lm25.asp

pdf paper on 7000 series needing 470'+ C to temper
http://www.ysxbcn.com/upfile/soft/20085 ... 458451.pdf

Cheesy · May 29, 2011

Carbonfibre said:
Seems to be a awful lot of confusion related to valve guides, so maybe this might be of interest: http://www.enginebuildermag.com/Article ... tions.aspx

You are more than welcome to sleeve as many guides as you like, I however wouldnt personally do it to a Norton guide as I have seen how weak the lower edge is and I dont want to drop bits of cast iron into the cylinder. They are definitely not difficult to replace, if you have already pulled out your rocker spindles you can do the valve guides

rvich · May 29, 2011

I stand corrected. I have obviously waded in above my head.

However, I will reserve the right to proceed with caution on my own projects since I don't have the technical skills nor the experience to judge whether I am improving the temper of my alloy head.

Cheesy · May 29, 2011

hobot said:
Solution heat treatment
is where the material is heated to a certain temperature and then cooled
rapidly , usually by quenching in water. The process uses different
temperatures for different alloy specs. The solution referred to is the
solution of the molecules of the material.. Age hardening is another way of
achieving strength. This is achieved by either leaving in normal air temps,
or by heating to 100-200 degrees C for a suitable period, this can be as
little as 2 hours or thirty , depending on spec. This is artificial
hardening.
By the way there is no such thing as T0 Heat treatment scale goes from T1
to T9 . The spec for T6 is Solution treat and artificially age.
0 is for the completely annealed state.
Trevor Southwell UK

This is slightly ambiguous, for Al to be age hardened it has to be solution treated first, however the solution treatment may be part of the actual manufacturing process. Some alloys will naturally age to what would be close to a T6 temper in as little as 24hrs room temp, others wont. The aging process is the precipitation of the dissolved copper atoms (in the solution treatment). The precipitation process is diffusion controlled therefore temperature is a driving factor. The precipitates that form are also metastable so further heating (above an 'activation' temp) will cause further aging. The first stage of precipitation is the formation of GP zones, these are a very fine dispersion of copper in the Al matrix, this stage is characterised by a slight increase in strength and almost no loss in ductility over the solution treated state. With a sufficient activation energy some of the GP zones will be absorbed by others, this is a coarser theta1 precipitate, in relative terms this is still a very fine particle that is evenly distributed through the Al matrix, in this state the Al has reached its peak(or close to) strength and still has very good ductility, in this state the material is not considered to be under or over aged. With the application of further energy the theta1 precipitates will form theta2 precipitates through a similar mechanism, some will diffuse and others will grow. Theta2 ppts have a more plate like shape and are significantly bigger than Theta1 ppts, in this state the strength will be slightly reduced and the ductility will be massively reduced, this is an over aged condition.

Hobot · May 29, 2011

Thanks for more confusing details cheesy but as useless to me in real life as my solid state physics courses. Best I can glean from your response and my searches is heating short of melting the Al base metal tends to toughen the alloy not weaken it. My only point is - heating head into its normal running temp zone to fit and remove guides or spindles or valve seats is a non issue to its endurance or plastic deformation.

Still don't know what Al alloy Norton heads are but think its the Mg and Cu plus a bit of slilycone. Might be what was called Dural with Mg, Mn, Cu.
http://en.wikipedia.org/wiki/Duralumin

grandpaul · May 30, 2011

I've never had to use higher than 250F for working with valve guides, combined with simply using a proper drift and a smart rap with a hammer square-on.

Same with bearing R & R on the cases; 250F and you only need to drop the case on it's face from about a foot off a sheet of plywood or any flat wooden surface like your wife's grandmother's antique coffee table (or front porch in my case).

john robert bould · May 30, 2011

The guy only asked about guide removal!
As Normal on the forum.............reams of posts with no constructive info, as granpaul said Bit of heat and a stepped drift..couple of sharp taps.nothing magic there .
As i said in my post....if there is hard carbon on the guide...drill the entire protruding bit off that is in the port saves a carbon broach in the guide bore...done it dozens of times.

T95 · May 31, 2011

pvisseriii said:
However, I think most of us Nortoneers would rather be the masters of our own fate. Short of grinding crank journals, I cannot think of anything i haven't done or would not do again if given the opportunity or need to do so.
The bottom end may be the heart of Norton but it's the top end that makes it happen. A job well done on a head rebuild is a great accomplishment and something to be proud of.

Edit:
Sorry, I didn't want to post I thought I was doing a PM to pvisseriii!

I am extremely interested in this valve guide post and am preparing myself to rebuild my motor starting next month. Your comment above about being the master of our own fate really states how I feel. I want to do as much of this rebuild that is reasonable, even if it has me doing tasks that I have never done before. I just took a look at some of the Neway valve seat kits on e-bay to see what they were about. I need to weigh the price of buying the tools over the cost of having a machine shop do it for me, but then I will be missing that experience.

It appears this is all hand work. Is this a task that you had experience with prior to doing your Norton head? I was also wondering if you could recall the size or sizes of cutters you used.
Thanks, Gary

Hobot · May 31, 2011

If ya search it up, there are hi end guide repair and upgrades that retain the stuck in place guides but use a new bore with sleeve/material that both corrects valve seat alignment and less friction/striction, leaking.

