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I don't agree with skimming heads in any degree to straighten a bend, only a minimum clean up skim to reclaim a damaged surface on a flat one.
Reason?
If the bottom face is bent then so is the top one and if only the bottom surface is skimmed and not the top one as well then your going to introduce some bending to the rocker shafts when the boxes are are tightened up which isn't a good idea.
Then of course there remains the pushrod tube length issue as well.

davy
 

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I would have thought that the tappet adjustment could take care of the head skim differences?

But the problem would be the fixed PRT length? If you could "skim" the tubes wouldn't that be better and less damaging?

Not that I would skim a head.

I don't know anything about Harleys but don't their PRTs telescope?
 

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Discussion Starter #104
Fair enough, and happy holidays to you also, but please go back and see who brought john healy into this on page 2 of the never ending thread. This is where someone contacted me and said that they thought that I was being quoted and that it had nothing to do with the subject which originally was about replacing crankshaft bearings or valve guides. I had absolutely no interest in this thread or plans to post to it until then.

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John, You got quoted by JohnA with info that wasn't the intent of this thread I started. Then you got real interested judging by your replies :D

I'll just continue to gauge head temperature on a running engine by spitting on it to see if it evaporates quickly or dances around...;)
You all have Merry Christmas
 

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I would have thought that the tappet adjustment could take care of the head skim differences?

But the problem would be the fixed PRT length? If you could "skim" the tubes wouldn't that be better and less damaging?

Not that I would skim a head.

I don't know anything about Harleys but don't their PRTs telescope?
David you are not alone in this thinking. Triumph heads have bent, and have been sent to the machine shop to be cut since Triumph chose to make the head from aluminum. Along with bent carburetors (which should be straightened also), this is right up there as problem #1 of Triumph owners. It has caused more frustration for anyone wishing to have fun on his Triumph.

I have seen factory fresh engines with over .100" push rod tube seal crush. Needless to say these bikes puked oil out of the push rod tube seals, the head was bent, the bike didn't run that well and the owner was less than impressed with his new Triumph. And to be honest back in the early 1960's I cut my fair share of heads. So even the factory wasn't paying attention even though it was well known to the distributors (albeit tucked away in a 1965 Service Bulletin where it seems no one read it).

I have seen heads with crush so bad that material had to be taken off the top of the tappet guide block to get a satisfactory repair. Dave Madigan makes telescoping tubes for triples (who's tubes put pressure on the rocker box, not the head) but there isn't much room to do it on a twin. To use these heads that were cut today you can buy a head gasket that that is either .030" or .070" thicker than the .050" original and make up some of the aluminum that has been cut off.

Sorry, got to return to this after reading the link TT posted on another thread, in which you (JH) say (on the subject of straightening Triumph heads using heat and setting them back using bolt tension against shims):-
JohnA, the link to my post of 4 years ago was mine, not TT's. That post was 4 years old and on Britbike. It was one of my first iterations of coming to grips with all of ruined heads I was seeing. It came about from watching how friends were straightening automobile heads and I thought that we could do the same with our Triumph heads. Of course I have come to learn that the heads are so soft that you can do it cold, just as we have been doing to carburetors for years.

You brought up, not me, the 100°F from a quote of mine about installing guides on Britbike. I am sure you would say that it is common sense not to heat a head with an acetylene torch until a fin started to droop, but common sense isn't as common over here as it seems in England. Yes, you don't need the warning, but I am here to say that 1. I am not writing for you and 2. Over the years I have had the not so unique experience of knowing those that do.

There is a very good reason we have warnings on nearly every thing one can work with, play with or purchase here in the U.S.. Sure we kid about the lawyers, but they didn't stick their finger in the light socket. When we kid about this being a country "of more is better" or if it doesn't move "get a bigger hammer" we are only half kidding.

And if the truth be known according to Norman Hyde the Triumph factory installed guides into a cold head. This found when I saw his mechanic pressing new guides using a small jig and arbor press. The jig kept guide alignment (and looking at the valve jobs done on Triumph heads this is something few people seem to have a handle on), and the press with some grease on the guide, to send the guide home.
 

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Norman Hyde recommends fitting guides (his guides anyway) cold, just as you say. NH guides are a lot better than those that just about all spares retailers I know of sell, whether they happen to be Emgo/Wassell or Harris, they're all sloppy from new.

I can see your point re. common sense John, though I don't think its a very common commodity here in the UK either! Definitely not something to be taken for granted.

It was TT who posted the link, I didn't mean it was TT's words that the link was to, I realised the words were yours, just to clear that up.

And just to clear up the point about me supposedly misquoting you on Loctite,

"No, No , No, No to Thread Lock!!!!!!!!!!!
Thread Sealant, OK, but on servicing a sludge tube a single punch pushing plug metal into the small divot remaining from properly removing the plug is the way to go."

is what you said on this forum back in January. I did ask, several times, for more info to support this but I didn't get any. Maybe the confusion has come about through differing interpretations of terms. I think of Blue Loctite 243, (which as you said above somewhere is acceptable whereas Red is not) as a thread sealant and medium strength thread locker. It was 243 that I was hoping, back then, to get clarification about as I could see no reason why it should not be used in that application (I think this has now been confirmed). And for the sake of clarity, I did not mean to imply in any way that you recommend multiple punching of crank plugs - I meant that somebody (lacking common sense) might think if they can't use Loctite, then several punch indents would be good. As you say, popular thinking has it that more is better. I can see why you could have read my words as misquoting and I should have taken the trouble to find the actual quote (above) back then.
 

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Discussion Starter #107
Since pushod tubes are being discussed.....I work on beat up chopper/bobber Triumphs Triumphs for owners who don't always have a lot of money....Many are mismatched parts ,milled heads and all sorts of oil leaks.
Rather than machine tappet blocks or whatever I made this simple tool to move the o ring seat on later model tubes to get the crush correct. It's quite easy to heat the tube,melt the braze and move the ring.Then silver soldier if necessary.The owners don't care about the heat discoloration on the ratty looking engines.
 

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Never seen that done before Truckedup. I had thought about how to achieve the same effect but all I could come up with was buying some of the aftermarket aluminium prts and getting the required amount turned off the upper shoulder. Some of the alloy prts I've seen are well made and have plenty of material where it matters in this context. At least with pre-1980(?) engines there's some scope for adjustment using different thickness square section O rings. Post '80, even that option is lost.

At risk of opening up a hornets nest, I'll say that I don;t think one skim of up to about .005" will cause any problems. The rockerbox mating surfaces can be dome at the same time (again, just 'kissed', sufficient only to get the faces clean)
 

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would the good old grinding paste on plate glass not be a safer option?

in theory your arms get tired before you muller the head
 

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Discussion Starter #111
Never seen that done before Truckedup. I had thought about how to achieve the same effect but all I could come up with was buying some of the aftermarket aluminium prts and getting the required amount turned off the upper shoulder. Some of the alloy prts I've seen are well made and have plenty of material where it matters in this context. At least with pre-1980(?) engines there's some scope for adjustment using different thickness square section O rings. Post '80, even that option is lost.
Yes, different section rubber rings will usually do it. What I do is for a pile of mismatched parts .....
 

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<I hasten to add I had a quick look online for an alloy for air-cooled heads but couldn't find one.>
It seems I wasn't looking hard enough. I found this link http://www.heat-treat-doctor.com/documents/Aluminum Castings.pdf
about heat treating aluminium castings and it lists in Table 4 that A380 (identified by AA Gaskets as the material used in it's cylinder heads) as suitable for "Housings (lawn mowers), heads (air-cooled cylinders), gear cases, radio transmitters - Applications for general-purpose die castings with good mechanical properties."

Whereas at the top of the table, alloy 242 is shown for use as "Cylinder heads, generator housings (aircraft), pistons (aircraft, diesel, motorcycle) - Applications where strength and hardness at high temperatures are desirable."

In summary 380 would be the alloy to use for cast water-cooled cylinder heads and 242 for air-cooled.
 

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T-up: There were a few of the pushrod tubes with brazed rings but most were either a flared bottom tube with a straight section pressed into the top or a straight tube that was crimped in a press to form the lip. Good idea but limited to those tubes that have a brazed ring.
Ja: While the aluminum tubes present a workable solution they are quite expensive. and as T-up mention a lot of these problems come about because of lack of customer funds.

If you get a good push rod crush measurement, and have a good gasket surface, a little bit of bending can be over looked. The T140's with an indented surface from the steel ring in a composite gasket is another story. Cutting in this case is unavoidable.
 

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So in summary Johntioc says …

<To keep the discussion related to the engines we are talking about one only has to look at the damage done to oil in frame heads where the head bolt washer imbeds itself into the cylinder head. >
<While the overall problem is mostly related to the size of the washer used it is common for the indentation to be much deeper on the exhaust side.>
<Most temperatures shown for light aircraft use spark plug thermocouples which read the spark plug temperature, not cylinder head temperature which will be at least 20% less. >
<I think you need to look at the experience of people who straighten automobile heads it might give some perspective.>
<I am only here because JohnA, for reasons he felt were relevant to the conversation, brought up a quote of mine, and I believe it was totally out of context and I wished to explain myself.>
<To be able to pay for Mick Duckworth and Kevin Cameron I need subscribers.>
 

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<To keep the discussion related to the engines we are talking about> and having <little interest in theory>
But according to heat treat doctor, those alloys are for permanent molds or die casting. See the chart for sand cast, which the Triumph head is sand cast. In the good doctor's chart 319 and 356 would be more appropriate. The 300 odd aluminum alloys available today were not available when these Triumph heads were cast. Neither was the machinery that could hold the tolerances of the engines made today.

I have had little interest in theory as I have spent most of my working life trying to adapt products that theoretically should have worked, but practical modifications were required to allow them to do so.
 

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Discussion Starter #117
I have had little interest in theory as I have spent most of my working life trying to adapt products that theoretically should have worked, but practical modifications were required to allow them to do so.
Just think,if Triumphs were properly engineered and problems corrected as they cropped up you would have nothing to talk about. :D
 

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Big under current of animosity towards some humble gent- just trying to help and be of service to one and all.
. . and so the world turns . . .

Merry Christmas to all,
Santa

:eek:
 

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That's a very informative article Derry, thanks for posting it. Sand cast aluminium alloys are clearly superior to die cast where ability to be heat treated in almost every way is concerned. The 319 and 356 alloys in the table look probably more suited to air cooled cylinder heads than 242, but I think the main point is that unless Triumph heads were made from an alloy that really is quite poor, there seems no reason to regard them as inherently weak as far as the metal goes. Design improvements of the type John H alludes to (eg: replacing the small diameter head nut washers) can improve the service life and reduce mechanical problems.

While there must have been a more limited range of alloys to choose from several decades back, there would surely have been a good range for the applications we're discussing. Am I daydreaming here, or did one manufacturer (AJS? Moto Guzzi?) actually make a cylinder head out of solid silver once, as a racing experiment? Maybe if they'd had the massive range we have today, they could have saved the expense and weight!

For me, this has been a useful and educational thread, despite occasional misunderstandings.
 
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