ML · May 31, 2011

hobot said:
Still don't know what Al alloy Norton heads are but think its the Mg and Cu plus a bit of slilycone. Might be what was called Dural with Mg, Mn, Cu.http://en.wikipedia.org/wiki/Duralumin

Head material for 750 and 850 is Aluminium RR 53B.

Mick

Hobot · May 31, 2011

RR 53B, Alrighty Mick, then the heat range to work guides is in the hardening-toughing temp zone not the soften-weaken zone.
http://en.wikipedia.org/wiki/Hiduminium

Composition, R.R.53 B [15]
Copper 2.5%
Nickel 1.5%
Magnesium 0.8%
Iron 1.2%
Silicon 1.2%
Aluminium remainder

As for many of the aluminium alloys, Y alloy age hardens spontaneously at normal temperatures after solution heat treating. In contrast, R.R. alloys remain soft afterwards, until deliberately heat treated again by precipitation hardening for artificial ageing.[3] This simplifies their machining in the soft state, particularly where component blanks are made by a subcontractor and must be shipped to another site before machining. For R.R.56 the solution treatment is to quench from 530°C and ageing is carried out at 175°C.[3] For R.R.50, the solution treatment may be omitted and the metal taken directly to precipitation hardening (155°C-170°C).[14]

After solution treatment, the tensile strength of the alloy increases, but its Young's modulus decreases. The second stage of artificial aging increases the strength slightly, but also restores or improves the modulus.[15]

Stillreel · Nov 25, 2015

Peter R said:
Another method to remove old valve guides is the following;
Tap a screw thread in the top of the old valve guide, and insert a suitable bolt.
Use a long drift to drive the valve guide out from the other side, by knocking on the underside of the bolt.
This method prevents the valve guide end from forming a "bellmouth " and makes it easier to remove,
since the valve guide is "stretched" rather than compressed during the removal operation.
Of course, removing carbon and heating the head may still be necessary too.

Peter.

This technique worked well for me. Drifted out the old guides easily after tapping, heating to 500F (600F+ is the annealing temp. for alum. casting), inserting bolt then drifting out with second, smaller diameter bolt through the guide. Now to attempt installing new guides.

Stillreel · Nov 25, 2015

Peter R said:
Another method to remove old valve guides is the following;
Tap a screw thread in the top of the old valve guide, and insert a suitable bolt.
Use a long drift to drive the valve guide out from the other side, by knocking on the underside of the bolt.
This method prevents the valve guide end from forming a "bellmouth " and makes it easier to remove,
since the valve guide is "stretched" rather than compressed during the removal operation.
Of course, removing carbon and heating the head may still be necessary too.

Peter.

This technique worked well for me. Drifted out the old guides easily after tapping, heating to 500F (600F+ is the annealing temp. for alum. casting), inserting bolt then drifting out with second, smaller diameter bolt through the guide. Now to attempt installing new guides.

batrider · Nov 25, 2015

The important part of all this is to remove any carbon before driving the guide out. If you don't you'll destroy the interference fit. I won't do this job myself anymore although I have the tool. I would send it to Leo Goff or Jim Comstock so it's done right. Sorry but this is not really a home mechanic job.

RoadScholar · Nov 26, 2015

Years ago I purchased a worn Mk3, stripped it to components. On the to-do list was a valve job with a high quality cutting of the valve seats and I realized that, for consistencies sake, I'd need new valve guides. I'd heard about Leo Goff at Memphis Motor Werks, so I called him. No problem he said we do these frequently, and BTW I used to be a Norton/Royal Enfield dealer so I can safely say I've seen just about all the combinations between bad and worse.

He told me to ship the head and he'd quote me before doing the work. I told him that I would knock out the guides to save him time and me money, I had/have the punch tool that bolts up tight to the guides, one that I had used many times back in the day. NO, NO he said we machine the guides out, measure the bore and pick/machine the new guides for the correct pressed fit.

In this thread only one poster suggested this method, are we missing something?

There are posters that say use heat, somewhere between 250/300, but not above 375; doesn't the head, in the valve guide area get hotter during operation? And if so I'd think that you would need a rather precise pressed fit to insure that you'd have some spare gray matter to worry about something else??

Just asking.

Torontonian · Nov 26, 2015

I would listen to whatever Leo says.

edgefinder · Nov 26, 2015

I'm a cheap bastard, my bike looks rough but I'm trying to make it mechanically sound. I have a machine shop and I can do all this work myself but prefer to spend good money and let a pro do it. I like the idea of drilling the old guide and tapping it to relieve some of the tension. Yes with heat. Machining it out is also a good idea. Now you need to measure the hole and guide for correct fit and install it straight. You'll need some tools and experience to get this right. Next step is trickier. You've got to get the hole in the guide round, straight, the correct size, good finish and true enough to the seat that not much needs cut. Have to ask yourself can I really measure to a couple ten thousandnths or am I wingen it. Now the seats need cut. I wouldn't want to discourage anyone from doing their own head work but its about as easy to do right as grinding a crankshaft if you've never done it.

installing valve guides question

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